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Editor’s Choice Articles

Editor’s Choice articles are based on recommendations by the scientific editors of MDPI journals from around the world. Editors select a small number of articles recently published in the journal that they believe will be particularly interesting to readers, or important in the respective research area. The aim is to provide a snapshot of some of the most exciting work published in the various research areas of the journal.

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33 pages, 7933 KiB  
Review
Surface Plasmon Resonance (SPR) Sensor for Cancer Biomarker Detection
by Sreyashi Das, Ram Devireddy and Manas Ranjan Gartia
Biosensors 2023, 13(3), 396; https://doi.org/10.3390/bios13030396 - 17 Mar 2023
Cited by 93 | Viewed by 13617
Abstract
A biomarker is a physiological observable marker that acts as a stand-in and, in the best-case scenario, forecasts a clinically significant outcome. Diagnostic biomarkers are more convenient and cost-effective than directly measuring the ultimate clinical outcome. Cancer is among the most prominent global [...] Read more.
A biomarker is a physiological observable marker that acts as a stand-in and, in the best-case scenario, forecasts a clinically significant outcome. Diagnostic biomarkers are more convenient and cost-effective than directly measuring the ultimate clinical outcome. Cancer is among the most prominent global health problems and a major cause of morbidity and death globally. Therefore, cancer biomarker assays that are trustworthy, consistent, precise, and verified are desperately needed. Biomarker-based tumor detection holds a lot of promise for improving disease knowledge at the molecular scale and early detection and surveillance. In contrast to conventional approaches, surface plasmon resonance (SPR) allows for the quick and less invasive screening of a variety of circulating indicators, such as circulating tumor DNA (ctDNA), microRNA (miRNA), circulating tumor cells (CTCs), lipids, and proteins. With several advantages, the SPR technique is a particularly beneficial choice for the point-of-care identification of biomarkers. As a result, it enables the timely detection of tumor markers, which could be used to track cancer development and suppress the relapse of malignant tumors. This review emphasizes advancements in SPR biosensing technologies for cancer detection. Full article
(This article belongs to the Special Issue Biosensors for the Analysis and Detection of Drug, Food and Disease Markers)
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14 pages, 2869 KiB  
Review
Wavelength-Dependent Metal-Enhanced Fluorescence Biosensors via Resonance Energy Transfer Modulation
by Seungah Lee and Seong Ho Kang
Biosensors 2023, 13(3), 376; https://doi.org/10.3390/bios13030376 - 13 Mar 2023
Cited by 13 | Viewed by 4418
Abstract
Fluorescence can be enhanced or quenched depending on the distance between the surface of a metal nanoparticle and the fluorophore molecule. Fluorescence enhancement by nearby metal particles is called metal-enhanced fluorescence (MEF). MEF shows promising potential in the field of fluorescence-based biological sensing. [...] Read more.
Fluorescence can be enhanced or quenched depending on the distance between the surface of a metal nanoparticle and the fluorophore molecule. Fluorescence enhancement by nearby metal particles is called metal-enhanced fluorescence (MEF). MEF shows promising potential in the field of fluorescence-based biological sensing. MEF-based biosensor systems generally fall into two platform categories: (1) a two/three-dimensional scaffold, or (2) a colloidal suspension. This review briefly summarizes the application studies using wavelength-dependent carbon dots (UV-VIS), noble metals (VIS), and upconversion nanoparticles (NIR to VIS), representative nanomaterials that contribute to the enhancement of fluorescence through the resonance energy transfer modulation and then presents a perspective on this topic. Full article
(This article belongs to the Special Issue Plasmonic Based Biosensors)
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20 pages, 23002 KiB  
Article
Design and Testing of a Smart Facemask for Respiratory Monitoring during Cycling Exercise
by Chiara Romano, Andrea Nicolò, Lorenzo Innocenti, Massimo Sacchetti, Emiliano Schena and Carlo Massaroni
Biosensors 2023, 13(3), 369; https://doi.org/10.3390/bios13030369 - 10 Mar 2023
Cited by 15 | Viewed by 3020
Abstract
Given the importance of respiratory frequency (fR) as a valid marker of physical effort, there is a growing interest in developing wearable devices measuring fR in applied exercise settings. Biosensors measuring chest wall movements are attracting attention as they [...] Read more.
Given the importance of respiratory frequency (fR) as a valid marker of physical effort, there is a growing interest in developing wearable devices measuring fR in applied exercise settings. Biosensors measuring chest wall movements are attracting attention as they can be integrated into textiles, but their susceptibility to motion artefacts may limit their use in some sporting activities. Hence, there is a need to exploit sensors with signals minimally affected by motion artefacts. We present the design and testing of a smart facemask embedding a temperature biosensor for fR monitoring during cycling exercise. After laboratory bench tests, the proposed solution was tested on cyclists during a ramp incremental frequency test (RIFT) and high-intensity interval training (HIIT), both indoors and outdoors. A reference flowmeter was used to validate the fR extracted from the temperature respiratory signal. The smart facemask showed good performance, both at a breath-by-breath level (MAPE = 2.56% and 1.64% during RIFT and HIIT, respectively) and on 30 s average fR values (MAPE = 0.37% and 0.23% during RIFT and HIIT, respectively). Both accuracy and precision (MOD ± LOAs) were generally superior to those of other devices validated during exercise. These findings have important implications for exercise testing and management in different populations. Full article
(This article belongs to the Special Issue Current Accuracy and Advances in Wearable Sensors and Biosensors for Physiological Signals Measurement)
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24 pages, 4979 KiB  
Article
Development of Electrochemical Immunosensors for HER-1 and HER-2 Analysis in Serum for Breast Cancer Patients
by Shayalini Wignarajah, Iva Chianella and Ibtisam E. Tothill
Biosensors 2023, 13(3), 355; https://doi.org/10.3390/bios13030355 - 7 Mar 2023
Cited by 30 | Viewed by 4269
Abstract
In this work, two human epidermal growth factor receptors, HER-1 and HER-2, were selected as biomarkers to enable the detection of breast cancer. Therefore, two biosensors were developed using gold sensor chips coupled with amperometric detection of the enzyme label horse radish peroxidase [...] Read more.
In this work, two human epidermal growth factor receptors, HER-1 and HER-2, were selected as biomarkers to enable the detection of breast cancer. Therefore, two biosensors were developed using gold sensor chips coupled with amperometric detection of the enzyme label horse radish peroxidase (HRP). The biosensors/immunosensors relied on indirect sandwich enzyme-linked immunosorbent assays with monoclonal antibodies (Ab) against HER-1 and HER-2 attached to the sensors to capture the biomarkers. Detection polyclonal antibodies followed by secondary anti-rabbit (for HER-1) and anti-goat (for HER-2) IgG antibody-HRP were then applied for signal generation. In buffer, the developed sensors showed limits of detections (LOD) of 1.06 ng mL−1 and 0.95 ng mL−1 and limits of quantification (LOQ) of 2.1 ng mL−1 and 1.5 ng mL−1 for HER-1 and HER-2, respectively. In 100% (undiluted) serum, LODs of 1.2 ng mL−1 and 1.47 ng mL−1 and LOQs of 1.5 ng mL−1 and 2.1 ng mL−1 were obtained for HER-1 and HER-2, respectively. Such limits of detections are within the serum clinical range for the two biomarkers. Furthermore, gold nanoparticles (AuNP) labelled with secondary anti-rabbit and anti-goat IgG antibody-HRP were then used to enhance the assay signal and increase the sensitivity. In buffers, LODs of 30 pg mL−1 were seen for both sensors and LOQs of 98 pg mL−1 and 35 pg mL−1 were recorded for HER-1 and HER-2, respectively. For HER-2 the AuNPs biosensor was also tested in 100% serum obtaining a LOD of 50 pg mL−1 and a LOQ of 80 pg mL−1. The HER-2 AuNP electrochemical immunosensor showed high specificity with very low cross-reactivity to HER-1. These findings demonstrate that the two developed sensors can enable early detection as well as monitoring of disease progression with a beneficial impact on patient survival and clinical outcomes. Full article
(This article belongs to the Special Issue Biosensing and Diagnosis of Cancer)
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22 pages, 4339 KiB  
Review
Recent Progress of Surface-Enhanced Raman Spectroscopy for Bacteria Detection
by Lulu Liu, Wenrui Ma, Xiang Wang and Shunbo Li
Biosensors 2023, 13(3), 350; https://doi.org/10.3390/bios13030350 - 6 Mar 2023
Cited by 36 | Viewed by 6315
Abstract
There are various pathogenic bacteria in the surrounding living environment, which not only pose a great threat to human health but also bring huge losses to economic development. Conventional methods for bacteria detection are usually time-consuming, complicated and labor-intensive, and cannot meet the [...] Read more.
There are various pathogenic bacteria in the surrounding living environment, which not only pose a great threat to human health but also bring huge losses to economic development. Conventional methods for bacteria detection are usually time-consuming, complicated and labor-intensive, and cannot meet the growing demands for on-site and rapid analyses. Sensitive, rapid and effective methods for pathogenic bacteria detection are necessary for environmental monitoring, food safety and infectious bacteria diagnosis. Recently, benefiting from its advantages of rapidity and high sensitivity, surface-enhanced Raman spectroscopy (SERS) has attracted significant attention in the field of bacteria detection and identification as well as drug susceptibility testing. Here, we comprehensively reviewed the latest advances in SERS technology in the field of bacteria analysis. Firstly, the mechanism of SERS detection and the fabrication of the SERS substrate were briefly introduced. Secondly, the label-free SERS applied for the identification of bacteria species was summarized in detail. Thirdly, various SERS tags for the high-sensitivity detection of bacteria were also discussed. Moreover, we emphasized the application prospects of microfluidic SERS chips in antimicrobial susceptibility testing (AST). In the end, we gave an outlook on the future development and trends of SERS in point-of-care diagnoses of bacterial infections. Full article
(This article belongs to the Special Issue High Performance Integrated Biosensors Based on SERS)
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18 pages, 6876 KiB  
Article
MoS2-Carbon Nanodots as a New Electrochemiluminescence Platform for Breast Cancer Biomarker Detection
by Laura Gutiérrez-Gálvez, Manuel Vázquez Sulleiro, Cristina Gutiérrez-Sánchez, Daniel García-Nieto, Mónica Luna, Emilio M. Pérez, Tania García-Mendiola and Encarnación Lorenzo
Biosensors 2023, 13(3), 348; https://doi.org/10.3390/bios13030348 - 5 Mar 2023
Cited by 19 | Viewed by 3713
Abstract
In this work, we present the combination of two different types of nanomaterials, 2D molybdenum disulfide nanosheets (MoS2-NS) and zero-dimensional carbon nanodots (CDs), for the development of a new electrochemiluminescence (ECL) platform for the early detection and quantification of the biomarker [...] Read more.
In this work, we present the combination of two different types of nanomaterials, 2D molybdenum disulfide nanosheets (MoS2-NS) and zero-dimensional carbon nanodots (CDs), for the development of a new electrochemiluminescence (ECL) platform for the early detection and quantification of the biomarker human epidermal growth factor receptor 2 (HER2), whose overexpression is associated with breast cancer. MoS2-NS are used as an immobilization platform for the thiolated aptamer, which can recognize the HER2 epitope peptide with high affinity, and CDs act as coreactants of the anodic oxidation of the luminophore [Ru(bpy)3]2+. The HER2 biomarker is detected by changes in the ECL signal of the [Ru(bpy)3]2+/CD system, with a low detection limit of 1.84 fg/mL and a wide linear range. The proposed method has been successfully applied to detect the HER2 biomarker in human serum samples. Full article
(This article belongs to the Special Issue New Opportunities for Emerging 2D Materials in Bioelectronics and Biosensors)
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15 pages, 5053 KiB  
Article
An Impedimetric Biosensor for Detection of Volatile Organic Compounds in Food
by Alessia Calabrese, Pietro Battistoni, Seniz Ceylan, Luigi Zeni, Alessandro Capo, Antonio Varriale, Sabato D’Auria and Maria Staiano
Biosensors 2023, 13(3), 341; https://doi.org/10.3390/bios13030341 - 4 Mar 2023
Cited by 14 | Viewed by 4154
Abstract
The demand for a wide choice of food that is safe and palatable increases every day. Consumers do not accept off-flavors that have atypical odors resulting from internal deterioration or contamination by substances alien to the food. Odor response depends on the volatile [...] Read more.
The demand for a wide choice of food that is safe and palatable increases every day. Consumers do not accept off-flavors that have atypical odors resulting from internal deterioration or contamination by substances alien to the food. Odor response depends on the volatile organic compounds (VOCs), and their detection can provide information about food quality. Gas chromatography/mass spectrometry is the most powerful method available for the detection of VOC. However, it is laborious, costly, and requires the presence of a trained operator. To develop a faster analytic tool, we designed a non-Faradaic impedimetric biosensor for monitoring the presence of VOCs involved in food spoilage. The biosensor is based on the use of the pig odorant-binding protein (pOBP) as the molecular recognition element. We evaluated the affinity of pOBP for three different volatile organic compounds (1-octen-3-ol, trans-2-hexen-1-ol, and hexanal) related to food spoilage. We developed an electrochemical biosensor conducting impedimetric measurements in liquid and air samples. The impedance changes allowed us to detect each VOC sample at a minimum concentration of 0.1 μM. Full article
(This article belongs to the Special Issue Biosensing and Diagnosis)
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11 pages, 1859 KiB  
Article
Real-Time Temperature Sensing Using a Ratiometric Dual Fluorescent Protein Biosensor
by Alanna E. Sorenson and Patrick M. Schaeffer
Biosensors 2023, 13(3), 338; https://doi.org/10.3390/bios13030338 - 3 Mar 2023
Cited by 4 | Viewed by 3453
Abstract
Accurate temperature control within biological and chemical reaction samples and instrument calibration are essential to the diagnostic, pharmaceutical and chemical industries. This is particularly challenging for microlitre-scale reactions typically used in real-time PCR applications and differential scanning fluorometry. Here, we describe the development [...] Read more.
Accurate temperature control within biological and chemical reaction samples and instrument calibration are essential to the diagnostic, pharmaceutical and chemical industries. This is particularly challenging for microlitre-scale reactions typically used in real-time PCR applications and differential scanning fluorometry. Here, we describe the development of a simple, inexpensive ratiometric dual fluorescent protein temperature biosensor (DFPTB). A combination of cycle three green fluorescent protein and a monomeric red fluorescent protein enabled the quantification of relative temperature changes and the identification of temperature discrepancies across a wide temperature range of 4–70 °C. The maximal sensitivity of 6.7% °C−1 and precision of 0.1 °C were achieved in a biologically relevant temperature range of 25–42 °C in standard phosphate-buffered saline conditions at a pH of 7.2. Good temperature sensitivity was achieved in a variety of biological buffers and pH ranging from 4.8 to 9.1. The DFPTB can be used in either purified or mixed bacteria-encapsulated formats, paving the way for in vitro and in vivo applications for topologically precise temperature measurements. Full article
(This article belongs to the Special Issue Fluorescent Protein-Based Sensing and Detection)
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36 pages, 4969 KiB  
Review
Review on Carbon Dot-Based Fluorescent Detection of Biothiols
by Muthaiah Shellaiah and Kien Wen Sun
Biosensors 2023, 13(3), 335; https://doi.org/10.3390/bios13030335 - 2 Mar 2023
Cited by 38 | Viewed by 4409
Abstract
Biothiols, such as cysteine (Cys), homocysteine (Hcy), and glutathione (GSH), play a vital role in gene expression, maintaining redox homeostasis, reducing damages caused by free radicals/toxins, etc. Likewise, abnormal levels of biothiols can lead to severe diseases, such as Alzheimer’s disease (AD), neurotoxicity, [...] Read more.
Biothiols, such as cysteine (Cys), homocysteine (Hcy), and glutathione (GSH), play a vital role in gene expression, maintaining redox homeostasis, reducing damages caused by free radicals/toxins, etc. Likewise, abnormal levels of biothiols can lead to severe diseases, such as Alzheimer’s disease (AD), neurotoxicity, hair depigmentation, liver/skin damage, etc. To quantify the biothiols in a biological system, numerous low-toxic probes, such as fluorescent quantum dots, emissive organic probes, composited nanomaterials, etc., have been reported with real-time applications. Among these fluorescent probes, carbon-dots (CDs) have become attractive for biothiols quantification because of advantages of easy synthesis, nano-size, crystalline properties, low-toxicity, and real-time applicability. A CDs-based biothiols assay can be achieved by fluorescent “Turn-On” and “Turn-Off” responses via direct binding, metal complex-mediated detection, composite enhanced interaction, reaction-based reports, and so forth. To date, the availability of a review focused on fluorescent CDs-based biothiols detection with information on recent trends, mechanistic aspects, linear ranges, LODs, and real applications is lacking, which allows us to deliver this comprehensive review. This review delivers valuable information on reported carbon-dots-based biothiols assays, the underlying mechanism, their applications, probe/CDs selection, sensory requirement, merits, limitations, and future scopes. Full article
(This article belongs to the Special Issue Recent Advances in Nano-Biomaterial-Based Biosensors)
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17 pages, 4338 KiB  
Article
Nucleic Acid Quantification by Multi-Frequency Impedance Cytometry and Machine Learning
by Mahtab Kokabi, Jianye Sui, Neeru Gandotra, Arastou Pournadali Khamseh, Curt Scharfe and Mehdi Javanmard
Biosensors 2023, 13(3), 316; https://doi.org/10.3390/bios13030316 - 24 Feb 2023
Cited by 16 | Viewed by 3294
Abstract
Determining nucleic acid concentrations in a sample is an important step prior to proceeding with downstream analysis in molecular diagnostics. Given the need for testing DNA amounts and its purity in many samples, including in samples with very small input DNA, there is [...] Read more.
Determining nucleic acid concentrations in a sample is an important step prior to proceeding with downstream analysis in molecular diagnostics. Given the need for testing DNA amounts and its purity in many samples, including in samples with very small input DNA, there is utility of novel machine learning approaches for accurate and high-throughput DNA quantification. Here, we demonstrated the ability of a neural network to predict DNA amounts coupled to paramagnetic beads. To this end, a custom-made microfluidic chip is applied to detect DNA molecules bound to beads by measuring the impedance peak response (IPR) at multiple frequencies. We leveraged electrical measurements including the frequency and imaginary and real parts of the peak intensity within a microfluidic channel as the input of deep learning models to predict DNA concentration. Specifically, 10 different deep learning architectures are examined. The results of the proposed regression model indicate that an R_Squared of 97% with a slope of 0.68 is achievable. Consequently, machine learning models can be a suitable, fast, and accurate method to measure nucleic acid concentration in a sample. The results presented in this study demonstrate the ability of the proposed neural network to use the information embedded in raw impedance data to predict the amount of DNA concentration. Full article
(This article belongs to the Special Issue Nano-Biosensors for Detection and Monitoring)
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30 pages, 4707 KiB  
Review
Stimulus-Responsive DNA Hydrogel Biosensors for Food Safety Detection
by Huiyuan Wang, Xinyu Wang, Keqiang Lai and Juan Yan
Biosensors 2023, 13(3), 320; https://doi.org/10.3390/bios13030320 - 24 Feb 2023
Cited by 23 | Viewed by 4142
Abstract
Food safety has always been a major global challenge to human health and the effective detection of harmful substances in food can reduce the risk to human health. However, the food industry has been plagued by a lack of effective and sensitive safety [...] Read more.
Food safety has always been a major global challenge to human health and the effective detection of harmful substances in food can reduce the risk to human health. However, the food industry has been plagued by a lack of effective and sensitive safety monitoring methods due to the tension between the cost and effectiveness of monitoring. DNA-based hydrogels combine the advantages of biocompatibility, programmability, the molecular recognition of DNA molecules, and the hydrophilicity of hydrogels, making them a hotspot in the research field of new nanomaterials. The stimulus response property greatly broadens the function and application range of DNA hydrogel. In recent years, DNA hydrogels based on stimulus-responsive mechanisms have been widely applied in the field of biosensing for the detection of a variety of target substances, including various food contaminants. In this review, we describe the recent advances in the preparation of stimuli-responsive DNA hydrogels, highlighting the progress of its application in food safety detection. Finally, we also discuss the challenges and future application of stimulus-responsive DNA hydrogels. Full article
(This article belongs to the Special Issue Functional Nanomaterials for Biosensing)
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15 pages, 2560 KiB  
Article
Surface Micro-Patterned Biofunctionalized Hydrogel for Direct Nucleic Acid Hybridization Detection
by Paola Zezza, María Isabel Lucío, Estrella Fernández, Ángel Maquieira and María-José Bañuls
Biosensors 2023, 13(3), 312; https://doi.org/10.3390/bios13030312 - 23 Feb 2023
Cited by 7 | Viewed by 2555
Abstract
The present research is focused on the development of a biofunctionalized hydrogel with a surface diffractive micropattern as a label-free biosensing platform. The biosensors described in this paper were fabricated with a holographic recording of polyethylene terephthalate (PET) surface micro-structures, which were then [...] Read more.
The present research is focused on the development of a biofunctionalized hydrogel with a surface diffractive micropattern as a label-free biosensing platform. The biosensors described in this paper were fabricated with a holographic recording of polyethylene terephthalate (PET) surface micro-structures, which were then transferred into a hydrogel material. Acrylamide-based hydrogels were obtained with free radical polymerization, and propargyl acrylate was added as a comonomer, which allowed for covalent immobilization of thiolated oligonucleotide probes into the hydrogel network, via thiol-yne photoclick chemistry. The comonomer was shown to significantly contribute to the immobilization of the probes based on fluorescence imaging. Two different immobilization approaches were demonstrated: during or after hydrogel synthesis. The second approach showed better loading capacity of the bioreceptor groups. Diffraction efficiency measurements of hydrogel gratings at 532 nm showed a selective response reaching a limit of detection in the complementary DNA strand of 2.47 µM. The label-free biosensor as designed could significantly contribute to direct and accurate analysis in medical diagnosis as it is cheap, easy to fabricate, and works without the need for further reagents. Full article
(This article belongs to the Special Issue Biosensing for Point-of-Care Diagnostics)
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29 pages, 6877 KiB  
Review
Epidermal Wearable Biosensors for Monitoring Biomarkers of Chronic Disease in Sweat
by Xichen Yuan, Chen Li, Xu Yin, Yang Yang, Bowen Ji, Yinbo Niu and Li Ren
Biosensors 2023, 13(3), 313; https://doi.org/10.3390/bios13030313 - 23 Feb 2023
Cited by 24 | Viewed by 7325
Abstract
Biological information detection technology is mainly used for the detection of physiological and biochemical parameters closely related to human tissues and organ lesions, such as biomarkers. This technology has important value in the clinical diagnosis and treatment of chronic diseases in their early [...] Read more.
Biological information detection technology is mainly used for the detection of physiological and biochemical parameters closely related to human tissues and organ lesions, such as biomarkers. This technology has important value in the clinical diagnosis and treatment of chronic diseases in their early stages. Wearable biosensors can be integrated with the Internet of Things and Big Data to realize the detection, transmission, storage, and comprehensive analysis of human physiological and biochemical information. This technology has extremely wide applications and considerable market prospects in frontier fields including personal health monitoring, chronic disease diagnosis and management, and home medical care. In this review, we systematically summarized the sweat biomarkers, introduced the sweat extraction and collection methods, and discussed the application and development of epidermal wearable biosensors for monitoring biomarkers in sweat in preclinical research in recent years. In addition, the current challenges and development prospects in this field were discussed. Full article
(This article belongs to the Special Issue Artificial Skins and Wearable Biosensors for Healthcare Monitoring)
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30 pages, 8961 KiB  
Review
Magnetite-Based Biosensors and Molecular Logic Gates: From Magnetite Synthesis to Application
by Nataliia Dudchenko, Shweta Pawar, Ilana Perelshtein and Dror Fixler
Biosensors 2023, 13(3), 304; https://doi.org/10.3390/bios13030304 - 21 Feb 2023
Cited by 6 | Viewed by 2976
Abstract
In the last few decades, point-of-care (POC) sensors have become increasingly important in the detection of various targets for the early diagnostics and treatment of diseases. Diverse nanomaterials are used as building blocks for the development of smart biosensors and magnetite nanoparticles (MNPs) [...] Read more.
In the last few decades, point-of-care (POC) sensors have become increasingly important in the detection of various targets for the early diagnostics and treatment of diseases. Diverse nanomaterials are used as building blocks for the development of smart biosensors and magnetite nanoparticles (MNPs) are among them. The intrinsic properties of MNPs, such as their large surface area, chemical stability, ease of functionalization, high saturation magnetization, and more, mean they have great potential for use in biosensors. Moreover, the unique characteristics of MNPs, such as their response to external magnetic fields, allow them to be easily manipulated (concentrated and redispersed) in fluidic media. As they are functionalized with biomolecules, MNPs bear high sensitivity and selectivity towards the detection of target biomolecules, which means they are advantageous in biosensor development and lead to a more sensitive, rapid, and accurate identification and quantification of target analytes. Due to the abovementioned properties of functionalized MNPs and their unique magnetic characteristics, they could be employed in the creation of new POC devices, molecular logic gates, and new biomolecular-based biocomputing interfaces, which would build on new ideas and principles. The current review outlines the synthesis, surface coverage, and functionalization of MNPs, as well as recent advancements in magnetite-based biosensors for POC diagnostics and some perspectives in molecular logic, and it also contains some of our own results regarding the topic, which include synthetic MNPs, their application for sample preparation, and the design of fluorescent-based molecular logic gates. Full article
(This article belongs to the Special Issue Biosensors and Bioelectronics Based on Molecular Logic Computing)
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29 pages, 5955 KiB  
Review
Review of HIV Self Testing Technologies and Promising Approaches for the Next Generation
by Amanda Bacon, Weijing Wang, Hankeun Lee, Saurabh Umrao, Prima Dewi Sinawang, Demir Akin, Kodchakorn Khemtonglang, Anqi Tan, Sabina Hirshfield, Utkan Demirci, Xing Wang and Brian T. Cunningham
Biosensors 2023, 13(2), 298; https://doi.org/10.3390/bios13020298 - 20 Feb 2023
Cited by 15 | Viewed by 10769
Abstract
The ability to self-test for HIV is vital to preventing transmission, particularly when used in concert with HIV biomedical prevention modalities, such as pre-exposure prophylaxis (PrEP). In this paper, we review recent developments in HIV self-testing and self-sampling methods, and the potential future [...] Read more.
The ability to self-test for HIV is vital to preventing transmission, particularly when used in concert with HIV biomedical prevention modalities, such as pre-exposure prophylaxis (PrEP). In this paper, we review recent developments in HIV self-testing and self-sampling methods, and the potential future impact of novel materials and methods that emerged through efforts to develop more effective point-of-care (POC) SARS-CoV-2 diagnostics. We address the gaps in existing HIV self-testing technologies, where improvements in test sensitivity, sample-to-answer time, simplicity, and cost are needed to enhance diagnostic accuracy and widespread accessibility. We discuss potential paths toward the next generation of HIV self-testing through sample collection materials, biosensing assay techniques, and miniaturized instrumentation. We discuss the implications for other applications, such as self-monitoring of HIV viral load and other infectious diseases. Full article
(This article belongs to the Special Issue Smart Materials for Chemical and Biosensing)
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23 pages, 5454 KiB  
Review
Multiplex Surface-Enhanced Raman Scattering: An Emerging Tool for Multicomponent Detection of Food Contaminants
by Qingyi Wei, Qirong Dong and Hongbin Pu
Biosensors 2023, 13(2), 296; https://doi.org/10.3390/bios13020296 - 19 Feb 2023
Cited by 18 | Viewed by 5403
Abstract
For survival and quality of human life, the search for better ways to ensure food safety is constant. However, food contaminants still threaten human health throughout the food chain. In particular, food systems are often polluted with multiple contaminants simultaneously, which can cause [...] Read more.
For survival and quality of human life, the search for better ways to ensure food safety is constant. However, food contaminants still threaten human health throughout the food chain. In particular, food systems are often polluted with multiple contaminants simultaneously, which can cause synergistic effects and greatly increase food toxicity. Therefore, the establishment of multiple food contaminant detection methods is significant in food safety control. The surface-enhanced Raman scattering (SERS) technique has emerged as a potent candidate for the detection of multicomponents simultaneously. The current review focuses on the SERS-based strategies in multicomponent detection, including the combination of chromatography methods, chemometrics, and microfluidic engineering with the SERS technique. Furthermore, recent applications of SERS in the detection of multiple foodborne bacteria, pesticides, veterinary drugs, food adulterants, mycotoxins and polycyclic aromatic hydrocarbons are summarized. Finally, challenges and future prospects for the SERS-based detection of multiple food contaminants are discussed to provide research orientation for further. Full article
(This article belongs to the Special Issue Application of Biosensors in Food Safety Analysis)
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17 pages, 2950 KiB  
Article
Difunctional Hydrogel Optical Fiber Fluorescence Sensor for Continuous and Simultaneous Monitoring of Glucose and pH
by Yangjie Li, Site Luo, Yongqiang Gui, Xin Wang, Ziyuan Tian and Haihu Yu
Biosensors 2023, 13(2), 287; https://doi.org/10.3390/bios13020287 - 17 Feb 2023
Cited by 23 | Viewed by 4587
Abstract
It is significant for people with diabetes to know their body’s real-time glucose level, which can guide the diagnosis and treatment. Therefore, it is necessary to research continuous glucose monitoring (CGM) as it gives us real-time information about our health condition and its [...] Read more.
It is significant for people with diabetes to know their body’s real-time glucose level, which can guide the diagnosis and treatment. Therefore, it is necessary to research continuous glucose monitoring (CGM) as it gives us real-time information about our health condition and its dynamic changes. Here, we report a novel hydrogel optical fiber fluorescence sensor segmentally functionalized with fluorescein derivative and CdTe QDs/3-APBA, which can continuously monitor pH and glucose simultaneously. In the glucose detection section, the complexation of PBA and glucose will expand the local hydrogel and decrease the fluorescence of the quantum dots. The fluorescence can be transmitted to the detector by the hydrogel optical fiber in real time. As the complexation reaction and the swelling–deswelling of the hydrogel are all reversible, the dynamic change of glucose concentration can be monitored. For pH detection, the fluorescein attached to another segment of the hydrogel exhibits different protolytic forms when pH changes and the fluorescence changes correspondingly. The significance of pH detection is compensation for pH errors in glucose detection because the reaction between PBA and glucose is sensitive to pH. The emission peaks of the two detection units are 517 nm and 594 nm, respectively, so there is no signal interference between them. The sensor can continuously monitor glucose in 0–20 mM and pH in 5.4–7.8. The advantages of this sensor are multi-parameter simultaneous detection, transmission-detection integration, real-time dynamic detection, and good biocompatibility. Full article
(This article belongs to the Special Issue Advanced Optical Fiber Sensors for Chemical and Biological Detection)
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13 pages, 3195 KiB  
Article
Horseradish Peroxidase-Encapsulated Fluorescent Bio-Nanoparticle for Ultra-Sensitive and Easy Detection of Hydrogen Peroxide
by Myeong-Jun Lee, Ji-Ae Song, Jin-Ha Choi, Jeong-Hyeop Shin, Ji-Woon Myeong, Ki-Ppeum Lee, Taehwan Kim, Ki-Eob Park and Byung-Keun Oh
Biosensors 2023, 13(2), 289; https://doi.org/10.3390/bios13020289 - 17 Feb 2023
Cited by 11 | Viewed by 3258
Abstract
Hydrogen peroxide (H2O2) has been a fascinating target in various chemical, biological, clinical, and industrial fields. Several types of fluorescent protein-stabilized gold nanoclusters (protein-AuNCs) have been developed for sensitive and easy detection of H2O2. However, [...] Read more.
Hydrogen peroxide (H2O2) has been a fascinating target in various chemical, biological, clinical, and industrial fields. Several types of fluorescent protein-stabilized gold nanoclusters (protein-AuNCs) have been developed for sensitive and easy detection of H2O2. However, its low sensitivity makes is difficult to measure negligible concentrations of H2O2. Therefore, to overcome this limitation, we developed a horseradish peroxidase-encapsulated fluorescent bio-nanoparticle (HEFBNP), comprising bovine serum albumin-stabilized gold nanoclusters (BSA-AuNCs) and horseradish peroxidase-stabilized gold nanoclusters (HRP-AuNCs). The fabricated HEFBNP can sensitively detect H2O2 owing to its two properties. The first is that HEFBNPs have a continuous two-step fluorescence quenching mechanism, which comes from the heterogenous fluorescence quenching mechanism of HRP-AuNCs and BSA-AuNCs. Second, the proximity of two protein-AuNCs in a single HEFBNP allows a reaction intermediate (•OH) to rapidly reach the adjacent protein-AuNCs. As a result, HEFBNP can improve the overall reaction event and decrease the loss of intermediate in the solution. Due to the continuous quenching mechanism and effective reaction event, a HEFBNP-based sensing system can measure very low concentrations of H2O2 up to 0.5 nM and show good selectivity. Furthermore, we design a glass-based microfluidic device to make it easier use HEFBNP, which allowed us to detect H2O2 with the naked eye. Overall, the proposed H2O2 sensing system is expected to be an easy and highly sensitive on-site detection tool in chemistry, biology, clinics, and industry fields. Full article
(This article belongs to the Special Issue Nanomaterials and Their Applications in Sensing and Biosensing)
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18 pages, 5371 KiB  
Review
Covalent Organic Frameworks-Based Electrochemical Sensors for Food Safety Analysis
by Zhenyu Lu, Yingying Wang and Gongke Li
Biosensors 2023, 13(2), 291; https://doi.org/10.3390/bios13020291 - 17 Feb 2023
Cited by 16 | Viewed by 4596
Abstract
Food safety is a key issue in promoting human health and sustaining life. Food analysis is essential to prevent food components or contaminants causing foodborne-related illnesses to consumers. Electrochemical sensors have become a desirable method for food safety analysis due to their simple, [...] Read more.
Food safety is a key issue in promoting human health and sustaining life. Food analysis is essential to prevent food components or contaminants causing foodborne-related illnesses to consumers. Electrochemical sensors have become a desirable method for food safety analysis due to their simple, accurate and rapid response. The low sensitivity and poor selectivity of electrochemical sensors working in complex food sample matrices can be overcome by coupling them with covalent organic frameworks (COFs). COFs are a kind of novel porous organic polymer formed by light elements, such as C, H, N and B, via covalent bonds. This review focuses on the recent progress in COF-based electrochemical sensors for food safety analysis. Firstly, the synthesis methods of COFs are summarized. Then, a discussion of the strategies is given to improve the electrochemistry performance of COFs. There follows a summary of the recently developed COF-based electrochemical sensors for the determination of food contaminants, including bisphenols, antibiotics, pesticides, heavy metal ions, fungal toxin and bacterium. Finally, the challenges and the future directions in this field are discussed. Full article
(This article belongs to the Special Issue Advanced Materials for Electrochemical Sensors and Biosensors Development)
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17 pages, 4810 KiB  
Review
MOFs-Modified Electrochemical Sensors and the Application in the Detection of Opioids
by Jiaqi Zhao, Ying Kan, Zhi Chen, Hongmei Li and Weifei Zhang
Biosensors 2023, 13(2), 284; https://doi.org/10.3390/bios13020284 - 16 Feb 2023
Cited by 21 | Viewed by 4817
Abstract
Opioids are widely used in clinical practice, but drug overdoses can lead to many adverse reactions, and even endanger life. Therefore, it is essential to implement real-time measurement of drug concentrations to adjust the dosage given during treatment, keeping drug levels within therapeutic [...] Read more.
Opioids are widely used in clinical practice, but drug overdoses can lead to many adverse reactions, and even endanger life. Therefore, it is essential to implement real-time measurement of drug concentrations to adjust the dosage given during treatment, keeping drug levels within therapeutic levels. Metal-Organic frameworks (MOFs) and their composite materials modified bare electrode electrochemical sensors have the advantages of fast production, low cost, high sensitivity, and low detection limit in the detection of opioids. In this review, MOFs and MOFs composites, electrochemical sensors modified with MOFs for the detection of opioids, as well as the application of microfluidic chips in combination with electrochemical methods are all reviewed, and the potential for the development of microfluidic chips electrochemical methods with MOFs surface modifications for the detection of opioids is also prospected. We hope that this review will provide contributions to the study of electrochemical sensors modified with MOFs for the detection of opioids. Full article
(This article belongs to the Special Issue Microfluidics for Detection and Analysis)
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17 pages, 4807 KiB  
Article
Detection of Rice Fungal Spores Based on Micro- Hyperspectral and Microfluidic Techniques
by Xiaodong Zhang, Houjian Song, Yafei Wang, Lian Hu, Pei Wang and Hanping Mao
Biosensors 2023, 13(2), 278; https://doi.org/10.3390/bios13020278 - 15 Feb 2023
Cited by 9 | Viewed by 3347
Abstract
As rice is one of the world’s most important food crops, protecting it from fungal diseases is very important for agricultural production. At present, it is difficult to diagnose rice fungal diseases at an early stage using relevant technologies, and there are a [...] Read more.
As rice is one of the world’s most important food crops, protecting it from fungal diseases is very important for agricultural production. At present, it is difficult to diagnose rice fungal diseases at an early stage using relevant technologies, and there are a lack of rapid detection methods. This study proposes a microfluidic chip-based method combined with microscopic hyperspectral detection of rice fungal disease spores. First, a microfluidic chip with a dual inlet and three-stage structure was designed to separate and enrich Magnaporthe grisea spores and Ustilaginoidea virens spores in air. Then, the microscopic hyperspectral instrument was used to collect the hyperspectral data of the fungal disease spores in the enrichment area, and the competitive adaptive reweighting algorithm (CARS) was used to screen the characteristic bands of the spectral data collected from the spores of the two fungal diseases. Finally, the support vector machine (SVM) and convolutional neural network (CNN) were used to build the full-band classification model and the CARS filtered characteristic wavelength classification model, respectively. The results showed that the actual enrichment efficiency of the microfluidic chip designed in this study on Magnaporthe grisea spores and Ustilaginoidea virens spores was 82.67% and 80.70%, respectively. In the established model, the CARS-CNN classification model is the best for the classification of Magnaporthe grisea spores and Ustilaginoidea virens spores, and its F1-core index can reach 0.960 and 0.949, respectively. This study can effectively isolate and enrich Magnaporthe grisea spores and Ustilaginoidea virens spores, providing new methods and ideas for early detection of rice fungal disease spores. Full article
(This article belongs to the Special Issue Development of Point-of-Care Diagnostic Tools and New Bioassays)
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17 pages, 3348 KiB  
Article
SERS Determination of Oxidative Stress Markers in Saliva Using Substrates with Silver Nanoparticle-Decorated Silicon Nanowires
by Anastasia Kanioura, Georgia Geka, Ioannis Kochylas, Vlassis Likodimos, Spiros Gardelis, Anastasios Dimitriou, Nikolaos Papanikolaou, Sotirios Kakabakos and Panagiota Petrou
Biosensors 2023, 13(2), 273; https://doi.org/10.3390/bios13020273 - 14 Feb 2023
Cited by 11 | Viewed by 2577
Abstract
Glutathione and malondialdehyde are two compounds commonly used to evaluate the oxidative stress status of an organism. Although their determination is usually performed in blood serum, saliva is gaining ground as the biological fluid of choice for oxidative stress determination at the point [...] Read more.
Glutathione and malondialdehyde are two compounds commonly used to evaluate the oxidative stress status of an organism. Although their determination is usually performed in blood serum, saliva is gaining ground as the biological fluid of choice for oxidative stress determination at the point of need. For this purpose, surface-enhanced Raman spectroscopy (SERS), which is a highly sensitive method for the detection of biomolecules, could offer additional advantages regarding the analysis of biological fluids at the point of need. In this work, silicon nanowires decorated with silver nanoparticles made by metal-assisted chemical etching were evaluated as substrates for the SERS determination of glutathione and malondialdehyde in water and saliva. In particular, glutathione was determined by monitoring the reduction in the Raman signal obtained from substrates modified with crystal violet upon incubation with aqueous glutathione solutions. On the other hand, malondialdehyde was detected after a reaction with thiobarbituric acid to produce a derivative with a strong Raman signal. The detection limits achieved after optimization of several assay parameters were 50 and 3.2 nM for aqueous solutions of glutathione and malondialdehyde, respectively. In artificial saliva, however, the detection limits were 2.0 and 0.32 μM for glutathione and malondialdehyde, respectively, which are, nonetheless, adequate for the determination of these two markers in saliva. Full article
(This article belongs to the Special Issue Surface-Enhanced Raman Scattering Biosensors)
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12 pages, 5951 KiB  
Article
Mn3O4/NiO Nanoparticles Decorated on Carbon Nanofibers as an Enzyme-Free Electrochemical Sensor for Glucose Detection
by Mengjie Li, Jie Dong, Dongmei Deng, Xun Ouyang, Xiaoxia Yan, Shima Liu and Liqiang Luo
Biosensors 2023, 13(2), 264; https://doi.org/10.3390/bios13020264 - 13 Feb 2023
Cited by 18 | Viewed by 3045
Abstract
Transition metal oxides have garnered a lot of attention in the field of electrocatalysis along with their unique crystal structure and excellent catalytic properties. In this study, carbon nanofibers (CNFs) decorated with Mn3O4/NiO nanoparticles were made using electrospinning and [...] Read more.
Transition metal oxides have garnered a lot of attention in the field of electrocatalysis along with their unique crystal structure and excellent catalytic properties. In this study, carbon nanofibers (CNFs) decorated with Mn3O4/NiO nanoparticles were made using electrospinning and calcination. The conductive network constructed by CNFs not only facilitates electron transport, but also provides landing sites for nanoparticles, thus reducing nanoparticle aggregation and exposing more active sites. Additionally, the synergistic interaction between Mn3O4 and NiO improved electrocatalytic capacity for glucose oxidation. The Mn3O4/NiO/CNFs modified glassy carbon electrode shows satisfactory results in terms of linear range and anti-interference capability for glucose detection, suggesting that the constructed enzyme-free sensor has a promising application in clinical diagnosis. Full article
(This article belongs to the Special Issue Electrochemical Biosensors for Disease Detection)
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41 pages, 7602 KiB  
Review
Recent Advances on Peptide-Based Biosensors and Electronic Noses for Foodborne Pathogen Detection
by Vanessa Escobar, Natale Scaramozzino, Jasmina Vidic, Arnaud Buhot, Raphaël Mathey, Carole Chaix and Yanxia Hou
Biosensors 2023, 13(2), 258; https://doi.org/10.3390/bios13020258 - 11 Feb 2023
Cited by 35 | Viewed by 5599
Abstract
Foodborne pathogens present a serious issue around the world due to the remarkably high number of illnesses they cause every year. In an effort to narrow the gap between monitoring needs and currently implemented classical detection methodologies, the last decades have seen an [...] Read more.
Foodborne pathogens present a serious issue around the world due to the remarkably high number of illnesses they cause every year. In an effort to narrow the gap between monitoring needs and currently implemented classical detection methodologies, the last decades have seen an increased development of highly accurate and reliable biosensors. Peptides as recognition biomolecules have been explored to develop biosensors that combine simple sample preparation and enhanced detection of bacterial pathogens in food. This review first focuses on the selection strategies for the design and screening of sensitive peptide bioreceptors, such as the isolation of natural antimicrobial peptides (AMPs) from living organisms, the screening of peptides by phage display and the use of in silico tools. Subsequently, an overview on the state-of-the-art techniques in the development of peptide-based biosensors for foodborne pathogen detection based on various transduction systems was given. Additionally, limitations in classical detection strategies have led to the development of innovative approaches for food monitoring, such as electronic noses, as promising alternatives. The use of peptide receptors in electronic noses is a growing field and the recent advances of such systems for foodborne pathogen detection are presented. All these biosensors and electronic noses are promising alternatives for the pathogen detection with high sensitivity, low cost and rapid response, and some of them are potential portable devices for on-site analyses. Full article
(This article belongs to the Special Issue Biosensors for Monitoring Pathogenic Agents)
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21 pages, 7941 KiB  
Review
Self-Powered Biosensors for Monitoring Human Physiological Changes
by Ziao Xue, Li Wu, Junlin Yuan, Guodong Xu and Yuxiang Wu
Biosensors 2023, 13(2), 236; https://doi.org/10.3390/bios13020236 - 7 Feb 2023
Cited by 23 | Viewed by 4796
Abstract
Human physiological signals have an important role in the guidance of human health or exercise training and can usually be divided into physical signals (electrical signals, blood pressure, temperature, etc.) and chemical signals (saliva, blood, tears, sweat). With the development and upgrading of [...] Read more.
Human physiological signals have an important role in the guidance of human health or exercise training and can usually be divided into physical signals (electrical signals, blood pressure, temperature, etc.) and chemical signals (saliva, blood, tears, sweat). With the development and upgrading of biosensors, many sensors for monitoring human signals have appeared. These sensors are characterized by softness and stretching and are self-powered. This article summarizes the progress in self-powered biosensors in the past five years. Most of these biosensors are used as nanogenerators and biofuel batteries to obtain energy. A nanogenerator is a kind of generator that collects energy at the nanoscale. Due to its characteristics, it is very suitable for bioenergy harvesting and sensing of the human body. With the development of biological sensing devices, the combination of nanogenerators and classical sensors so that they can more accurately monitor the physiological state of the human body and provide energy for biosensor devices has played a great role in long-range medical care and sports health. A biofuel cell has a small volume and good biocompatibility. It is a device in which electrochemical reactions convert chemical energy into electrical energy and is mostly used for monitoring chemical signals. This review analyzes different classifications of human signals and different forms of biosensors (implanted and wearable) and summarizes the sources of self-powered biosensor devices. Self-powered biosensor devices based on nanogenerators and biofuel cells are also summarized and presented. Finally, some representative applications of self-powered biosensors based on nanogenerators are introduced. Full article
(This article belongs to the Section Biosensors and Healthcare)
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18 pages, 3840 KiB  
Article
Nonenzymatic Electrochemical Glutamate Sensor Using Copper Oxide Nanomaterials and Multiwall Carbon Nanotubes
by Md Younus Ali, Dorian Knight and Matiar M. R. Howlader
Biosensors 2023, 13(2), 237; https://doi.org/10.3390/bios13020237 - 7 Feb 2023
Cited by 12 | Viewed by 3984
Abstract
Glutamate is an important neurotransmitter due to its critical role in physiological and pathological processes. While enzymatic electrochemical sensors can selectively detect glutamate, enzymes cause instability of the sensors, thus necessitating the development of enzyme-free glutamate sensors. In this paper, we developed an [...] Read more.
Glutamate is an important neurotransmitter due to its critical role in physiological and pathological processes. While enzymatic electrochemical sensors can selectively detect glutamate, enzymes cause instability of the sensors, thus necessitating the development of enzyme-free glutamate sensors. In this paper, we developed an ultrahigh sensitive nonenzymatic electrochemical glutamate sensor by synthesizing copper oxide (CuO) nanostructures and physically mixing them with multiwall carbon nanotubes (MWCNTs) onto a screen-printed carbon electrode. We comprehensively investigated the sensing mechanism of glutamate; the optimized sensor showed irreversible oxidation of glutamate involving one electron and one proton, and a linear response from 20 μM to 200 μM at pH 7. The limit of detection and sensitivity of the sensor were about 17.5 μM and 8500 μA·mM−1·cm−2, respectively. The enhanced sensing performance is attributed to the synergetic electrochemical activities of CuO nanostructures and MWCNTs. The sensor detected glutamate in whole blood and urine and had minimal interference with common interferents, suggesting its potential for healthcare applications. Full article
(This article belongs to the Special Issue New Opportunities for Emerging 2D Materials in Bioelectronics and Biosensors)
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17 pages, 5288 KiB  
Article
Development of a Point-of-Care SPR Sensor for the Diagnosis of Acute Myocardial Infarction
by Sunil Choudhary and Zeynep Altintas
Biosensors 2023, 13(2), 229; https://doi.org/10.3390/bios13020229 - 5 Feb 2023
Cited by 36 | Viewed by 5394
Abstract
A novel point-of-care surface plasmon resonance (SPR) sensor was developed for the sensitive and real-time detection of cardiac troponin I (cTnI) using epitope-imprinted molecular receptors. The surface coverage of a nano-molecularly imprinted polymer (nanoMIP)-functionalized SPR sensor chip and the size of nanoMIPs (155.7 [...] Read more.
A novel point-of-care surface plasmon resonance (SPR) sensor was developed for the sensitive and real-time detection of cardiac troponin I (cTnI) using epitope-imprinted molecular receptors. The surface coverage of a nano-molecularly imprinted polymer (nanoMIP)-functionalized SPR sensor chip and the size of nanoMIPs (155.7 nm) were characterized using fluorescence microscopy and dynamic light scattering techniques, respectively. Atomic force microscopy, electrochemical impedance spectroscopy, square wave voltammetry and cyclic voltammetry techniques confirmed the successful implementation of each step of the sensor fabrication. The SPR bio-detection assay was initially established by targeting the cTnI peptide template, and the sensor allowed the detection of the peptide in the concentration range of 100–1000 nM with a correlation coefficient (R2) of 0.96 and limit of detection (LOD) of 76.47 nM. The optimum assay conditions for protein recognition were subsequently determined, and the cTnI biomarker could be detected in a wide concentration range (0.78–50 ng mL−1) with high reproducibility (R2 = 0.91) and sensitivity (LOD: 0.52 ng mL−1). The overall sensor results were subjected to three binding isotherm models, where nanoMIP-cTnI interaction followed the Langmuir binding isotherm with the dissociation constant of 2.99 × 10−11 M, indicating a very strong affinity between the cTnI biomarker and epitope-imprinted synthetic receptor. Furthermore, the selectivity of the sensor was confirmed through studying with a control nanoMIP that was prepared by imprinting a non-specific peptide template. Based on the cross-reactivity tests with non-specific molecules (i.e., glucose, p53 protein, transferrin and bovine serum albumin), the nanoMIP-SPR sensor is highly specific for the target biomarker. The developed biomimetic sensor, relying on the direct assay strategy, holds great potential not only for the early and point-of-care testing of acute myocardial infarction but also for other life-threatening diseases that can be diagnosed by determining the elevated levels of certain biomarkers. Full article
(This article belongs to the Special Issue Advances in Molecular Biosensors)
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14 pages, 3575 KiB  
Article
Fabrication of P and N Co-Doped Carbon Dots for Fe3+ Detection in Serum and Lysosomal Tracking in Living Cells
by Yanzhi Xing, Mei Yang and Xuwei Chen
Biosensors 2023, 13(2), 230; https://doi.org/10.3390/bios13020230 - 5 Feb 2023
Cited by 11 | Viewed by 3246
Abstract
Doping with heteroatoms allows the retention of the general characteristics of carbon dots while allowing their physicochemical and photochemical properties to be effectively modulated. In this work, we report the preparation of ultrastable P and N co-doped carbon dots (PNCDs) that can be [...] Read more.
Doping with heteroatoms allows the retention of the general characteristics of carbon dots while allowing their physicochemical and photochemical properties to be effectively modulated. In this work, we report the preparation of ultrastable P and N co-doped carbon dots (PNCDs) that can be used for the highly selective detection of Fe3+ and the tracking of lysosomes in living cells. Fluorescent PNCDs were facilely prepared via a hydrothermal treatment of ethylenediamine and phytic acid, and they exhibited a high quantum yield of 22.0%. The strong coordination interaction between the phosphorus groups of PNCDs and Fe3+ rendered them efficient probes for use in selective Fe3+ detection, with a detection limit of 0.39 μM, and we demonstrated their practicability by accurately detecting the Fe3+ contents in bio-samples. At the same time, PNCDs exhibited high lysosomal location specificity in different cell lines due to surface lipophilic amino groups, and real-time tracking of the lysosome morphology in HeLa cells was achieved. The present work suggests that the fabrication of heteroatom-doped CDs might be an effective strategy to provide promising tools for cytology, such as organelle tracking. Full article
(This article belongs to the Special Issue Polymer-Dot-Based Biosensors for Biomedical Applications)
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35 pages, 5596 KiB  
Review
Advanced Nanomaterials-Based Electrochemical Biosensors for Catecholamines Detection: Challenges and Trends
by Zina Fredj and Mohamad Sawan
Biosensors 2023, 13(2), 211; https://doi.org/10.3390/bios13020211 - 31 Jan 2023
Cited by 39 | Viewed by 6550
Abstract
Catecholamines, including dopamine, epinephrine, and norepinephrine, are considered one of the most crucial subgroups of neurotransmitters in the central nervous system (CNS), in which they act at the brain’s highest levels of mental function and play key roles in neurological disorders. Accordingly, the [...] Read more.
Catecholamines, including dopamine, epinephrine, and norepinephrine, are considered one of the most crucial subgroups of neurotransmitters in the central nervous system (CNS), in which they act at the brain’s highest levels of mental function and play key roles in neurological disorders. Accordingly, the analysis of such catecholamines in biological samples has shown a great interest in clinical and pharmaceutical importance toward the early diagnosis of neurological diseases such as Epilepsy, Parkinson, and Alzheimer diseases. As promising routes for the real-time monitoring of catecholamine neurotransmitters, optical and electrochemical biosensors have been widely adopted and perceived as a dramatically accelerating development in the last decade. Therefore, this review aims to provide a comprehensive overview on the recent advances and main challenges in catecholamines biosensors. Particular emphasis is given to electrochemical biosensors, reviewing their sensing mechanism and the unique characteristics brought by the emergence of nanotechnology. Based on specific biosensors’ performance metrics, multiple perspectives on the therapeutic use of nanomaterial for catecholamines analysis and future development trends are also summarized. Full article
(This article belongs to the Special Issue Advanced Materials for Electrochemical Sensors and Biosensors Development)
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17 pages, 1744 KiB  
Review
Salivary Diagnostics in Pediatrics and the Status of Saliva-Based Biosensors
by Hayeon Min, Sophie Zhu, Lydia Safi, Munzer Alkourdi, Bich Hong Nguyen, Akshaya Upadhyay and Simon D. Tran
Biosensors 2023, 13(2), 206; https://doi.org/10.3390/bios13020206 - 30 Jan 2023
Cited by 13 | Viewed by 5216
Abstract
Salivary biomarkers are increasingly being used as an alternative to diagnose and monitor the progression of various diseases due to their ease of use, on site application, non-invasiveness, and most likely improved patient compliance. Here, we highlight the role of salivary biosensors in [...] Read more.
Salivary biomarkers are increasingly being used as an alternative to diagnose and monitor the progression of various diseases due to their ease of use, on site application, non-invasiveness, and most likely improved patient compliance. Here, we highlight the role of salivary biosensors in the general population, followed by the application of saliva as a diagnostic tool in the pediatric population. We searched the literature for pediatric applications of salivary biomarkers, more specifically, in children from 0 to 18 years old. The use of those biomarkers spans autoimmune, developmental disorders, oncology, neuropsychiatry, respiratory illnesses, gastrointestinal disorders, and oral diseases. Four major applications of salivary proteins as biomarkers are: (1) dental health (caries, stress from orthodontic appliances, and gingivitis); (2) gastrointestinal conditions (eosinophilic esophagitis, acid reflux, appendicitis); (3) metabolic conditions (obesity, diabetes); and (4) respiratory conditions (asthma, allergic rhinitis, small airway inflammation, pneumonia). Genomics, metabolomics, microbiomics, proteomics, and transcriptomics, are various other classifications for biosensing based on the type of biomarkers used and reviewed here. Lastly, we describe the recent advances in pediatric biosensing applications using saliva. This work guides scientists in fabricating saliva-based biosensors by comprehensively overviewing the potential markers and techniques that can be employed. Full article
(This article belongs to the Special Issue Non-invasive Medical Devices for Detection and Monitoring within Healthcare)
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24 pages, 5113 KiB  
Review
Nanotechnology-Assisted Biosensors for the Detection of Viral Nucleic Acids: An Overview
by Hye Kyu Choi and Jinho Yoon
Biosensors 2023, 13(2), 208; https://doi.org/10.3390/bios13020208 - 30 Jan 2023
Cited by 21 | Viewed by 5942
Abstract
The accurate and rapid diagnosis of viral diseases has garnered increasing attention in the field of biosensors. The development of highly sensitive, selective, and accessible biosensors is crucial for early disease detection and preventing mortality. However, developing biosensors optimized for viral disease diagnosis [...] Read more.
The accurate and rapid diagnosis of viral diseases has garnered increasing attention in the field of biosensors. The development of highly sensitive, selective, and accessible biosensors is crucial for early disease detection and preventing mortality. However, developing biosensors optimized for viral disease diagnosis has several limitations, including the accurate detection of mutations. For decades, nanotechnology has been applied in numerous biological fields such as biosensors, bioelectronics, and regenerative medicine. Nanotechnology offers a promising strategy to address the current limitations of conventional viral nucleic acid-based biosensors. The implementation of nanotechnologies, such as functional nanomaterials, nanoplatform-fabrication techniques, and surface nanoengineering, to biosensors has not only improved the performance of biosensors but has also expanded the range of sensing targets. Therefore, a deep understanding of the combination of nanotechnologies and biosensors is required to prepare for sanitary emergencies such as the recent COVID-19 pandemic. In this review, we provide interdisciplinary information on nanotechnology-assisted biosensors. First, representative nanotechnologies for biosensors are discussed, after which this review summarizes various nanotechnology-assisted viral nucleic acid biosensors. Therefore, we expect that this review will provide a valuable basis for the development of novel viral nucleic acid biosensors. Full article
(This article belongs to the Special Issue Nanomaterial-Based Biosensors for DNA and RNA Detection)
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12 pages, 2427 KiB  
Article
Highly Stable InSe-FET Biosensor for Ultra-Sensitive Detection of Breast Cancer Biomarker CA125
by Hao Ji, Zhenhua Wang, Shun Wang, Chao Wang, Kai Zhang, Yu Zhang and Lin Han
Biosensors 2023, 13(2), 193; https://doi.org/10.3390/bios13020193 - 28 Jan 2023
Cited by 17 | Viewed by 3698
Abstract
Two-dimensional materials-based field-effect transistors (FETs) are promising biosensors because of their outstanding electrical properties, tunable band gap, high specific surface area, label-free detection, and potential miniaturization for portable diagnostic products. However, it is crucial for FET biosensors to have a high electrical performance [...] Read more.
Two-dimensional materials-based field-effect transistors (FETs) are promising biosensors because of their outstanding electrical properties, tunable band gap, high specific surface area, label-free detection, and potential miniaturization for portable diagnostic products. However, it is crucial for FET biosensors to have a high electrical performance and stability degradation in liquid environments for their practical application. Here, a high-performance InSe-FET biosensor is developed and demonstrated for the detection of the CA125 biomarker in clinical samples. The InSe-FET is integrated with a homemade microfluidic channel, exhibiting good electrical stability during the liquid channel process because of the passivation effect on the InSe channel. The InSe-FET biosensor is capable of the quantitative detection of the CA125 biomarker in breast cancer in the range of 0.01–1000 U/mL, with a detection time of 20 min. This work provides a universal detection tool for protein biomarker sensing. The detection results of the clinical samples demonstrate its promising application in early screenings of major diseases. Full article
(This article belongs to the Special Issue Biosensing and Diagnosis)
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13 pages, 2152 KiB  
Article
Breath Analysis of COVID-19 Patients in a Tertiary UK Hospital by Optical Spectrometry: The E-Nose CoVal Study
by Steven Laird, Luke Debenham, Danny Chandla, Cathleen Chan, Emma Daulton, Johnathan Taylor, Palashika Bhat, Lisa Berry, Peter Munthali and James A. Covington
Biosensors 2023, 13(2), 165; https://doi.org/10.3390/bios13020165 - 20 Jan 2023
Cited by 13 | Viewed by 2812
Abstract
Throughout the SARS-CoV-2 pandemic, diagnostic technology played a crucial role in managing outbreaks on a national and global level. One diagnostic modality that has shown promise is breath analysis, due to its non-invasive nature and ability to give a rapid result. In this [...] Read more.
Throughout the SARS-CoV-2 pandemic, diagnostic technology played a crucial role in managing outbreaks on a national and global level. One diagnostic modality that has shown promise is breath analysis, due to its non-invasive nature and ability to give a rapid result. In this study, a portable FTIR (Fourier Transform Infra-Red) spectrometer was used to detect chemical components in the breath from Covid positive symptomatic and asymptomatic patients versus a control cohort of Covid negative patients. Eighty-five patients who had a nasopharyngeal polymerase chain reaction (PCR) test for the detection of SARS-CoV-2 within the last 5 days were recruited to the study (36 symptomatic PCR positive, 23 asymptomatic PCR positive and 26 asymptomatic PCR negative). Data analysis indicated significant difference between the groups, with SARS-CoV-2 present on PCR versus the negative PCR control group producing an area under the curve (AUC) of 0.87. Similar results were obtained comparing symptomatic versus control and asymptomatic versus control. The asymptomatic results were higher than the symptomatic (0.88 vs. 0.80 AUC). When analysing individual chemicals, we found ethanol, methanol and acetaldehyde were the most important, with higher concentrations in the COVID-19 group, with symptomatic patients being higher than asymptomatic patients. This study has shown that breath analysis can provide significant results that distinguish patients with or without COVID-19 disease/carriage. Full article
(This article belongs to the Special Issue Gas Detection Biosensors for Medical and Health Applications)
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17 pages, 4276 KiB  
Review
Conjugated Aggregation-Induced Fluorescent Materials for Biofluorescent Probes: A Review
by Zheng Wang, Ji Ma, Changlin Li and Haichang Zhang
Biosensors 2023, 13(2), 159; https://doi.org/10.3390/bios13020159 - 19 Jan 2023
Cited by 18 | Viewed by 4275
Abstract
The common fluorescent conjugated materials present weak or quenching luminescent phenomena in the solid or aggregate state (ACQ), which limits their applications in medicine and biology. In the last two decades, certain materials, named aggregation-induced emission (AIE) fluorescent materials, have exhibited strong luminescent [...] Read more.
The common fluorescent conjugated materials present weak or quenching luminescent phenomena in the solid or aggregate state (ACQ), which limits their applications in medicine and biology. In the last two decades, certain materials, named aggregation-induced emission (AIE) fluorescent materials, have exhibited strong luminescent properties in the aggregate state, which can overcome the ACQ phenomenon. Due to their intrinsic properties, the AIE materials have been successfully used in biolabeling, where they can not only detect the species of ions and their concentrations in organisms, but can also monitor the organisms’ physiological activity. In addition, these kinds of materials often present non-biological toxicity. Thus, AIE materials have become some of the most popular biofluorescent probe materials and are attracting more and more attention. This field is still in its early infancy, and several open challenges urgently need to be addressed, such as the materials’ biocompatibility, metabolism, and so on. Designing a high-performance AIE material for biofluorescent probes is still challenging. In this review, based on the molecular design concept, various AIE materials with functional groups in the biofluorescent probes are introduced, including tetrastyrene materials, distilbene anthracene materials, triphenylamine materials, and hexaphenylsilole materials. In addition, according to the molecular system design strategy, the donor–acceptor (D-A) system and hydrogen-bonding AIE materials used as biofluorescent probes are reviewed. Finally, the biofluorescent probe design concept and potential evolution trends are discussed. The final goal is to outline a theoretical scaffold for the design of high-performance AIE biofluorescent probes that can at the same time further the development of the applications of AIE-based biofluorescent probes. Full article
(This article belongs to the Special Issue Fluorescent Materials with Excellent Biocompatibility and Their Application in Bio-Sensing, Bio-Imaging)
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14 pages, 2135 KiB  
Article
Wearable Electrocardiography for Physical Activity Monitoring: Definition of Validation Protocol and Automatic Classification
by Gloria Cosoli, Luca Antognoli and Lorenzo Scalise
Biosensors 2023, 13(2), 154; https://doi.org/10.3390/bios13020154 - 18 Jan 2023
Cited by 12 | Viewed by 3351
Abstract
Wearable devices are rapidly spreading thanks to multiple advantages. Their use is expanding in several fields, from medicine to personal assessment and sport applications. At present, more and more wearable devices acquire an electrocardiographic (ECG) signal (in correspondence to the wrist), providing potentially [...] Read more.
Wearable devices are rapidly spreading thanks to multiple advantages. Their use is expanding in several fields, from medicine to personal assessment and sport applications. At present, more and more wearable devices acquire an electrocardiographic (ECG) signal (in correspondence to the wrist), providing potentially useful information from a diagnostic point of view, particularly in sport medicine and in rehabilitation fields. They are remarkably relevant, being perceived as a common watch and, hence, considered neither intrusive nor a cause of the so-called “white coat effect”. Their validation and metrological characterization are fundamental; hence, this work aims at defining a validation protocol tested on a commercial smartwatch (Samsung Galaxy Watch3, Samsung Electronics Italia S.p.A., Milan, Italy) with respect to a gold standard device (Zephyr BioHarness 3.0, Zephyr Technology Corporation, Annapolis, MD, USA, accuracy of ±1 bpm), reporting results on 30 subjects. The metrological performance is provided, supporting final users to properly interpret the results. Moreover, machine learning and deep learning models are used to discriminate between resting and activity-related ECG signals. The results confirm the possibility of using heart rate data from wearable sensors for activity identification (best results obtained by Random Forest, with accuracy of 0.81, recall of 0.80, and precision of 0.81, even using ECG signals of limited duration, i.e., 30 s). Moreover, the effectiveness of the proposed validation protocol to evaluate measurement accuracy and precision in a wide measurement range is verified. A bias of −1 bpm and an experimental standard deviation of 11 bpm (corresponding to an experimental standard deviation of the mean of ≈0 bpm) were found for the Samsung Galaxy Watch3, indicating a good performance from a metrological point of view. Full article
(This article belongs to the Special Issue Current Accuracy and Advances in Wearable Sensors and Biosensors for Physiological Signals Measurement)
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26 pages, 4410 KiB  
Review
Semiconducting Polymer Dots for Point-of-Care Biosensing and In Vivo Bioimaging: A Concise Review
by Sile Deng, Lingfeng Li, Jiaxi Zhang, Yongjun Wang, Zhongchao Huang and Haobin Chen
Biosensors 2023, 13(1), 137; https://doi.org/10.3390/bios13010137 - 14 Jan 2023
Cited by 15 | Viewed by 4231
Abstract
In recent years, semiconducting polymer dots (Pdots) have attracted much attention due to their excellent photophysical properties and applicability, such as large absorption cross section, high brightness, tunable fluorescence emission, excellent photostability, good biocompatibility, facile modification and regulation. Therefore, Pdots have been widely [...] Read more.
In recent years, semiconducting polymer dots (Pdots) have attracted much attention due to their excellent photophysical properties and applicability, such as large absorption cross section, high brightness, tunable fluorescence emission, excellent photostability, good biocompatibility, facile modification and regulation. Therefore, Pdots have been widely used in various types of sensing and imaging in biological medicine. More importantly, the recent development of Pdots for point-of-care biosensing and in vivo imaging has emerged as a promising class of optical diagnostic technologies for clinical applications. In this review, we briefly outline strategies for the preparation and modification of Pdots and summarize the recent progress in the development of Pdots-based optical probes for analytical detection and biomedical imaging. Finally, challenges and future developments of Pdots for biomedical applications are given. Full article
(This article belongs to the Special Issue Nanometre-Scale Biosensors for Applications in Medicine/Environment/Food/Biomedical Research)
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30 pages, 3266 KiB  
Review
Review of Bacterial Nanocellulose-Based Electrochemical Biosensors: Functionalization, Challenges, and Future Perspectives
by Samuel Chagas de Assis, Daniella Lury Morgado, Desiree Tamara Scheidt, Samara Silva de Souza, Marco Roberto Cavallari, Oswaldo Hideo Ando Junior and Emanuel Carrilho
Biosensors 2023, 13(1), 142; https://doi.org/10.3390/bios13010142 - 14 Jan 2023
Cited by 23 | Viewed by 5254
Abstract
Electrochemical biosensing devices are known for their simple operational procedures, low fabrication cost, and suitable real-time detection. Despite these advantages, they have shown some limitations in the immobilization of biochemicals. The development of alternative materials to overcome these drawbacks has attracted significant attention. [...] Read more.
Electrochemical biosensing devices are known for their simple operational procedures, low fabrication cost, and suitable real-time detection. Despite these advantages, they have shown some limitations in the immobilization of biochemicals. The development of alternative materials to overcome these drawbacks has attracted significant attention. Nanocellulose-based materials have revealed valuable features due to their capacity for the immobilization of biomolecules, structural flexibility, and biocompatibility. Bacterial nanocellulose (BNC) has gained a promising role as an alternative to antifouling surfaces. To widen its applicability as a biosensing device, BNC may form part of the supports for the immobilization of specific materials. The possibilities of modification methods and in situ and ex situ functionalization enable new BNC properties. With the new insights into nanoscale studies, we expect that many biosensors currently based on plastic, glass, or paper platforms will rely on renewable platforms, especially BNC ones. Moreover, substrates based on BNC seem to have paved the way for the development of sensing platforms with minimally invasive approaches, such as wearable devices, due to their mechanical flexibility and biocompatibility. Full article
(This article belongs to the Special Issue Microfluidics, Bioelectronics, and MEMS-Based Devices for Diagnostics and Biomedical Application)
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16 pages, 9117 KiB  
Article
Development of a Wearable Ultrasound Transducer for Sensing Muscle Activities in Assistive Robotics Applications
by Xiangming Xue, Bohua Zhang, Sunho Moon, Guo-Xuan Xu, Chih-Chung Huang, Nitin Sharma and Xiaoning Jiang
Biosensors 2023, 13(1), 134; https://doi.org/10.3390/bios13010134 - 13 Jan 2023
Cited by 33 | Viewed by 6830
Abstract
Robotic prostheses and powered exoskeletons are novel assistive robotic devices for modern medicine. Muscle activity sensing plays an important role in controlling assistive robotics devices. Most devices measure the surface electromyography (sEMG) signal for myoelectric control. However, sEMG is an integrated signal from [...] Read more.
Robotic prostheses and powered exoskeletons are novel assistive robotic devices for modern medicine. Muscle activity sensing plays an important role in controlling assistive robotics devices. Most devices measure the surface electromyography (sEMG) signal for myoelectric control. However, sEMG is an integrated signal from muscle activities. It is difficult to sense muscle movements in specific small regions, particularly at different depths. Alternatively, traditional ultrasound imaging has recently been proposed to monitor muscle activity due to its ability to directly visualize superficial and at-depth muscles. Despite their advantages, traditional ultrasound probes lack wearability. In this paper, a wearable ultrasound (US) transducer, based on lead zirconate titanate (PZT) and a polyimide substrate, was developed for a muscle activity sensing demonstration. The fabricated PZT-5A elements were arranged into a 4 × 4 array and then packaged in polydimethylsiloxane (PDMS). In vitro porcine tissue experiments were carried out by generating the muscle activities artificially, and the muscle movements were detected by the proposed wearable US transducer via muscle movement imaging. Experimental results showed that all 16 elements had very similar acoustic behaviors: the averaged central frequency, −6 dB bandwidth, and electrical impedance in water were 10.59 MHz, 37.69%, and 78.41 Ω, respectively. The in vitro study successfully demonstrated the capability of monitoring local muscle activity using the prototyped wearable transducer. The findings indicate that ultrasonic sensing may be an alternative to standardize myoelectric control for assistive robotics applications. Full article
(This article belongs to the Special Issue Ultrasound Imaging and Sensing in Medicine with Innovative Transducers)
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23 pages, 2138 KiB  
Review
Microfluidic Gut-on-a-Chip: Fundamentals and Challenges
by Dimple Palanilkunnathil Thomas, Jun Zhang, Nam-Trung Nguyen and Hang Thu Ta
Biosensors 2023, 13(1), 136; https://doi.org/10.3390/bios13010136 - 13 Jan 2023
Cited by 33 | Viewed by 11389
Abstract
The human gut is responsible for food digestion and absorption. Recently, growing evidence has shown its vital role in the proper functioning of other organs. Advances in microfluidic technologies have made a significant impact on the biomedical field. Specifically, organ-on-a-chip technology (OoC), which [...] Read more.
The human gut is responsible for food digestion and absorption. Recently, growing evidence has shown its vital role in the proper functioning of other organs. Advances in microfluidic technologies have made a significant impact on the biomedical field. Specifically, organ-on-a-chip technology (OoC), which has become a popular substitute for animal models, is capable of imitating complex systems in vitro and has been used to study pathology and pharmacology. Over the past decade, reviews published focused more on the applications and prospects of gut-on-a-chip (GOC) technology, but the challenges and solutions to these limitations were often overlooked. In this review, we cover the physiology of the human gut and review the engineering approaches of GOC. Fundamentals of GOC models including materials and fabrication, cell types, stimuli and gut microbiota are thoroughly reviewed. We discuss the present GOC model applications, challenges, possible solutions and prospects for the GOC models and technology. Full article
(This article belongs to the Special Issue Microfluidics and Organ-on-a-Chip for Disease Modeling and Drug Screening)
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22 pages, 4791 KiB  
Review
Current Advances in Technologies for Single Extracellular Vesicle Analysis and Its Clinical Applications in Cancer Diagnosis
by Lei Qiu, Xingzhu Liu, Libo Zhu, Liqiang Luo, Na Sun and Renjun Pei
Biosensors 2023, 13(1), 129; https://doi.org/10.3390/bios13010129 - 12 Jan 2023
Cited by 11 | Viewed by 5203
Abstract
Extracellular vesicles (EVs) have been regarded as one of the most potential diagnostic biomarkers for different cancers, due to their unique physiological and pathological functions. However, it is still challenging to precisely analyze the contents and sources of EVs, due to their heterogeneity. [...] Read more.
Extracellular vesicles (EVs) have been regarded as one of the most potential diagnostic biomarkers for different cancers, due to their unique physiological and pathological functions. However, it is still challenging to precisely analyze the contents and sources of EVs, due to their heterogeneity. Herein, we summarize the advances in technologies for a single EV analysis, which may provide new strategies to study the heterogeneity of EVs, as well as their cargo, more specifically. Furthermore, the applications of a single EV analysis on cancer early diagnosis are also discussed. Full article
(This article belongs to the Special Issue Biosensing and Diagnosis of Cancer)
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24 pages, 4667 KiB  
Review
Recent Advances in Electrochemical Immunosensors with Nanomaterial Assistance for Signal Amplification
by Avinash V. Police Patil, Yu-Sheng Chuang, Chenzhong Li and Ching-Chou Wu
Biosensors 2023, 13(1), 125; https://doi.org/10.3390/bios13010125 - 11 Jan 2023
Cited by 49 | Viewed by 6268
Abstract
Electrochemical immunosensors have attracted immense attention due to the ease of mass electrode production and the high compatibility of the miniature electric reader, which is beneficial for developing point-of-care diagnostic devices. Electrochemical immunosensors can be divided into label-free and label-based sensing strategies equipped [...] Read more.
Electrochemical immunosensors have attracted immense attention due to the ease of mass electrode production and the high compatibility of the miniature electric reader, which is beneficial for developing point-of-care diagnostic devices. Electrochemical immunosensors can be divided into label-free and label-based sensing strategies equipped with potentiometric, amperometric, voltammetric, or impedimetric detectors. Emerging nanomaterials are frequently used on electrochemical immunosensors as a highly rough and conductive interface of the electrodes or on nanocarriers of immobilizing capture antibodies, electroactive mediators, or catalyzers. Adopting nanomaterials can increase immunosensor characteristics with lower detection limits and better sensitivity. Recent research has shown innovative immobilization procedures of nanomaterials which meet the requirements of different electrochemical immunosensors. This review discusses the past five years of advances in nanomaterials (metal nanoparticles, metal nanostructures, carbon nanotubes, and graphene) integrated into the electrochemical immunosensor. Furthermore, the new tendency and endeavors of nanomaterial-based electrochemical immunosensors are discussed. Full article
(This article belongs to the Special Issue Advanced Label-Free Electrochemical Affinity Biosensors)
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11 pages, 2273 KiB  
Article
A Label-Free, Mix-and-Detect ssDNA-Binding Assay Based on Cationic Conjugated Polymers
by Pengbo Zhang, Mohamad Zandieh, Yuzhe Ding, Lyuyuan Wu, Xiaoyu Wang, Juewen Liu and Zhengping Li
Biosensors 2023, 13(1), 122; https://doi.org/10.3390/bios13010122 - 10 Jan 2023
Cited by 8 | Viewed by 3556
Abstract
The accurate, simple, and efficient measurement of the concentration of single-stranded DNA (ssDNA) is important for many analytical applications, such as DNA adsorption, biosensor design, and disease diagnosis, but it is still a challenge. Herein, we studied a cationic conjugated polymer (CCP)-based ssDNA [...] Read more.
The accurate, simple, and efficient measurement of the concentration of single-stranded DNA (ssDNA) is important for many analytical applications, such as DNA adsorption, biosensor design, and disease diagnosis, but it is still a challenge. Herein, we studied a cationic conjugated polymer (CCP)-based ssDNA assay taking advantage of the obvious fluorescence change of CCPs upon binding ssDNA. Poly(3-(3′-N,N,N-triethylamino-1′-propyloxy)-4-methyl-2,5-thiophene hydrochloride) (PMNT) achieved an apparent dissociation constant (Kd) of 57 ± 4 nM for ssDNA, indicating a very high binding affinity between PMNT and ssDNA. This allowed us to develop a CCP-based ssDNA biosensor with a detection limit of 0.6 nM, similar to the fluorescence-dye-based method using SYBR Green I and SYBR Gold. Our CCP-based biosensor produced smaller differences among ssDNA samples with different base compositions. In addition, the existence of double-stranded DNA (dsDNA) at different concentrations did not interfere with the fluorescence of PMNT, indicating that our CCP-based biosensor was more suitable for the measurement of ssDNA. Compared with fluorescence-intensity-based quantification, our CCP system allowed ratiometric quantification, which made the calibration easier and more robust. We then applied our method to the quantification of ssDNA on AuNPs using both unmodified and thiolated ssDNA, and the accurate quantification of ssDNA was achieved without any fluorophore modification. This method provides an alternative approach for the measurement of ssDNA. Full article
(This article belongs to the Special Issue Current Trends in Polymer-Based Biosensors)
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34 pages, 6276 KiB  
Review
From Piezoelectric Nanogenerator to Non-Invasive Medical Sensor: A Review
by Qiliang Zhu, Tong Wu and Ning Wang
Biosensors 2023, 13(1), 113; https://doi.org/10.3390/bios13010113 - 9 Jan 2023
Cited by 29 | Viewed by 6293
Abstract
Piezoelectric nanogenerators (PENGs) not only are able to harvest mechanical energy from the ambient environment or body and convert mechanical signals into electricity but can also inform us about pathophysiological changes and communicate this information using electrical signals, thus acting as medical sensors [...] Read more.
Piezoelectric nanogenerators (PENGs) not only are able to harvest mechanical energy from the ambient environment or body and convert mechanical signals into electricity but can also inform us about pathophysiological changes and communicate this information using electrical signals, thus acting as medical sensors to provide personalized medical solutions to patients. In this review, we aim to present the latest advances in PENG-based non-invasive sensors for clinical diagnosis and medical treatment. While we begin with the basic principles of PENGs and their applications in energy harvesting, this review focuses on the medical sensing applications of PENGs, including detection mechanisms, material selection, and adaptive design, which are oriented toward disease diagnosis. Considering the non-invasive in vitro application scenario, discussions about the individualized designs that are intended to balance a high performance, durability, comfortability, and skin-friendliness are mainly divided into two types: mechanical sensors and biosensors, according to the key role of piezoelectric effects in disease diagnosis. The shortcomings, challenges, and possible corresponding solutions of PENG-based medical sensing devices are also highlighted, promoting the development of robust, reliable, scalable, and cost-effective medical systems that are helpful for the public. Full article
(This article belongs to the Special Issue Self-Powered Flexible Biosensors and Electronic Skin)
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11 pages, 4407 KiB  
Article
A Dual-Function Wearable Electrochemical Sensor for Uric Acid and Glucose Sensing in Sweat
by Zhanhong Li, Yuwei Wang, Zheyuan Fan, Yufan Sun, Yue Sun, Yiduo Yang, Yifan Zhang, Junjie Ma, Zifeng Wang and Zhigang Zhu
Biosensors 2023, 13(1), 105; https://doi.org/10.3390/bios13010105 - 6 Jan 2023
Cited by 49 | Viewed by 7755
Abstract
Simultaneous detection of uric acid and glucose using a non-invasive approach can be a promising strategy for related diseases, e.g., diabetes, gout, kidney disease, and cardiovascular disease. In this study, we have proposed a dual-function wearable electrochemical sensor for uric acid and glucose [...] Read more.
Simultaneous detection of uric acid and glucose using a non-invasive approach can be a promising strategy for related diseases, e.g., diabetes, gout, kidney disease, and cardiovascular disease. In this study, we have proposed a dual-function wearable electrochemical sensor for uric acid and glucose detection in sweat. The sensor with a four-electrode system was prepared by printing the ink on a common rubber glove. CV and chronoamperometry were used to characterize the prepared sensor’s electrochemical sensing performance. The sensors exhibited the linear range from 0 to 1.6 mM and 0 to 3.7 mM towards uric acid and glucose electrochemical sensing in phosphate-buffered solution, with the corresponding limit of detection of 3.58 μM and 9.10 μM obtained, respectively. Moreover, the sensors had shown their feasibility of real sample sensing in sweat. The linear detection range for uric acid (0 to 40 μM) and glucose (0 to 1.6 mM) in the sweat can well cover their concentration range in physiological conditions. The prepared dual-function wearable electrochemical sensor features easy preparation, fast detection, high sensitivity, high selectivity, and the practical application potential in uric acid and glucose sensing. Full article
(This article belongs to the Special Issue Electrochemical Biosensors for Disease Detection)
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33 pages, 11521 KiB  
Review
Recent Trends in Metal Nanoparticles Decorated 2D Materials for Electrochemical Biomarker Detection
by Aneesh Koyappayil, Ajay Kumar Yagati and Min-Ho Lee
Biosensors 2023, 13(1), 91; https://doi.org/10.3390/bios13010091 - 5 Jan 2023
Cited by 20 | Viewed by 5006
Abstract
Technological advancements in the healthcare sector have pushed for improved sensors and devices for disease diagnosis and treatment. Recently, with the discovery of numerous biomarkers for various specific physiological conditions, early disease screening has become a possibility. Biomarkers are the body’s early warning [...] Read more.
Technological advancements in the healthcare sector have pushed for improved sensors and devices for disease diagnosis and treatment. Recently, with the discovery of numerous biomarkers for various specific physiological conditions, early disease screening has become a possibility. Biomarkers are the body’s early warning systems, which are indicators of a biological state that provides a standardized and precise way of evaluating the progression of disease or infection. Owing to the extremely low concentrations of various biomarkers in bodily fluids, signal amplification strategies have become crucial for the detection of biomarkers. Metal nanoparticles are commonly applied on 2D platforms to anchor antibodies and enhance the signals for electrochemical biomarker detection. In this context, this review will discuss the recent trends and advances in metal nanoparticle decorated 2D materials for electrochemical biomarker detection. The prospects, advantages, and limitations of this strategy also will be discussed in the concluding section of this review. Full article
(This article belongs to the Special Issue Nanometre-Scale Biosensors for Applications in Medicine/Environment/Food/Biomedical Research)
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30 pages, 7931 KiB  
Review
Liquid Metal-Based Electronics for On-Skin Healthcare
by Jinwei Cao, Xin Li, Yiwei Liu, Guang Zhu and Run-Wei Li
Biosensors 2023, 13(1), 84; https://doi.org/10.3390/bios13010084 - 3 Jan 2023
Cited by 23 | Viewed by 6000
Abstract
Wearable devices are receiving growing interest in modern technologies for realizing multiple on-skin purposes, including flexible display, flexible e-textiles, and, most importantly, flexible epidermal healthcare. A ‘BEER’ requirement, i.e., biocompatibility, electrical elasticity, and robustness, is first proposed here for all the [...] Read more.
Wearable devices are receiving growing interest in modern technologies for realizing multiple on-skin purposes, including flexible display, flexible e-textiles, and, most importantly, flexible epidermal healthcare. A ‘BEER’ requirement, i.e., biocompatibility, electrical elasticity, and robustness, is first proposed here for all the on-skin healthcare electronics for epidermal applications. This requirement would guide the designing of the next-generation on-skin healthcare electronics. For conventional stretchable electronics, the rigid conductive materials, e.g., gold nanoparticles and silver nanofibers, would suffer from an easy-to-fail interface with elastic substrates due to a Young’s modulus mismatch. Liquid metal (LM) with high conductivity and stretchability has emerged as a promising solution for robust stretchable epidermal electronics. In addition, the fundamental physical, chemical, and biocompatible properties of LM are illustrated. Furthermore, the fabrication strategies of LM are outlined for pure LM, LM composites, and LM circuits based on the surface tension control. Five dominant epidermal healthcare applications of LM are illustrated, including electrodes, interconnectors, mechanical sensors, thermal management, and biomedical and sustainable applications. Finally, the key challenges and perspectives of LM are identified for the future research vision. Full article
(This article belongs to the Special Issue Liquid Metal Based Biosensors and Bioelectronic Devices)
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27 pages, 6797 KiB  
Review
Applications of Optical Fiber in Label-Free Biosensors and Bioimaging: A Review
by Baocheng Li, Ruochong Zhang, Renzhe Bi and Malini Olivo
Biosensors 2023, 13(1), 64; https://doi.org/10.3390/bios13010064 - 30 Dec 2022
Cited by 18 | Viewed by 4540
Abstract
Biosensing and bioimaging are essential in understanding biological and pathological processes in a living system, for example, in detecting and understanding certain diseases. Optical fiber has made remarkable contributions to the biosensing and bioimaging areas due to its unique advantages of compact size, [...] Read more.
Biosensing and bioimaging are essential in understanding biological and pathological processes in a living system, for example, in detecting and understanding certain diseases. Optical fiber has made remarkable contributions to the biosensing and bioimaging areas due to its unique advantages of compact size, immunity to electromagnetic interference, biocompatibility, fast response, etc. This review paper will present an overview of seven common types of optical fiber biosensors and optical fiber-based ultrasound detection in photoacoustic imaging (PAI) and the applications of these technologies in biosensing and bioimaging areas. Of course, there are many types of optical fiber biosensors. Still, this paper will review the most common ones: optical fiber grating, surface plasmon resonance, Sagnac interferometer, Mach–Zehnder interferometer, Michelson interferometer, Fabry–Perot Interferometer, lossy mode resonance, and surface-enhanced Raman scattering. Furthermore, different optical fiber techniques for detecting ultrasound in PAI are summarized. Finally, the main challenges and future development direction are briefly discussed. Full article
(This article belongs to the Special Issue Emerging Applications of Label-Free Optical Biosensors)
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27 pages, 3529 KiB  
Review
Microfluidic Strategies for Extracellular Vesicle Isolation: Towards Clinical Applications
by Alessio Meggiolaro, Valentina Moccia, Paola Brun, Matteo Pierno, Giampaolo Mistura, Valentina Zappulli and Davide Ferraro
Biosensors 2023, 13(1), 50; https://doi.org/10.3390/bios13010050 - 29 Dec 2022
Cited by 28 | Viewed by 5232
Abstract
Extracellular vesicles (EVs) are double-layered lipid membrane vesicles released by cells. Currently, EVs are attracting a lot of attention in the biological and medical fields due to their role as natural carriers of proteins, lipids, and nucleic acids. Thus, they can transport useful [...] Read more.
Extracellular vesicles (EVs) are double-layered lipid membrane vesicles released by cells. Currently, EVs are attracting a lot of attention in the biological and medical fields due to their role as natural carriers of proteins, lipids, and nucleic acids. Thus, they can transport useful genomic information from their parental cell through body fluids, promoting cell-to-cell communication even between different organs. Due to their functionality as cargo carriers and their protein expression, they can play an important role as possible diagnostic and prognostic biomarkers in various types of diseases, e.g., cancers, neurodegenerative, and autoimmune diseases. Today, given the invaluable importance of EVs, there are some pivotal challenges to overcome in terms of their isolation. Conventional methods have some limitations: they are influenced by the starting sample, might present low throughput and low purity, and sometimes a lack of reproducibility, being operator dependent. During the past few years, several microfluidic approaches have been proposed to address these issues. In this review, we summarize the most important microfluidic-based devices for EV isolation, highlighting their advantages and disadvantages compared to existing technology, as well as the current state of the art from the perspective of the use of these devices in clinical applications. Full article
(This article belongs to the Special Issue Microfluidics for Biomedical Applications)
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21 pages, 2988 KiB  
Review
Analyte Sensing with Catalytic Micromotors
by Mihail N. Popescu and Szilveszter Gáspár
Biosensors 2023, 13(1), 45; https://doi.org/10.3390/bios13010045 - 28 Dec 2022
Cited by 7 | Viewed by 2423
Abstract
Catalytic micromotors can be used to detect molecules of interest in several ways. The straightforward approach is to use such motors as sensors of their “fuel” (i.e., of the species consumed for self-propulsion). Another way is in the detection of species which are [...] Read more.
Catalytic micromotors can be used to detect molecules of interest in several ways. The straightforward approach is to use such motors as sensors of their “fuel” (i.e., of the species consumed for self-propulsion). Another way is in the detection of species which are not fuel but still modulate the catalytic processes facilitating self-propulsion. Both of these require analysis of the motion of the micromotors because the speed (or the diffusion coefficient) of the micromotors is the analytical signal. Alternatively, catalytic micromotors can be used as the means to enhance mass transport, and thus increase the probability of specific recognition events in the sample. This latter approach is based on “classic” (e.g., electrochemical) analytical signals and does not require an analysis of the motion of the micromotors. Together with a discussion of the current limitations faced by sensing concepts based on the speed (or diffusion coefficient) of catalytic micromotors, we review the findings of the studies devoted to the analytical performances of catalytic micromotor sensors. We conclude that the qualitative (rather than quantitative) analysis of small samples, in resource poor environments, is the most promising niche for the catalytic micromotors in analytical chemistry. Full article
(This article belongs to the Special Issue Feature Issue of Biosensors and Bioelectronic Devices Section)
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22 pages, 2844 KiB  
Review
Review on the Selection of Aptamers and Application in Paper-Based Sensors
by Kaifei Wang, Minglu Wang, Teng Ma, Wenyu Li and Hongyan Zhang
Biosensors 2023, 13(1), 39; https://doi.org/10.3390/bios13010039 - 27 Dec 2022
Cited by 28 | Viewed by 5676
Abstract
An aptamer is a synthetic oligonucleotide, referring to a single-stranded deoxyribonucleic acid or ribonucleic acid ligand produced by synthesis from outside the body using systematic evolution of ligands by exponential enrichment (SELEX) technology. Owing to their special screening process and adjustable tertiary structures, [...] Read more.
An aptamer is a synthetic oligonucleotide, referring to a single-stranded deoxyribonucleic acid or ribonucleic acid ligand produced by synthesis from outside the body using systematic evolution of ligands by exponential enrichment (SELEX) technology. Owing to their special screening process and adjustable tertiary structures, aptamers can bind to multiple targets (small molecules, proteins, and even whole cells) with high specificity and affinity. Moreover, due to their simple preparation and stable modification, they have been widely used to construct biosensors for target detection. The paper-based sensor is a product with a low price, short detection time, simple operation, and other superior characteristics, and is widely used as a rapid detection method. This review mainly focuses on the screening methods of aptamers, paper-based devices, and applicable sensing strategies. Furthermore, the design of the aptamer-based lateral flow assay (LFA), which underlies the most promising devices for commercialization, is emphasized. In addition, the development prospects and potential applications of paper-based biosensors using aptamers as recognition molecules are also discussed. Full article
(This article belongs to the Special Issue Paper-Based Biosensors)
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