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Biosensors, Volume 12, Issue 2 (February 2022) – 89 articles

Cover Story (view full-size image): In the era of personalized medicine, liquid biopsy represents a minimally invasive valuable tool for mutational profiling of tumors. It involves the detection of mutations in circulating tumor DNA (ctDNA) that represents a challenging analyte. In this study, a rapid, gold nanoparticle-based multiplex strip test was developed for visual detection of mutations in ctDNA. The strip-test achieved visual multiplex detection of clinically relevant KRAS mutations in blood samples of colorectal cancer patients with high specificity, repeatability, and a 15 min analysis time. This test represents a simple, rapid, cost-effective, portable, universal test with advanced multiplexing potential that shows great promise as a diagnostic tool for liquid biopsy applications. View this paper
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13 pages, 2776 KiB  
Article
Colorimetric Biosensor Based on Magnetic Enzyme and Gold Nanorods for Visual Detection of Fish Freshness
by Xia Xu, Xiaotian Wu, Shunqian Zhuang, Yucong Zhang, Yuting Ding and Xuxia Zhou
Biosensors 2022, 12(2), 135; https://doi.org/10.3390/bios12020135 - 21 Feb 2022
Cited by 8 | Viewed by 3284
Abstract
Histamine, an important safety index for aquatic products, can also be used as a freshness indicator for red-fleshed fish. In this work, magnetic graphene oxide (Fe3O4@GO, MGO) was applied to immobilize diamine oxidase (DAO) through a method of adsorption [...] Read more.
Histamine, an important safety index for aquatic products, can also be used as a freshness indicator for red-fleshed fish. In this work, magnetic graphene oxide (Fe3O4@GO, MGO) was applied to immobilize diamine oxidase (DAO) through a method of adsorption and covalent bonding. Under the optimized conditions, magnetic DAO prepared by adsorption immobilization had a higher enzyme activity than that of free enzyme, which was selected for the sensor construction. A colorimetric biosensor based on magnetic DAO induced etching of gold nanorods (AuNRs) was developed for the detection of histamine in fish. The developed biosensor showed an excellent response toward histamine with a low detection limit of 1.23 μM and had negligible interference from other diamines. With increasing the histamine concentration, the AuNRs after the reaction exhibited colors ranging from dark green to blue-green, blue, purple, red, and colorless. The etching induced multicolor change of AuNRs indicated the presence of different contents of histamine in mackerel during storage, and was consistent with the overall change in the content of the total volatile basic nitrogen (TVB-N). Thus, it was indicated that the proposed colorimetric biosensor with a naked-eye-detectable readout has a great potential to evaluate the freshness of red-fleshed fish high in histamine. Full article
(This article belongs to the Section Biosensor and Bioelectronic Devices)
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17 pages, 3395 KiB  
Article
Radiometal-Based PET/MRI Contrast Agents for Sensing Tumor Extracellular pH
by Alyssa C. Pollard, Jorge de la Cerda, F. William Schuler, Tyler R. Pollard, Aikaterini Kotrotsou, Federica Pisaneschi and Mark D. Pagel
Biosensors 2022, 12(2), 134; https://doi.org/10.3390/bios12020134 - 20 Feb 2022
Cited by 5 | Viewed by 2918
Abstract
Acidosis is a useful biomarker for tumor diagnoses and for evaluating early response to anti-cancer treatments. Despite these useful applications, there are few methods for non-invasively measuring tumor extracellular pH, and none are routinely used in clinics. Responsive MRI contrast agents have been [...] Read more.
Acidosis is a useful biomarker for tumor diagnoses and for evaluating early response to anti-cancer treatments. Despite these useful applications, there are few methods for non-invasively measuring tumor extracellular pH, and none are routinely used in clinics. Responsive MRI contrast agents have been developed, and they undergo a change in MRI signal with pH. However, these signal changes are concentration-dependent, and it is difficult to accurately measure the concentration of an MRI contrast agent in vivo. PET/MRI provides a unique opportunity to overcome this concentration dependence issue by using the PET component to report on the concentration of the pH-responsive MRI agent. Herein, we synthesized PET/MRI co-agents based on the design of a pH-dependent MRI agent, and we have correlated pH with the r1 relaxivity of the MRI co-agent. We have also developed a procedure that uses PET radioactivity measurements and MRI R1 relaxation rate measurements to determine the r1 relaxivity of the MRI co-agent, which can then be used to estimate pH. This simultaneous PET/MRI procedure accurately measured pH in solution, with a precision that depended on the concentration of the MRI co-agent. We used our procedure to measure extracellular pH in a subcutaneous flank model of MIA PaCa-2 pancreatic cancer. Although the PET co-agents were stable in serum, post-imaging studies showed evidence that the PET co-agents were degraded in vivo. These results showed that tumor acidosis can be evaluated with simultaneous PET/MRI, although improvements are needed to more precisely measure MRI R1 relaxation rates, and ensure the in vivo stability of the agents. Full article
(This article belongs to the Special Issue In Vivo Imaging and Sensing of Biomarkers)
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18 pages, 4355 KiB  
Article
A Wearable and Real-Time Pulse Wave Monitoring System Based on a Flexible Compound Sensor
by Xiaoxiao Kang, Jun Zhang, Zheming Shao, Guotai Wang, Xingguang Geng, Yitao Zhang and Haiying Zhang
Biosensors 2022, 12(2), 133; https://doi.org/10.3390/bios12020133 - 20 Feb 2022
Cited by 16 | Viewed by 3817
Abstract
Continuous monitoring of pulse waves plays a significant role in reflecting physical conditions and disease diagnosis. However, the current collection equipment cannot simultaneously achieve wearable and continuous monitoring under varying pressure and provide personalized pulse wave monitoring targeted different human bodies. To solve [...] Read more.
Continuous monitoring of pulse waves plays a significant role in reflecting physical conditions and disease diagnosis. However, the current collection equipment cannot simultaneously achieve wearable and continuous monitoring under varying pressure and provide personalized pulse wave monitoring targeted different human bodies. To solve the above problems, this paper proposed a novel wearable and real-time pulse wave monitoring system based on a novel flexible compound sensor. Firstly, a custom-packaged pressure sensor, a signal stabilization structure, and a micro pressurization system make up the flexible compound sensor to complete the stable acquisition of pulse wave signals under continuously varying pressure. Secondly, a real-time algorithm completes the analysis of the trend of the pulse wave peak, which can quickly and accurately locate the best pulse wave for different individuals. Finally, the experimental results show that the wearable system can both realize continuous monitoring and reflecting trend differences and quickly locate the best pulse wave for different individuals with the 95% accuracy. The weight of the whole system is only 52.775 g, the working current is 46 mA, and the power consumption is 160 mW. Its small size and low power consumption meet wearable and portable scenarios, which has significant research value and commercialization prospects. Full article
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11 pages, 12983 KiB  
Communication
The Introduction of a New Diagnostic Tool in Forensic Pathology: LiDAR Sensor for 3D Autopsy Documentation
by Aniello Maiese, Alice Chiara Manetti, Costantino Ciallella and Vittorio Fineschi
Biosensors 2022, 12(2), 132; https://doi.org/10.3390/bios12020132 - 19 Feb 2022
Cited by 10 | Viewed by 5098
Abstract
Autopsy is a complex and unrepeatable procedure. It is essential to have the possibility of reviewing the autoptic findings, especially when it is done for medico-legal purposes. Traditional photography is not always adequate to record forensic practice since two-dimensional images could lead to [...] Read more.
Autopsy is a complex and unrepeatable procedure. It is essential to have the possibility of reviewing the autoptic findings, especially when it is done for medico-legal purposes. Traditional photography is not always adequate to record forensic practice since two-dimensional images could lead to distortion and misinterpretation. Three-dimensional (3D) reconstructions of autoptic findings could be a new way to document the autopsy. Besides, nowadays, smartphones and tablets equipped with a LiDAR sensor make it extremely easy to elaborate a 3D model directly in the autopsy room. Herein, a quality and trustworthiness evaluation of 3D models obtained during ten autopsies is made comparing 3D models and conventional autopsy photographic records. Three-dimensional models were realistic and accurate and allowed precise measurements. The review of the autoptic report was facilitated by the 3D model. Conclusions: The LiDAR sensor and 3D models have been demonstrated to be a valid tool to introduce some kind of reproducibility into the autoptic practice. Full article
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25 pages, 10272 KiB  
Review
Luminescent Lifetime Regulation of Lanthanide-Doped Nanoparticles for Biosensing
by Mingkai Wang, Chuanyu Hu and Qianqian Su
Biosensors 2022, 12(2), 131; https://doi.org/10.3390/bios12020131 - 19 Feb 2022
Cited by 17 | Viewed by 3578
Abstract
Lanthanide-doped nanoparticles possess numerous advantages including tunable luminescence emission, narrow peak width and excellent optical and thermal stability, especially concerning the long lifetime from microseconds to milliseconds. Differing from other shorter-lifetime fluorescent nanomaterials, the long lifetime of lanthanide-doped nanomaterials is independent with background [...] Read more.
Lanthanide-doped nanoparticles possess numerous advantages including tunable luminescence emission, narrow peak width and excellent optical and thermal stability, especially concerning the long lifetime from microseconds to milliseconds. Differing from other shorter-lifetime fluorescent nanomaterials, the long lifetime of lanthanide-doped nanomaterials is independent with background fluorescence interference and biological tissue depth. This review presents the recent advances in approaches to regulating the lifetime and applications of bioimaging and biodetection. We begin with the introduction of the strategies for regulating the lifetime by modulating the core–shell structure, adjusting the concentration of sensitizer and emitter, changing energy transfer channel, establishing a fluorescence resonance energy transfer pathway and changing temperature. We then summarize the applications of these nanoparticles in biosensing, including ion and molecule detecting, DNA and protease detection, cell labeling, organ imaging and thermal and pH sensing. Finally, the prospects and challenges of the lanthanide lifetime regulation for fundamental research and practical applications are also discussed. Full article
(This article belongs to the Special Issue Nanobiosensors Based on Energy Transfer)
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10 pages, 2405 KiB  
Communication
Carnation-like Morphology of BiVO4-7 Enables Sensitive Photoelectrochemical Determination of Cr(VI) in the Food and Environment
by Wenqin Wu, Zhao Tan, Xiao Chen, Xiaomei Chen, Ling Cheng, Huimin Wu, Peiwu Li and Zhaowei Zhang
Biosensors 2022, 12(2), 130; https://doi.org/10.3390/bios12020130 - 19 Feb 2022
Cited by 10 | Viewed by 2287
Abstract
Hexavalent chromium, namely, Cr(VI), is a significant threat to ecological and food safety. Current detection methods are not sensitive to Cr(VI). A photoelectrochemical (PEC) sensor based on bismuth vanadate (BiVO4) was developed for sensitive detection of Cr(VI). First, BiVO4-X [...] Read more.
Hexavalent chromium, namely, Cr(VI), is a significant threat to ecological and food safety. Current detection methods are not sensitive to Cr(VI). A photoelectrochemical (PEC) sensor based on bismuth vanadate (BiVO4) was developed for sensitive detection of Cr(VI). First, BiVO4-X (X: the pH of the reaction precursor solution) was synthesized using a facile surfactant-free hydrothermal method. The BiVO4-X morphology was well controlled according to pH values, showing rock-like (X = 1), wrinkled bark-like (X = 4), carnation-like (X = 7), and the collapsed sheet-like morphologies (X = 9, 12). BiVO4-7 exhibited excellent photoelectric performance due to a proper band structure under visible light and a large specific surface area. Then, BiVO4-7 was used to construct a PEC sensor to detect Cr(VI), which was demonstrated to have a low detection limit (10 nM) and wide detection range (2–210 μM). The BiVO4-7 PEC sensor had a stable output signal, as well as excellent reproducibility, repeatability, and selectivity. We used the BiVO4-7 PEC sensor to detect Cr(VI) in real environmental and food samples, resulting in a satisfactory recovery of 90.3–103.0%, as determined by comparison with results obtained using a spectrophotometric method. The BiVO4-7 PEC sensor is promising for practical application to heavy metal detection in the food and environment. Full article
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20 pages, 3652 KiB  
Article
A Hybrid Titanium-Softmaterial, High-Strength, Transparent Cranial Window for Transcranial Injection and Neuroimaging
by Nana Yang, Fengyu Liu, Xinyue Zhang, Chenni Chen, Zhiyuan Xia, Su Fu, Jiaxin Wang, Jingjing Xu, Shuang Cui, Yong Zhang, Ming Yi, You Wan, Qing Li and Shengyong Xu
Biosensors 2022, 12(2), 129; https://doi.org/10.3390/bios12020129 - 18 Feb 2022
Cited by 5 | Viewed by 3082
Abstract
A transparent and penetrable cranial window is essential for neuroimaging, transcranial injection and comprehensive understanding of cortical functions. For these applications, cranial windows made from glass coverslip, polydimethylsiloxane (PDMS), polymethylmethacrylate, crystal and silicone hydrogel have offered remarkable convenience. However, there is a lack [...] Read more.
A transparent and penetrable cranial window is essential for neuroimaging, transcranial injection and comprehensive understanding of cortical functions. For these applications, cranial windows made from glass coverslip, polydimethylsiloxane (PDMS), polymethylmethacrylate, crystal and silicone hydrogel have offered remarkable convenience. However, there is a lack of high-strength, high-transparency, penetrable cranial window with clinical application potential. We engineer high-strength hybrid Titanium-PDMS (Ti-PDMS) cranial windows, which allow large transparent area for in vivo two-photon imaging, and provide a soft window for transcranial injection. Laser scanning and 3D printing techniques are used to match the hybrid cranial window to different skull morphology. A multi-cycle degassing pouring process ensures a good combination of PDMS and Ti frame. Ti-PDMS cranial windows have a high fracture strength matching human skull bone, excellent light transmittance up to 94.4%, and refractive index close to biological tissue. Ti-PDMS cranial windows show excellent bio-compatibility during 21-week implantation in mice. Dye injection shows that the PDMS window has a “self-sealing” to keep liquid from leaking out. Two-photon imaging for brain tissues could be achieved up to 450 µm in z-depth. As a novel brain-computer-interface, this Ti-PDMS device offers an alternative choice for in vivo drug delivery, optical experiments, ultrasonic treatment and electrophysiology recording. Full article
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14 pages, 3575 KiB  
Article
FDTD Analysis of Hotspot-Enabling Hybrid Nanohole-Nanoparticle Structures for SERS Detection
by Juan Gomez-Cruz, Yazan Bdour, Kevin Stamplecoskie and Carlos Escobedo
Biosensors 2022, 12(2), 128; https://doi.org/10.3390/bios12020128 - 17 Feb 2022
Cited by 14 | Viewed by 3527
Abstract
Metallic nanoparticles (MNPs) and metallic nanostructures are both commonly used, independently, as SERS substrates due to their enhanced plasmonic activity. In this work, we introduce and investigate a hybrid nanostructure with strong SERS activity that benefits from the collective plasmonic response of the [...] Read more.
Metallic nanoparticles (MNPs) and metallic nanostructures are both commonly used, independently, as SERS substrates due to their enhanced plasmonic activity. In this work, we introduce and investigate a hybrid nanostructure with strong SERS activity that benefits from the collective plasmonic response of the combination of MNPs and flow-through nanohole arrays (NHAs). The electric field distribution and electromagnetic enhancement factor of hybrid structures composed of silver NPs on both silver and gold NHAs are investigated via finite-difference time-domain (FDTD) analyses. This computational approach is used to find optimal spatial configurations of the nanoparticle positions relative to the nanoapertures and investigate the difference between Ag-NP-on-Ag-NHAs and Ag-NP-on-Au-NHAs hybrid structures. A maximum GSERS value of 6.8 × 109 is achieved with the all-silver structure when the NP is located 0.5 nm away from the rim of the NHA, while the maximum of 4.7 × 1010 is obtained when the nanoparticle is in full contact with the NHA for the gold-silver hybrid structure. These results demonstrate that the hybrid nanostructures enable hotspot formation with strong SERS activity and plasmonic enhancement compatible with SERS-based sensing applications. Full article
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15 pages, 11811 KiB  
Article
Detection and Quantification of Tp53 and p53-Anti-p53 Autoantibody Immune Complex: Promising Biomarkers in Early Stage Lung Cancer Diagnosis
by Keum-Soo Song, Satish Balasaheb Nimse, Shrikant Dashrath Warkad, Jung-Hoon Kim, Hey-Jin Kim and Taisun Kim
Biosensors 2022, 12(2), 127; https://doi.org/10.3390/bios12020127 - 16 Feb 2022
Cited by 2 | Viewed by 3171
Abstract
Lung cancer is a leading cause of death worldwide, claiming nearly 1.80 million lives in 2020. Screening with low-dose computed tomography (LDCT) reduces lung cancer mortality by about 20% compared to standard chest X-rays among current or heavy smokers. However, several reports indicate [...] Read more.
Lung cancer is a leading cause of death worldwide, claiming nearly 1.80 million lives in 2020. Screening with low-dose computed tomography (LDCT) reduces lung cancer mortality by about 20% compared to standard chest X-rays among current or heavy smokers. However, several reports indicate that LDCT has a high false-positive rate. In this regard, methods based on biomarker detection offer excellent potential for developing noninvasive cancer diagnostic tests to complement LDCT for detecting stage 0∼IV lung cancers. Herein, we have developed a method for detecting and quantifying a p53-anti-p53 autoantibody complex and the total p53 antigen (wild and mutant). The LOD for detecting Tp53 and PIC were 7.41 pg/mL and 5.74 pg/mL, respectively. The detection ranges for both biomarkers were 0–7500 pg/mL. The known interfering agents in immunoassays such as biotin, bilirubin, intra-lipid, and hemoglobin did not detect Tp53 and PIC, even at levels that were several folds higher levels than their normal levels. Furthermore, the present study provides a unique report on this preliminary investigation using the PIC/Tp53 ratio to detect stage I–IV lung cancers. The presented method detects lung cancers with 81.6% sensitivity and 93.3% specificity. These results indicate that the presented method has high applicability for the identification of lung cancer patients from the healthy population. Full article
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10 pages, 1013 KiB  
Perspective
Academic User View: Organ-on-a-Chip Technology
by Mathias Busek, Aleksandra Aizenshtadt, Mikel Amirola-Martinez, Ludivine Delon and Stefan Krauss
Biosensors 2022, 12(2), 126; https://doi.org/10.3390/bios12020126 - 16 Feb 2022
Cited by 16 | Viewed by 4938
Abstract
Organ-on-a-Chip (OoC) systems bring together cell biology, engineering, and material science for creating systems that recapitulate the in vivo microenvironment of tissues and organs. The versatility of OoC systems enables in vitro models for studying physiological processes, drug development, and testing in both [...] Read more.
Organ-on-a-Chip (OoC) systems bring together cell biology, engineering, and material science for creating systems that recapitulate the in vivo microenvironment of tissues and organs. The versatility of OoC systems enables in vitro models for studying physiological processes, drug development, and testing in both academia and industry. This paper evaluates current platforms from the academic end-user perspective, elaborating on usability, complexity, and robustness. We surveyed 187 peers in 35 countries and grouped the responses according to preliminary knowledge and the source of the OoC systems that are used. The survey clearly shows that current commercial OoC platforms provide a substantial level of robustness and usability—which is also indicated by an increasing adaptation of the pharmaceutical industry—but a lack of complexity can challenge their use as a predictive platform. Self-made systems, on the other hand, are less robust and standardized but provide the opportunity to develop customized and more complex models, which are often needed for human disease modeling. This perspective serves as a guide for researchers in the OoC field and encourages the development of next-generation OoCs. Full article
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9 pages, 2245 KiB  
Communication
A Novel Enzyme-Free Ratiometric Fluorescence Immunoassay Based on Silver Nanoparticles for the Detection of Dibutyl Phthalate from Environmental Waters
by Hui Meng, Nannan Yao, Kun Zeng, Nuanfei Zhu, Yue Wang, Biying Zhao and Zhen Zhang
Biosensors 2022, 12(2), 125; https://doi.org/10.3390/bios12020125 - 16 Feb 2022
Cited by 8 | Viewed by 2649
Abstract
A novel ratiometric fluorescent immunoassay was developed based on silver nanoparticles (AgNPs) for the sensitive determination of dibutyl phthalate (DBP). In the detection system, AgNPs were labeled on the secondary antibody (AgNPs@Ab2) for signal amplification, which aimed to regulate the H [...] Read more.
A novel ratiometric fluorescent immunoassay was developed based on silver nanoparticles (AgNPs) for the sensitive determination of dibutyl phthalate (DBP). In the detection system, AgNPs were labeled on the secondary antibody (AgNPs@Ab2) for signal amplification, which aimed to regulate the H2O2 concentrations. When AgNPs-Ab2 and antigen–primary antibody (Ab1) were linked by specific recognition, the blue fluorescence of Scopoletin (SC) could be effectively quenched by the H2O2 added while the red fluorescence of Amplex Red (AR) was generated. Under the optimized conditions, the calculated detection of limit (LOD, 90% inhibition) reached 0.86 ng/mL with a wide linear range of 2.31–66.84 ng/mL, which was approximately eleven times lower than that by HRP-based traditional ELISA with the same antibody. Meanwhile, it could improve the inherent built-in rectification to the environment by the combination of the dual-output ratiometric fluorescence assays with ELISA, which also enhanced the accuracy and precision (recoveries, 87.20–106.62%; CV, 2.57–6.54%), indicating it can be applied to investigate the concentration of DBP in water samples. Full article
(This article belongs to the Special Issue Bioassays and Biosensors for Rapid Detection and Analysis)
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16 pages, 1784 KiB  
Review
REASSURED Multiplex Diagnostics: A Critical Review and Forecast
by Jonas A. Otoo and Travis S. Schlappi
Biosensors 2022, 12(2), 124; https://doi.org/10.3390/bios12020124 - 16 Feb 2022
Cited by 43 | Viewed by 5814
Abstract
The diagnosis of infectious diseases is ineffective when the diagnostic test does not meet one or more of the necessary standards of affordability, accessibility, and accuracy. The World Health Organization further clarifies these standards with a set of criteria that has the acronym [...] Read more.
The diagnosis of infectious diseases is ineffective when the diagnostic test does not meet one or more of the necessary standards of affordability, accessibility, and accuracy. The World Health Organization further clarifies these standards with a set of criteria that has the acronym ASSURED (Affordable, Sensitive, Specific, User-friendly, Rapid and robust, Equipment-free and Deliverable to end-users). The advancement of the digital age has led to a revision of the ASSURED criteria to REASSURED: Real-time connectivity, Ease of specimen collection, Affordable, Sensitive, Specific, User-friendly, Rapid and robust, Equipment-free or simple, and Deliverable to end-users. Many diagnostic tests have been developed that aim to satisfy the REASSURED criteria; however, most of them only detect a single target. With the progression of syndromic infections, coinfections and the current antimicrobial resistance challenges, the need for multiplexed diagnostics is now more important than ever. This review summarizes current diagnostic technologies for multiplexed detection and forecasts which methods have promise for detecting multiple targets and meeting all REASSURED criteria. Full article
(This article belongs to the Special Issue Biosensors for Diagnosis and Monitoring)
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25 pages, 2472 KiB  
Article
PEGylation of Metal Oxide Nanoparticles Modulates Neutrophil Extracellular Trap Formation
by Hunter T. Snoderly, Kasey A. Freshwater, Celia Martinez de la Torre, Dhruvi M. Panchal, Jenna N. Vito and Margaret F. Bennewitz
Biosensors 2022, 12(2), 123; https://doi.org/10.3390/bios12020123 - 16 Feb 2022
Cited by 10 | Viewed by 3467
Abstract
Novel metal oxide nanoparticle (NP) contrast agents may offer safety and functionality advantages over conventional gadolinium-based contrast agents (GBCAs) for cancer diagnosis by magnetic resonance imaging. However, little is known about the behavior of metal oxide NPs, or of their effect, upon coming [...] Read more.
Novel metal oxide nanoparticle (NP) contrast agents may offer safety and functionality advantages over conventional gadolinium-based contrast agents (GBCAs) for cancer diagnosis by magnetic resonance imaging. However, little is known about the behavior of metal oxide NPs, or of their effect, upon coming into contact with the innate immune system. As neutrophils are the body’s first line of defense, we sought to understand how manganese oxide and iron oxide NPs impact leukocyte functionality. Specifically, we evaluated whether contrast agents caused neutrophils to release web-like fibers of DNA known as neutrophil extracellular traps (NETs), which are known to enhance metastasis and thrombosis in cancer patients. Murine neutrophils were treated with GBCA, bare manganese oxide or iron oxide NPs, or poly(lactic-co-glycolic acid) (PLGA)-coated metal oxide NPs with different incorporated levels of poly(ethylene glycol) (PEG). Manganese oxide NPs elicited the highest NETosis rates and had enhanced neutrophil uptake properties compared to iron oxide NPs. Interestingly, NPs with low levels of PEGylation produced more NETs than those with higher PEGylation. Despite generating a low rate of NETosis, GBCA altered neutrophil cytokine expression more than NP treatments. This study is the first to investigate whether manganese oxide NPs and GBCAs modulate NETosis and reveals that contrast agents may have unintended off-target effects which warrant further investigation. Full article
(This article belongs to the Special Issue Bio–Nano-Interfaces for Engineering and Biomedical Applications)
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10 pages, 1707 KiB  
Article
A Recombinase-Based Genetic Circuit for Heavy Metal Monitoring
by Doğuş Akboğa, Behide Saltepe, Eray Ulaş Bozkurt and Urartu Özgür Şafak Şeker
Biosensors 2022, 12(2), 122; https://doi.org/10.3390/bios12020122 - 16 Feb 2022
Cited by 11 | Viewed by 3403
Abstract
Rapid progress in the genetic circuit design enabled whole-cell biosensors (WCBs) to become prominent in detecting an extensive range of analytes with promise in many fields, from medical diagnostics to environmental toxicity assessment. However, several drawbacks, such as high background signal or low [...] Read more.
Rapid progress in the genetic circuit design enabled whole-cell biosensors (WCBs) to become prominent in detecting an extensive range of analytes with promise in many fields, from medical diagnostics to environmental toxicity assessment. However, several drawbacks, such as high background signal or low precision, limit WCBs to transfer from proof-of-concept studies to real-world applications, particularly for heavy metal toxicity monitoring. For an alternative WCB module design, we utilized Bxb1 recombinase that provides tight control as a switch to increase dose-response behavior concerning leakiness. The modularity of Bxb1 recombinase recognition elements allowed us to combine an engineered semi-specific heat shock response (HSR) promoter, sensitive to stress conditions including toxic ions such as cadmium, with cadmium resistance regulatory elements; a cadmium-responsive transcription factor and its cognitive promoter. We optimized the conditions for the recombinase-based cadmium biosensor to obtain increased fold change and shorter response time. This system can be expanded for various heavy metals to make an all-in-one type of WCB, even using semi-specific parts of a sensing system. Full article
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13 pages, 2784 KiB  
Article
Exploring Sensitive Label-Free Multiplex Analysis with Raman-Coded Microbeads and SERS-Coded Reporters
by Umar Azhar, Qazi Ahmed, Saira Ishaq, Zeyad T. Alwahabi and Sheng Dai
Biosensors 2022, 12(2), 121; https://doi.org/10.3390/bios12020121 - 16 Feb 2022
Cited by 5 | Viewed by 2697
Abstract
Suspension microsphere immunoassays are rapidly gaining attention in multiplex bioassays. Accurate detection of multiple analytes from a single measurement is critical in modern bioanalysis, which always requires complex encoding systems. In this study, a novel bioassay with Raman-coded antibody supports (polymer microbeads with [...] Read more.
Suspension microsphere immunoassays are rapidly gaining attention in multiplex bioassays. Accurate detection of multiple analytes from a single measurement is critical in modern bioanalysis, which always requires complex encoding systems. In this study, a novel bioassay with Raman-coded antibody supports (polymer microbeads with different Raman signatures) and surface-enhanced Raman scattering (SERS)-coded nanotags (organic thiols on a gold nanoparticle surface with different SERS signatures) was developed as a model fluorescent, label-free, bead-based multiplex immunoassay system. The developed homogeneous immunoassays included two surface-functionalized monodisperse Raman-coded microbeads of polystyrene and poly(4-tert-butylstyrene) as the immune solid supports, and two epitope modified nanotags (self-assembled 4-mercaptobenzoic acid or 3-mercaptopropionic acid on gold nanoparticles) as the SERS-coded reporters. Such multiplex Raman/SERS-based microsphere immunoassays could selectively identify specific paratope–epitope interactions from one mixture sample solution under a single laser illumination, and thus hold great promise in future suspension multiplex analysis for diverse biomedical applications. Full article
(This article belongs to the Special Issue Nanoprobes for Tumor Theranostics)
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12 pages, 2787 KiB  
Article
Enhanced Blood Plasma Extraction Utilising Viscoelastic Effects in a Serpentine Microchannel
by Yuchen Dai, Haotian Cha, Michael J. Simmonds, Hedieh Fallahi, Hongjie An, Hang T. Ta, Nam-Trung Nguyen, Jun Zhang and Antony P. McNamee
Biosensors 2022, 12(2), 120; https://doi.org/10.3390/bios12020120 - 14 Feb 2022
Cited by 4 | Viewed by 2874
Abstract
Plasma extraction from blood is essential for diagnosis of many diseases. The critical process of plasma extraction requires removal of blood cells from whole blood. Fluid viscoelasticity promotes cell migration towards the central axis of flow due to differences in normal stress and [...] Read more.
Plasma extraction from blood is essential for diagnosis of many diseases. The critical process of plasma extraction requires removal of blood cells from whole blood. Fluid viscoelasticity promotes cell migration towards the central axis of flow due to differences in normal stress and physical properties of cells. We investigated the effects of altering fluid viscoelasticity on blood plasma extraction in a serpentine microchannel. Poly (ethylene oxide) (PEO) was dissolved into blood to increase its viscoelasticity. The influences of PEO concentration, blood dilution, and flow rate on the performance of cell focusing were examined. We found that focusing performance can be significantly enhanced by adding PEO into blood. The optimal PEO concentration ranged from 100 to 200 ppm with respect to effective blood cell focusing. An optimal flow rate from 1 to 15 µL/min was determined, at least for our experimental setup. Given less than 1% haemolysis was detected at the outlets in all experimental combinations, the proposed microfluidic methodology appears suitable for applications sensitive to haemocompatibility. Full article
(This article belongs to the Special Issue Microfluidics for Biomedical Applications)
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18 pages, 10135 KiB  
Article
Haemoprocessor: A Portable Platform Using Rapid Acoustically Driven Plasma Separation Validated by Infrared Spectroscopy for Point-of-Care Diagnostics
by Kamal Prakash Prasanna Ravindran Nair, Thulya Chakkumpulakkal Puthan Veettil, Bayden R. Wood, Debjani Paul and Tuncay Alan
Biosensors 2022, 12(2), 119; https://doi.org/10.3390/bios12020119 - 14 Feb 2022
Cited by 6 | Viewed by 3356
Abstract
The identification of biomarkers from blood plasma is at the heart of many diagnostic tests. These tests often need to be conducted frequently and quickly, but the logistics of sample collection and processing not only delays the test result, but also puts a [...] Read more.
The identification of biomarkers from blood plasma is at the heart of many diagnostic tests. These tests often need to be conducted frequently and quickly, but the logistics of sample collection and processing not only delays the test result, but also puts a strain on the healthcare system due to the sheer volume of tests that need to be performed. The advent of microfluidics has made the processing of samples quick and reliable, with little or no skill required on the user’s part. However, while several microfluidic devices have been demonstrated for plasma separation, none of them have validated the chemical integrity of the sample post-process. Here, we present Haemoprocessor: a portable, robust, open-fluidic system that utilizes Travelling Surface Acoustic Waves (TSAW) with the expression of overtones to separate plasma from 20× diluted human blood within a span of 2 min to achieve 98% RBC removal. The plasma and red blood cell separation quality/integrity was validated through Attenuated Total Reflection Fourier Transform Infrared (ATR-FTIR) spectroscopy and multivariate analyses to ascertain device performance and reproducibility when compared to centrifugation (the prevailing gold-standard for plasma separation). Principal Component Analysis (PCA) showed a remarkable separation of 92.21% between RBCs and plasma components obtained through both centrifugation and Haemoprocessor methods. Moreover, a close association between plasma isolates acquired by both approaches in PCA validated the potential of the proposed system as an eminent cell enrichment and plasma separation platform. Thus, compared to contemporary acoustic devices, this system combines the ease of operation, low sample requirement of an open system, the versatility of a SAW device using harmonics, and portability. Full article
(This article belongs to the Section Nano- and Micro-Technologies in Biosensors)
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10 pages, 2577 KiB  
Article
High-Aspect-Ratio Microfluidic Channel with Parallelogram Cross-Section for Monodisperse Droplet Generation
by Hyeonyeong Ji, Jaehun Lee, Jaewon Park, Jungwoo Kim, Hyun Soo Kim and Younghak Cho
Biosensors 2022, 12(2), 118; https://doi.org/10.3390/bios12020118 - 14 Feb 2022
Cited by 6 | Viewed by 3171
Abstract
Droplet-based microfluidics has been widely used as a potent high-throughput platform due to various advantages, such as a small volume of reagent consumption, massive production of droplets, fast reaction time, and independent control of each droplet. Therefore, droplet microfluidic systems demand the reliable [...] Read more.
Droplet-based microfluidics has been widely used as a potent high-throughput platform due to various advantages, such as a small volume of reagent consumption, massive production of droplets, fast reaction time, and independent control of each droplet. Therefore, droplet microfluidic systems demand the reliable generation of droplets with precise and effective control over their size and distribution, which is critically important for various applications in the fields of chemical analysis, material synthesis, lab-on-a-chip, cell research, diagnostic test, and so on. In this study, we propose a microfluidic device with a high-aspect-ratio (HAR) channel, which has a parallelogram cross-section, for generating monodisperse droplets. The HAR channel was fabricated using simple and cheap MEMS processes, such as photolithography, anisotropic wet etching, and PDMS molding, without expensive equipment. In addition, the parallelogram cross-section channel structure, regarded as a difficult shape to implement in previous fabrication methods, was easily formed by the self-alignment between the silicon channel and the PDMS mold, both of which were created from a single crystal silicon through an anisotropic etching process. We investigated the effects of the cross-sectional shape (parallelogram vs. rectangle) and height-to-width ratio of microfluidic channels on the size and uniformity of generated droplets. Using the developed HAR channel with the parallelogram cross-section, we successfully obtained smaller monodisperse droplets for a wider range of flow rates, compared with a previously reported HAR channel with a rectangular cross-section. Full article
(This article belongs to the Special Issue Biomarkers Used for the Diagnosis of Diseases)
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15 pages, 2505 KiB  
Article
Hammerstein–Wiener Multimodel Approach for Fast and Efficient Muscle Force Estimation from EMG Signals
by Ines Chihi, Lilia Sidhom and Ernest Nlandu Kamavuako
Biosensors 2022, 12(2), 117; https://doi.org/10.3390/bios12020117 - 13 Feb 2022
Cited by 8 | Viewed by 2615
Abstract
This paper develops a novel approach to characterise muscle force from electromyography (EMG) signals, which are the electric activities generated by muscles. Based on the nonlinear Hammerstein–Wiener model, the first part of this study outlines the estimation of different sub-models to mimic diverse [...] Read more.
This paper develops a novel approach to characterise muscle force from electromyography (EMG) signals, which are the electric activities generated by muscles. Based on the nonlinear Hammerstein–Wiener model, the first part of this study outlines the estimation of different sub-models to mimic diverse force profiles. The second part fixes the appropriate sub-models of a multimodel library and computes the contribution of sub-models to estimate the desired force. Based on a pre-existing dataset, the obtained results show the effectiveness of the proposed approach to estimate muscle force from EMG signals with reasonable accuracy. The coefficient of determination ranges from 0.6568 to 0.9754 using the proposed method compared with a range of 0.5060 to 0.9329 using an artificial neural network (ANN), generating significantly different accuracy (p < 0.03). Results imply that the use of multimodel approach can improve the accuracy in proportional control of prostheses. Full article
(This article belongs to the Section Intelligent Biosensors and Bio-Signal Processing)
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12 pages, 2037 KiB  
Article
Electrical Impedance-Based Characterization of Hepatic Tissue with Early-Stage Fibrosis
by Susana Fuentes-Vélez, Sharmila Fagoonee, Alessandro Sanginario, Marco Pizzi, Fiorella Altruda and Danilo Demarchi
Biosensors 2022, 12(2), 116; https://doi.org/10.3390/bios12020116 - 13 Feb 2022
Cited by 4 | Viewed by 2555
Abstract
Liver fibrosis is a key pathological precondition for hepatocellular carcinoma in which the severity is confidently correlated with liver cancer. Liver fibrosis, characterized by gradual cell loss and excessive extracellular matrix deposition, can be reverted if detected at the early stage. The gold [...] Read more.
Liver fibrosis is a key pathological precondition for hepatocellular carcinoma in which the severity is confidently correlated with liver cancer. Liver fibrosis, characterized by gradual cell loss and excessive extracellular matrix deposition, can be reverted if detected at the early stage. The gold standard for staging and diagnosis of liver fibrosis is undoubtedly biopsy. However, this technique needs careful sample preparation and expert analysis. In the present work, an ex vivo, minimally destructive, label-free characterization of liver biopsies is presented. Through a custom-made experimental setup, liver biopsies of bile-duct-ligated and sham-operated mice were measured at 8, 15, and 21 days after the procedure. Changes in impedance were observed with the progression of fibrosis, and through data fitting, tissue biopsies were approximated to an equivalent RC circuit model. The model was validated by means of 3D hepatic cell culture measurement, in which the capacitive part of impedance was proportionally associated with cell number and the resistive one was proportionally associated with the extracellular matrix. While the sham-operated samples presented a decrease in resistance with time, the bile-duct-ligated ones exhibited an increase in this parameter with the evolution of fibrosis. Moreover, since the largest difference in resistance between healthy and fibrotic tissue, of around 2 kΩ, was found at 8 days, this method presents great potential for the study of fibrotic tissue at early stages. Our data point out the great potential of exploiting the proposed needle setup in clinical applications. Full article
(This article belongs to the Section Biosensors and Healthcare)
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12 pages, 7565 KiB  
Article
Silicon Nanowires Length and Numbers Dependence on Sensitivity of the Field-Effect Transistor Sensor for Hepatitis B Virus Surface Antigen Detection
by Chi-Chang Wu
Biosensors 2022, 12(2), 115; https://doi.org/10.3390/bios12020115 - 12 Feb 2022
Cited by 9 | Viewed by 3530
Abstract
Silicon nanowire field effect transistor (NWFET) sensors have been demonstrated to have high sensitivity, are label free, and offer specific detection. This study explored the effect of nanowire dimensions on sensors’ sensitivity. We used sidewall spacer etching to fabricate polycrystalline silicon NWFET sensors. [...] Read more.
Silicon nanowire field effect transistor (NWFET) sensors have been demonstrated to have high sensitivity, are label free, and offer specific detection. This study explored the effect of nanowire dimensions on sensors’ sensitivity. We used sidewall spacer etching to fabricate polycrystalline silicon NWFET sensors. This method does not require expensive nanoscale exposure systems and reduces fabrication costs. We designed transistor sensors with nanowires of various lengths and numbers. Hepatitis B surface antigen (HBsAg) was used as the sensing target to explore the relationships of nanowire length and number with biomolecule detection. The experimental results revealed that the sensor with a 3 µm nanowire exhibited high sensitivity in detecting low concentrations of HBsAg. However, the sensor reached saturation when the biomolecule concentration exceeded 800 fg/mL. Sensors with 1.6 and 5 µm nanowires exhibited favorable linear sensing ranges at concentrations from 800 ag/mL to 800 pg/mL. The results regarding the number of nanowires revealed that the use of few nanowires in transistor sensors increases sensitivity. The results demonstrate the effects of nanowire dimensions on the silicon NWFET biosensors. Full article
(This article belongs to the Special Issue Immunosensors - Trends and Perspective)
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14 pages, 2459 KiB  
Article
Decoding Vagus-Nerve Activity with Carbon Nanotube Sensors in Freely Moving Rodents
by Joseph T. Marmerstein, Grant A. McCallum and Dominique M. Durand
Biosensors 2022, 12(2), 114; https://doi.org/10.3390/bios12020114 - 11 Feb 2022
Cited by 6 | Viewed by 2880
Abstract
The vagus nerve is the largest autonomic nerve and a major target of stimulation therapies for a wide variety of chronic diseases. However, chronic recording from the vagus nerve has been limited, leading to significant gaps in our understanding of vagus nerve function [...] Read more.
The vagus nerve is the largest autonomic nerve and a major target of stimulation therapies for a wide variety of chronic diseases. However, chronic recording from the vagus nerve has been limited, leading to significant gaps in our understanding of vagus nerve function and therapeutic mechanisms. In this study, we use a carbon nanotube yarn (CNTY) biosensor to chronically record from the vagus nerves of freely moving rats for over 40 continuous hours. Vagal activity was analyzed using a variety of techniques, such as spike sorting, spike-firing rates, and interspike intervals. Many spike-cluster-firing rates were found to correlate with food intake, and the neural-firing rates were used to classify eating and other behaviors. To our knowledge, this is the first chronic recording and decoding of activity in the vagus nerve of freely moving animals enabled by the axon-like properties of the CNTY biosensor in both size and flexibility and provides an important step forward in our ability to understand spontaneous vagus-nerve function. Full article
(This article belongs to the Special Issue Intelligent Biosignal Processing in Wearable and Implantable Sensors)
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15 pages, 2495 KiB  
Article
Microbial Fuel Cell Based on Nitrogen-Fixing Rhizobium anhuiense Bacteria
by Rokas Žalnėravičius, Algimantas Paškevičius, Urtė Samukaitė-Bubnienė, Simonas Ramanavičius, Monika Vilkienė, Ieva Mockevičienė and Arūnas Ramanavičius
Biosensors 2022, 12(2), 113; https://doi.org/10.3390/bios12020113 - 11 Feb 2022
Cited by 14 | Viewed by 4177
Abstract
In this study, the nitrogen-fixing, Gram-negative soil bacteria Rhizobium anhuiense was successfully utilized as the main biocatalyst in a bacteria-based microbial fuel cell (MFC) device. This research investigates the double-chambered, H-type R. anhuiense-based MFC that was operated in modified Norris medium (pH [...] Read more.
In this study, the nitrogen-fixing, Gram-negative soil bacteria Rhizobium anhuiense was successfully utilized as the main biocatalyst in a bacteria-based microbial fuel cell (MFC) device. This research investigates the double-chambered, H-type R. anhuiense-based MFC that was operated in modified Norris medium (pH = 7) under ambient conditions using potassium ferricyanide as an electron acceptor in the cathodic compartment. The designed MFC exhibited an open-circuit voltage (OCV) of 635 mV and a power output of 1.07 mW m−2 with its maximum power registered at 245 mV. These values were further enhanced by re-feeding the anode bath with 25 mM glucose, which has been utilized herein as the main carbon source. This substrate addition led to better performance of the constructed MFC with a power output of 2.59 mW m−2 estimated at an operating voltage of 281 mV. The R. anhuiense-based MFC was further developed by improving the charge transfer through the bacterial cell membrane by applying 2-methyl-1,4-naphthoquinone (menadione, MD) as a soluble redox mediator. The MD-mediated MFC device showed better performance, resulting in a slightly higher OCV value of 683 mV and an almost five-fold increase in power density to 4.93 mW cm−2. The influence of different concentrations of MD on the viability of R. anhuiense bacteria was investigated by estimating the optical density at 600 nm (OD600) and comparing the obtained results with the control aliquot. The results show that lower concentrations of MD, ranging from 1 to 10 μM, can be successfully used in an anode compartment in which R. anhuiense bacteria cells remain viable and act as a main biocatalyst for MFC applications. Full article
(This article belongs to the Special Issue Photonic Sensors in Chemical and Biological Applications)
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15 pages, 1280 KiB  
Review
Current Methods for Extraction and Concentration of Foodborne Bacteria with Glycan-Coated Magnetic Nanoparticles: A Review
by Emma Dester and Evangelyn Alocilja
Biosensors 2022, 12(2), 112; https://doi.org/10.3390/bios12020112 - 11 Feb 2022
Cited by 17 | Viewed by 4021
Abstract
Rapid and accurate food pathogen detection is an essential step to preventing foodborne illnesses. Before detection, removal of bacteria from the food matrix and concentration to detectable levels are often essential steps. Although many reviews discuss rapid concentration methods for foodborne pathogens, the [...] Read more.
Rapid and accurate food pathogen detection is an essential step to preventing foodborne illnesses. Before detection, removal of bacteria from the food matrix and concentration to detectable levels are often essential steps. Although many reviews discuss rapid concentration methods for foodborne pathogens, the use of glycan-coated magnetic nanoparticles (MNPs) is often omitted. This review seeks to analyze the potential of this technique as a rapid and cost-effective solution for concentration of bacteria directly from foods. The primary focus is the mechanism of glycan-coated MNP binding, as well as its current applications in concentration of foodborne pathogens. First, a background on the synthesis, properties, and applications of MNPs is provided. Second, synthesis of glycan-coated particles and their theorized mechanism for bacterial adhesion is described. Existing research into extraction of bacteria directly from food matrices is also analyzed. Finally, glycan-coated MNPs are compared to the magnetic separation technique of immunomagnetic separation (IMS) in terms of cost, time, and other factors. At its current state, glycan-coated MNPs require more research to fully identify the mechanism, potential for optimization, and extraction capabilities directly in food matrices. However, current research indicates glycan-coated MNPs are an incredibly cost-effective method for rapid food pathogen extraction and concentration. Full article
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12 pages, 3620 KiB  
Article
Hydrogen Peroxide and Hypochlorite Responsive Fluorescent Nanoprobes for Sensitive Cancer Cell Imaging
by Yun Chen, Jing Ye, Gang Lv, Weiwei Liu, Hui Jiang, Xiaohui Liu and Xuemei Wang
Biosensors 2022, 12(2), 111; https://doi.org/10.3390/bios12020111 - 11 Feb 2022
Cited by 10 | Viewed by 2806
Abstract
Accurate diagnosis of cancer cells directly affects the clinical treatment of cancer and can significantly improve the therapeutic effect of cancer patients. Cancer cells have a unique microenvironment with a large amount of peroxide inside, effectively differentiated from relevant microenvironment normal cells. Therefore, [...] Read more.
Accurate diagnosis of cancer cells directly affects the clinical treatment of cancer and can significantly improve the therapeutic effect of cancer patients. Cancer cells have a unique microenvironment with a large amount of peroxide inside, effectively differentiated from relevant microenvironment normal cells. Therefore, designing the high-sensitive probes to recognize and distinguish the special physiological microenvironment of cancer cells can shed light on the early diagnosis of cancers. In this article, we design and construct a fluorescence (FL) contrast agent for cancer cell recognition and imaging analysis. Firstly, luminol-gold NPs (Lum-AuNPs) have been initially built, and then successfully loaded with the fluorescent receptor Chlorin e6 (Ce6) to prepare the luminescent nanoprobes (Ce6@Lum-AuNPs) with green synthesis, i.e., with biocompatible agents and mild temperature. The as-prepared fluorescent Ce6@Lum-AuNPs can efficiently and sensitively realize FL bioimaging of cancer cells. The relevant bio-sensing mechanism pertains to the presence of hypochlorite (ClO); hydrogen peroxide (H2O2) in cancer cells could readily interact with luminol to produce chemiluminescence, which can activate the Ce6 component to emit near-infrared (NIR) FL. Therefore, this raises the possibility of utilizing the Ce6@Lum-AuNPs as efficient fluorescent nanoprobes for promising cancer early diagnosis and other relevant disease bioanalysis. Full article
(This article belongs to the Section Biosensors and Healthcare)
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21 pages, 1963 KiB  
Review
Review of Microdevices for Hemozoin-Based Malaria Detection
by Vitória Baptista, Weng Kung Peng, Graça Minas, Maria Isabel Veiga and Susana O. Catarino
Biosensors 2022, 12(2), 110; https://doi.org/10.3390/bios12020110 - 11 Feb 2022
Cited by 14 | Viewed by 4635
Abstract
Despite being preventable and treatable, malaria still puts almost half of the world’s population at risk. Thus, prompt, accurate and sensitive malaria diagnosis is crucial for disease control and elimination. Optical microscopy and immuno-rapid tests are the standard malaria diagnostic methods in the [...] Read more.
Despite being preventable and treatable, malaria still puts almost half of the world’s population at risk. Thus, prompt, accurate and sensitive malaria diagnosis is crucial for disease control and elimination. Optical microscopy and immuno-rapid tests are the standard malaria diagnostic methods in the field. However, these are time-consuming and fail to detect low-level parasitemia. Biosensors and lab-on-a-chip devices, as reported to different applications, usually offer high sensitivity, specificity, and ease of use at the point of care. Thus, these can be explored as an alternative for malaria diagnosis. Alongside malaria infection inside the human red blood cells, parasites consume host hemoglobin generating the hemozoin crystal as a by-product. Hemozoin is produced in all parasite species either in symptomatic and asymptomatic individuals. Furthermore, hemozoin crystals are produced as the parasites invade the red blood cells and their content relates to disease progression. Hemozoin is, therefore, a unique indicator of infection, being used as a malaria biomarker. Herein, the so-far developed biosensors and lab-on-a-chip devices aiming for malaria detection by targeting hemozoin as a biomarker are reviewed and discussed to fulfil all the medical demands for malaria management towards elimination. Full article
(This article belongs to the Special Issue Advanced Biosensing Technologies in Medical Applications)
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23 pages, 3487 KiB  
Review
Recent Advances of Mesoporous Silica as a Platform for Cancer Immunotherapy
by Albert Yu, Xiaoyong Dai, Zixian Wang, Huaqing Chen, Bing Guo and Laiqiang Huang
Biosensors 2022, 12(2), 109; https://doi.org/10.3390/bios12020109 - 10 Feb 2022
Cited by 18 | Viewed by 4249 | Correction
Abstract
Immunotherapy is a promising modality of treatment for cancer. Immunotherapy is comprised of systemic and local treatments that induce an immune response, allowing the body to fight back against cancer. Systemic treatments such as cancer vaccines harness antigen presenting cells (APCs) to activate [...] Read more.
Immunotherapy is a promising modality of treatment for cancer. Immunotherapy is comprised of systemic and local treatments that induce an immune response, allowing the body to fight back against cancer. Systemic treatments such as cancer vaccines harness antigen presenting cells (APCs) to activate T cells with tumor-associated antigens. Small molecule inhibitors can be employed to inhibit immune checkpoints, disrupting tumor immunosuppression and immune evasion. Despite the current efficacy of immunotherapy, improvements to delivery can be made. Nanomaterials such as mesoporous silica can facilitate the advancement of immunotherapy. Mesoporous silica has high porosity, decent biocompatibility, and simple surface functionalization. Mesoporous silica can be utilized as a versatile carrier of various immunotherapeutic agents. This review gives an introduction on mesoporous silica as a nanomaterial, briefly covering synthesis and biocompatibility, and then an overview of the recent progress made in the application of mesoporous silica to cancer immunotherapy. Full article
(This article belongs to the Special Issue Advances in Nanomedicines for Disease Diagnosis and Therapeutics)
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16 pages, 3899 KiB  
Article
Design and Optimisation of Elliptical-Shaped Planar Hall Sensor for Biomedical Applications
by Shah Mukim Uddin, Abkar Sayad, Jianxiong Chan, Efstratios Skafidas and Patrick Kwan
Biosensors 2022, 12(2), 108; https://doi.org/10.3390/bios12020108 - 10 Feb 2022
Cited by 3 | Viewed by 2966
Abstract
The magnetic beads detection-based immunoassay, also called magneto-immunoassay, has potential applications in point-of-care testing (POCT) due to its unique advantage of minimal background interference from the biological sample and associated reagents. While magnetic field detection technologies are well established for numerous applications in [...] Read more.
The magnetic beads detection-based immunoassay, also called magneto-immunoassay, has potential applications in point-of-care testing (POCT) due to its unique advantage of minimal background interference from the biological sample and associated reagents. While magnetic field detection technologies are well established for numerous applications in the military, as well as in geology, archaeology, mining, spacecraft, and mobile phones, adaptation into magneto-immunoassay is yet to be explored. The magnetic field biosensors under development tend to be multilayered and require an expensive fabrication process. A low-cost and affordable biosensing platform is required for an effective point-of-care diagnosis in a resource-limited environment. Therefore, we evaluated a single-layered magnetic biosensor in this study to overcome this limitation. The shape-induced magnetic anisotropy-based planar hall effect sensor was recently developed to detect a low-level magnetic field, but was not explored for medical application. In this study, the elliptical-shaped planar hall effect (EPHE) sensor was designed, fabricated, characterized, and optimized for the magneto-immunoassay, specifically. Nine sensor variants were designed and fabricated. A customized measurement setup incorporating a lock-in amplifier was used to quantify 4.5 µm magnetic beads in a droplet. The result indicated that the single-domain behaviour of the magnetic film and larger sensing area with a thinner magnetic film had the highest sensitivity. The developed sensor was tested with a range of magnetic bead concentrations, demonstrating a limit of detection of 200 beads/μL. The sensor performance encourages employing magneto-immunoassay towards developing a low-cost POCT device in the future. Full article
(This article belongs to the Special Issue Feature Issue of Biosensors and Bioelectronic Devices Section)
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12 pages, 2126 KiB  
Communication
Non-Destructive Monitoring via Electrochemical NADH Detection in Murine Cells
by Ju Kyung Lee, Han Na Suh, Sung Hoon Yoon, Kyu Hong Lee, Sae Young Ahn, Hyung Jin Kim and Sang Hee Kim
Biosensors 2022, 12(2), 107; https://doi.org/10.3390/bios12020107 - 10 Feb 2022
Cited by 3 | Viewed by 2298
Abstract
Nicotinamide adenine dinucleotide (NADH) is an important cofactor involved in metabolic redox reactions in living cells. The detection of NADH in living animal cells is a challenge. We developed a one-step monitoring method for NADH via an electrocatalytic reaction that uses a surface-modified, [...] Read more.
Nicotinamide adenine dinucleotide (NADH) is an important cofactor involved in metabolic redox reactions in living cells. The detection of NADH in living animal cells is a challenge. We developed a one-step monitoring method for NADH via an electrocatalytic reaction that uses a surface-modified, screen-printed electrode (SPE) having a redox active monolayer 4′-mercapto-N-phenlyquinone diamine (NPQD) formed by a self-assembled monolayer (SAM) of an aromatic thiol, 4-aminothiophenol (4-ATP). This electrode has a limit of detection (LOD) of 0.49 μM and a sensitivity of 0.0076 ± 0.0006 μM/μA in cell culture media, which indicates that it retains its selectivity. The applicability of this NADH sensor was demonstrated for the first time by cell viability monitoring via NADH-sensing in cell culture supernatants. Full article
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8 pages, 813 KiB  
Article
Accuracy Assessment of the GlucoMen® Day CGM System in Individuals with Type 1 Diabetes: A Pilot Study
by Daniel A. Hochfellner, Amra Simic, Marlene T. Taucher, Lea S. Sailer, Julia Kopanz, Tina Pöttler and Julia K. Mader
Biosensors 2022, 12(2), 106; https://doi.org/10.3390/bios12020106 - 9 Feb 2022
Cited by 7 | Viewed by 3079
Abstract
The aim of this study was to evaluate the accuracy and usability of a novel continuous glucose monitoring (CGM) system designed for needle-free insertion and reduced environmental impact. We assessed the sensor performance of two GlucoMen® Day CGM systems worn simultaneously by [...] Read more.
The aim of this study was to evaluate the accuracy and usability of a novel continuous glucose monitoring (CGM) system designed for needle-free insertion and reduced environmental impact. We assessed the sensor performance of two GlucoMen® Day CGM systems worn simultaneously by eight participants with type 1 diabetes. Self-monitoring of blood glucose (SMBG) was performed regularly over 14 days at home. Participants underwent two standardized, 5-h meal challenges at the research center with frequent plasma glucose (PG) measurements using a laboratory reference (YSI) instrument. When comparing CGM to PG, the overall mean absolute relative difference (MARD) was 9.7 [2.6–14.6]%. The overall MARD for CGM vs. SMBG was 13.1 [3.5–18.6]%. The consensus error grid (CEG) analysis showed 98% of both CGM/PG and CGM/SMBG pairs in the clinically acceptable zones A and B. The analysis confirmed that GlucoMen® Day CGM meets the clinical requirements for state-of-the-art CGM. In addition, the needle-free insertion technology is well tolerated by users and reduces medical waste compared to conventional CGM systems. Full article
(This article belongs to the Special Issue Glucose Sensors—an Essential Tool in Diabetes Management)
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