Biosensors

15 pages, 2966 KiB

Open AccessArticle

A Microfluidic Chip-Based Integrated Device Combining Aerosol Sampling and LAMP–CRISPR Detection for Airborne Virus Surveillance

by Anlan Zhang, Yuqing Chang, Wen Li, Yuanbao Zhang, Yuqian Wang, Haohan Xie, Tao Zuo, Yu Zhang, Jiyu Xi, Xin Wu, Zewen Wei and Rui Chen

Biosensors 2025, 15(8), 475; https://doi.org/10.3390/bios15080475 - 23 Jul 2025

Abstract

Detecting airborne viruses using an integrated aerosol sampling detection device is of great significance in epidemic prevention and control. Most of the applicable aerosol samplers have a flow rate of less than 1000 L/min, which is insufficient for application in large public spaces. [...] Read more.

Detecting airborne viruses using an integrated aerosol sampling detection device is of great significance in epidemic prevention and control. Most of the applicable aerosol samplers have a flow rate of less than 1000 L/min, which is insufficient for application in large public spaces. Recent research, on the other hand, has revealed the advantages of microfluidic chip-based LAMP–CRISPR in airborne virus detection; however, this promising detection method has yet to be integrated with an aerosol sampler. Herein, we present an aerosol sampling and microfluidic chip-based detection (ASMD) device that couples a high-flow-rate aerosol sampling (HFAS) system with a microfluidic LAMP–CRISPR detection (MLCD) chip for surveilling airborne viruses, as represented by SARS-CoV-2. The HFAS system achieved a 6912 L/min flow rate while retaining a satisfactory collection efficiency, and achieved an enrichment ratio of 1.93 × 10⁷ that facilitated subsequent detection by the MLCD chip. The MLCD chip integrates the whole LAMP–CRISPR procedure into a single chip and is compatible with the HFAS system. Environmental detection experiments show the feasibility of the ASMD device for aerosol sampling and detection. Our ASMD device is a promising tool for large space aerosol detection for airborne virus surveillance. Full article

(This article belongs to the Special Issue Biosensors Based on Microfluidic Devices—2nd Edition)

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33 pages, 1232 KiB

Open AccessReview

Microfluidic Sensors for Micropollutant Detection in Environmental Matrices: Recent Advances and Prospects

by Mohamed A. A. Abdelhamid, Mi-Ran Ki, Hyo Jik Yoon and Seung Pil Pack

Biosensors 2025, 15(8), 474; https://doi.org/10.3390/bios15080474 - 22 Jul 2025

Abstract

The widespread and persistent occurrence of micropollutants—such as pesticides, pharmaceuticals, heavy metals, personal care products, microplastics, and per- and polyfluoroalkyl substances (PFAS)—has emerged as a critical environmental and public health concern, necessitating the development of highly sensitive, selective, and field-deployable detection technologies. Microfluidic [...] Read more.

The widespread and persistent occurrence of micropollutants—such as pesticides, pharmaceuticals, heavy metals, personal care products, microplastics, and per- and polyfluoroalkyl substances (PFAS)—has emerged as a critical environmental and public health concern, necessitating the development of highly sensitive, selective, and field-deployable detection technologies. Microfluidic sensors, including biosensors, have gained prominence as versatile and transformative tools for real-time environmental monitoring, enabling precise and rapid detection of trace-level contaminants in complex environmental matrices. Their miniaturized design, low reagent consumption, and compatibility with portable and smartphone-assisted platforms make them particularly suited for on-site applications. Recent breakthroughs in nanomaterials, synthetic recognition elements (e.g., aptamers and molecularly imprinted polymers), and enzyme-free detection strategies have significantly enhanced the performance of these biosensors in terms of sensitivity, specificity, and multiplexing capabilities. Moreover, the integration of artificial intelligence (AI) and machine learning algorithms into microfluidic platforms has opened new frontiers in data analysis, enabling automated signal processing, anomaly detection, and adaptive calibration for improved diagnostic accuracy and reliability. This review presents a comprehensive overview of cutting-edge microfluidic sensor technologies for micropollutant detection, emphasizing fabrication strategies, sensing mechanisms, and their application across diverse pollutant categories. We also address current challenges, such as device robustness, scalability, and potential signal interference, while highlighting emerging solutions including biodegradable substrates, modular integration, and AI-driven interpretive frameworks. Collectively, these innovations underscore the potential of microfluidic sensors to redefine environmental diagnostics and advance sustainable pollution monitoring and management strategies. Full article

(This article belongs to the Special Issue Biosensors Based on Microfluidic Devices—2nd Edition)

32 pages, 3198 KiB

Open AccessReview

Shining the Path of Precision Diagnostic: Advancements in Photonic Sensors for Liquid Biopsy

by Paola Colapietro, Giuseppe Brunetti, Carlotta Panciera, Aurora Elicio and Caterina Ciminelli

Biosensors 2025, 15(8), 473; https://doi.org/10.3390/bios15080473 - 22 Jul 2025

Abstract

Liquid biopsy (LB) has gained attention as a valuable approach for cancer diagnostics, providing a minimally invasive option compared to conventional tissue biopsies and helping to overcome issues related to patient discomfort and procedural invasiveness. Recent advances in biosensor technologies, particularly photonic sensors, [...] Read more.

Liquid biopsy (LB) has gained attention as a valuable approach for cancer diagnostics, providing a minimally invasive option compared to conventional tissue biopsies and helping to overcome issues related to patient discomfort and procedural invasiveness. Recent advances in biosensor technologies, particularly photonic sensors, have improved the accuracy, speed, and real-time capabilities for detecting circulating biomarkers in biological fluids. Incorporating these tools into clinical practice facilitates more informed therapeutic choices and contributes to tailoring treatments to individual patient profiles. This review highlights the clinical potential of LB, examines technological limitations, and outlines future research directions. Departing from traditional biosensor focused reviews, it adopts a reverse-mapping approach grounded in clinically relevant tumor biomarkers. Specifically, biomarkers associated with prevalent cancers, such as breast, prostate, and lung cancers, serve as the starting point for identifying the most suitable photonic sensing platforms. The analysis underscores the need to align sensor design with the physicochemical properties of each biomarker and the operational requirements of the application. No photonic platform is universally optimal; rather, each exhibits specific strengths depending on performance metrics such as sensitivity, limit of detection, and easy system integration. Within this framework, the review provides a comprehensive assessment of emerging photonic biosensors and outlines key priorities to support their effective clinical translation in cancer diagnostics. Full article

(This article belongs to the Special Issue Lab-on-a-Chip Devices for Point-of-Care Diagnostics)

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41 pages, 3816 KiB

Open AccessReview

Updates on the Advantages and Disadvantages of Microscopic and Spectroscopic Characterization of Magnetotactic Bacteria for Biosensor Applications

by Natalia Lorela Paul, Catalin Ovidiu Popa and Rodica Elena Ionescu

Biosensors 2025, 15(8), 472; https://doi.org/10.3390/bios15080472 - 22 Jul 2025

Abstract

Magnetotactic bacteria (MTB), a unique group of Gram-negative prokaryotes, have the remarkable ability to biomineralize magnetic nanoparticles (MNPs) intracellularly, making them promising candidates for various biomedical applications such as biosensors, drug delivery, imaging contrast agents, and cancer-targeted therapies. To fully exploit the potential [...] Read more.

Magnetotactic bacteria (MTB), a unique group of Gram-negative prokaryotes, have the remarkable ability to biomineralize magnetic nanoparticles (MNPs) intracellularly, making them promising candidates for various biomedical applications such as biosensors, drug delivery, imaging contrast agents, and cancer-targeted therapies. To fully exploit the potential of MTB, a precise understanding of the structural, surface, and functional properties of these biologically produced nanoparticles is required. Given these concerns, this review provides a focused synthesis of the most widely used microscopic and spectroscopic methods applied in the characterization of MTB and their associated MNPs, covering the latest research from January 2022 to May 2025. Specifically, various optical microscopy techniques (e.g., transmission electron microscopy (TEM), scanning electron microscopy (SEM), and atomic force microscopy (AFM)) and spectroscopic approaches (e.g., localized surface plasmon resonance (LSPR), surface-enhanced Raman scattering (SERS), and X-ray photoelectron spectroscopy (XPS)) relevant to ultrasensitive MTB biosensor development are herein discussed and compared in term of their advantages and disadvantages. Overall, the novelty of this work lies in its clarity and structure, aiming to consolidate and simplify access to the most current and effective characterization techniques. Furthermore, several gaps in the characterization methods of MTB were identified, and new directions of methods that can be integrated into the study, analysis, and characterization of these bacteria are suggested in exhaustive manner. Finally, to the authors’ knowledge, this is the first comprehensive overview of characterization techniques that could serve as a practical resource for both younger and more experienced researchers seeking to optimize the use of MTB in the development of advanced biosensing systems and other biomedical tools. Full article

(This article belongs to the Special Issue Material-Based Biosensors and Biosensing Strategies)

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27 pages, 7794 KiB

Open AccessReview

Recent Advances in Aggregation-Induced Electrochemiluminescent Biosensors

by Likang Zhou, Junhao Fei, Suping Zhang and Tianyu Shan

Biosensors 2025, 15(8), 471; https://doi.org/10.3390/bios15080471 - 22 Jul 2025

Abstract

Electrochemiluminescence (ECL) biosensors based on aggregation-induced emission (AIE) emitters have recently emerged as highly sensitive tools for biosensing. The AIE phenomenon, characterized by a significant luminescence change upon aggregation due to restricted intramolecular rotation or vibration, effectively enhances ECL intensity and efficiency, endowing [...] Read more.

Electrochemiluminescence (ECL) biosensors based on aggregation-induced emission (AIE) emitters have recently emerged as highly sensitive tools for biosensing. The AIE phenomenon, characterized by a significant luminescence change upon aggregation due to restricted intramolecular rotation or vibration, effectively enhances ECL intensity and efficiency, endowing AIECL emitters with high selectivity and stability. This review provides an overview of the developmental trajectory of AIECL, systematically elaborates and comparatively analyzes the mechanisms and luminophore systems of conventional ECL and AIECL, discusses the design strategies and construction methods of AIECL luminophores, and comprehensively summarizes the innovative applications of AIECL in the realm of biosensors. Finally, some of the current challenges in this emerging field are outlined, along with perspectives on future trends. Full article

(This article belongs to the Special Issue Progress in Electrochemiluminescence Biosensors)

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20 pages, 1471 KiB

Open AccessArticle

A New Approach for Interferent-Free Amperometric Biosensor Production Based on All-Electrochemically Assisted Procedures

by Rosanna Ciriello, Maria Assunta Acquavia, Giuliana Bianco, Angela Di Capua and Antonio Guerrieri

Biosensors 2025, 15(8), 470; https://doi.org/10.3390/bios15080470 - 22 Jul 2025

Abstract

A new approach in amperometric enzyme electrodes production based on all-electrochemically assisted procedures will be described. Enzyme (glucose oxidase) immobilization was performed by in situ co-crosslinking of enzyme molecules through electrophoretic protein deposition, assuring enzyme immobilization exclusively onto the transducer surface (Pt electrode). [...] Read more.

A new approach in amperometric enzyme electrodes production based on all-electrochemically assisted procedures will be described. Enzyme (glucose oxidase) immobilization was performed by in situ co-crosslinking of enzyme molecules through electrophoretic protein deposition, assuring enzyme immobilization exclusively onto the transducer surface (Pt electrode). Analogously, the poor selectivity of the transducer was dramatically improved by the electrosynthesis of non-conducting polymers with built-in permselectivity, permitting the formation of a thin permselective film onto the transducer surface, able to reject common interferents usually found in real samples. Since both approaches required a proper and distinct electrochemical perturbation (a pulsed current sequence for electrophoretic protein deposition and cyclic voltammetry for the electrosynthesis of non-conducting polymers), an appropriate coupling of the two all-electrochemical approaches was assured by a thorough study of the likely combinations of the electrosynthesis of permselective polymers with enzyme immobilization by electrophoretic protein deposition and by the use of several electrosynthesized polymers. For each investigated combination and for each polymer, the analytical performances and the rejection capabilities of the resulting biosensor were acquired so to gain information about their sensing abilities eventually in real sample analysis. This study shows that the proper coupling of the two all-electrochemical approaches and the appropriate choice of the electrosynthesized, permselective polymer permits the easy fabrication of novel glucose oxidase biosensors with good analytical performance and low bias in glucose measurement from typical interferent in serum. This novel approach, resembling classical electroplating procedures, is expected to allow all the advantages expected from such procedures like an easy preparation biosensor, a bi-dimensional control of enzyme immobilization and thickness, interferent- and fouling-free transduction of the electrodic sensor and, last but not the least, possibility of miniaturization of the biosensing device. Full article

(This article belongs to the Special Issue Novel Designs and Applications for Electrochemical Biosensors)

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29 pages, 23821 KiB

Open AccessReview

Covalent Organic Frameworks for Immunoassays: A Review

by Suling Yang and Hongmin Liu

Biosensors 2025, 15(7), 469; https://doi.org/10.3390/bios15070469 - 21 Jul 2025

Abstract

Immunoassays relying on highly specific antigen–antibody recognition are important tools for effectively measuring the levels of various targets. Efforts have been made in the development of various methods to improve the detection sensitivity and stability of immunoassays. Covalent organic frameworks (COFs), as an [...] Read more.

Immunoassays relying on highly specific antigen–antibody recognition are important tools for effectively measuring the levels of various targets. Efforts have been made in the development of various methods to improve the detection sensitivity and stability of immunoassays. Covalent organic frameworks (COFs), as an emerging class of novel crystalline porous materials, have unique advantages such as flexible designability, high surface area, excellent stability, tunable pore sizes, and multiple functionalities. They have great potential as novel sensory materials. Herein, we summarize the advances of COFs in electrochemical and optical immunoassays serving as electrode modifiers, signal indicators, enzyme or probe carriers, etc. Meanwhile, the design and application of typical COFs-based immunoassays in the determination of different targets are discussed in detail. Finally, challenges and future perspectives are presented. Full article

(This article belongs to the Special Issue Biosensors Based on Self-Assembly and Boronate Affinity Interaction)

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58 pages, 6017 KiB

Open AccessReview

Electrochemical (Bio)Sensors for Toxins, Foodborne Pathogens, Pesticides, and Antibiotics Detection: Recent Advances and Challenges in Food Analysis

by Marta Feroci, Gerardo Grasso, Roberto Dragone and Antonella Curulli

Biosensors 2025, 15(7), 468; https://doi.org/10.3390/bios15070468 - 21 Jul 2025

Abstract

Food safety plays an important and fundamental role, primarily for human health and certainly for the food industry. In this context, developing efficient, highly sensitive, safe, inexpensive, and fast analytical methods for determining chemical and biological contaminants, such as electrochemical (bio)sensors, is crucial. [...] Read more.

Food safety plays an important and fundamental role, primarily for human health and certainly for the food industry. In this context, developing efficient, highly sensitive, safe, inexpensive, and fast analytical methods for determining chemical and biological contaminants, such as electrochemical (bio)sensors, is crucial. The development of innovative and high-performance electrochemical (bio)sensors can significantly support food chain monitoring. In this review, we have surveyed and analyzed the latest examples of electrochemical (bio)sensors for the analysis of some common biological contaminants, such as toxins and pathogenic bacteria and chemical contaminants, such as pesticides, and antibiotics. Full article

(This article belongs to the Special Issue Biosensors for Food Safety)

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Graphical abstract

33 pages, 5344 KiB

Open AccessReview

Graphene–Bacteriophage Hybrid Nanomaterials for Specific and Rapid Electrochemical Detection of Pathogenic Bacteria

by José M. Campiña, António F. Silva and Carlos M. Pereira

Biosensors 2025, 15(7), 467; https://doi.org/10.3390/bios15070467 - 19 Jul 2025

Abstract

Efficient and rapid detection of bacterial pathogens is crucial for food safety and effective disease control. While conventional methods such as PCR and ELISA are accurate, they are time-consuming, costly, and often require specialized infrastructure. Recently, electrochemical biosensors integrating graphene nanomaterials with bacteriophages—termed [...] Read more.

Efficient and rapid detection of bacterial pathogens is crucial for food safety and effective disease control. While conventional methods such as PCR and ELISA are accurate, they are time-consuming, costly, and often require specialized infrastructure. Recently, electrochemical biosensors integrating graphene nanomaterials with bacteriophages—termed graphages—have emerged as promising platforms for pathogen detection, offering fast, specific, and highly responsive detection. This review critically examines all electrochemical biosensors reported to date that utilize graphene–phage hybrids. Key aspects addressed include the types of graphene nanomaterials and bacteriophages used, immobilization strategies, electrochemical transduction mechanisms, and sensor metrics—such as detection limits, linear ranges, and ability to perform in real matrices. Particular attention is given to the role of phage orientation, surface functionalization, and the use of receptor binding proteins. Finally, current limitations and opportunities for future research are outlined, including prospects for genetic engineering and sensor miniaturization. This review serves as a comprehensive reference for researchers developing phage-based biosensors, especially those interested in integrating carbon nanomaterials for improved electroanalytical performance. Full article

(This article belongs to the Special Issue Biosensors for Food Safety)

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14 pages, 1452 KiB

Open AccessReview

Recent Advances in Liquid Metal-Based Stretchable and Conductive Composites for Wearable Sensor Applications

by Boo Young Kim, Wan Yusmawati Wan Yusoff, Paolo Matteini, Peter Baumli and Byungil Hwang

Biosensors 2025, 15(7), 466; https://doi.org/10.3390/bios15070466 - 19 Jul 2025

Abstract

Liquid metals (LMs), with their unique combination of high electrical conductivity and mechanical deformability, have emerged as promising materials for stretchable electronics and biointerfaces. However, the practical application of bulk LMs in wearable sensors has been hindered by processing challenges and low stability. [...] Read more.

Liquid metals (LMs), with their unique combination of high electrical conductivity and mechanical deformability, have emerged as promising materials for stretchable electronics and biointerfaces. However, the practical application of bulk LMs in wearable sensors has been hindered by processing challenges and low stability. To overcome these limitations, liquid metal particles (LMPs) encapsulated by native oxide shells have gained attention as versatile and stable fillers for stretchable and conductive composites. Recent advances have focused on the development of LM-based hybrid composites that combine LMPs with metal, carbon, or polymeric fillers. These systems offer enhanced electrical and mechanical properties and can form conductive networks without the need for additional sintering processes. They also impart composites with multiple functions such as self-healing, electromagnetic interference shielding, and recyclability. Hence, the present review summarizes the fabrication methods and functional properties of LM-based composites, with a particular focus on their applications in wearable sensing. In addition, recent developments in the use of LM composites for physical motion monitoring (e.g., strain and pressure sensing) and electrophysiological signal recording (e.g., EMG and ECG) are presented, and the key challenges and opportunities for next-generation wearable platforms are discussed. Full article

(This article belongs to the Special Issue The Application of Biomaterials in Electronics and Biosensors)

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14 pages, 11910 KiB

Open AccessArticle

Electrochemical Immunosensor Using COOH-Functionalized 3D Graphene Electrodes for Sensitive Detection of Tau-441 Protein

by Sophia Nazir, Muhsin Dogan, Yinghui Wei and Genhua Pan

Biosensors 2025, 15(7), 465; https://doi.org/10.3390/bios15070465 - 19 Jul 2025

Abstract

Early diagnosis of Alzheimer’s disease (AD) is essential for effective treatment; however current diagnostic methods are often complex, costly, and unsuitable for point-of-care testing. Graphene-based biosensors offer an alternative due to their affordability, versatility, and high conductivity. However, graphene’s conductivity can be compromised [...] Read more.

Early diagnosis of Alzheimer’s disease (AD) is essential for effective treatment; however current diagnostic methods are often complex, costly, and unsuitable for point-of-care testing. Graphene-based biosensors offer an alternative due to their affordability, versatility, and high conductivity. However, graphene’s conductivity can be compromised when its carbon lattice is oxidized to introduce functional groups for biomolecule immobilization. This study addresses this challenge by developing an electrochemical immunosensor using carboxyl-modified commercial graphene foam (COOH-GF) electrodes. The conductivity of graphene is preserved by enabling efficient COOH modification through π–π non-covalent interactions, while antibody immobilization is optimized via EDC-NHS carbodiimide chemistry. The immunosensor detects tau-441, an AD biomarker, using differential pulse voltammetry (DPV), achieving a detection range of 1 fM–1 nM, with a limit of detection (LOD) of 0.14 fM both in PBS and human serum. It demonstrates high selectivity against other AD-related proteins, including tau-217, tau-181, amyloid beta (Aβ_1-40 and Aβ_1-42), and 1% BSA. These findings underscore its potential as a highly sensitive, cost-effective tool for early AD diagnosis. Full article

(This article belongs to the Section Biosensor and Bioelectronic Devices)

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16 pages, 3231 KiB

Open AccessArticle

Aptamer-Conjugated Magnetic Nanoparticles Integrated with SERS for Multiplex Salmonella Detection

by Fan Sun, Kun Pang, Keke Yang, Li Zheng, Mengmeng Wang, Yufeng Wang, Qiang Chen, Zihong Ye, Pei Liang and Xiaoping Yu

Biosensors 2025, 15(7), 464; https://doi.org/10.3390/bios15070464 - 19 Jul 2025

Abstract

Salmonella is a rapidly spreading and widespread zoonotic infectious disease that poses a serious threat to the safety of both poultry and human lives. Therefore, the timely detection of Salmonella in foods and animals has become an urgent need for food safety. This [...] Read more.

Salmonella is a rapidly spreading and widespread zoonotic infectious disease that poses a serious threat to the safety of both poultry and human lives. Therefore, the timely detection of Salmonella in foods and animals has become an urgent need for food safety. This work describes the construction of an aptamer-based sensor for Salmonella detection, using Fe₃O₄ magnetic beads and Ag@Au core–shell nanoparticles-embedded 4-mercaptobenzoic acid (4MBA). Leveraging the high affinity between biotin and streptavidin, aptamers were conjugated to Fe₃O₄ magnetic beads. These beads were then combined with Ag@4MBA@Au nanoparticles functionalized with complementary aptamers through hydrogen bonding and π-π stacking interactions, yielding a SERS-based aptamer sensor with optimized Raman signals from 4MBA. When target bacteria are present, aptamer-conjugated magnetic beads exhibit preferential binding to the bacteria, leading to a decrease in the surface-enhanced Raman scattering (SERS) signal. And it was used for the detection of five different serotypes of Salmonella, respectively, and the results showed that the aptamer sensor exhibited a good linear relationship between the concentration range of 10²–10⁸ CFU/mL and LOD is 35.51 CFU/mL. The SERS aptasensor was utilized for the detection of spiked authentic samples with recoveries between 94.0 and 100.4%, which proved the usability of the method and helped to achieve food safety detection. Full article

(This article belongs to the Special Issue Aptamer-Based Sensing: Designs and Applications)

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35 pages, 6415 KiB

Open AccessReview

Recent Advances in Conductive Hydrogels for Electronic Skin and Healthcare Monitoring

by Yan Zhu, Baojin Chen, Yiming Liu, Tiantian Tan, Bowen Gao, Lijun Lu, Pengcheng Zhu and Yanchao Mao

Biosensors 2025, 15(7), 463; https://doi.org/10.3390/bios15070463 - 18 Jul 2025

Abstract

In recent decades, flexible electronics have witnessed remarkable advancements in multiple fields, encompassing wearable electronics, human–machine interfaces (HMI), clinical diagnosis, and treatment, etc. Nevertheless, conventional rigid electronic devices are fundamentally constrained by their inherent non-stretchability and poor conformability, limitations that substantially impede their [...] Read more.

In recent decades, flexible electronics have witnessed remarkable advancements in multiple fields, encompassing wearable electronics, human–machine interfaces (HMI), clinical diagnosis, and treatment, etc. Nevertheless, conventional rigid electronic devices are fundamentally constrained by their inherent non-stretchability and poor conformability, limitations that substantially impede their practical applications. In contrast, conductive hydrogels (CHs) for electronic skin (E-skin) and healthcare monitoring have attracted substantial interest owing to outstanding features, including adjustable mechanical properties, intrinsic flexibility, stretchability, transparency, and diverse functional and structural designs. Considerable efforts focus on developing CHs incorporating various conductive materials to enable multifunctional wearable sensors and flexible electrodes, such as metals, carbon, ionic liquids (ILs), MXene, etc. This review presents a comprehensive summary of the recent advancements in CHs, focusing on their classifications and practical applications. Firstly, CHs are categorized into five groups based on the nature of the conductive materials employed. These categories include polymer-based, carbon-based, metal-based, MXene-based, and ionic CHs. Secondly, the promising applications of CHs for electrophysiological signals and healthcare monitoring are discussed in detail, including electroencephalogram (EEG), electrocardiogram (ECG), electromyogram (EMG), respiratory monitoring, and motion monitoring. Finally, this review concludes with a comprehensive summary of current research progress and prospects regarding CHs in the fields of electronic skin and health monitoring applications. Full article

(This article belongs to the Special Issue Artificial Skins and Wearable Biosensors for Healthcare Monitoring—2nd Edition)

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2 pages, 337 KiB

Open AccessCorrection

Correction: Kaur et al. Nanocomposite of MgFe₂O₄ and Mn₃O₄ as Polyphenol Oxidase Mimic for Sensing of Polyphenols. Biosensors 2022, 12, 428

by Harmilan Kaur, Manpreet Kaur, Renuka Aggarwal, Sucheta Sharma and Davinder Singh

Biosensors 2025, 15(7), 462; https://doi.org/10.3390/bios15070462 - 18 Jul 2025

Abstract

Error in Figure/Table [...] Full article

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19 pages, 4194 KiB

Open AccessArticle

3D-Printed PLA Hollow Microneedles Loaded with Chitosan Nanoparticles for Colorimetric Glucose Detection in Sweat Using Machine Learning

by Anastasia Skonta, Myrto G. Bellou and Haralambos Stamatis

Biosensors 2025, 15(7), 461; https://doi.org/10.3390/bios15070461 - 18 Jul 2025

Abstract

Biosensors play a central role in the early detection of abnormal glucose levels in individuals with diabetes; therefore, the development of less invasive systems is essential. Herein, a 3D-printed colorimetric biosensor combining microneedles and chitosan nanoparticles was developed for glucose detection in sweat [...] Read more.

Biosensors play a central role in the early detection of abnormal glucose levels in individuals with diabetes; therefore, the development of less invasive systems is essential. Herein, a 3D-printed colorimetric biosensor combining microneedles and chitosan nanoparticles was developed for glucose detection in sweat using machine learning. Briefly, hollow 3D-printed polylactic acid microneedles were constructed and loaded with chitosan nanoparticles encapsulating glucose oxidase, horseradish peroxidase, and the chromogenic substrate 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid), resulting in the formation of the chitosan nanoparticle−microneedle patches. Glucose detection was performed colorimetrically by first incubating the chitosan nanoparticle−microneedle patches with glucose samples of varying concentrations and then by using photographs of the top side of each microneedle and a color recognition application on a smartphone. The Random Sample Consensus algorithm was used to train a simple linear regression model to predict glucose concentrations in unknown samples. The developed biosensor system exhibited a good linear response range toward glucose (0.025−0.375 mM), a low limit of detection (0.023 mM), a limit of quantification (0.078 mM), high specificity, and recovery rates ranging between 86–112%. Lastly, the biosensor was applied to glucose detection in spiked artificial sweat samples, confirming the potential of the proposed methodology for glucose detection in real samples. Full article

(This article belongs to the Special Issue Recent Advances in Glucose Biosensors)

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41 pages, 7605 KiB

Open AccessSystematic Review

Optical and Electrochemical Biosensors for Detection of Pathogens Using Metal Nanoclusters: A Systematic Review

by Mahsa Shahrashoob, Mahdiyar Dehshiri, Vahid Yousefi, Mahdi Moassesfar, Hamidreza Saberi, Fatemeh Molaabasi, Yasser Zare and Kyong Yop Rhee

Biosensors 2025, 15(7), 460; https://doi.org/10.3390/bios15070460 - 17 Jul 2025

Abstract

The rapid and accurate detection of pathogenic bacteria and viruses is critical for infectious disease control and public health protection. While conventional methods (e.g., culture, microscopy, serology, and PCR) are widely used, they are often limited by lengthy processing times, high costs, and [...] Read more.

The rapid and accurate detection of pathogenic bacteria and viruses is critical for infectious disease control and public health protection. While conventional methods (e.g., culture, microscopy, serology, and PCR) are widely used, they are often limited by lengthy processing times, high costs, and specialized equipment requirements. In recent years, metal nanocluster (MNC)-based biosensors have emerged as powerful diagnostic platforms due to their unique optical, catalytic, and electrochemical properties. This systematic review comprehensively surveys advancements in MNC-based biosensors for bacterial and viral pathogen detection, focusing on optical (colorimetric and fluorescence) and electrochemical platforms. Three key aspects are emphasized: (1) detection mechanisms, (2) nanocluster types and properties, and (3) applications in clinical diagnostics, environmental monitoring, and food safety. The literature demonstrates that MNC-based biosensors provide high sensitivity, specificity, portability, and cost-efficiency. Moreover, the integration of nanotechnology with biosensing platforms enables real-time and point-of-care diagnostics. This review also discusses the limitations and future directions of the technology, emphasizing the need for enhanced stability, multiplex detection capability, and clinical validation. The findings offer valuable insights for developing next-generation biosensors with improved functionality and broader applicability in microbial diagnostics. Full article

(This article belongs to the Special Issue Electrochemical (Bio)Sensors as Promising Analytical Tools in the Analysis of Soils, Plants and Environmental Monitoring)

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20 pages, 3037 KiB

Open AccessArticle

An Automated Microfluidic Platform for In Vitro Raman Analysis of Living Cells

by Illya Klyusko, Stefania Scalise, Francesco Guzzi, Luigi Randazzini, Simona Zaccone, Elvira Immacolata Parrotta, Valeria Lucchino, Alessio Merola, Carlo Cosentino, Ulrich Krühne, Isabella Aquila, Giovanni Cuda, Enzo Di Fabrizio, Patrizio Candeloro and Gerardo Perozziello

Biosensors 2025, 15(7), 459; https://doi.org/10.3390/bios15070459 - 16 Jul 2025

Abstract

We present a miniaturized, inexpensive, and user-friendly microfluidic platform to support biological applications. The system integrates a mini-incubator providing controlled environmental conditions and housing a microfluidic device for long-term cell culture experiments. The incubator is designed to be compatible with standard inverted optical [...] Read more.

We present a miniaturized, inexpensive, and user-friendly microfluidic platform to support biological applications. The system integrates a mini-incubator providing controlled environmental conditions and housing a microfluidic device for long-term cell culture experiments. The incubator is designed to be compatible with standard inverted optical microscopes and Raman spectrometers, allowing for the non-invasive imaging and spectroscopic analysis of cell cultures in vitro. The microfluidic device, which reproduces a dynamic environment, was optimized to sustain a passive, gravity-driven flow of medium, eliminating the need for an external pumping system and reducing mechanical stress on the cells. The platform was tested using Raman analysis and adherent tumoral cells to assess proliferation prior and subsequent to hydrogen peroxide treatment for oxidative stress induction. The results demonstrated a successful adhesion of cells onto the substrate and their proliferation. Furthermore, the platform is suitable for carrying out optical monitoring of cultures and Raman analysis. In fact, it was possible to discriminate spectra deriving from control and hydrogen peroxide-treated cells in terms of DNA backbone and cellular membrane modification effects provoked by reactive oxygen species (ROS) activity. The 800–1100 cm⁻¹ band highlights the destructive effects of ROS on the DNA backbone’s structure, as its rupture modifies its vibration; moreover, unpaired nucleotides are increased in treated sample, as shown in the 1154–1185 cm⁻¹ band. Protein synthesis deterioration, led by DNA structure damage, is highlighted in the 1257–1341 cm⁻¹, 1440–1450 cm⁻¹, and 1640–1670 cm⁻¹ bands. Furthermore, membrane damage is emphasized in changes in the 1270, 1301, and 1738 cm⁻¹ frequencies, as phospholipid synthesis is accelerated in an attempt to compensate for the membrane damage brought about by the ROS attack. This study highlights the potential use of this platform as an alternative to conventional culturing and analysis procedures, considering that cell culturing, optical imaging, and Raman spectroscopy can be performed simultaneously on living cells with minimal cellular stress and without the need for labeling or fixation. Full article

(This article belongs to the Special Issue Microfluidic Devices for Biological Sample Analysis)

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16 pages, 2946 KiB

Open AccessArticle

AI-Driven Comprehensive SERS-LFIA System: Improving Virus Automated Diagnostics Through SERS Image Recognition and Deep Learning

by Shuai Zhao, Meimei Xu, Chenglong Lin, Weida Zhang, Dan Li, Yusi Peng, Masaki Tanemura and Yong Yang

Biosensors 2025, 15(7), 458; https://doi.org/10.3390/bios15070458 - 16 Jul 2025

Abstract

Highly infectious and pathogenic viruses seriously threaten global public health, underscoring the need for rapid and accurate diagnostic methods to effectively manage and control outbreaks. In this study, we developed a comprehensive Surface-Enhanced Raman Scattering–Lateral Flow Immunoassay (SERS-LFIA) detection system that integrates SERS [...] Read more.

Highly infectious and pathogenic viruses seriously threaten global public health, underscoring the need for rapid and accurate diagnostic methods to effectively manage and control outbreaks. In this study, we developed a comprehensive Surface-Enhanced Raman Scattering–Lateral Flow Immunoassay (SERS-LFIA) detection system that integrates SERS scanning imaging with artificial intelligence (AI)-based result discrimination. This system was based on an ultra-sensitive SERS-LFIA strip with SiO₂-Au NSs as the immunoprobe (with a theoretical limit of detection (LOD) of 1.8 pg/mL). On this basis, a negative–positive discrimination method combining SERS scanning imaging with a deep learning model (ResNet-18) was developed to analyze probe distribution patterns near the T line. The proposed machine learning method significantly reduced the interference of abnormal signals and achieved reliable detection at concentrations as low as 2.5 pg/mL, which was close to the theoretical Raman LOD. The accuracy of the proposed ResNet-18 image recognition model was 100% for the training set and 94.52% for the testing set, respectively. In summary, the proposed SERS-LFIA detection system that integrates detection, scanning, imaging, and AI automated result determination can achieve the simplification of detection process, elimination of the need for specialized personnel, reduction in test time, and improvement of diagnostic reliability, which exhibits great clinical potential and offers a robust technical foundation for detecting other highly pathogenic viruses, providing a versatile and highly sensitive detection method adaptable for future pandemic prevention. Full article

(This article belongs to the Special Issue Surface-Enhanced Raman Scattering in Biosensing Applications)

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14 pages, 2434 KiB

Open AccessArticle

Rapid Detection of VOCs from Pocket Park Surfaces for Health Risk Monitoring Using SnO₂/Nb₂C Sensors

by Peng Wang, Yuhang Liu, Sheng Hu, Haoran Han, Liangchao Guo and Yan Xiao

Biosensors 2025, 15(7), 457; https://doi.org/10.3390/bios15070457 - 15 Jul 2025

Abstract

The organic volatile compound gases (VOCs) emitted by the rubber running tracks in the park pose a threat to human health. Currently, the challenge lies in how to detect the VOC gas concentration to ensure it is below the level that is harmful [...] Read more.

The organic volatile compound gases (VOCs) emitted by the rubber running tracks in the park pose a threat to human health. Currently, the challenge lies in how to detect the VOC gas concentration to ensure it is below the level that is harmful to human health. This study developed a low-power acetone gas sensor based on SnO₂/Nb₂C MXene composites, designed for monitoring acetone gas in pocket park rubber tracks at room temperature. Nb₂C MXene was combined with SnO₂ nanoparticles through a hydrothermal method, and the results showed that the SnO₂/Nb₂C MXene composite sensor (SnM-2) exhibited a response value of 146.5% in detecting 1 ppm acetone gas, with a response time of 155 s and a recovery time of 295 s. This performance was significantly better than that of the pure SnO₂ sensor, with a 6-fold increase in response value. Additionally, the sensor exhibits excellent selectivity against VOCs, such as ethanol, formaldehyde, and isopropanol, with good stability (~20 days) and reversibility (~50). It can accurately recognize acetone gas concentrations and has been successfully used to simulate rubber track environments and provide accurate acetone concentration data. This study provides a feasible solution for monitoring VOCs in rubber tracks and the foundation for the development of low-power, high-performance, and 2D MXene gas sensors. Full article

(This article belongs to the Special Issue Advances, Challenges and Opportunities in the Use of 2D Materials for Biosensing and Biomedical Applications)

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