Biosensors

26 pages, 3049 KB

Open AccessReview

Progress in Electrode Modifiers for Nitrite Electrochemical Sensing Applications

by Mohammad Aslam, Saood Ali, Khaled Hamdy, Danishuddin, Khursheed Ahmad and Rohit Kumar Singh Gautam

Biosensors 2025, 15(12), 783; https://doi.org/10.3390/bios15120783 - 27 Nov 2025

Abstract

It is well known that nitrite is widely used in industrial and agricultural sectors as a preservative, corrosion inhibitor, and intermediate in chemical synthesis; consequently, nitrite residues are often present in food, water, and the environment as a result of meat curing, fertilizer [...] Read more.

It is well known that nitrite is widely used in industrial and agricultural sectors as a preservative, corrosion inhibitor, and intermediate in chemical synthesis; consequently, nitrite residues are often present in food, water, and the environment as a result of meat curing, fertilizer use, and wastewater discharge. Despite having several applications, nitrite exerts toxic effects on human beings and aquatic life. Therefore, the monitoring of nitrite is of particular significance to avoid negative impacts on human health, the environment, and aquatic life. Previously, the electrochemical method has been extensively used for the development of nitrite sensors using various advanced electrode materials. Additionally, zinc oxide (ZnO), cerium oxide (CeO₂), titanium dioxide (TiO₂), copper oxide (CuO), iron oxides, nickel oxide (NiO), polymers, MXenes, reduced graphene oxide (rGO), carbon nanotubes (CNTs), graphitic carbon nitride (gCN), metal–organic frameworks (MOFs), and other composites have been utilized as electrocatalysts for the fabrication of nitrite electrochemical sensors. This review article provides an overview of the construction of nitrite sensors using advanced electrode materials. The electrochemical activities of the reported nitrite sensors are discussed. Furthermore, limitations and future perspectives regarding the determination of nitrite are discussed. Full article

(This article belongs to the Special Issue Electrochemical Biosensing at the Frontier: Materials, Mechanisms, and Applications)

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32 pages, 6343 KB

Open AccessArticle

Transcriptomic Evaluation of Hollow Microneedles-Mediated Drug Delivery for Rheumatoid Arthritis Therapy

by Zhibo Liu, Xiaotong Li, Suhang Liu, Yijing Cai, Xingyuan Xu, Siqi Gao, Chuanjie Yao, Linge Wang, Xi Xie, Yanbin Cai, Lelun Jiang, Jing Liu, Mingqiang Li, Yan Li, Xinshuo Huang and Huijiuan Chen

Biosensors 2025, 15(12), 782; https://doi.org/10.3390/bios15120782 - 27 Nov 2025

Abstract

Microneedle array-based drug delivery offers a minimally invasive and safe approach for breaching the skin barrier, enabling localized and targeted treatment—an advantage particularly valuable in chronic condition management, such as rheumatoid arthritis (RA). RA presents a multifaceted pathophysiology, often necessitating long-term pharmacological management. [...] Read more.

Microneedle array-based drug delivery offers a minimally invasive and safe approach for breaching the skin barrier, enabling localized and targeted treatment—an advantage particularly valuable in chronic condition management, such as rheumatoid arthritis (RA). RA presents a multifaceted pathophysiology, often necessitating long-term pharmacological management. However, conventional oral administration may lead to systemic drug distribution, increasing the likelihood of adverse effects, and ultimately undermining therapeutic efficacy. In this study, a hollow microneedle array was employed for effective delivery of Tofacitinib and the antioxidant N-acetylcysteine (NAC). A comprehensive evaluation was conducted across multiple levels, in which inflammation and cartilage degradation were assessed histologically using hematoxylin-eosin (H&E) and Safranin O–Fast Green staining. Radiologically, micro-computed tomography (micro-CT) was employed to visualize bone structure alterations. On the molecular level, enzyme-linked immunosorbent assay (ELISA) was used to quantify inflammatory cytokines and oxidative stress markers. Furthermore, differentially expressed genes and enriched signaling pathways were identified through transcriptomic profiling pre- and post-treatment. And the potential regulatory targets and mechanistic insights into the therapeutic response were elucidated through correlation analyses between gene expression profiles and pathological indicators. This study provides a mechanistic and computational basis for precision targeted therapy, validates the efficacy and safety of microneedle delivery in a rheumatoid arthritis (RA) model, and demonstrates its potential application in local drug delivery strategies. Full article

(This article belongs to the Special Issue Wearable Sensors and Systems for Continuous Health Monitoring)

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13 pages, 1398 KB

Open AccessArticle

Antibody-Based Biolayer Interferometry Platform for Rapid Detection of Neutrophil Gelatinase-Associated Lipocalin

by Somphot Saoin, Sawitree Nangola, Kannaporn Intachai, Eakkapote Prompunt, Chiraphat Kloypan, Trairak Pisitkun and Chatikorn Boonkrai

Biosensors 2025, 15(12), 781; https://doi.org/10.3390/bios15120781 - 27 Nov 2025

Abstract

Neutrophil gelatinase-associated lipocalin (NGAL) has emerged as a critical biomarker for the early diagnosis of acute kidney injury (AKI). The development of novel detection platforms that combine rapid analysis with high sensitivity is essential for improving clinical outcomes. In this study, we established [...] Read more.

Neutrophil gelatinase-associated lipocalin (NGAL) has emerged as a critical biomarker for the early diagnosis of acute kidney injury (AKI). The development of novel detection platforms that combine rapid analysis with high sensitivity is essential for improving clinical outcomes. In this study, we established an antibody-based detection system for NGAL using biolayer interferometry (BLI), a label-free optical biosensing technique that monitors real-time interference patterns generated by white light reflected from biomolecular binding events on a biosensor surface. A panel of six anti-NGAL monoclonal antibodies was generated and characterized for its binding properties, identifying candidates with high specificity for NGAL. For robust sensor functionalization, selected monoclonal antibodies were biotinylated and immobilized onto streptavidin-coated biosensor tips, establishing a stable and efficient detection interface. The optimized BLI platform demonstrated a limit of detection (LOD) of 46.1 ng/mL with wild dynamic range of 19 to 40,000 ng/mL. The platform’s accuracy was validated using human serum samples, with spike-and-recovery experiments yielding recovery rates of 96.6–104.6%. This demonstrates the capability to accurately quantify NGAL under physiologically relevant conditions with minimal matrix interference. Furthermore, the real-time kinetic measurements enabled rapid analysis, with the entire assay completed in less than half an hour. These findings establish a proof-of-concept for a BLI-based biosensor for NGAL detection, demonstrating sensitivity and specificity that show potential for clinical applications. Full article

(This article belongs to the Special Issue Immunosensors: Design and Applications)

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23 pages, 8446 KB

Open AccessArticle

Bacterial lux-Biosensors for Detecting Specific Cell Responses to Membrane Damage

by Vladimir A. Plyuta, Evgeny Y. Gnuchikh, Anastasiia A. Gorbunova, Veronika D. Udovichenko, Kristina A. Sinyakova, Daria E. Sidorova, Olga A. Koksharova, Sergey V. Bazhenov and Olga E. Melkina

Biosensors 2025, 15(12), 780; https://doi.org/10.3390/bios15120780 - 26 Nov 2025

Abstract

Whole-cell biosensors represent one of the tools used for assessing the effects of various agents on living cells. Here we have constructed and tested whole-cell lux-biosensors to detect membrane damage in both Gram-negative and Gram-positive bacteria using the stress-inducible promoter of the [...] Read more.

Whole-cell biosensors represent one of the tools used for assessing the effects of various agents on living cells. Here we have constructed and tested whole-cell lux-biosensors to detect membrane damage in both Gram-negative and Gram-positive bacteria using the stress-inducible promoter of the pspA gene from Escherichia coli and Bacillus subtilis fused to the lux genes from Photorhabdus luminescens. These biosensors increase their luminescence in response to treatment with a number of known membrane-damaging compounds, such as ethanol, Triton X-100, polymyxin B, dimethylsulfoxide (DMSO) and melittin. E. coli- and B. subtilis-based biosensors demonstrated differences in response to the action of the same membrane-damaging agent. Thus, ethanol and polymyxin B specifically induced the pspA promoter in both lux-biosensors, but the induction amplitude was higher in the E. coli. Triton X-100 and melittin specifically induced the pspA promoter exclusively in B. subtilis cells, while DMSO induced it only in E. coli cells. This indicates a difference in the stress response of the Psp system to membrane-damaging agents in E. coli and B. subtilis cells. Thus, we demonstrated the functionality and efficiency of the constructed lux-biosensors and, using them, showed that some of the tested compounds are able to specifically activate Psp stress response systems in case of membrane damage. Full article

(This article belongs to the Special Issue Microbial Biosensor: From Design to Applications—2nd Edition)

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Graphical abstract

11 pages, 1138 KB

Open AccessArticle

Ultra-Sensitive Detection of Mercury by Using Field-Effect Transistor Biosensors Based on Single-Walled Carbon Nanotubes

by Chao Lu, Qiuxiang Lv, Yuanwei Lin and Li Gao

Biosensors 2025, 15(12), 779; https://doi.org/10.3390/bios15120779 - 26 Nov 2025

Abstract

In recent years, the amount of mercury discharged by human activities has continued to increase. Most of the mercury in surface water settles into the sediment, where it can be directly or indirectly transformed into mercury ion (Hg²⁺) compounds (such as [...] Read more.

In recent years, the amount of mercury discharged by human activities has continued to increase. Most of the mercury in surface water settles into the sediment, where it can be directly or indirectly transformed into mercury ion (Hg²⁺) compounds (such as dimethylmercury) under the action of microorganisms. Hg²⁺ display high toxicity and bioaccumulation in food, such as fish and rice, and thus the contamination of mercury ion is a serious concern for human health. Practical Hg²⁺ detection methods are usually limited by the sensitivity and selectivity of the used methods, such as colorimetric determination and fluorescence biosensor based on the solution phase. Therefore, it is urgent to develop Hg²⁺ detection methods in the practical environment with high sensitivity and selectivity. DNA is low-cost, relatively stable, and has been used for different fields. In this study, DNA for Hg²⁺detection was absorbed on the surface of single-walled carbon nanotubes (SWNTs) by using 1,5-diaminonaphthalene (DAN) based on field-effect transistor (FET) biosensors. The interaction between DNA and Hg²⁺ can be directly converted into electrical signals based on the SWNTs biosensors. The experimental results showed that the limit of detection (LOD) of Hg²⁺ without the phase-locked amplifier was about 42.6 pM. The function of the phase-locked amplifier is to achieve fast detection of the biosensor with strong anti-noise ability. Intriguingly, the sensitivity of the biosensor combined with a phase-locked amplifier to detect Hg²⁺ was further improved to be 5.14 pM compared with some current methods of biosensors. Furthermore, this biosensor has an excellent selectivity and practical detection in tap water, which demonstrates its high performance and low cost in practical application in Hg²⁺ detection. These results show this method for Hg²⁺ detection using SWNTs biosensors with a phase-locked amplifier is promising. Full article

(This article belongs to the Special Issue Nano-Biosensors and Their Applications for In Vivo/Vitro Diagnosis—3rd Edition)

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32 pages, 6586 KB

Open AccessReview

Research Progress of Biosensors in the Detection of Pesticide Residues and Heavy Metals in Tea Leaves

by Pin Li, Miaopeng Chen, Tianle Yao, Long Wu, Shanran Wang, Yu Han, Ying Song and Jia Yin

Biosensors 2025, 15(12), 778; https://doi.org/10.3390/bios15120778 - 26 Nov 2025

Abstract

Tea, a worldwide prevalent beverage, is continually contaminated by pesticide residues and heavy metals, presenting considerable health concerns to consumers. Nonetheless, effective monitoring is limited by conventional detection techniques—such as gas chromatography (GC) and inductively coupled plasma mass spectrometry (ICP-MS)—which, despite their high [...] Read more.

Tea, a worldwide prevalent beverage, is continually contaminated by pesticide residues and heavy metals, presenting considerable health concerns to consumers. Nonetheless, effective monitoring is limited by conventional detection techniques—such as gas chromatography (GC) and inductively coupled plasma mass spectrometry (ICP-MS)—which, despite their high precision, necessitate intricate pretreatment, incur substantial operational expenses, and are inadequate for swift on-site analysis. Biosensors have emerged as a viable option, addressing this gap with their exceptional sensitivity, rapid response, and ease of operation.This review rigorously evaluates recent advancements in biosensing technologies for the detection of pesticide residues and heavy metals in tea, emphasizing the mechanisms, analytical performance, and practical applicability of prominent platforms such as fluorescence, surface-enhanced Raman scattering (SERS), surface plasmon resonance (SPR), colorimetric, and electrochemical biosensors. Electrochemical and fluorescent biosensors provide the highest promise for portable, on-site use owing to their enhanced sensitivity, cost-effectiveness, and flexibility to intricate tea matrices. The paper further emphasizes upcoming techniques such multi-component detection, microfluidic integration, and AI-enhanced data processing. Biosensors provide significant potential to revolutionize tea safety monitoring, with future advancements dependent on the synergistic incorporation of sophisticated nanomaterials, intelligent microdevices, and real-time analytics across the whole “tea garden-to-cup” supply chain. Full article

(This article belongs to the Special Issue Bioassays and Biosensors for Rapid Detection and Analysis (2nd Edition))

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23 pages, 921 KB

Open AccessReview

Nano-Engineered Sensor Systems for Disease Diagnostics: Advances in Smart Healthcare Applications

by Tianjun Ma, Jianhai Sun, Ning Xue, Jamal N. A. Hassan and Adeel Abbas

Biosensors 2025, 15(12), 777; https://doi.org/10.3390/bios15120777 - 26 Nov 2025

Abstract

Nano-engineered sensor systems represent a paradigm shift in disease diagnostics, offering unprecedented capabilities for precision medicine. This review methodically evaluates these advanced platforms, consolidating recent advancements across four critical clinical domains: diabetes monitoring, cancer detection, infectious disease diagnostics and cardiac/genetic health. We demonstrate [...] Read more.

Nano-engineered sensor systems represent a paradigm shift in disease diagnostics, offering unprecedented capabilities for precision medicine. This review methodically evaluates these advanced platforms, consolidating recent advancements across four critical clinical domains: diabetes monitoring, cancer detection, infectious disease diagnostics and cardiac/genetic health. We demonstrate how the unique properties of nanomaterials, such as graphene, quantum dots and plasmonic nanoparticles, are being harnessed to achieve remarkable gains in analytical sensitivity, selectivity and real-time monitoring. Specific breakthroughs include graphene-based sensors attaining clinically significant limits for continuous glucose monitoring, quantum dot bioconjugates enabling ultrasensitive imaging of cancer biomarkers and surface-enhanced Raman spectroscopy (SERS) probes facilitating early tumor identification. Furthermore, nanosensors exhibit exceptional precision in detecting viral antigens and genetic mutations, underscoring their robust translational potential. Collectively, these developments signal a clear trajectory toward integrated, intelligent healthcare ecosystems. However, for these promising technologies to transition into accessible and cost-effective diagnostic solutions, persistent challenges in scalability, manufacturing reproducibility and long-term biocompatibility must be addressed through continued interdisciplinary innovation. Full article

(This article belongs to the Special Issue Recent Advances in Biosensing Technologies for Single Cell Analysis)

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12 pages, 2487 KB

Open AccessArticle

Aptamer-Based Gold Nanoparticle Lateral Flow Assay for Rapid Detection of Cardiac Troponin I

by Jing Zhang, Jiayi Pang and Cheng Cui

Biosensors 2025, 15(12), 776; https://doi.org/10.3390/bios15120776 - 26 Nov 2025

Abstract

Cardiac troponin I (cTnI) is a critical biomarker for the diagnosis of acute myocardial infarction (AMI), but conventional detection methods are often time-consuming and require specialized laboratory equipment. To meet the need for rapid and feasible detection, there is an urgent demand for [...] Read more.

Cardiac troponin I (cTnI) is a critical biomarker for the diagnosis of acute myocardial infarction (AMI), but conventional detection methods are often time-consuming and require specialized laboratory equipment. To meet the need for rapid and feasible detection, there is an urgent demand for methods that are fast, specific, and easy to use. In this study, two aptamers (Tro4 and Tro6), which specifically bind to different epitopes of cTnI, were employed to construct a dual-aptamer sandwich system on a lateral flow assay (LFA) strip. The test strip can deliver results within 10 min and shows a detection limit of 11.70 ng·mL⁻¹. It also exhibited excellent stability after storage at room temperature for up to four months. The assay demonstrated high analytical accuracy, as evidenced by recovery rates from spiked serum samples ranging from 95.11% to 103.17%. These results suggest that the proposed aptamer-based LFA is highly suitable for rapid screening of cTnI, especially in point-of-care settings and resource-limited environments. From a diagnostic perspective, this method holds great promise for improving the timely detection and management of AMI and other myocardial injuries. Full article

(This article belongs to the Section Biosensors and Healthcare)

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16 pages, 1634 KB

Open AccessReview

Recent Advances in the Detection of Aflatoxin M1 in Milk and Dairy Products

by Anna Maria Maurelli, Lucia Catucci, Michelangelo Pascale, Sabato D’Auria and Maria Staiano

Biosensors 2025, 15(12), 775; https://doi.org/10.3390/bios15120775 - 26 Nov 2025

Abstract

There is an increasing demand to design user-friendly specific assays for the detection of analytes of interest for healthcare, environment, and agrifood. Modern biotechnology has approached this problem by using proteins, enzymes, or RNA/DNA fragments (aptamers) as biological recognition elements for biosensors/assays. The [...] Read more.

There is an increasing demand to design user-friendly specific assays for the detection of analytes of interest for healthcare, environment, and agrifood. Modern biotechnology has approached this problem by using proteins, enzymes, or RNA/DNA fragments (aptamers) as biological recognition elements for biosensors/assays. The idea is to exploit the extremely wide range of selective affinities sculpted into the various proteins or aptamers by biological evolution. The number of compounds specifically recognized by different proteins and aptamers is very large and ranges from small molecules to macromolecules. The advantages of using proteins and aptamers as molecular recognition elements (MRE) for assays/biosensors are many, and involve relatively low costs in design and synthesis, water solubility, and finally high specificity. Many of the analytes of interest in the food control industry are relatively small. In this case, aptamers and antibodies are widely used as specific MREs in designing advanced biosensors. Aflatoxin B1 (AFB1) is the most frequently found aflatoxin in contaminated food samples, and is one of the most potent natural compounds in terms of genotoxicity and carcinogenicity. Aflatoxin M1 (AFM1) is the hydroxylated metabolite of AFB1 and is usually found in milk and milk products as a carry-over of AFB1 in animals that have ingested contaminated feed. AFM1 is also found in human milk, and has been shown to be hepatotoxic and carcinogenic. Here, we present recent advances in assays and biosensors based on the use of antibodies and aptamers as MREs that have been developed for monitoring the presence of AFM1 in milk and dairy products. The limitations and advantages of aptamer- and antibody-based assays/biosensors are discussed, as well as future research perspectives. Full article

(This article belongs to the Section Environmental Biosensors and Biosensing)

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26 pages, 1923 KB

Open AccessReview

The Development of Foodborne Pathogen Detection and Biosensor Design for Surface Plasmon Resonance Technology

by Ye Hu, Jun Yang, Jian Chen, Xiaojie Sun, Wenyan Hu and Xinmei Liu

Biosensors 2025, 15(12), 774; https://doi.org/10.3390/bios15120774 - 25 Nov 2025

Abstract

The rapid detection of pathogenic bacteria is important for the global public health field. Existing detection technologies are generally limited by log efficiency, high costs, and susceptibility to contamination. Advanced detection methods, such as surface plasmon resonance (SPR), have been proposed to break [...] Read more.

The rapid detection of pathogenic bacteria is important for the global public health field. Existing detection technologies are generally limited by log efficiency, high costs, and susceptibility to contamination. Advanced detection methods, such as surface plasmon resonance (SPR), have been proposed to break these limitations, with the advantages of fast detection speed and high sensitivity. SPR operates on the principle of attenuated total internal reflection at a metal–dielectric interface. This technique exploits the resonant absorption of incident photons by surface plasmons, facilitating the detection of tiny variations in the local refractive index by tracking the resonance condition change. This review provides a comprehensive overview of the development in the detection of foodborne pathogens using SPR technology, including a detailed discussion of the working principles of SPR, related instrumentation, and various detection methods. Specifically, this review focuses on a discussion of different SPR detection methods in terms of assembly processes, detection specificity, sensitivity, and detection limits in SPR biosensors, aiming to provide the readers with a fundamental knowledge of SPR. Full article

(This article belongs to the Special Issue Advances in Portable and Wearable Sensing Systems for Biochemical Monitoring)

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22 pages, 2583 KB

Open AccessReview

Intelligent Biosensors Based on Hyaluronic Acid Hydrogels for Monitoring Chronic Wound Healing with the Involvement of Artificial Intelligence

by Antonia-Mihaela Nicolae, Mihaela Badea, Sandica Bucurica, Florina Rasaliu and Elena Mihaela Constantinescu

Biosensors 2025, 15(12), 773; https://doi.org/10.3390/bios15120773 - 25 Nov 2025

Abstract

Chronic wounds, such as those caused by diabetes, burns, and pressure ulcers, pose significant healthcare challenges due to their slow healing and potential for infections. Traditional methods for monitoring wound healing are often intrusive, slow, and lack real-time data. To overcome these limitations, [...] Read more.

Chronic wounds, such as those caused by diabetes, burns, and pressure ulcers, pose significant healthcare challenges due to their slow healing and potential for infections. Traditional methods for monitoring wound healing are often intrusive, slow, and lack real-time data. To overcome these limitations, innovative biosensors using hyaluronic acid hydrogels have emerged as a promising solution. As a non-intrusive, biocompatible platform, these biosensors can track pH, glucose levels, inflammatory proteins, and other key biomarkers as wounds heal. With the integration of artificial intelligence (AI), they enable personalized treatment adjustments and early complication detection through real-time data analysis and predictive modeling. This review discusses the recent progress of hyaluronic acid hydrogel biosensors for long-term wound healing, evaluating their strengths, challenges, and potential future improvements. This work aims to enhance chronic wound management and improve multiple clinical outcomes by focusing on the intersection of biomaterial innovation and AI. Full article

(This article belongs to the Special Issue Hydrogel-Based Biosensors: From Design to Applications)

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17 pages, 3317 KB

Open AccessArticle

Research on Optimizing Electronic Nose Sensor Arrays for Oyster Cold Chain Detection Based on Multi-Algorithm Collaborative Optimization

by Yirui Kong, Zhenhua Guo, Weifu Kong, Hongjuan Li, Xinrui Li, Xiaoshuan Zhang, Xinzhe Liu, Ruihan Wu and Baichuan Wang

Biosensors 2025, 15(12), 772; https://doi.org/10.3390/bios15120772 - 25 Nov 2025

Abstract

Real-time quality monitoring during oyster cold chain transportation is a critical component in ensuring food safety. Addressing the issues of high redundancy and insufficient environmental adaptability in existing electronic nose systems, this study proposes a multi-algorithm collaborative optimization strategy for sensor array optimization. [...] Read more.

Real-time quality monitoring during oyster cold chain transportation is a critical component in ensuring food safety. Addressing the issues of high redundancy and insufficient environmental adaptability in existing electronic nose systems, this study proposes a multi-algorithm collaborative optimization strategy for sensor array optimization. The system integrates ten gas sensors (TGS series, MQ series), employing Random Forest (RFA), Simulated Annealing (SA), and Genetic Quantum Particle Swarm Optimization (GA-QPSO) for sensor selection. KNN combined with K-means analysis validates the optimization outcomes. Under cold chain environments at 4 °C, 12 °C, 20 °C, and 28 °C, a multidimensional dataset was constructed by extracting global variables using feature correlation functions. Experiments demonstrate that the optimized sensor count decreases from 10 to 5–6 units while maintaining recognition accuracy above 95%, with redundancy decreased by over 40%. This multi-algorithm collaborative optimization effectively balances sensor array recognition precision, resource efficiency, and environmental adaptability, providing an intelligent, high-precision technical solution for oyster cold chain monitoring. Full article

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

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20 pages, 4882 KB

Open AccessArticle

Mn Oxide Nanowire/ZIF-8 Composites with Multiple Enzyme-like Activities for Enantioselective Glutamate Sensing

by Guo-Ying Chen, Mao-Ling Luo, Jing-Jing Dai and Feng-Qing Yang

Biosensors 2025, 15(12), 771; https://doi.org/10.3390/bios15120771 - 25 Nov 2025

Abstract

A composite material of Mn oxide nanowires and ZIF-8 (Mn_xO_y NWs@ZIF-8-RD) with controllable sizes and morphologies (rhombic dodecahedron-shape) was successfully synthesized under mild reaction conditions. The systematic investigation into the effects of synthesis conditions of the material on their microstructure [...] Read more.

A composite material of Mn oxide nanowires and ZIF-8 (Mn_xO_y NWs@ZIF-8-RD) with controllable sizes and morphologies (rhombic dodecahedron-shape) was successfully synthesized under mild reaction conditions. The systematic investigation into the effects of synthesis conditions of the material on their microstructure and crystalline morphology was conducted. The material function as “tandem enzymes”, exhibiting multiple enzyme-like activities, such as peroxidase (POD)- and glutamate-oxidase (Glu OXD)-like activities. Kinetic studies reveal that the Mn_xO_y NWs@ZIF-8-RD has excellent enzyme-like catalytic activity, with high substrate affinity and a maximum reaction rate of (H₂O₂: 840.52 × 10⁻⁸ M·S⁻¹). Mn_xO_y NWs@ZIF-8-RD shows remarkable enantioselectivity for Glu enantiomers based on its POD- and Glu OXD-like activities. By integrating theoretical and experimental approaches, the recognition mechanism was preliminarily elucidated. In short, this study offered valuable insights for developing sophisticated functional materials and provided methodological references for Glu enantiomer recognition and quantitative detection. Full article

(This article belongs to the Section Biosensor Materials)

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28 pages, 8033 KB

Open AccessReview

The Application of Microfluidics in Traditional Chinese Medicine Research

by Shanxi Zhu, Xuanqi Ke, Yayuan Li, Zixuan Shu, Jiale Zheng, Zihan Xue, Wuzhen Qi and Bing Xu

Biosensors 2025, 15(12), 770; https://doi.org/10.3390/bios15120770 - 25 Nov 2025

Abstract

Microfluidics enables precise manipulation of scarce Traditional Chinese Medicine (TCM) samples while accelerating analysis and enhancing sensitivity. Device-level structures explain these gains: staggered herringbone and serpentine mixers overcome low-Reynolds-number constraints to shorten diffusion distances and reduce incubation time; flow-focusing or T-junction droplet generators [...] Read more.

Microfluidics enables precise manipulation of scarce Traditional Chinese Medicine (TCM) samples while accelerating analysis and enhancing sensitivity. Device-level structures explain these gains: staggered herringbone and serpentine mixers overcome low-Reynolds-number constraints to shorten diffusion distances and reduce incubation time; flow-focusing or T-junction droplet generators create one-droplet–one-reaction compartments that suppress cross-talk and support high-throughput screening; “Christmas-tree” gradient generators deliver quantitative dosing landscapes for mechanism-aware assays; micropillar/weir arrays and nanostructured capture surfaces raise surface-to-volume ratios and probe density, improving capture efficiency and limits of detection; porous-membrane, perfused organ-on-a-chip architectures recreate apical–basolateral transport and physiological shear, enabling metabolism-aware pharmacology and predictive toxicology; wax-patterned paper microfluidics (µPADs) use capillary networks for instrument-free metering in field settings; and lab-on-a-disc radial channels/valves exploit centrifugal pumping for parallelised workflows. Framed by key performance indicators—sensitivity (LOD/LOQ), reliability/reproducibility, time-to-result, throughput, sample volume, and sustainability/cost—this review synthesises how such structures translate into value across TCM quality/safety control, toxicology, pharmacology, screening, and delivery. Emphasis on structure–function relationships clarifies where microfluidics most effectively closes gaps between chemical fingerprints and biological potency and indicates practical routes for standardisation and deployment. Full article

(This article belongs to the Special Issue Recent Advances in Biosensors for Pharmaceutical Analysis)

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10 pages, 2402 KB

Open AccessArticle

Novel System for Measuring Tension Force in Eyeball Movement

by Jae Yun Sung, Ju Mi Kim, Il Doh and Yeon-Hee Lee

Biosensors 2025, 15(12), 769; https://doi.org/10.3390/bios15120769 - 25 Nov 2025

Abstract

Accurate assessment of extraocular muscle mechanics is crucial for diagnosing and treating ocular motility disorders, yet current methods, such as the forced duction test, rely on subjective tactile sensation and gross visual observation. To overcome the limitations of subjectivity and the impracticality of [...] Read more.

Accurate assessment of extraocular muscle mechanics is crucial for diagnosing and treating ocular motility disorders, yet current methods, such as the forced duction test, rely on subjective tactile sensation and gross visual observation. To overcome the limitations of subjectivity and the impracticality of previous quantitative devices, we developed a novel biosensing system capable of simultaneously and objectively measuring passive ocular tension and rotation angle during forced duction. The system integrates custom-engineered surgical forceps equipped with dual strain gauges and an infrared video camera that precisely tracks pupil displacement to calculate real-time rotation angle. We clinically validated this system in a prospective study involving 10 patients (20 eyes) with intermittent exotropia, with measurements performed under general anesthesia. Reliable tension–angle curves were successfully obtained in all cases without complications. Passive tension increased progressively with ocular rotation, following a linear-parabolic trajectory up to 40°. The mean duction force of the medial and lateral rectus muscles showed comparable symmetry. This lightweight, practical, and objective biosensing system offers a reliable tool for quantifying ocular mechanics, with the potential to enhance diagnostic accuracy, enable individualized surgical planning, and support fundamental research in ocular motility disorders. Full article

(This article belongs to the Section Biosensors and Healthcare)

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20 pages, 2593 KB

Open AccessArticle

Size Effects of Silver Nanoparticles and Magnetic Beads on Silver-Gold Galvanic Exchange in Aptamer-Based Electrochemical Assays

by Eman Alwarsh, Trang Bui, Marco Cardenas, Daniel Adrian and Charuksha Walgama

Biosensors 2025, 15(12), 768; https://doi.org/10.3390/bios15120768 - 25 Nov 2025

Abstract

In this work, we investigated the influence of silver nanoparticle (AgNP) size (diameters of 20, 50, and 100 nm) and magnetic bead (MB) size (diameters from 100 to 4500 nm) on silver-gold galvanic exchange signal generation in magnetic electrochemical assays. Two conjugation strategies, [...] Read more.

In this work, we investigated the influence of silver nanoparticle (AgNP) size (diameters of 20, 50, and 100 nm) and magnetic bead (MB) size (diameters from 100 to 4500 nm) on silver-gold galvanic exchange signal generation in magnetic electrochemical assays. Two conjugation strategies, including biotin-streptavidin interaction and a streptavidin-specific aptamer interaction, were compared to assess differences in binding chemistry and conjugation efficiency. Calibration studies showed that 50 nm diameter AgNPs provided the best sensitivity and galvanic exchange efficiency, yielding the lowest detection limits across both conjugation strategies. Larger AgNPs produced stronger signals but reached saturation rapidly, whereas smaller particles required higher concentrations to achieve equivalent silver content. Among MBs, 1000 nm beads consistently gave the highest galvanic exchange efficiency, offering sufficient surface area for AgNP loading while minimizing steric hindrance and electrode obstruction. These findings were confirmed by complementary electrochemical impedance spectroscopy, UV-Vis absorbance, and SEM imaging, which collectively demonstrated the strong influence of bead size on charge transfer resistance and conjugation efficiency. Overall, the combination of 50 nm AgNPs with 1000 nm MBs emerged as the optimal configuration, providing improved sensitivity and reproducibility. We believe these results offer valuable design guidelines for the development of next-generation aptamer-based electrochemical biosensors for biomarker detection. Full article

(This article belongs to the Special Issue Aptamer-Based Biosensors for Point-of-Care Diagnostics)

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16 pages, 1582 KB

Open AccessArticle

Monitoring Inhibition of Hemoglobin Peroxidase Activity After Exposure to Cigarette Smoke Using an Electrochemical Biosensor

by Alfonso Sequeda-Juárez, Flor Cortés-Ortegón, Diego Ortega-Picazo, José Antonio García-García, Ana María Espinosa-García and Celia Sánchez-Pérez

Biosensors 2025, 15(12), 767; https://doi.org/10.3390/bios15120767 - 25 Nov 2025

Abstract

This work presents a catalysis-based electrochemical biosensor to evaluate the peroxidase-like activity of methemoglobin (Hb-PLA) after exposure to cigarette smoke (CS) at different time intervals. The system consists of a microelectrode array coupled with a PDMS chamber containing a methemoglobin solution (biorecognition element). [...] Read more.

This work presents a catalysis-based electrochemical biosensor to evaluate the peroxidase-like activity of methemoglobin (Hb-PLA) after exposure to cigarette smoke (CS) at different time intervals. The system consists of a microelectrode array coupled with a PDMS chamber containing a methemoglobin solution (biorecognition element). Hydrogen peroxide (H₂O₂) acts as the substrate, while 3,3′,5,5′-tetramethylbenzidine (TMB) functions as the chromogenic substrate for the Hb-PLA through its oxidation reaction. A spectrophotometric technique is used as a reference method to assess the catalytic activity of methemoglobin. Positive control samples exhibited higher absorbance, indicating strong catalytic activity, whereas CS-exposed samples showed a marked reduction, which was confirmed by the negative control. Cyclic voltammetry revealed significant alterations in the oxidation and reduction peaks of the CS-exposed samples. Therefore, chronoamperometry was employed to quantify the charge transfer as the electrochemical response associated with Hb-PLA, yielding a sensitivity of 0.86 ± 0.06 (%Hb-PLA/mC) and a limit of detection (LOD) of 0.23 (mC). The results demonstrate that cigarette smoke impairs the Hb-PLA in a time-dependent manner, with longer exposure reducing the activity by up to 25%. The proposed biosensor provides a rapid, sensitive, and straightforward strategy for detecting functional alterations in solutions of methemoglobin induced by environmental pollutants such as cigarette smoke. Full article

(This article belongs to the Special Issue Bioassays and Biosensors for Rapid Detection and Analysis (2nd Edition))

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33 pages, 3693 KB

Open AccessReview

Nanomaterials-Enhanced Electrochemical Biosensors for Epithelial Cancer Diagnosis: Recent Advances

by Matías Regiart, Alba M. Gimenez, Francisco G. Ortega, Germán E. Gómez, Juan Sainz, Gonzalo R. Tortella and Martín A. Fernández-Baldo

Biosensors 2025, 15(12), 766; https://doi.org/10.3390/bios15120766 - 22 Nov 2025

Abstract

In recent years, the interest in electrochemical biosensors has been constantly growing for epithelial cancer diagnosis and prognosis. The incorporation of the different nanomaterials as metal nanoparticles, magnetic nanoparticles, carbon nanomaterials, Metal–Organic Frameworks (MOFs), and nanocomposites, along with specific monoclonal antibodies, and nucleic [...] Read more.

In recent years, the interest in electrochemical biosensors has been constantly growing for epithelial cancer diagnosis and prognosis. The incorporation of the different nanomaterials as metal nanoparticles, magnetic nanoparticles, carbon nanomaterials, Metal–Organic Frameworks (MOFs), and nanocomposites, along with specific monoclonal antibodies, and nucleic acids (aptamers) has improved both sensitivity and specificity in these methodologies. In this review, we have presented examples of electrochemical biosensors for the determination of different epithelial cancer biomarkers. Based on numerous reports in the recent literature, we highlight the use of single and multiplexed analytical platforms for the quantification of epithelial cancer biomarkers. In addition, we outline potential development pathways, current challenges, and future prospects in the field of electrochemical immuno-, apta-, and genosensors. Full article

(This article belongs to the Special Issue Advanced Nanomaterials for Electrochemical Biosensing Application—2nd Edition)

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Graphical abstract

19 pages, 2325 KB

Open AccessArticle

Double Lateral Flow Test System for Simultaneous Immunodetection of Enantiomeric Forms of Antibiotics: An Ofloxacin Case Study

by Olga D. Hendrickson, Nadezhda A. Byzova, Anatoly V. Zherdev and Boris B. Dzantiev

Biosensors 2025, 15(12), 765; https://doi.org/10.3390/bios15120765 - 21 Nov 2025

Abstract

Antibiotic stereoisomers as components of medicines are typically characterized by different biological activities. Because pharmaceuticals can include a racemic mixture of stereoisomers, monitoring of all forms is required. One contaminant of food products, antibiotic ofloxacin (OFL), as a chiral compound, has two enantiomers—the [...] Read more.

Antibiotic stereoisomers as components of medicines are typically characterized by different biological activities. Because pharmaceuticals can include a racemic mixture of stereoisomers, monitoring of all forms is required. One contaminant of food products, antibiotic ofloxacin (OFL), as a chiral compound, has two enantiomers—the biologically active S-isomer and less active R-isomer. In this study, a sensitive immunochromatographic test system for simultaneous enantiospeсific detection of the two OFL isomers was developed for the first time. For this, polyclonal antibodies were produced, and conditions for a double lateral flow immunoassay (LFIA) were selected and optimized so that the cross-reactivity with another enantiomer was negligible. The LFIA was performed in a competitive format with gold nanoparticles as a label for secondary antibodies. The achieved LODs/cutoffs were 0.001/10 and 0.007/30 ng/mL for S-OFL and R-OFL detection, respectively; the assay procedure took only 15 min. A double LFIA was performed to detect S-OFL and R-OFL in milk with minimal sample pretreatment; the recoveries were 85–95%. The developed test system is an effective tool for the selective detection of both isomers of OFL, allowing for the avoidance of false negative results. This immunochromatographic approach can be promising for the control of other optically active food toxicants. Full article

(This article belongs to the Special Issue Biosensors for Healthcare and Environment: Current and Future Perspectives)

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