Biosensors

13 pages, 1507 KB

Open AccessArticle

SERS-Based Immunoassay for α-Fetoprotein Biomarker Detection Using an Au-Ag Nanostars Platform

by Josué Ismael García-Ramírez, Marcos Luna-Cervantes, Irma Yadira Izaguirre-Hernández, Julián Hernández-Torres, Enrique Juárez-Aguilar, Pablo Thomas-Dupont, José María Remes-Troche and Luis Zamora-Peredo

Biosensors 2025, 15(9), 632; https://doi.org/10.3390/bios15090632 - 22 Sep 2025

Viewed by 513

Abstract

Spiky Au-Ag nanostars offer intense plasmonic enhancement due to their sharp-tipped morphology, enabling powerful surface-enhanced Raman scattering (SERS). Here, we report a liquid-phase SERS platform that addresses current limitations in cancer biomarker detection, such as low sensitivity and dependence on Raman reporters. Nanostar [...] Read more.

Spiky Au-Ag nanostars offer intense plasmonic enhancement due to their sharp-tipped morphology, enabling powerful surface-enhanced Raman scattering (SERS). Here, we report a liquid-phase SERS platform that addresses current limitations in cancer biomarker detection, such as low sensitivity and dependence on Raman reporters. Nanostar concentration was tuned by simple centrifugation (10, 30, and 60 min), and their SERS performance was evaluated using methylene blue (MB) and mercaptopropionic acid (MPA) as probe molecules. Signal intensity scaled with nanostar content, enabling sensitive detection. Optimized nanostars were functionalized with MPA, 1-Ethyl-3-(3-dimethylamino1-Ethyl-3-(3dimethylaminopropyl1) carbodiimide (EDC), and N-Hydroxy succinimide (NHS) for covalent attachment of monoclonal anti-α-fetoprotein antibodies (AFP-Ab), facilitating the detection of AFP antigens across 167–38 ng/mL (antibody) and 500–0 ng/mL (antigen) ranges. The limit of detection (LOD) for the antigens was determined to be 16.73 ng/mL. Unlike conventional SERS systems, this aqueous, surfactant-free platform exploits the intrinsic vibrational modes of AFP, enabling sensitive and rapid biomarker detection with strong potential for early cancer diagnostics. Full article

(This article belongs to the Special Issue Surface Plasmon Resonance-Based Biosensors and Their Applications)

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27 pages, 2644 KB

Open AccessReview

by Agata Pane, Silvia Vicenzi, Chiara Mattioli, Dario Mordini, Arianna Menichetti and Marco Montalti

Biosensors 2025, 15(9), 631; https://doi.org/10.3390/bios15090631 - 22 Sep 2025

Viewed by 536

Abstract

Melanin-related materials efficiently emulate the adhesion properties of natural mussel filaments and have been used advantageously for surface modification and for fabrication of electrochemical sensors for detection of environmentally relevant targets. The most applicable advantages of melanin-based coatings are their biocompatibility and versatility, [...] Read more.

Melanin-related materials efficiently emulate the adhesion properties of natural mussel filaments and have been used advantageously for surface modification and for fabrication of electrochemical sensors for detection of environmentally relevant targets. The most applicable advantages of melanin-based coatings are their biocompatibility and versatility, and they can be easily prepared and modified according to simple and highly environmentally friendly procedures. For these reasons, melanin-related materials, in particular polydopamine, which can be obtained simply via oxidative polymerization of dopamine in an aqueous solution in the presence of atmospheric oxygen, have been applied in a large variety of scientific and technological fields. Here, we summarize and critically discuss the most recent and important applications of melanin-related materials in the development of electrochemical sensors for monitoring the environment and food. In particular, the examples used in this paper include toxic metal ions, drugs, and pesticides. In the final section of this paper, the actual limitations of the existing approach are discussed and possible future design improvements are suggested. 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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13 pages, 2593 KB

Open AccessArticle

Highly Sensitive THz SPR Biosensor Based on Graphene-Coupled Prism Otto Structure

by Yu Xie, Zean Shen, Mingming Zhang, Mengjiao Ren, Wei Huang and Leyong Jiang

Biosensors 2025, 15(9), 630; https://doi.org/10.3390/bios15090630 - 21 Sep 2025

Viewed by 433

Abstract

This study presents a theoretical investigation of a terahertz (THz) surface plasmon resonance (SPR) optical biosensor utilizing a graphene-integrated Otto configuration. Through systematic numerical simulations, we demonstrate that actively modulating graphene’s conductivity via an external magnetic field enables tunable SPR behavior with high [...] Read more.

This study presents a theoretical investigation of a terahertz (THz) surface plasmon resonance (SPR) optical biosensor utilizing a graphene-integrated Otto configuration. Through systematic numerical simulations, we demonstrate that actively modulating graphene’s conductivity via an external magnetic field enables tunable SPR behavior with high phase sensitivity. The proposed sensor achieves a phase sensitivity of up to

3.1043 \times 10^{5}

deg RIU⁻¹ in liquid sensing and

2.5854 \times 10^{4}

deg RIU⁻¹ in gas sensing. This simulation-based work establishes a foundational framework for the development of highly sensitive, magneto-optically tunable optical sensors, highlighting their potential in chemical detection and medical diagnostics. Full article

(This article belongs to the Special Issue Nanophotonics and Surface Waves in Biosensing Applications)

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32 pages, 4416 KB

Open AccessReview

Aptasensors for Rapid Detection of Hazards in Food: Latest Developments and Trends

by Anjie Guo, Yuan Zhang, Meifeng Jiang, Li Chen, Xinrong Jiang, Xiaobo Zou and Zongbao Sun

Biosensors 2025, 15(9), 629; https://doi.org/10.3390/bios15090629 - 21 Sep 2025

Viewed by 718

Abstract

The presence of hazardous substances in food poses a serious threat to our health. It is important to develop fast, convenient, and inexpensive assays for on-site sensitive analysis of various hazards in food. With the emergence and popularization of aptamers and biosensors, aptasensors [...] Read more.

The presence of hazardous substances in food poses a serious threat to our health. It is important to develop fast, convenient, and inexpensive assays for on-site sensitive analysis of various hazards in food. With the emergence and popularization of aptamers and biosensors, aptasensors have gradually become one of the most important detection techniques for substances such as nucleic acids and small molecules. This paper reviews the recent research progress in the field of aptasensor based on different technologies (such as electrochemistry, fluorescence, colorimetry, among others) for the rapid detection of hazards (such as foodborne pathogens, mycotoxins, pesticides, among others) in food. In addition, the current challenges of different aptasensors are described for the readers, and the future direction of aptasensors is envisioned by comparing the different technologies in order to develop a more suitable aptasensor. This review will not only promote the advancement of aptasensors but also their practical application in daily life to safeguard human health and food safety. Full article

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

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17 pages, 2088 KB

Open AccessReview

Rolling Circle Amplification as a Molecular Tool for Spatially Resolved Signal Amplification in Single Molecule Counting Assay

by Juhwan Park

Biosensors 2025, 15(9), 628; https://doi.org/10.3390/bios15090628 - 21 Sep 2025

Viewed by 579

Abstract

There have been rising interests in ultra-sensitive biosensing technologies for early diagnosis and prognosis monitoring of infectious diseases, cancers, and neurodegenerative diseases. Digital signal readout strategy represented by digital ELISA or digital PCR, advanced biosensing field enormously, which enables detection of biomolecules under [...] Read more.

There have been rising interests in ultra-sensitive biosensing technologies for early diagnosis and prognosis monitoring of infectious diseases, cancers, and neurodegenerative diseases. Digital signal readout strategy represented by digital ELISA or digital PCR, advanced biosensing field enormously, which enables detection of biomolecules under the detection limit of conventional biosensing methods. However, due to the need for compartmentalization and limited multiplex capability, it has been hurdled for utilization in applications requiring hierarchical resolution analysis such as sub-cellular molecules or molecular cargo of single cells or single extracellular vesicles (EVs). Rolling circle amplification (RCA), an isothermal DNA amplification method enabling localization of an amplified signal, can eliminate the need for compartmentalization and increase multiplex capability. It also has potential to expand applications of single molecule counting assay for understanding hierarchy of biological systems. In this review, recent advances in RCA-based single molecule counting assay are overviewed and their applications in single cells and single EVs quantitative analysis are discussed. Furthermore, the limitations and outlook of RCA-based single molecule counting assay are highlighted. Full article

(This article belongs to the Special Issue Point-of-Care Testing: Advances and Perspectives)

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15 pages, 1302 KB

Open AccessReview

Recent Advances in Microfluidic Biofuel Cells

by Takahiro Kawaguchi, Shota Ito, Daisuke Nakane and Takashiro Akitsu

Biosensors 2025, 15(9), 627; https://doi.org/10.3390/bios15090627 - 20 Sep 2025

Viewed by 437

Abstract

Traditionally, fuel cells operate by using small fuel molecules such as hydrogen and methanol to produce energy, water, and carbon dioxide. Enzyme biofuel cells use enzymes rather than precious metals as electrode catalysts. In recent years, enzyme-immobilized electrodes have been developed by combining [...] Read more.

Traditionally, fuel cells operate by using small fuel molecules such as hydrogen and methanol to produce energy, water, and carbon dioxide. Enzyme biofuel cells use enzymes rather than precious metals as electrode catalysts. In recent years, enzyme-immobilized electrodes have been developed by combining enzyme biofuel cells with microfluidic technology to improve the efficiency and performance of fuel cells. In this review, we will provide an overview and describe the current status of recent enzyme biofuel cells, microfluidic technology, and their applications to microfluidic fuel cells. Full article

(This article belongs to the Special Issue Microfluidics for Biomedical Applications (3rd Edition))

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36 pages, 2691 KB

Open AccessReview

Advanced Electrochemical Sensors for Rapid and Sensitive Monitoring of Tryptophan and Tryptamine in Clinical Diagnostics

by Janani Sridev, Arif R. Deen, Md Younus Ali, Wei-Ting Ting, M. Jamal Deen and Matiar M. R. Howlader

Biosensors 2025, 15(9), 626; https://doi.org/10.3390/bios15090626 - 19 Sep 2025

Viewed by 859

Abstract

Tryptophan (Trp) and tryptamine (Tryp), critical biomarkers in mood regulation, immune function, and metabolic homeostasis, are increasingly recognized for their roles in both oral and systemic pathologies, including neurodegenerative disorders, cancers, and inflammatory conditions. Their rapid, sensitive detection in biofluids such as saliva—a [...] Read more.

Tryptophan (Trp) and tryptamine (Tryp), critical biomarkers in mood regulation, immune function, and metabolic homeostasis, are increasingly recognized for their roles in both oral and systemic pathologies, including neurodegenerative disorders, cancers, and inflammatory conditions. Their rapid, sensitive detection in biofluids such as saliva—a non-invasive, real-time diagnostic medium—offers transformative potential for early disease identification and personalized health monitoring. This review synthesizes advancements in electrochemical sensor technologies tailored for Trp and Tryp quantification, emphasizing their clinical relevance in diagnosing conditions like oral squamous cell carcinoma (OSCC), Alzheimer’s disease (AD), and breast cancer, where dysregulated Trp metabolism reflects immune dysfunction or tumor progression. Electrochemical platforms have overcome the limitations of conventional techniques (e.g., enzyme-linked immunosorbent assays (ELISA) and mass spectrometry) by integrating innovative nanomaterials and smart engineering strategies. Carbon-based architectures, such as graphene (Gr) and carbon nanotubes (CNTs) functionalized with metal nanoparticles (Ni and Co) or nitrogen dopants, amplify electron transfer kinetics and catalytic activity, achieving sub-nanomolar detection limits. Synergies between doping and advanced functionalization—via aptamers (Apt), molecularly imprinted polymers (MIPs), or metal-oxide hybrids—impart exceptional selectivity, enabling the precise discrimination of Trp and Tryp in complex matrices like saliva. Mechanistically, redox reactions at the indole ring are optimized through tailored electrode interfaces, which enhance reaction kinetics and stability over repeated cycles. Translational strides include 3D-printed microfluidics and wearable sensors for continuous intraoral health surveillance, demonstrating clinical utility in detecting elevated Trp levels in OSCC and breast cancer. These platforms align with point-of-care (POC) needs through rapid response times, minimal fouling, and compatibility with scalable fabrication. However, challenges persist in standardizing saliva collection, mitigating matrix interference, and validating biomarkers across diverse populations. Emerging solutions, such as AI-driven analytics and antifouling coatings, coupled with interdisciplinary efforts to refine device integration and manufacturing, are critical to bridging these gaps. By harmonizing material innovation with clinical insights, electrochemical sensors promise to revolutionize precision medicine, offering cost-effective, real-time diagnostics for both localized oral pathologies and systemic diseases. As the field advances, addressing stability and scalability barriers will unlock the full potential of these technologies, transforming them into indispensable tools for early intervention and tailored therapeutic monitoring in global healthcare. Full article

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

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17 pages, 3286 KB

Open AccessArticle

Haptens Optimization Using Molecular Modeling and Paper-Based Immunosensor for On-Site Detection of Carbendazim in Vegetable Products

by Wenjing Chen, Zhuzeyang Yuan, Kangliang Pan, Yu Wang, Xiaoqin Yu, Tian Guan, Jiahong Chen and Hongtao Lei

Biosensors 2025, 15(9), 625; https://doi.org/10.3390/bios15090625 - 19 Sep 2025

Viewed by 312

Abstract

Carbendazim is a benzimidazole fungicide widely used in the prevention and control of vegetable diseases. However, if misused, it may result in residues in agricultural products, not only reducing vegetable quality but also posing potential risks to human health. Currently, the on-site rapid [...] Read more.

Carbendazim is a benzimidazole fungicide widely used in the prevention and control of vegetable diseases. However, if misused, it may result in residues in agricultural products, not only reducing vegetable quality but also posing potential risks to human health. Currently, the on-site rapid detection technology for carbendazim still faces challenges, including insufficient antibody specificity and low sensitivity, which hinder its ability to meet practical regulatory requirements. Therefore, this study screened a rational hapten structure by applying a computer-aided hapten design and obtained a specific antibody. Compared to previous studies, the cross-reactivity rate of the antibody with thiabendazole-methyl was less than 0.1%, and the cross-reactivity rate with 2-aminobenzimidazole was 52.7% lower than that of the existing reported antibodies, which significantly improved the detection specificity of the method. Based on a high-specificity antibody, a gold nanoparticle-based lateral flow immunoassay (AuNPs-LFIA) for carbendazim was established. The detection limits of green beans and leeks are 3.80 μg/kg and 1.80 μg/kg, respectively, which still maintain high specificity in complex samples. Good agreement was also demonstrated between the results of blind samples detected by AuNPs-LFIA and LC-MS/MS, respectively. The establishment of AuNPs-LFIA provides an effective solution for the rapid and specific detection of carbendazim. Full article

(This article belongs to the Special Issue Artificial Intelligence (AI) and Machine Learning (ML) in Biosensors: Innovation, Application, and Challenge)

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25 pages, 13991 KB

Open AccessReview

Progress and Prospects in FRET for the Investigation of Protein–Protein Interactions

by Yue Zhang, Xinyue Ma, Meihua Zhu, Vivien Ya-Fan Wang and Jiajia Guo

Biosensors 2025, 15(9), 624; https://doi.org/10.3390/bios15090624 - 19 Sep 2025

Viewed by 639

Abstract

Protein–protein interactions (PPIs) play a crucial role in various biological processes, including signal transduction, transcriptional regulation, and metabolic pathways. Over the years, many methods have been developed to study PPIs, such as yeast two-hybrid (Y2H), co-immunoprecipitation (Co-IP), pull-down assays, and surface plasmon resonance [...] Read more.

Protein–protein interactions (PPIs) play a crucial role in various biological processes, including signal transduction, transcriptional regulation, and metabolic pathways. Over the years, many methods have been developed to study PPIs, such as yeast two-hybrid (Y2H), co-immunoprecipitation (Co-IP), pull-down assays, and surface plasmon resonance (SPR). However, each of these techniques has its own limitations, including false positives, a lack of specific binding partners, and restricted interaction zones. Fluorescence resonance energy transfer (FRET) has emerged as a powerful technique for investigating PPIs, offering several advantages over traditional methods. Recent advancements in fluorescence microscopy have further enhanced its application in PPI studies. In this review, we summarize recent developments in FRET-based approaches and their applications in PPIs research over the past five years, including conventional FRET, time-resolved FRET (TR-FRET), fluorescence lifetime imaging microscopy-FRET (FLIM-FRET), single-molecule FRET (smFRET), fluorescence cross-correlation spectroscopy FRET (FCCS-FRET), and provide guidance on selecting the most appropriate method for PPIs studies. Full article

(This article belongs to the Special Issue Advancements in Molecular Diagnostics and Biosensing: Harnessing the Power of FRET Technology)

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17 pages, 2262 KB

Open AccessArticle

Fiber Bragg Grating Embedded 3D-Printed Insole with Commercial and Portable Reader for Stance Phase Determination

by Arnaldo Leal-Junior, Mariana Silveira, Jan Nedoma and Radek Martinek

Biosensors 2025, 15(9), 623; https://doi.org/10.3390/bios15090623 - 19 Sep 2025

Viewed by 455

Abstract

This paper presents development and application of a Fiber Bragg Grating (FBG) array embedded in a 3D-printed insole for ground reaction force (GRF) estimation. In this case, a 3D-printed insole is fabricated from a scanned commercial insole in which a 5-FBGs array is [...] Read more.

This paper presents development and application of a Fiber Bragg Grating (FBG) array embedded in a 3D-printed insole for ground reaction force (GRF) estimation. In this case, a 3D-printed insole is fabricated from a scanned commercial insole in which a 5-FBGs array is integrated. The FBGs are characterized as a function of the applied transverse force, where a mean sensitivity of 0.11 ± 0.10 pm/N was obtained considering all FBGs. A portable FBG signal acquisition system was connected to the FBG array embedded in the insole and tested for the GRF analysis in a healthy volunteer. The gait tests results indicate stance and swing phases of 41.0 ± 6.5% and 59 ± 6.5%, respectively, which are within reference values of the literature. Furthermore, a 0.904 R² was found in the correlation analysis of the measured GRF response and the conventional M-shaped curve for the GRF in which all subdivisions of the stance phase were detected. Full article

(This article belongs to the Special Issue Wearable Sensors for Precise Exercise Monitoring and Analysis)

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17 pages, 3883 KB

Open AccessArticle

Interaction of Organic Semiconductors and Graphene Materials in the Source-Drain Channel of Field-Effect Transistors

by Eugen Chiriac, Bianca Adiaconita, Tiberiu Burinaru, Catalin Marculescu, Marius Stoian, Catalin Parvulescu and Marioara Avram

Biosensors 2025, 15(9), 622; https://doi.org/10.3390/bios15090622 - 19 Sep 2025

Viewed by 476

Abstract

This study investigates the interfacial interactions between two organic semiconductors (tetrathiafulvalene (TTF) and hexaazatriphenylene-hexacarbonitrile (HAT-CN)) and graphene-based materials (nanocrystalline graphite and vertically aligned graphene) used in Field-Effect Transistors (FETs). The interaction mechanisms, including π–π stacking, charge transfer, and dipole–dipole interactions, were explored through [...] Read more.

This study investigates the interfacial interactions between two organic semiconductors (tetrathiafulvalene (TTF) and hexaazatriphenylene-hexacarbonitrile (HAT-CN)) and graphene-based materials (nanocrystalline graphite and vertically aligned graphene) used in Field-Effect Transistors (FETs). The interaction mechanisms, including π–π stacking, charge transfer, and dipole–dipole interactions, were explored through SEM imaging, Raman and FTIR spectroscopy, and FET transfer characteristics. Spectroscopic data confirmed strong π–π and charge-transfer interactions, with distinct modifications in graphene structural and electronic features. Electrical measurements revealed significant modulation of channel conductivity, confirming effective surface functionalization. These findings provide a framework for engineering high-performance organic/graphene hybrid interfaces in electronic devices and biosensors. Importantly, the results demonstrate that molecular design and interfacial control at the nanoscale can be strategically used to modulate charge transport in graphene-based FETs. This approach opens new pathways for developing tunable, molecule-specific biosensors and nanoelectronic platforms with enhanced sensitivity and selectivity. Full article

(This article belongs to the Special Issue Transistor-Based Biosensors and Their Applications)

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18 pages, 1396 KB

Open AccessArticle

Kinematic Biomarkers of Functional Disability in Older Adults: Analysis of the Timed Up and Go Test

by Juliana Moreira, Bruno Cunha, José Félix, Rubim Santos and Andreia S. P. Sousa

Biosensors 2025, 15(9), 621; https://doi.org/10.3390/bios15090621 - 19 Sep 2025

Viewed by 408

Abstract

The Timed Up and Go (TUG) test is used to assess mobility in older adults, but its reliance on completion time limits its insight into detailed movement patterns that could serve as early indicators of functional decline. This study aimed to identify lower [...] Read more.

The Timed Up and Go (TUG) test is used to assess mobility in older adults, but its reliance on completion time limits its insight into detailed movement patterns that could serve as early indicators of functional decline. This study aimed to identify lower limb and trunk kinematic biomarkers during the TUG test that distinguish between older adults with and without functional disability, emphasizing the potential for wearable sensor applications. Sixty adults aged 60+ participated in this cross-sectional study. Three-dimensional lower limb and trunk range of motion (ROM), velocity, center of mass (CoM) displacement, and velocity were analyzed using an optoelectronic system across TUG subphases: sit-to-walk, walk-forward, turn, walk-back, and turn-to-sit. Principal component analysis identified eleven principal components (PCs), explaining 84.33% of the total variance. PCs included sagittal hip and knee motion and CoM velocity during turn-to-sit and walking (PC1); tri-dimensional trunk velocity during turning, walk-back, and sit-to-walk transitions (PC2, PC4, PC6); sagittal knee and hip velocity in sit-to-walk (PC3); and frontal and transverse plane knee ROM and velocity during turning (PC5). Significant differences between functional disability groups were found for PC1 and PC4. These findings provide benchmark data for developing and validating wearable biosensors aimed at monitoring kinematic biomarkers. Full article

(This article belongs to the Special Issue Biomarkers of Disability and Movement Disorders: Insights from Wearable Devices)

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15 pages, 502 KB

Open AccessArticle

Possible Use of the SUDOSCAN Nephropathy Risk Score in Chronic Kidney Disease Diagnosis: Application in Patients with Type 2 Diabetes

by Claudiu Cobuz, Mădălina Ungureanu-Iuga, Dana-Teodora Anton-Paduraru and Maricela Cobuz

Biosensors 2025, 15(9), 620; https://doi.org/10.3390/bios15090620 - 18 Sep 2025

Viewed by 442

Abstract

The use of quick and non-invasive techniques for detecting chronic kidney disease (CKD) in patients with type 2 diabetes mellitus is desirable and has recently garnered attention. One of these techniques is the evaluation of nephropathy risk based on electrochemical skin conductance (ESC) [...] Read more.

The use of quick and non-invasive techniques for detecting chronic kidney disease (CKD) in patients with type 2 diabetes mellitus is desirable and has recently garnered attention. One of these techniques is the evaluation of nephropathy risk based on electrochemical skin conductance (ESC) measured with a SUDOSCAN device. This paper aims to evaluate the possibility of using SUDOSCANs in chronic kidney disease prediction in diabetic patients and to investigate the relationships between clinical characteristics and SUDOSCAN parameters. The number of patients with type 2 diabetes included in this study was 254. Clinical metabolic characteristics like glycated hemoglobin, total and LDL cholesterol, triglyceride, blood pressure, and creatinine were determined along with body mass index, diabetes duration, and age. The estimated glomerular filtration rate (EGFR) was calculated and patients were grouped into three CKD stages based on EGFR values. Electrochemical skin conductance in hands and feet was determined with a SUDOSCAN device. The results showed that patients with symptomatic CKD (S2 and 3) presented lower ESC values, along with lower EFGRs and higher creatinine levels. A significant positive but weak correlation (p < 0.05) was observed between SUDOSCAN nephropathy risk and EGFR. The general linear model indicated that the SUDOSCAN nephropathy risk score could be used in CKD diagnosis only if considering age, diabetes duration, and body mass index. The area under the curve (AUC) of the receiver operating characteristic (ROC) analysis revealed the moderate possibility of using the SUDOSCAN nephropathy risk score to predict CKD, since it was 0.61 (p < 0.01, 95% CI 0.54–0.68), but only if the other factors mentioned above are included. Based on the cut-off value of 59.50 identified, patients were grouped (values above and below cut-off), and the results showed that patients with a SUDOSCAN nephropathy risk score of <59.50 have lower SUDOSCAN-ESC values measured in their hands and feet, lower EGFR and higher creatinine levels. These results indicated the possibility of using SUDOSCAN as a supporting tool to identify CKD if it is correlated with other factors like age, diabetes duration, and body mass index. This is important for medical progress regarding the use of novel non-invasive technologies in identifying CKD associated with type 2 diabetes. Full article

(This article belongs to the Special Issue Trends in Development of Biosensors for Disease Diagnosis, Treatment and Management—2nd Edition)

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46 pages, 4316 KB

Open AccessReview

3D Printing Assisted Wearable and Implantable Biosensors

by Somnath Maji, Myounggyu Kwak, Reetesh Kumar and Hyungseok Lee

Biosensors 2025, 15(9), 619; https://doi.org/10.3390/bios15090619 - 17 Sep 2025

Viewed by 855

Abstract

Biosensors have undergone transformative advancements, evolving into sophisticated wearable and implantable devices capable of real-time health monitoring. Traditional manufacturing methods, however, face limitations in scalability, cost, and design complexity, particularly for miniaturized, multifunctional biosensors. The integration of 3D printing technology addresses these challenges [...] Read more.

Biosensors have undergone transformative advancements, evolving into sophisticated wearable and implantable devices capable of real-time health monitoring. Traditional manufacturing methods, however, face limitations in scalability, cost, and design complexity, particularly for miniaturized, multifunctional biosensors. The integration of 3D printing technology addresses these challenges by enabling rapid prototyping, customization, and the production of intricate geometries with high precision. This review explores how additive manufacturing techniques facilitate the fabrication of flexible, stretchable, and biocompatible biosensors. By incorporating advanced materials like conductive polymers, nanocomposites, and hydrogels, 3D-printed biosensors achieve enhanced sensitivity, durability, and seamless integration with biological systems. Innovations such as biodegradable substrates and multi-material printing further expand applications in continuous glucose monitoring, neural interfaces, and point-of-care diagnostics. Despite challenges in material optimization and regulatory standardization, the convergence of 3D printing with nanotechnology and smart diagnostics heralds a new era of personalized, proactive healthcare, offering scalable solutions for both clinical and remote settings. This synthesis underscores the pivotal role of additive manufacturing in advancing wearable and implantable biosensor technology, paving the way for next-generation devices that prioritize patient-specific care and real-time health management. Full article

(This article belongs to the Special Issue Biological Sensors Based on 3D Printing Technologies)

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25 pages, 3651 KB

Open AccessArticle

Machine Learning-Based Framework for Pre-Impact Same-Level Fall and Fall-from-Height Detection in Construction Sites Using a Single Wearable Inertial Measurement Unit

by Oleksandr Yuhai, Yubin Cho and Joung Hwan Mun

Biosensors 2025, 15(9), 618; https://doi.org/10.3390/bios15090618 - 17 Sep 2025

Viewed by 570

Abstract

Same-level-falls (SLFs) and falls-from-height (FFHs) remain major causes of severe injuries and fatalities on construction sites. Researchers are actively developing fall-prevention systems requiring accurate SLF and FFH detection in construction settings prone to false positives. In this study, a machine learning-based approach was [...] Read more.

Same-level-falls (SLFs) and falls-from-height (FFHs) remain major causes of severe injuries and fatalities on construction sites. Researchers are actively developing fall-prevention systems requiring accurate SLF and FFH detection in construction settings prone to false positives. In this study, a machine learning-based approach was established for accurate identification of SLF, FFH, and non-fall events using a single waist-mounted inertial measurement unit (IMU). A total of 48 participants executed 39 non-fall activities, 10 types of SLFs, and 8 types of FFHs, with a dummy used for falls exceeding 0.5 m. A two-stage feature extraction yielded 168 descriptors per data window, and an ensemble SHAP-PFI method selected the 153 most informative variables. The weighted XGBoost classifier, optimized via Bayesian techniques, outperformed other current boosting algorithms. Using 5-fold cross-validation, it achieved an average macro F1-score of 0.901 and macro Matthews correlation coefficient of 0.869, with a latency of 1.51 × 10⁻³ ms per window. Notably, the average lead times were 402 ms for SLFs and 640 ms for FFHs, surpassing the 130 ms inflation time required for wearable airbags. This pre-impact SLF and FFH detection approach delivers both rapid and precise detection, positioning it as a viable central component for wearable fall-prevention devices in fast-paced construction scenarios. Full article

(This article belongs to the Special Issue Sensors for Human Activity Recognition: 3rd Edition)

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17 pages, 6009 KB

Open AccessArticle

Sensitive and Selective Electrochemical Detection of Hydrogen Peroxide Using a Silver-Incorporated CeO₂/Ag₂O Nanocomposite

by Gunasekaran Manibalan, Govindhasamy Murugadoss, Dharmalingam Krishnamoorthy, Venkataraman Dharuman and Shaik Gouse Peera

Biosensors 2025, 15(9), 617; https://doi.org/10.3390/bios15090617 - 17 Sep 2025

Viewed by 427

Abstract

Precision and real-time detection of hydrogen peroxide (H₂O₂) are essential in pharmaceutical, industrial, and defence sectors due to its strong oxidizing nature. In this study, silver (Ag)-doped CeO₂/Ag₂O-modified glassy carbon electrode (Ag-CeO₂/Ag₂ [...] Read more.

Precision and real-time detection of hydrogen peroxide (H₂O₂) are essential in pharmaceutical, industrial, and defence sectors due to its strong oxidizing nature. In this study, silver (Ag)-doped CeO₂/Ag₂O-modified glassy carbon electrode (Ag-CeO₂/Ag₂O/GCE) has been developed as a non-enzymatic electrochemical sensor for the sensitive and selective detection of H₂O₂. The synthesized Ag-doped CeO₂/Ag₂O nanocomposite was characterized using various advanced techniques, including X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), field-emission scanning electron microscopy (FE-SEM), and high-resolution transmission electron microscopy (HR-TEM). Their optical, magnetic, thermal, and chemical properties were further analyzed using UV–vis spectroscopy, electron paramagnetic resonance (EPR), thermogravimetric-differential thermal analysis (TG-DTA), and X-ray photoelectron spectroscopy (XPS). Electrochemical sensing performance was evaluated using cyclic voltammetry and amperometry. The Ag-CeO₂/Ag₂O/GCE exhibited superior electrocatalytic activity for H₂O₂, attributed to the increased number of active sites and enhanced electron transfer. The sensor displayed a high sensitivity of 2.728 µA cm⁻² µM⁻¹, significantly outperforming the undoped CeO₂/GCE (0.0404 µA cm⁻² µM⁻¹). The limit of detection (LOD) and limit of quantification (LOQ) were found to be 6.34 µM and 21.1 µM, respectively, within a broad linear detection range of 1 × 10⁻⁸ to 0.5 × 10⁻³ M. The sensor also demonstrated excellent selectivity with minimal interference from common analytes, along with outstanding storage stability, reproducibility, and repeatability. Owing to these attributes, the Ag-CeO₂/Ag₂O/GCE sensor proved effective for real sample analysis, showcasing its potential as a reliable, non-enzymatic platform for H₂O₂ detection. Full article

(This article belongs to the Special Issue Biosensors Based on Electrochemical Catalysis, Biofuels, or Functional Nanomaterials)

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14 pages, 2658 KB

Open AccessArticle

Comparative Evaluation of Combined Denoising and Resolution Enhancement Algorithms for Intravital Two-Photon Imaging of Organs

by Saeed Bohlooli Darian, Woo June Choi, Jeongmin Oh and Jun Ki Kim

Biosensors 2025, 15(9), 616; https://doi.org/10.3390/bios15090616 - 17 Sep 2025

Viewed by 458

Abstract

Intravital two-photon microscopy enables deep-tissue imaging of subcellular structures in live animals, but its original spatial resolution and image quality are limited by scattering, motion, and low signal-to-noise ratios. To address these challenges, we used a combination of tissue stabilization, denoising methods, and [...] Read more.

Intravital two-photon microscopy enables deep-tissue imaging of subcellular structures in live animals, but its original spatial resolution and image quality are limited by scattering, motion, and low signal-to-noise ratios. To address these challenges, we used a combination of tissue stabilization, denoising methods, and motion correction, together with resolution enhancement algorithms, including enhanced Super-Resolution Radial Fluctuations (eSRRF) and deconvolution, to acquire high-fidelity time-lapse images of internal organs. We applied this imaging pipeline to image genetically labeled mitochondria in vivo, in Dendra2 mice. Our results demonstrate that the eSRRF-combined method, compared to other evaluated algorithms, significantly shows improved spatial resolution and mitochondrial structure visualization, while each method exhibiting distinct strengths in terms of noise tolerance, edge preservation, and computational efficiency. These findings provide a practical framework for selecting enhancement strategies in intravital imaging studies targeting dynamic subcellular processes. Full article

(This article belongs to the Special Issue Optical Sensors for Biological Detection)

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19 pages, 3250 KB

Open AccessArticle

Pancreatic Lipase in Eutectogels as Emerging Materials: Exploring Their Properties and Potential Applications in Biosensing

by Raúl Martínez-Baquero, María José Martínez-Tomé, Javier Gómez, Rocío Esquembre and C. Reyes Mateo

Biosensors 2025, 15(9), 615; https://doi.org/10.3390/bios15090615 - 17 Sep 2025

Viewed by 507

Abstract

Eutectogels are advanced gel-based systems that integrate deep eutectic solvents (DES) into polymer networks. In this study, we report the first detailed characterization of an enzyme-containing eutectogel, representing a significant step toward advanced biosensing and biocatalytic applications. Specifically, we have incorporated pancreatic lipase, [...] Read more.

Eutectogels are advanced gel-based systems that integrate deep eutectic solvents (DES) into polymer networks. In this study, we report the first detailed characterization of an enzyme-containing eutectogel, representing a significant step toward advanced biosensing and biocatalytic applications. Specifically, we have incorporated pancreatic lipase, one of the main target enzymes in the treatment of obesity, in eutectogels via UV-induced radical polymerization of suitable precursors in appropriate DESs. Prior to immobilization, the enzyme was solubilized in selected DESs and its activity and conformational stability were evaluated using colorimetry and intrinsic fluorescence. Combinations of choline chloride/glycerol and tetramethylammonium chloride/glycerol were shown to be effective media for preserving and enhancing enzymatic function and conformational stability. The enzyme immersed in eutectogel exhibited high structural integrity and excellent thermal stability, maintaining its activity over several weeks. The ability of this new material to screen enzyme inhibitors was assessed using orlistat, a well-established anti-obesity agent. The results demonstrated clear detection of the drug’s inhibitory effect, even at nanomolar concentrations, highlighting the material’s potential as a screening platform for novel inhibitors with prospective anti-obesity activity. Furthermore, the device proved effective in quantifying drug presence, offering a promising and highly sensitive tool for pharmaceutical quality control applications. Full article

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

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16 pages, 1616 KB

Open AccessReview

Decoding Molecular Network Dynamics in Cells: Advances in Multiplexed Live Imaging of Fluorescent Biosensors

by Qiaowen Chen, Yichu Xu, Jhen-Wei Wu, Jr-Ming Yang and Chuan-Hsiang Huang

Biosensors 2025, 15(9), 614; https://doi.org/10.3390/bios15090614 - 17 Sep 2025

Viewed by 693

Abstract

Genetically encoded fluorescent protein (FP)-based biosensors have revolutionized cell biology research by enabling real-time monitoring of molecular activities in live cells with exceptional spatial and temporal resolution. Multiplexed biosensing advances this capability by allowing the simultaneous tracking of multiple signaling pathways to uncover [...] Read more.

Genetically encoded fluorescent protein (FP)-based biosensors have revolutionized cell biology research by enabling real-time monitoring of molecular activities in live cells with exceptional spatial and temporal resolution. Multiplexed biosensing advances this capability by allowing the simultaneous tracking of multiple signaling pathways to uncover network interactions and dynamic coordination. However, challenges in spectral overlap limit broader implementation. Innovative strategies have been devised to address these challenges, including spectral separation through FP palette expansion and novel biosensor designs, temporal differentiation using photochromic or reversibly switching FPs, and spatial segregation of biosensors to specific subcellular regions or through cell barcoding techniques. Combining multiplexed biosensors with artificial intelligence-driven analysis holds great potential for uncovering cellular decision-making processes. Continued innovation in this field will deepen our understanding of molecular networks in cells, with implications for both fundamental biology and therapeutic development. Full article

(This article belongs to the Special Issue Cell-Based Biosensors for Rapid Detection and Monitoring (2nd Edition))

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19 pages, 5854 KB

Open AccessArticle

Exploration and Analysis of GaN-Based FETs with Varied Doping Concentration in Nano Regime for Biosensing Application

by Abhishek Saha, Sneha Singh, Rudra Sankar Dhar, Kajjwal Ghosh, A. Y. Seteikin, Amit Banerjee and I. G. Samusev

Biosensors 2025, 15(9), 613; https://doi.org/10.3390/bios15090613 - 16 Sep 2025

Viewed by 414

Abstract

This study conducts a comprehensive examination of a GaN channel-based nanobiosensor featuring a dielectrically modulated trigate FinFET structure, incorporating both uniform and Gaussian channel doping. The proposed device incorporates a nanocavity structure situated beneath the gate region, intended for the analysis of diverse [...] Read more.

This study conducts a comprehensive examination of a GaN channel-based nanobiosensor featuring a dielectrically modulated trigate FinFET structure, incorporating both uniform and Gaussian channel doping. The proposed device incorporates a nanocavity structure situated beneath the gate region, intended for the analysis of diverse biomolecules in biosensing applications. The proposed biosensor employs HfO₂ as the gate dielectric, characterized by a dielectric constant of 25, leading to an enhanced switching ratio for the device. This study examines the electrical properties relevant to biomolecule identification, including the switching ratio, DIBL, threshold swing, threshold voltage, and transconductance. The sensitivity of these properties concerning the drain current is subsequently assessed. Enhanced sensitivity increases the likelihood of detecting biomolecules. The electrical property of a biomolecule is examined in the absence of another biomolecule within the cavity. The apparatus is designed to detect neutral biomolecules. Simultaneously, further investigational research has been undertaken regarding the linearity behavior of GAA FET, nanobiosensors, and dielectrically modulated TGFinFET. This study’s results have been compared with those of GaN-based FinFET and GaN SOI FinFET technologies. The data indicates approximately ∼103% and ∼42% improvements in I_OFF and Switching ratio, respectively, when compared to IRDS 2025. The nanobiosensor (GAA FET) demonstrates enhanced linear performance concerning higher-order voltage and current intercept points, including VIP2, VIP3, IIP3, and P1dB. Full article

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

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22 pages, 2692 KB

Open AccessArticle

Low-Cost AI-Enabled Optoelectronic Wearable for Gait and Breathing Monitoring: Design, Validation, and Applications

by Samilly Morau, Leandro Macedo, Eliton Morais, Rafael Menegardo, Jan Nedoma, Radek Martinek and Arnaldo Leal-Junior

Biosensors 2025, 15(9), 612; https://doi.org/10.3390/bios15090612 - 16 Sep 2025

Viewed by 539

Abstract

This paper presents the development of an optoelectronic wearable sensor system for portable monitoring of the movement and physiological parameters of patients. The sensor system is based on a low-cost inertial measurement unit (IMU) and an optical fiber-integrated chest belt for breathing rate [...] Read more.

This paper presents the development of an optoelectronic wearable sensor system for portable monitoring of the movement and physiological parameters of patients. The sensor system is based on a low-cost inertial measurement unit (IMU) and an optical fiber-integrated chest belt for breathing rate monitoring with wireless connection with a gateway connected to the cloud. The sensors also use artificial intelligence algorithms for clustering, classification, and regression of the data. Results show a root mean squared error (RMSE) between the reference data and the proposed breathing rate sensor of 0.6 BPM, whereas RMSEs of 0.037 m/s² and 0.27 °/s are obtained for the acceleration and angular velocity analysis, respectively. For the sensor validation under different movement analysis protocols, the balance and Timed up and Go (TUG) tests performed with 12 subjects demonstrate the feasibility of the proposed device for biomechanical and physical therapy protocols’ automatization and assessment. The balance tests were performed in two different conditions, with a wider and narrower base, whereas the TUG tests were made with the combination of cognitive and motor tests. The results demonstrate the influence of the change of base on the balance analysis as well as the dual task effect on the scores during the TUG testing, where the combination between motor and cognitive tests lead to smaller scores on the TUG tests due to the increase of complexity of the task. Therefore, the proposed approach results in a low-cost and fully automated sensor system that can be used in different protocols for physical rehabilitation. Full article

(This article belongs to the Special Issue Wearable Biosensors and Health Monitoring)

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28 pages, 2114 KB

Open AccessReview

Recent Advances in Flexible Materials for Wearable Optical Biosensors

by Linyan Xie, Kai Yang, Mengfei Wang, Wenli Hou and Qiongqiong Ren

Biosensors 2025, 15(9), 611; https://doi.org/10.3390/bios15090611 - 16 Sep 2025

Viewed by 1080

Abstract

The integration of flexible materials with optical sensing technologies has advanced wearable optical biosensors, offering significant potential in personalized medicine, health monitoring, and disease prevention. This review summarizes the recent advancements in flexible materials for wearable optical biosensors, with a focus on materials [...] Read more.

The integration of flexible materials with optical sensing technologies has advanced wearable optical biosensors, offering significant potential in personalized medicine, health monitoring, and disease prevention. This review summarizes the recent advancements in flexible materials for wearable optical biosensors, with a focus on materials such as polymer substrates, nanostructured materials, MXenes, hydrogels, and textile-based integrated platforms. These materials enhance the functionality, sensitivity, and adaptability of sensors, particularly in wearable applications. The review also explores various optical sensing mechanisms, including surface plasmon resonance (SPR), optical fiber sensing, fluorescence sensing, chemiluminescence, and surface-enhanced Raman spectroscopy (SERS), emphasizing their role in improving the detection capabilities for biomarkers, physiological parameters, and environmental pollutants. Despite significant advancements, critical challenges remain in the fabrication and practical deployment of flexible optical biosensors, particularly regarding the long-term stability of materials under dynamic environments, maintaining reliable biocompatibility during prolonged skin contact, and minimizing signal interference caused by motion artifacts and environmental fluctuations. Addressing these issues is vital to ensure robustness and accuracy in real-world applications. Looking forward, future research should emphasize the development of multifunctional and miniaturized devices, the integration of wireless communication and intelligent data analytics, and the improvement of environmental resilience. Such innovations are expected to accelerate the transition of flexible optical biosensors from laboratory research to practical clinical and consumer healthcare applications, paving the way for intelligent health management and early disease diagnostics. Overall, flexible optical biosensors hold great promise in personalized health management, early disease diagnosis, and continuous physiological monitoring, with the potential to revolutionize the healthcare sector. Full article

(This article belongs to the Special Issue Flexible Electronics for Biosensing)

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29 pages, 4099 KB

Open AccessReview

Deep Learning-Driven Multimodal Integration of miRNA and Radiomic for Lung Cancer Diagnosis

by Yuanyuan Chen, Dikang Chen, Xiaohui Liu, Hui Jiang and Xuemei Wang

Biosensors 2025, 15(9), 610; https://doi.org/10.3390/bios15090610 - 16 Sep 2025

Viewed by 732

Abstract

Lung cancer remains one of the most common and deadly malignancies worldwide. Current diagnosis and staging primarily rely on biopsy techniques, which fail to comprehensively characterize the molecular profiles and tumor microenvironment. Current studies demonstrate the promising performance (AUC = 82%) of miRNA-based [...] Read more.

Lung cancer remains one of the most common and deadly malignancies worldwide. Current diagnosis and staging primarily rely on biopsy techniques, which fail to comprehensively characterize the molecular profiles and tumor microenvironment. Current studies demonstrate the promising performance (AUC = 82%) of miRNA-based predictive models, but exclusive reliance on miRNA signatures is limited by incomplete capture of tumor heterogeneity. Integrating imaging and genomic data can further enhance model accuracy, with functional nanomaterials serving as core advanced biosensing platforms to bridge miRNA sensing and radiomic fusion. Consequently, integrating imaging and genomic data can further enhance model accuracy. Recent research employing DenseNet architecture for the multimodal fusion of miRNA and radiomic features achieved an AUC of 0.98 with 85.7% sensitivity. This review summarizes advances in miRNA biomarkers, deep learning-driven radiogenomics, and critical roles of functional nanomaterials in biosensing-enabled multimodal integration, along with challenges and future directions for clinical translation. Full article

(This article belongs to the Special Issue Functional Nanomaterials for Advanced Biosensing: From Molecular Design to Real-World Applications)

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2 pages, 739 KB

Open AccessCorrection

Correction: Li et al. Molybdenum Disulfide-Integrated Iron Organic Framework Hybrid Nanozyme-Based Aptasensor for Colorimetric Detection of Exosomes. Biosensors 2023, 13, 800

by Chao Li, Zichao Guo, Sisi Pu, Chaohui Zhou, Xi Cheng, Ren Zhao and Nengqin Jia

Biosensors 2025, 15(9), 609; https://doi.org/10.3390/bios15090609 - 16 Sep 2025

Viewed by 247

Abstract

In the original publication [...] Full article

(This article belongs to the Special Issue Novel Nanomaterials and Nanotechnology: From Fabrication Methods and Improvement Strategies to Applications in Biosensing and Biomedicine)

29 pages, 872 KB

Open AccessArticle

The Impact of Heat Stress on Dairy Cattle: Effects on Milk Quality, Rumination Behaviour, and Reticulorumen pH Response Using Machine Learning Models

by Karina Džermeikaitė, Justina Krištolaitytė, Dovilė Malašauskienė, Samanta Arlauskaitė, Akvilė Girdauskaitė and Ramūnas Antanaitis

Biosensors 2025, 15(9), 608; https://doi.org/10.3390/bios15090608 - 15 Sep 2025

Viewed by 805

Abstract

Heat stress has a major impact on dairy cow health and productivity, especially during early lactation. Conventional heat stress monitoring methods frequently rely on single indicators, such as the temperature–humidity index (THI), which may miss subtle physiological and metabolic responses. This study presents [...] Read more.

Heat stress has a major impact on dairy cow health and productivity, especially during early lactation. Conventional heat stress monitoring methods frequently rely on single indicators, such as the temperature–humidity index (THI), which may miss subtle physiological and metabolic responses. This study presents a novel threshold-based classification framework that integrates biologically meaningful combinations of environmental, behavioural, and physiological variables to detect early-stage heat stress responses in dairy cows. Six composite heat stress conditions (C1–C6) were developed using real-time THI, milk temperature, reticulorumen pH, rumination time, milk lactose, and milk fat-to-protein ratio. The study applied and assessed five supervised machine learning models (Partial Least Squares Discriminant Analysis (PLS-DA), Support Vector Machine (SVM), Random Forest (RF0, Neural Network (NN), and an Ensemble approach) trained on daily datasets gathered from early-lactation dairy cows fitted with intraruminal boluses and monitored through milking parlour sensor systems. The dataset comprised approximately 36,000 matched records from 200 cows monitored over 60 days. The highest classification performance was observed for RF and NN models, particularly under C1 (THI > 73 and milk temperature > 38.6 °C) and C6 (THI > 74 and milk temperature > 38.7 °C), with AUC values exceeding 0.90. SHAP analysis revealed that milk temperature, THI, rumination time, and milk lactose were the most informative features across conditions. This integrative approach enhances precision livestock monitoring by enabling individualised heat stress risk classification well before clinical or production-level consequences emerge. Full article

(This article belongs to the Special Issue Artificial Intelligence (AI) and Machine Learning (ML) in Biosensors: Innovation, Application, and Challenge)

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17 pages, 3093 KB

Open AccessArticle

Gold Nanoparticle-Enhanced Recombinase Polymerase Amplification for Rapid Visual Detection of Mycobacterium tuberculosis

by Sukanya Saikaew, Sirikwan Sangboonruang, Rodjana Pongsararuk, Prapaporn Srilohasin, Bordin Butr-Indr, Sorasak Intorasoot, Ponrut Phunpae, Chayada Sitthidet Tharinjaroen, Surachet Arunothong, Wutthichai Panyasit, Angkana Chaiprasert, Khajornsak Tragoolpua and Usanee Wattananandkul

Biosensors 2025, 15(9), 607; https://doi.org/10.3390/bios15090607 - 15 Sep 2025

Viewed by 539

Abstract

Tuberculosis (TB) remains a major global health challenge, particularly in resource-limited settings where access to rapid and reliable diagnostics is limited. Conventional diagnostic methods, such as smear microscopy and culture, are either time-consuming or lack adequate sensitivity. This study optimized recombinase polymerase amplification [...] Read more.

Tuberculosis (TB) remains a major global health challenge, particularly in resource-limited settings where access to rapid and reliable diagnostics is limited. Conventional diagnostic methods, such as smear microscopy and culture, are either time-consuming or lack adequate sensitivity. This study optimized recombinase polymerase amplification (RPA) using 16 primer combinations targeting IS6110 highly specific to the Mycobacterium tuberculosis complex (MTC). A novel naked-eye assay, TB-GoldDx, was developed by integrating RPA combined with gold nanoparticles (AuNPs), enabling equipment-free diagnostics. TB-GoldDx demonstrated a detection limit of 0.001 ng of MTB H37Rv DNA (~210 bacilli) per 25 µL reaction. Among 100 bacterial strains, it achieved 95.83% sensitivity and 100% specificity among 100 bacterial strains, comprising 72 MTB isolates and 28 nontuberculous bacterial species. In 140 sputum samples, the assay showed 81.43% sensitivity and 58.57% specificity versus acid-fast bacilli (AFB) smear microscopy, with sensitivity improving to 95.45% in high-load AFB 3+ specimens. Compared to a commercial line probe assay (LPA), TB-GoldDx exhibited slightly higher sensitivity (84.78% vs. 82.61%) but lower specificity (54.05% vs. 78.38%). Delivering rapid, visual results in under an hour, TB-GoldDx offers a low-cost, easily deployable solution for point-of-care tuberculosis detection, especially in underserved regions, reinforcing global End TB efforts. Full article

(This article belongs to the Section Biosensors and Healthcare)

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12 pages, 2384 KB

Open AccessArticle

Terahertz High-Sensitivity SPR Phase Biosensor Based on the Weyl Semimetals

by Yu Xie, Zean Shen, Mengjiao Ren, Mingming Zhang, Mingwei Guo and Leyong Jiang

Biosensors 2025, 15(9), 606; https://doi.org/10.3390/bios15090606 - 15 Sep 2025

Viewed by 392

Abstract

Optical biosensors play a crucial role in the field of biological detection by converting biological signals into optical signals for detection. Among them, Surface Plasmon Resonance (SPR) optical biosensors have become a research hotspot in this field due to their significant advantage of [...] Read more.

Optical biosensors play a crucial role in the field of biological detection by converting biological signals into optical signals for detection. Among them, Surface Plasmon Resonance (SPR) optical biosensors have become a research hotspot in this field due to their significant advantage of high sensitivity. Weyl Semimetals (WSMs), as a type of three-dimensional topological material with unique electronic structures and other properties, exhibit potential applications in the field of SPR sensing. Against this background, we designed a terahertz (THz) high-sensitivity SPR phase biosensor with a KR structure based on WSMs. When applied in gas sensing scenarios, the phase detection sensitivity of this sensor can reach 22,402

°

/RIU, showing a significant improvement compared to traditional SPR biosensors. Moreover, we found that the Weyl node separation distance and twist angle of WSMs have obvious effects on sensitivity regulation. Additionally, we optimized the sensitivity and structural parameters of this structure using a neural network-based deep learning algorithm. We expect that this proposed scheme can provide a feasible reference for the field of biological sensing. Full article

(This article belongs to the Special Issue New Progress in Optical Fiber-Based Biosensors—2nd Edition)

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20 pages, 3511 KB

Open AccessCommunication

An Aptamer-Based gFET-Sensor for Specific Quantification of Gene Therapeutic Human Adenovirus Type 5

by Runliu Li, Ann-Kathrin Kissmann, Hu Xing, Roger Hasler, Christoph Kleber, Wolfgang Knoll, Hannes Schmietendorf, Tatjana Engler, Lea Krutzke, Stefan Kochanek and Frank Rosenau

Biosensors 2025, 15(9), 605; https://doi.org/10.3390/bios15090605 - 14 Sep 2025

Viewed by 555

Abstract

The combination of rGO-FETs (reduced Graphene Oxide Field-Effect Transistors) and DNA-oligonucleotide aptamers to sense analytes has been shown to be a promising technological approach, achieving high sensitivity and selectivity. With human adenovirus type 5 (HAdV-5) particles as the target, we here demonstrate the [...] Read more.

The combination of rGO-FETs (reduced Graphene Oxide Field-Effect Transistors) and DNA-oligonucleotide aptamers to sense analytes has been shown to be a promising technological approach, achieving high sensitivity and selectivity. With human adenovirus type 5 (HAdV-5) particles as the target, we here demonstrate the application of the aptamer/FET combination for detection of this medically and biotechnologically relevant viral vector. A focused anti-HAdV-5 aptamer library was evolved in a nine-round SELEX process, allowing for the specific fluorescent labeling of HAdV-5 and related subtypes. Moreover, this library was already sufficient to serve as the binding entity on a gFET sensor for sensitive quantification of the virus particles. Adenoviruses have been widely used as gene delivery vectors for gene therapy and genetic vaccination. The use of adenoviral vectors within the vaccination campaign against COVID-19 emphasized the need for robust biotechnological production processes, which additionally require sensitive product formation monitoring. We believe that these type of gFET-based aptasensors can serve as the technological monitoring basis in virus production processes in the near future. Full article

(This article belongs to the Special Issue Transistor-Based Biosensors and Their Applications)

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20 pages, 2623 KB

Open AccessArticle

Construction of an Electrochemical Impedance Spectroscopy Matching Method Based on Adaptive Multi-Error Driving and Application Testing for Biofilm Impedance Verification

by Hanyang Bao, Fan Yu, Peiyan Dai, Boyu Guo and Ying Xu

Biosensors 2025, 15(9), 604; https://doi.org/10.3390/bios15090604 - 12 Sep 2025

Viewed by 417

Abstract

Electrochemical impedance spectroscopy (EIS) is a technique used to analyze the kinetics and interfacial processes of electrochemical systems. The selection of an appropriate equivalent circuit model for EIS interpretation was traditionally reliant on expert experience, rendering the process subjective and prone to error. [...] Read more.

Electrochemical impedance spectroscopy (EIS) is a technique used to analyze the kinetics and interfacial processes of electrochemical systems. The selection of an appropriate equivalent circuit model for EIS interpretation was traditionally reliant on expert experience, rendering the process subjective and prone to error. To address these limitations, an automated framework for both model selection and parameter estimation was proposed. The methodology was structured such that initial model screening was performed by a global heuristic search algorithm, adaptive optimization was guided by an integrated XGBoost-based error feedback mechanism, and precise parameter estimation was achieved using a Differential Evolution–Levenberg–Marquardt (DE-LM) algorithm. When evaluated on a purpose-built dataset comprising 4.8 × 10⁵ spectra across diverse circuit and biofilm scenarios, a model classification accuracy of 96.32% was achieved, and a 72.3% reduction in parameter estimation error was recorded. The practical utility of the method was validated through the quantitative analysis of bovine serum albumin–Clenbuterol hydrochloride (BSA-CLB), wherein an accuracy of 95.2% was demonstrated and a strong linear correlation with target concentration (R² = 0.999) was found. Through this approach, the limitations of traditional black-box models were mitigated by resolving the physical meaning of parameters. Consequently, the automated and quantitative monitoring of processes such as biofilm formation was facilitated, enabling the efficient evaluation of antimicrobial drugs or anti-fouling coatings. Full article

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

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28 pages, 4943 KB

Open AccessReview

From Biomarkers to Biosensors: Modern Approaches for the Detection of Matrix Metalloproteinases (MMPs)

by Raja Chinnappan, Lohit Ramachandran, Isha Uttam, Marimuthu Citartan, Nidambur Vasudev Ballal and Naresh Kumar Mani

Biosensors 2025, 15(9), 603; https://doi.org/10.3390/bios15090603 - 12 Sep 2025

Viewed by 629

Abstract

Matrix metalloproteinases (MMPs) are a class of extracellular Zn²⁺ peptidases involved in various physiological and pathological processes. These enzymes serve as excellent biomarkers for diagnosing various diseases, including cancer and periodontitis, to name a few. MMP levels also serve as a prognostic [...] Read more.

Matrix metalloproteinases (MMPs) are a class of extracellular Zn²⁺ peptidases involved in various physiological and pathological processes. These enzymes serve as excellent biomarkers for diagnosing various diseases, including cancer and periodontitis, to name a few. MMP levels also serve as a prognostic marker, which helps determine how much the disease has progressed. However, the current methods used to detect MMPs need a large sample volume, carry a high cost, and are not widely accessible to the public due to these challenges. Biosensing techniques tackle these problems by providing an efficient, cost-effective sensor with great sensitivity. This review provides a comprehensive overview of the latest developments and advancements in detecting MMPs using biosensors that employ various detection mechanisms such as electrochemical, colorimetric, and fluorescence methods. Furthermore, we have discussed the challenges and prospects of using MMPs as diagnostic tools. Full article

(This article belongs to the Special Issue Lighting Up Single-Molecule Biosensors and Bioimaging: Now and the Decade to Come)

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