Biosensors

41 pages, 7605 KiB

Open AccessSystematic Review

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

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

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

Abstract

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

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

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

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19 pages, 1758 KiB

Open AccessArticle

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

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

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

Abstract

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

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

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

16 pages, 2946 KiB

Open AccessArticle

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

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

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

Abstract

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

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

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

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14 pages, 2434 KiB

Open AccessArticle

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

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

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

Viewed by 50

Abstract

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

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

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

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18 pages, 2273 KiB

Open AccessArticle

Integrating Near-Infrared Spectroscopy and Proteomics for Semen Quality Biosensing

by Notsile H. Dlamini, Mariana Santos-Rivera, Carrie K. Vance-Kouba, Olga Pechanova, Tibor Pechan and Jean M. Feugang

Biosensors 2025, 15(7), 456; https://doi.org/10.3390/bios15070456 - 15 Jul 2025

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Abstract

Artificial insemination (AI) is a key breeding technique in the swine industry; however, the lack of reliable biomarkers for semen quality limits its effectiveness. Seminal plasma (SP) contains extracellular vesicles (EVs) that present a promising, non-invasive biomarker for semen quality. This study explores [...] Read more.

Artificial insemination (AI) is a key breeding technique in the swine industry; however, the lack of reliable biomarkers for semen quality limits its effectiveness. Seminal plasma (SP) contains extracellular vesicles (EVs) that present a promising, non-invasive biomarker for semen quality. This study explores the biochemical profiles of boar SP to assess semen quality through near-infrared spectroscopy (NIRS) and proteomics of SP-EVs. Fresh semen from mature Duroc boars was evaluated based on sperm motility, classifying samples as Passed (≥70%) or Failed (<70%). NIRS analysis identified distinct variations in water structures at specific wavelengths (C1, C5, C12 nm), achieving high accuracy (92.2%), sensitivity (94.2%), and specificity (90.3%) through PCA-LDA. Proteomic analysis of SP-EVs revealed 218 proteins in Passed and 238 in Failed samples. Nexin-1 and seminal plasma protein pB1 were upregulated in Passed samples, while LGALS3BP was downregulated. The functional analysis highlighted pathways associated with single fertilization, filament organization, and glutathione metabolism in Passed samples. Integrating NIRS with SP-EV proteomics provides a robust approach to non-invasive assessment of semen quality. These findings suggest that SP-EVs could serve as effective biosensors for rapid semen quality assessment, enabling better boar semen selection and enhancing AI practices in swine breeding. Full article

(This article belongs to the Section Optical and Photonic Biosensors)

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20 pages, 16333 KiB

Open AccessReview

The Burgeoning Importance of Nanomotion Sensors in Microbiology and Biology

by Marco Girasole and Giovanni Longo

Biosensors 2025, 15(7), 455; https://doi.org/10.3390/bios15070455 - 15 Jul 2025

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Abstract

Nanomotion sensors have emerged as a pivotal technology in microbiology and biology, leveraging advances in nanotechnology, microelectronics, and optics to provide a highly sensitive, label-free detection of biological activity and interactions. These sensors were first limited to nanomechanical oscillators like atomic force microscopy [...] Read more.

Nanomotion sensors have emerged as a pivotal technology in microbiology and biology, leveraging advances in nanotechnology, microelectronics, and optics to provide a highly sensitive, label-free detection of biological activity and interactions. These sensors were first limited to nanomechanical oscillators like atomic force microscopy cantilevers, but now they are expanding into new, more intriguing setups. The idea is to convert the inherent nanoscale movements of living organisms—a direct manifestation of their metabolic activity—into measurable signals. This review highlights the evolution and diverse applications of nanomotion sensing. Key methodologies include Atomic Force Microscopy-based sensors, optical nanomotion detection, graphene drum sensors, and optical fiber-based sensors, each offering unique advantages in sensitivity, cost, and applicability. The analysis of complex nanomotion data is increasingly supported by advanced modeling and the integration of artificial intelligence and machine learning, enhancing pattern recognition and automation. The versatility and real-time, label-free nature of nanomotion sensing position it as a transformative tool that could revolutionize diagnostics, therapeutics, and fundamental biological research. Full article

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

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11 pages, 1778 KiB

Open AccessCommunication

Ultra-Sensitive Detection of Chloramphenicol by CdS@NiMoS Nanorods-Based Photoelectrochemical Aptasensor

by Hebin Sun, Yimeng Sun, Tong Qi, Zhenyu Wang, Jianlong Zhao and Lijuan Liang

Biosensors 2025, 15(7), 454; https://doi.org/10.3390/bios15070454 - 14 Jul 2025

Viewed by 171

Abstract

A novel nanomaterial photoelectrochemical aptamer sensor based on CdS@NiMoS heterojunction nanocomposites was constructed for highly sensitive detection of chloramphenicol (CAP) in antibiotic residues. Through optimization of the material synthesis process, the optimal doping ratio of MoS₂ to Ni³⁺ (70% MoS₂ [...] Read more.

A novel nanomaterial photoelectrochemical aptamer sensor based on CdS@NiMoS heterojunction nanocomposites was constructed for highly sensitive detection of chloramphenicol (CAP) in antibiotic residues. Through optimization of the material synthesis process, the optimal doping ratio of MoS₂ to Ni³⁺ (70% MoS₂ and 10% Ni³⁺) was identified, which significantly enhanced the photogenerated carrier separation efficiency. In thin-film preparation, comparative analysis of four film-forming methods led to the determination of an optimal process with stability. To achieve highly specific CAP detection, the nanocomposite chip was integrated with nucleic acid aptamer biorecognition elements within a standard three-electrode detection system. Experimental results demonstrated a linear response (R² = 0.998) in the 0.1–2 μM concentration range, with a detection limit of 3.69 nM (3σ/S). Full article

(This article belongs to the Special Issue Nanotechnology Biosensing in Bioanalysis and Beyond)

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17 pages, 1413 KiB

Open AccessArticle

Sensitivity and Cross-Reactivity Analysis of Serotype-Specific Anti-NS1 Serological Assays for Dengue Virus Using Optical Modulation Biosensing

by Sophie Terenteva, Linoy Golani-Zaidie, Shira Avivi, Yaniv Lustig, Victoria Indenbaum, Ravit Koren, Tran Mai Hoa, Tong Thi Kim Tuyen, Ma Thi Huyen, Nguyen Minh Hoan, Le Thi Hoi, Nguyen Vu Trung, Eli Schwartz and Amos Danielli

Biosensors 2025, 15(7), 453; https://doi.org/10.3390/bios15070453 - 14 Jul 2025

Viewed by 198

Abstract

Dengue virus (DENV) poses a major global health concern, with over 6.5 million cases and 7300 deaths reported in 2023. Accurate serological assays are essential for tracking infection history, evaluating disease severity, and guiding vaccination strategies. However, existing assays are limited in their [...] Read more.

Dengue virus (DENV) poses a major global health concern, with over 6.5 million cases and 7300 deaths reported in 2023. Accurate serological assays are essential for tracking infection history, evaluating disease severity, and guiding vaccination strategies. However, existing assays are limited in their specificity, sensitivity, and cross-reactivity. Using optical modulation biosensing (OMB) technology and non-structural protein 1 (NS1) antigens from DENV-1–3, we developed highly sensitive and quantitative serotype-specific anti-DENV NS1 IgG serological assays. The OMB-based assays offered a wide dynamic range (~4-log), low detection limits (~400 ng/L), fast turnaround (1.5 h), and a simplified workflow. Using samples from endemic (Vietnam) and non-endemic (Israel) regions, we assessed intra-DENV and inter-Flavivirus cross-reactivity. Each assay detected DENV infection with a 100% sensitivity for the corresponding serotype and 64% to 90% for other serotypes. Cross-reactivity with Zika, Japanese encephalitis, and West Nile viruses ranged from 21% to 65%, reflecting NS1 antigen conservation. Our study provides valuable insights into the cross-reactivity of DENV NS1 antigens widely used in research and highlights the potential of OMB-based assays for quantitative and epidemiological studies. Ongoing efforts should aim to minimize cross-reactivity while maintaining sensitivity and explore integration with complementary platforms for improved diagnostic precision. Full article

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

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29 pages, 5230 KiB

Open AccessReview

Expanding Horizons in Advancements of FRET Biosensing Technologies

by Munazza Fatima and Naseem Abbas

Biosensors 2025, 15(7), 452; https://doi.org/10.3390/bios15070452 - 14 Jul 2025

Viewed by 78

Abstract

Förster resonance energy transfer (FRET)-based biosensors are versatile tools for obtaining insights into various biological processes. Their working principles are based on nonradiative energy transfer from donor to acceptor fluorophores. This energy transfer is responsible for a change in fluorescence intensity, which provides [...] Read more.

Förster resonance energy transfer (FRET)-based biosensors are versatile tools for obtaining insights into various biological processes. Their working principles are based on nonradiative energy transfer from donor to acceptor fluorophores. This energy transfer is responsible for a change in fluorescence intensity, which provides a basis for the detection of biomolecules. Advantageous features of FRET biosensors include their high sensitivity and specificity. Recently, there have been notable developments to extend the usage of FRET biosensors for diverse applications. In this review, we briefly summarize the state-of-the-art developments of FRET biosensors for cellular imaging, drug discovery, pathogen detection, and cancer diagnosis. Continued research on biosensor design, donor acceptor pair optimization, and integration of innovative materials can further extend the applications of FRET biosensors across health care settings. 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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20 pages, 1303 KiB

Open AccessReview

The Role of Nanomaterials in the Wearable Electrochemical Glucose Biosensors for Diabetes Management

by Tahereh Jamshidnejad-Tosaramandani, Soheila Kashanian, Kobra Omidfar and Helgi B. Schiöth

Biosensors 2025, 15(7), 451; https://doi.org/10.3390/bios15070451 - 14 Jul 2025

Viewed by 103

Abstract

The increasing prevalence of diabetes mellitus necessitates the development of advanced glucose-monitoring systems that are non-invasive, reliable, and capable of real-time analysis. Wearable electrochemical biosensors have emerged as promising tools for continuous glucose monitoring (CGM), particularly through sweat-based platforms. This review highlights recent [...] Read more.

The increasing prevalence of diabetes mellitus necessitates the development of advanced glucose-monitoring systems that are non-invasive, reliable, and capable of real-time analysis. Wearable electrochemical biosensors have emerged as promising tools for continuous glucose monitoring (CGM), particularly through sweat-based platforms. This review highlights recent advancements in enzymatic and non-enzymatic wearable biosensors, with a specific focus on the pivotal role of nanomaterials in enhancing sensor performance. In enzymatic sensors, nanomaterials serve as high-surface-area supports for glucose oxidase (GOx) immobilization and facilitate direct electron transfer (DET), thereby improving sensitivity, selectivity, and miniaturization. Meanwhile, non-enzymatic sensors leverage metal and metal oxide nanostructures as catalytic sites to mimic enzymatic activity, offering improved stability and durability. Both categories benefit from the integration of carbon-based materials, metal nanoparticles, conductive polymers, and hybrid composites, enabling the development of flexible, skin-compatible biosensing systems with wireless communication capabilities. The review critically evaluates sensor performance parameters, including sensitivity, limit of detection, and linear range. Finally, current limitations and future perspectives are discussed. These include the development of multifunctional sensors, closed-loop therapeutic systems, and strategies for enhancing the stability and cost-efficiency of biosensors for broader clinical adoption. Full article

(This article belongs to the Topic Applications of Nanomaterials in Biosensing: Current Trends and Future Prospects)

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Graphical abstract

14 pages, 1953 KiB

Open AccessArticle

Laser-Induced Solid-Phase UV Fluorescence Spectroscopy for Rapid Detection of Polycyclic Aromatic Hydrocarbons in the Land Snail Bioindicator, Cantareus aspersus

by Maxime Louzon, Thomas Bertoncini, Noah Casañas, Yves Perrette, Gaël Plassart, Marine Quiers, Tanguy Wallet, Mohamed Kamel and Lotfi Aleya

Biosensors 2025, 15(7), 450; https://doi.org/10.3390/bios15070450 - 14 Jul 2025

Viewed by 200

Abstract

In ecotoxicological risk assessment, current methods for measuring the transfer and bioavailability of organic pollutants like polycyclic aromatic hydrocarbons (PAHs) in bioindicators are often destructive and environmentally unfriendly. These limitations are especially problematic when only small amounts of biological material are available. Here, [...] Read more.

In ecotoxicological risk assessment, current methods for measuring the transfer and bioavailability of organic pollutants like polycyclic aromatic hydrocarbons (PAHs) in bioindicators are often destructive and environmentally unfriendly. These limitations are especially problematic when only small amounts of biological material are available. Here, we present a novel, high-throughput method combining laser-induced UV fluorescence spectroscopy (UV-LIF) and solid-phase spectroscopy (SPS) for rapid, in situ quantification of PAHs in land snails—a key bioindicator species. Using dual excitation wavelengths (266 nm and 355 nm), our method reliably detected pyrene and fluoranthene in snails exposed to varying concentrations, demonstrating clear dose-responses and inter-individual differences in bioaccumulation. The analysis time per sample was under four minutes. This approach allows simultaneous measurement of internal contaminant levels and health biomarkers in individual organisms and aligns with green chemistry principles. These findings establish a new, scalable tool for routine assessment of PAH transfer and bioavailability in diverse ecosystems. Full article

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

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18 pages, 3864 KiB

Open AccessArticle

Composite Metal Oxide Nanopowder-Based Fiber-Optic Fabry–Perot Interferometer for Protein Biomarker Detection

by Ulpan Balgimbayeva, Zhanar Kalkozova, Kuanysh Seitkamal, Daniele Tosi, Khabibulla Abdullin and Wilfried Blanc

Biosensors 2025, 15(7), 449; https://doi.org/10.3390/bios15070449 - 13 Jul 2025

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Abstract

In this paper, we present the development of a new semi-distributed interferometer (SDI) biosensor with a Zn, Cu, and Co metal oxide nanopowder coating for the detection of a kidney disease biomarker as a model system. The combination of nanopowder coating with the [...] Read more.

In this paper, we present the development of a new semi-distributed interferometer (SDI) biosensor with a Zn, Cu, and Co metal oxide nanopowder coating for the detection of a kidney disease biomarker as a model system. The combination of nanopowder coating with the SDI platform opens up unique opportunities for improving measurement reproducibility while maintaining high sensitivity. The fabrication of sensors is simple, which involves one splice and subsequent cutting at the end of an optical fiber. To ensure specific detection of the biomarker, a monoclonal antibody was immobilized on the surface of the probe. The biosensor has demonstrated an impressive ability to detect biomarkers in a wide range of concentrations, from 1 aM to 100 nM. The theoretical limit of detection was 126 fM, and the attomolar detection level was experimentally achieved. The sensors have achieved a maximum sensitivity of 190 dB/RIU and operate with improved stability and reduced dispersion. Quantitative analysis revealed that the sensor’s response gradually increases with increasing concentration. The signal varies from 0.05 dB at 1 aM to 0.81 dB at 100 nM, and the linear correlation coefficient was R² = 0.96. The sensor showed excellent specificity and reproducibility, maintaining detection accuracy at about 10⁻⁴ RIU. This opens up new horizons for reliable and highly sensitive biomarker detection, which can be useful for early disease diagnosis and monitoring using a cost-effective and reproducible sensor system. Full article

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

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13 pages, 2331 KiB

Open AccessCommunication

The Power of Old Hats: Rediscovering Inosine-EpPCR to Create Starting Libraries for Whole-Cell-SELEX

by Grigory Bolotnikov, Ann-Kathrin Kissmann, Daniel Gruber, Andreas Bellmann, Roger Hasler, Christoph Kleber, Wolfgang Knoll and Frank Rosenau

Biosensors 2025, 15(7), 448; https://doi.org/10.3390/bios15070448 - 12 Jul 2025

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Abstract

Shaking off the forgetfulness towards the methodological power of inosine-mediated error-prone PCR (epPCR), this study reintroduces an often-underappreciated method as a considerably powerful approach for generating aptamer libraries from a single decameric ATCG-repeat-oligonucleotide. The aim was to demonstrate that this simple way of [...] Read more.

Shaking off the forgetfulness towards the methodological power of inosine-mediated error-prone PCR (epPCR), this study reintroduces an often-underappreciated method as a considerably powerful approach for generating aptamer libraries from a single decameric ATCG-repeat-oligonucleotide. The aim was to demonstrate that this simple way of creating sequence diversity was suitable for delivering functional starting libraries for a set of ten whole-cell-SELEX (Systematic Evolution of Ligands by Exponential Enrichment) processes. This epPCR method uses inosine to introduce targeted mutations, avoiding the need for commercial oligo pools or large-scale synthesis. We applied this method to a “universal aptamer” and subjected the three resulting libraries to two rounds of selection against ten diverse targets including probiotic and pathogenic bacteria (Gram-negative and -positive) as well as human cell lines. The enriched aptamers exhibited new binding specificities, demonstrating that the approach supports functional selection. Much like dusting off an old tool and finding it perfectly suited for a modern task, this work shows that revisiting established techniques can address current challenges in aptamer development. Our main finding is that epPCR provides a robust, cost-effective strategy for generating starting libraries and lowers the barrier for initiating successful SELEX campaigns. Full article

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

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36 pages, 2877 KiB

Open AccessArticle

Dual-Oriented Targeted Nanostructured SERS Label-Free Immunosensor for Detection, Quantification, and Analysis of Breast Cancer Biomarker Concentrations in Blood Serum

by Mohammad E. Khosroshahi, Christine Gaoiran, Vithurshan Umashanker, Hayagreev Veeru and Pranav Panday

Biosensors 2025, 15(7), 447; https://doi.org/10.3390/bios15070447 - 11 Jul 2025

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Abstract

In clinical applications of surface-enhanced Raman spectroscopy (SERS) immunosensors, accurately determining analyte biomarker concentrations is essential. This study presents a non-invasive approach for quantifying various breast cancer biomarkers—including human epidermal growth factor receptor II (HER-II) (2+, 3+ (I), 3+ (II), 3+ (III), and [...] Read more.

In clinical applications of surface-enhanced Raman spectroscopy (SERS) immunosensors, accurately determining analyte biomarker concentrations is essential. This study presents a non-invasive approach for quantifying various breast cancer biomarkers—including human epidermal growth factor receptor II (HER-II) (2+, 3+ (I), 3+ (II), 3+ (III), and positive IV) and CA 15-3—using a directional, plasmonically active, label-free SERS sensor. Each stage of sensor functionalization, conjugation, and biomarker interaction was verified by UV–Vis spectroscopy. Atomic force microscopy (AFM) characterized the morphology of gold nanourchin (GNU)-immobilized printed circuit board (PCB) substrates. An enhancement factor of ≈ 0.5 × 10⁵ was achieved using Rhodamine 6G as the probe molecule. Calibration curves were initially established using standard HER-II solutions at concentrations ranging from 1 to 100 ng/mL and CA 15-3 at concentrations from 10 to 100 U/mL. The SERS signal intensities in the 620–720 nm region were plotted against concentration, yielding linear sensitivity with R² values of 0.942 and 0.800 for HER-II and CA15-3, respectively. The same procedure was applied to breast cancer serum (BCS) samples, allowing unknown biomarker concentrations to be determined based on the corresponding calibration curves. SERS data were processed using the filtfilt filter from scipy.signal for smoothing and then baseline-corrected with the Improved Asymmetric Least Squares (IASLS) algorithm from the pybaselines.Whittaker library. Principal Component Analysis (PCA) effectively distinguished the sample groups and revealed spectral differences before and after biomarker interactions. Key Raman peaks were attributed to functional groups including N–H (primary and secondary amines), C–H antisymmetric stretching, C–N (amines), C=O antisymmetric stretching, NH₃⁺ (amines), carbohydrates, glycine, alanine, amides III, C=N stretches, and NH₂ in primary amides. Full article

(This article belongs to the Special Issue Miniature Sensors Based on Highly Efficient Chemical and Biological Sensing Interfaces)

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14 pages, 1906 KiB

Open AccessArticle

FRET-Based TURN-ON Aptasensor for the Sensitive Detection of CK-MB

by Rabia Asghar, Madiha Rasheed, Xuefei Lv and Yulin Deng

Biosensors 2025, 15(7), 446; https://doi.org/10.3390/bios15070446 - 11 Jul 2025

Viewed by 209

Abstract

A fluorescent sandwich assay was devised to quantify CK-MB. In a typical immunoassay, antibodies bind to the target, and the detected signal is quantified according to the target’s concentration. We innovated a unique fluorescence assay known as the “enzyme-linked aptamer assay” (ELAA) by [...] Read more.

A fluorescent sandwich assay was devised to quantify CK-MB. In a typical immunoassay, antibodies bind to the target, and the detected signal is quantified according to the target’s concentration. We innovated a unique fluorescence assay known as the “enzyme-linked aptamer assay” (ELAA) by substituting antibodies with a pair of high-affinity aptamers labelled with biotin, namely apt. A1 and apt. A2. Avidin-labelled ALP binds to biotin-labelled aptamers, hydrolyzing its substrate, 2-phosphoascorbic acid trisodium salt, resulting in the formation of ascorbic acid. The catalytic hydrolysate functions as a reducing agent, causing the deterioration of MoS₂ nanosheets. This results in the transformation of MoS₂ nanosheets into nanoribbons, leading to the release of quenched AGQDs. The reestablishment of fluorescence is triggered by Förster Resonance Energy Transfer (FRET) between the MoS₂ nanoribbons and AGQDs, enhancing the sensitivity of disease biomarker detection. The working range for detection falls between 2.5 nM and 160 nM, and the limit of detection (LOD) for CK-MB is verified at 0.20 nM. Full article

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

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17 pages, 3107 KiB

Open AccessArticle

Performance of Colorimetric Lateral Flow Immunoassays for Renal Function Evaluation with Human Serum Cystatin C

by Xushuo Zhang, Sam Fishlock, Peter Sharpe and James McLaughlin

Biosensors 2025, 15(7), 445; https://doi.org/10.3390/bios15070445 - 11 Jul 2025

Viewed by 248

Abstract

Chronic kidney disease (CKD) is associated with heart failure and neurological disorders. Therefore, point-of-care (POC) detection of CKD is essential, allowing disease monitoring from home and alleviating healthcare professionals’ workload. Lateral flow immunoassays (LFIAs) facilitate POC testing for a renal function biomarker, serum [...] Read more.

Chronic kidney disease (CKD) is associated with heart failure and neurological disorders. Therefore, point-of-care (POC) detection of CKD is essential, allowing disease monitoring from home and alleviating healthcare professionals’ workload. Lateral flow immunoassays (LFIAs) facilitate POC testing for a renal function biomarker, serum Cystatin C (CysC). LF devices were fabricated and optimised by varying the diluted sample volume, the nitrocellulose (NC) membrane, bed volume, AuNPs’ OD value and volume, and assay formats of partial or full LF systems. Notably, 310 samples were analysed to satisfy the minimum sample size for statistical calculations. This allowed for a comparison between the LFIAs’ results and the general Roche standard assay results from the Southern Health and Social Care Trust. Bland–Altman plots indicated the LFIAs measured 0.51 mg/L lower than the Roche assays. With the 95% confidence interval, the Roche method might be 0.24 mg/L below the LFIAs’ results or 1.27 mg/L above the LFIAs’ results. In summary, the developed non-fluorescent LFIAs could detect clinical CysC values in agreement with Roche assays. Even though the developed LFIA had an increased bias in low CysC concentration (below 2 mg/L) detection, the developed LFIA can still alert patients at the early stages of renal function impairment. Full article

(This article belongs to the Section Biosensors and Healthcare)

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21 pages, 3587 KiB

Open AccessArticle

Carboxymethyl Dextran-Based Biosensor for Simultaneous Determination of IDO-1 and IFN-Gamma in Biological Material

by Zuzanna Zielinska, Anna Sankiewicz, Natalia Kalinowska, Beata Zelazowska-Rutkowska, Tomasz Guszcz, Leszek Ambroziak, Miroslaw Kondratiuk and Ewa Gorodkiewicz

Biosensors 2025, 15(7), 444; https://doi.org/10.3390/bios15070444 - 10 Jul 2025

Viewed by 174

Abstract

Indoleamine 2,3-dioxygenase 1 (IDO-1) and interferon-gamma (IFN-γ) are proteins that play a significant role in inflammatory conditions and tumor development. The detection of IDO1 and IFN-γ is crucial for understanding their interplay in immune responses. This study introduced a novel method for the [...] Read more.

Indoleamine 2,3-dioxygenase 1 (IDO-1) and interferon-gamma (IFN-γ) are proteins that play a significant role in inflammatory conditions and tumor development. The detection of IDO1 and IFN-γ is crucial for understanding their interplay in immune responses. This study introduced a novel method for the simultaneous quantitative determination of IDO-1 and IFN-γ in different biological samples/materials. The method is based on an optical biosensor, with surface plasmon resonance detection carried out by the imaging version of the sensor (SPRi). Biotinylated antibodies immobilized on the surfaces of the linker and carboxymethylated dextran served as the recognition elements for the developed biosensor. Relevant studies were conducted to optimize the activities of the biosensor by employing appropriate reagent concentrations. Validation was performed for each protein separately; low detection and quantification limits were obtained (for IDO-1 LOD = 0.27 ng/mL, LOQ = 0.81 ng/mL; for IFN-γ LOD = 1.76 pg/mL and LOQ = 5.29 pg/mL). The sensor operating ranges were 0.001–10 ng/mL for IDO-1 and 0.1–1000 pg/mL for IFN-γ. The constructed biosensor demonstrated its sensitivity and precision when the appropriate analytical parameters were determined, based on the proposed method. It can also selectively capture IDO-1 and IFN-γ from a large sample matrix. The biosensor efficiency was confirmed by the determination of IDO-1 and IFN-γ in simultaneous measurements of the plasma and urine samples of patients diagnosed with bladder cancer and the control group. The outcomes were compared to those obtained using a certified ELISA test, demonstrating convergence between the two methodologies. The preliminary findings demonstrate the biosensor’s efficacy and suitability for comprehensive analyses of the examined biological samples. Full article

(This article belongs to the Special Issue Micro/Nanofluidic System-Based Biosensors)

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40 pages, 2353 KiB

Open AccessReview

Electrochemical Impedance Spectroscopy-Based Biosensors for Label-Free Detection of Pathogens

by Huaiwei Zhang, Zhuang Sun, Kaiqiang Sun, Quanwang Liu, Wubo Chu, Li Fu, Dan Dai, Zhiqiang Liang and Cheng-Te Lin

Biosensors 2025, 15(7), 443; https://doi.org/10.3390/bios15070443 - 10 Jul 2025

Viewed by 153

Abstract

The escalating threat of infectious diseases necessitates the development of diagnostic technologies that are not only rapid and sensitive but also deployable at the point of care. Electrochemical impedance spectroscopy (EIS) has emerged as a leading technique for the label-free detection of pathogens, [...] Read more.

The escalating threat of infectious diseases necessitates the development of diagnostic technologies that are not only rapid and sensitive but also deployable at the point of care. Electrochemical impedance spectroscopy (EIS) has emerged as a leading technique for the label-free detection of pathogens, offering a unique combination of sensitivity, non-invasiveness, and adaptability. This review provides a comprehensive overview of the design and application of EIS-based biosensors tailored for pathogen detection, focusing on critical components such as biorecognition elements, electrode materials, nanomaterial integration, and surface immobilization strategies. Special emphasis is placed on the mechanisms of signal generation under Faradaic and non-Faradaic modes and how these underpin performance characteristics such as the limit of detection, specificity, and response time. The application spectrum spans bacterial, viral, fungal, and parasitic pathogens, with case studies highlighting detection in complex matrices such as blood, saliva, food, and environmental water. Furthermore, integration with microfluidics and point-of-care systems is explored as a pathway toward real-world deployment. Emerging strategies for multiplexed detection and the utilization of novel nanomaterials underscore the dynamic evolution of the field. Key challenges—including non-specific binding, matrix effects, the inherently low ΔR_ct/decade sensitivity of impedance transduction, and long-term stability—are critically evaluated alongside recent breakthroughs. This synthesis aims to support the future development of robust, scalable, and user-friendly EIS-based pathogen biosensors with the potential to transform diagnostics across healthcare, food safety, and environmental monitoring. Full article

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

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16 pages, 3497 KiB

Open AccessArticle

Utilizing Circadian Heart Rate Variability Features and Machine Learning for Estimating Left Ventricular Ejection Fraction Levels in Hypertensive Patients: A Composite Multiscale Entropy Analysis

by Nanxiang Zhang, Qi Pan, Shuo Yang, Leen Huang, Jianan Yin, Hai Lin, Xiang Huang, Chonglong Ding, Xinyan Zou, Yongjun Zheng and Jinxin Zhang

Biosensors 2025, 15(7), 442; https://doi.org/10.3390/bios15070442 - 10 Jul 2025

Viewed by 212

Abstract

Background: Early identification of left ventricular ejection fraction (LVEF) levels during the progression of hypertension is essential to prevent cardiac deterioration. However, achieving a non-invasive, cost-effective, and definitive assessment is challenging. It has prompted us to develop a comprehensive machine learning framework for [...] Read more.

Background: Early identification of left ventricular ejection fraction (LVEF) levels during the progression of hypertension is essential to prevent cardiac deterioration. However, achieving a non-invasive, cost-effective, and definitive assessment is challenging. It has prompted us to develop a comprehensive machine learning framework for the automatic quantitative estimation of LVEF levels from electrocardiography (ECG) signals. Methods: We enrolled 200 hypertensive patients from Zhongshan City, Guangdong Province, China, from 1 November 2022 to 1 January 2025. Participants underwent 24 h Holter monitoring and echocardiography for LVEF estimation. We developed a comprehensive machine learning framework that initiated with preprocessed ECG signal in one-hour intervals to extract CMSE-based heart rate variability (HRV) features, then utilized machine learning models such as linear regression (LR), Support Vector Machines (SVMs), and random forests (RFs) with recursive feature elimination for optimal LVEF estimation. Results: The LR model, notably during early night interval (20:00–21:00), achieved a RMSE of 4.61% and a MAE of 3.74%, highlighting its superiority. Compared with other similar studies, key CMSE parameters (Scales 1, 5, Slope 1–5, and Area 1–5) can effectively enhance regression models’ estimation performance. Conclusion: Our findings suggest that CMSE-derived circadian HRV features from Holter ECG could serve as a non-invasive, cost-effective, and interpretable solution for LVEF assessment in community settings. From a machine learning interpretable perspective, the proposed method emphasized CMSE’s clinical potential in capturing autonomic dynamics and cardiac function fluctuations. Full article

(This article belongs to the Special Issue Latest Wearable Biosensors—2nd Edition)

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24 pages, 5097 KiB

Open AccessArticle

Non-Monotonic Effect of Substrate Inhibition in Conjunction with Diffusion Limitation on the Response of Amperometric Biosensors

by Romas Baronas

Biosensors 2025, 15(7), 441; https://doi.org/10.3390/bios15070441 - 9 Jul 2025

Viewed by 151

Abstract

The non-monotonic behavior of amperometric enzyme-based biosensors under uncompetitive and noncompetitive (mixed) substrate inhibition is investigated computationally using a two-compartment model consisting of an enzyme layer and an outer diffusion layer. The model is based on a system of reaction–diffusion equations that includes [...] Read more.

The non-monotonic behavior of amperometric enzyme-based biosensors under uncompetitive and noncompetitive (mixed) substrate inhibition is investigated computationally using a two-compartment model consisting of an enzyme layer and an outer diffusion layer. The model is based on a system of reaction–diffusion equations that includes a nonlinear term associated with non-Michaelis–Menten kinetics of the enzymatic reaction and accounts for the partitioning between layers. In addition to the known effect of substrate inhibition, where the maximum biosensor current differs from the steady-state output, it has been determined that external diffusion limitations can also cause the appearance of a local minimum in the current. At substrate concentrations greater than both the Michaelis–Menten constant and the uncompetitive substrate inhibition constant, and in the presence of external diffusion limitation, the transient response of the biosensor, after immersion in the substrate solution, may follow a five-phase pattern depending on the model parameter values: it starts from zero, reaches a global or local maximum, decreases to a local minimum, increases again, and finally decreases to a steady intermediate value. The biosensor performance is analyzed numerically using the finite difference method. Full article

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

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19 pages, 690 KiB

Open AccessReview

Polymeric Composite-Based Electrochemical Sensing Devices Applied in the Analysis of Monoamine Neurotransmitters

by Stelian Lupu

Biosensors 2025, 15(7), 440; https://doi.org/10.3390/bios15070440 - 9 Jul 2025

Viewed by 260

Abstract

Electroanalysis of monoamine neurotransmitters is a useful tool for monitoring relevant neurodegenerative disorders and diseases. Electroanalysis of neurotransmitters using analytical devices consisting of electrodes modified with tailored and nanostructured composite materials is an active research topic nowadays. Nano- and microstructured composite materials composed [...] Read more.

Electroanalysis of monoamine neurotransmitters is a useful tool for monitoring relevant neurodegenerative disorders and diseases. Electroanalysis of neurotransmitters using analytical devices consisting of electrodes modified with tailored and nanostructured composite materials is an active research topic nowadays. Nano- and microstructured composite materials composed of various organic conductive polymers, metal/metal oxide nanoparticles, and carbonaceous materials enable an increase in the performance of electroanalytical sensing devices. Synergistic properties resulting from the combination of various pristine nanomaterials have enabled faster kinetics and increased overall performance. Herein, recent results related to the design and elaboration of electroanalytical sensing devices based on cost-effective and reliable nano- and microstructured composite materials for the quantification of monoamine neurotransmitters are presented. The discussion focuses on the fabrication procedures and detection strategies, highlighting the capabilities of the analytical platforms used in the determination of relevant analytes. The review aims to present the main benefits of using composite nanostructured materials in the electroanalysis of monoamine neurotransmitters. Full article

(This article belongs to the Special Issue Innovative Biosensing Technologies for Sustainable Healthcare)

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15 pages, 980 KiB

Open AccessArticle

Assessment of Microvascular Disturbances in Children with Type 1 Diabetes—A Pilot Study

by Anna Wołoszyn-Durkiewicz, Edyta Dąbrowska, Marcin Hellmann, Anna Jankowska, Mariusz J. Kujawa, Dominik Świętoń, Agata Durawa, Joanna Kuhn, Joanna Szypułowska-Grzyś, Agnieszka Brandt-Varma, Jacek Burzyński, Jędrzej Chrzanowski, Arkadiusz Michalak, Aleksandra Michnowska, Dalia Trzonek, Jacek Wolf, Krzysztof Narkiewicz, Edyta Szurowska and Małgorzata Myśliwiec

Biosensors 2025, 15(7), 439; https://doi.org/10.3390/bios15070439 - 8 Jul 2025

Viewed by 248

Abstract

Endothelial dysfunction appears early in type 1 diabetes (T1D). The detection of the first vascular disturbances in T1D patients is crucial, and the introduction of novel techniques, such as flow-mediated skin fluorescence (FMSF) and adaptive optics retinal camera (Rtx) imaging, gives hope for [...] Read more.

Endothelial dysfunction appears early in type 1 diabetes (T1D). The detection of the first vascular disturbances in T1D patients is crucial, and the introduction of novel techniques, such as flow-mediated skin fluorescence (FMSF) and adaptive optics retinal camera (Rtx) imaging, gives hope for better detection and prevention of angiopathies in the future. In this study, we aimed to investigate microcirculation disturbances in pediatric patients with T1D with the use of FMSF and Rtx imaging. This research focused especially on the relationship between microvascular parameters obtained in FMSF and Rtx measurements, and the glycemic control evaluated in continuous glucose monitoring (CGM) reports. We observed significantly increased wall thickness (WT) and wall-to-lumen ratio (WLR) values in T1D patients in comparison to the control group. Although we did not observe significant differences between the T1D and control groups in the FMSF results, a trend toward significance between the time in range (TIR) and hyperemic response (HR_max) and an interesting correlation between the carotid intima-media thickness (cIMT_max) and HR_max. were observed. In conclusion, FMSF and Rtx measurments are innovative techniques enabling the detection of early microvascular disturbances. Full article

(This article belongs to the Section Biosensors and Healthcare)

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21 pages, 2191 KiB

Open AccessReview

Heavy Metal Ion Detection Based on Lateral Flow Assay Technology: Principles and Applications

by Xiaobo Xie, Xinyue Hu, Xin Cao, Qianhui Zhou, Wei Yang, Ranran Yu, Shuaiqi Liu, Huili Hu, Ji Qi and Zhiyang Zhang

Biosensors 2025, 15(7), 438; https://doi.org/10.3390/bios15070438 - 7 Jul 2025

Viewed by 224

Abstract

Heavy metal ions pose a significant threat to the environment and human health due to their high toxicity and bioaccumulation. Traditional instrumentations, although sensitive, are often complex, costly, and unsuitable for on-site rapid detection of heavy metal ions. Lateral flow assay technology has [...] Read more.

Heavy metal ions pose a significant threat to the environment and human health due to their high toxicity and bioaccumulation. Traditional instrumentations, although sensitive, are often complex, costly, and unsuitable for on-site rapid detection of heavy metal ions. Lateral flow assay technology has emerged as a research hotspot due to its rapid, simple, and cost-effective advantages. This review summarizes the applications of lateral flow assay technology based on nucleic acid molecules and antigen–antibody interactions in heavy metal ion detection, focusing on recognition mechanisms such as DNA probes, nucleic acid enzymes, aptamers, and antigen–antibody binding, as well as signal amplification strategies on lateral flow testing strips. By incorporating these advanced technologies, the sensitivity and specificity of lateral flow assays have been significantly improved, enabling highly sensitive detection of various heavy metal ions, including Hg²⁺, Cd²⁺, Pb²⁺, and Cr³⁺. In the future, the development of lateral flow assay technology for detection of heavy metal ions will focus on multiplex detection, optimization of signal amplification strategies, integration with portable devices, and standardization and commercialization. With continuous technological advancements, lateral flow assay technology will play an increasingly important role in environmental monitoring, food safety, and public health. Full article

(This article belongs to the Special Issue Miniature Sensors Based on Highly Efficient Chemical and Biological Sensing Interfaces)

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38 pages, 3752 KiB

Open AccessReview

Recent Advances in Metal–Organic Framework-Based Nanozymes for Intelligent Microbial Biosensing: A Comprehensive Review of Biomedical and Environmental Applications

by Alemayehu Kidanemariam and Sungbo Cho

Biosensors 2025, 15(7), 437; https://doi.org/10.3390/bios15070437 - 7 Jul 2025

Viewed by 303

Abstract

Metal–organic framework (MOF)-based nanozymes represent a groundbreaking frontier in advanced microbial biosensing, offering unparalleled catalytic precision and structural tunability to mimic natural enzymes with superior stability and specificity. By engineering the structural features and forming composites, MOFs are precisely tailored to amplify nanozymatic [...] Read more.

Metal–organic framework (MOF)-based nanozymes represent a groundbreaking frontier in advanced microbial biosensing, offering unparalleled catalytic precision and structural tunability to mimic natural enzymes with superior stability and specificity. By engineering the structural features and forming composites, MOFs are precisely tailored to amplify nanozymatic activity, enabling the highly sensitive, rapid, and cost-effective detection of a broad spectrum of microbial pathogens critical to biomedical diagnostics and environmental monitoring. These advanced biosensors surpass traditional enzyme systems in robustness and reusability, integrating seamlessly with smart diagnostic platforms for real-time, on-site microbial identification. This review highlights cutting-edge developments in MOF nanozyme design, composite engineering, and signal transduction integration while addressing pivotal challenges such as biocompatibility, complex matrix interference, and scalable manufacturing. Looking ahead, the convergence of multifunctional MOF nanozymes with portable technologies and optimized in vivo performance will drive transformative breakthroughs in early disease detection, antimicrobial resistance surveillance, and environmental pathogen control, establishing a new paradigm in next-generation smart biosensing. Full article

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

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27 pages, 1846 KiB

Open AccessReview

Democratization of Point-of-Care Viral Biosensors: Bridging the Gap from Academia to the Clinic

by Westley Van Zant and Partha Ray

Biosensors 2025, 15(7), 436; https://doi.org/10.3390/bios15070436 - 7 Jul 2025

Viewed by 246

Abstract

The COVID-19 pandemic and recent viral outbreaks have highlighted the need for viral diagnostics that balance accuracy with accessibility. While traditional laboratory methods remain essential, point-of-care solutions are critical for decentralized testing at the population level. However, a gap persists between academic proof-of-concept [...] Read more.

The COVID-19 pandemic and recent viral outbreaks have highlighted the need for viral diagnostics that balance accuracy with accessibility. While traditional laboratory methods remain essential, point-of-care solutions are critical for decentralized testing at the population level. However, a gap persists between academic proof-of-concept studies and clinically viable tools, with novel technologies remaining inaccessible to clinics due to cost, complexity, training, and logistical constraints. Recent advances in surface functionalization, assay simplification, multiplexing, and performance in complex media have improved the feasibility of both optical and non-optical sensing techniques. These innovations, coupled with scalable manufacturing methods such as 3D printing and streamlined hardware production, pave the way for practical deployment in real-world settings. Additionally, software-assisted data interpretation, through simplified readouts, smartphone integration, and machine learning, enables the broader use of diagnostics once limited to experts. This review explores improvements in viral diagnostic approaches, including colorimetric, optical, and electrochemical assays, showcasing their potential for democratization efforts targeting the clinic. We also examine trends such as open-source hardware, modular assay design, and standardized reporting, which collectively reduce barriers to clinical adoption and the public dissemination of information. By analyzing these interdisciplinary advances, we demonstrate how emerging technologies can mature into accessible, low-cost diagnostic tools for widespread testing. Full article

(This article belongs to the Special Issue Biosensors for Monitoring and Diagnostics)

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13 pages, 1289 KiB

Open AccessReview

Peroxidase-Mimicking Nanozymes of Nitrogen Heteroatom-Containing Graphene Oxide for Biomedical Applications

by Phan Gia Le, Daesoo Kim, Jae-Pil Chung and Sungbo Cho

Biosensors 2025, 15(7), 435; https://doi.org/10.3390/bios15070435 - 7 Jul 2025

Viewed by 311

Abstract

Nanozymes constitute a rapidly advancing frontier in scientific research, attracting widespread international interest, particularly for their role in facilitating cascade reactions. Despite their initial discovery a few years ago, significant hurdles persist in optimizing their catalytic performance and substrate specificity—challenges that are especially [...] Read more.

Nanozymes constitute a rapidly advancing frontier in scientific research, attracting widespread international interest, particularly for their role in facilitating cascade reactions. Despite their initial discovery a few years ago, significant hurdles persist in optimizing their catalytic performance and substrate specificity—challenges that are especially critical in the context of biomedical diagnostics. Within this domain, nitrogen-containing graphene oxide-based nanozymes exhibiting peroxidase-mimicking activity have emerged as particularly promising candidates, owing to the exceptional electrical conductivity, mechanical flexibility, and structural resilience of reduced graphene oxide-based materials. Intensive efforts have been devoted to engineering graphene oxide structures to enhance their peroxidase-like functionality. Nonetheless, the practical implementation of such nanozymes remains under active investigation and demands further refinement. This review synthesizes the current developments in nitrogen heteroatom-containing graphene oxide nanozymes and their derivative nanozymes, emphasizing recent breakthroughs and biomedical applications. It concludes by exploring prospective directions and the broader potential of these materials in the biomedical landscape. Full article

(This article belongs to the Special Issue Cutting-Edge Nanozyme Biosensing Strategies for Biomedical and Environmental Applications)

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19 pages, 1908 KiB

Open AccessReview

Enhancing ELISA Sensitivity: From Surface Engineering to Synthetic Biology

by Hye-Bin Jeon, Dong-Yeon Song, Yu Jin Park and Dong-Myung Kim

Biosensors 2025, 15(7), 434; https://doi.org/10.3390/bios15070434 - 6 Jul 2025

Viewed by 429

Abstract

Accurate and sensitive detection of protein biomarkers is critical for advancing in vitro diagnostics (IVD), yet conventional enzyme-linked immunosorbent assays (ELISA) often fall short in terms of sensitivity compared to nucleic acid-based tests. Bridging this sensitivity gap is essential for improving diagnostic accuracy, [...] Read more.

Accurate and sensitive detection of protein biomarkers is critical for advancing in vitro diagnostics (IVD), yet conventional enzyme-linked immunosorbent assays (ELISA) often fall short in terms of sensitivity compared to nucleic acid-based tests. Bridging this sensitivity gap is essential for improving diagnostic accuracy, particularly in diseases where protein levels better reflect disease progression than nucleic acid biomarkers. In this review, we present strategies developed to enhance the sensitivity of ELISA, structured according to the sequential steps of the assay workflow. Beginning with surface modifications, we then discuss the methodologies to improve mixing and washing efficiency, followed by a summary of recent advances in signal generation and amplification techniques. In particular, we highlight the emerging role of cell-free synthetic biology in augmenting ELISA sensitivity. Recent developments such as expression immunoassays, CRISPR-linked immunoassays (CLISA), and T7 RNA polymerase–linked immunosensing assays (TLISA) demonstrate how programmable nucleic acid and protein synthesis systems can be integrated into ELISA workflows to surpass the present sensitivity, affordability, and accessibility. By combining synthetic biology-driven amplification and signal generation mechanisms with traditional immunoassay formats, ELISA is poised to evolve into a highly modular and adaptable diagnostic platform, representing a significant step toward the next generation of highly sensitive and programmable immunoassays. 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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13 pages, 1457 KiB

Open AccessArticle

A Signal On-Off Ratiometric Molecularly Imprinted Electrochemical Sensor Based on MXene/PEI-MWCNTs Signal Amplification for the Detection of Diuron

by Yi He, Jin Zhu, Libo Li, Tianyan You and Xuegeng Chen

Biosensors 2025, 15(7), 433; https://doi.org/10.3390/bios15070433 - 5 Jul 2025

Viewed by 324

Abstract

Diuron (DU) is a widely used phenylurea herbicide designed to inhibit weed growth, but its high toxicity and prolonged half-life contribute significantly to environmental contamination. The majority of electrochemical (EC) sensors typically rely on a single response signal for the detection of DU, [...] Read more.

Diuron (DU) is a widely used phenylurea herbicide designed to inhibit weed growth, but its high toxicity and prolonged half-life contribute significantly to environmental contamination. The majority of electrochemical (EC) sensors typically rely on a single response signal for the detection of DU, rendering them highly susceptible to interference from variable background noise in complex environments, thereby reducing the selectivity and robustness. By integrating molecularly imprinted polymer (MIP) with a ratiometric strategy, the aforementioned issues could be solved. In this study, a novel signal on-off ratiometric MIP-EC sensor was developed based on the MXene/PEI-MWCNTs nanocomposite for the detection of DU. Positively charged PEI-MWCNTs was used as an interlayer spacer and embedded into negatively charged MXene by a simple electrostatic self-assembly method. This effectively prevented the agglomeration of MXene and enhanced its electrocatalytic performance. The MIP was synthesized via electropolymerization with DU serving as the template molecule and the selectivity was enhanced by leveraging the gate effect of MIP. Subsequently, a ratiometric MIP-EC sensor was designed by introducing [Fe(CN)₆]^3−/4− into the electrolyte solution as an internal reference. Additionally, the current ratio signal (I_DU/I_[Fe(CN)6]^3−/4−) and DU concentration exhibited a good linear relationship within the range of 0.1 to 100 µM, with a limit of detection (LOD) of 30 nM (S/N = 3). In comparison with conventional single-signal MIP-EC sensing, the developed ratiometric MIP-EC sensing demonstrates superior reproducibility and accuracy. At the same time, the proposed sensor was successfully applied to the quantitative analysis of DU residues in soil samples, yielding highly satisfactory results. Full article

(This article belongs to the Special Issue Advances in Biosensors Based on Framework Materials)

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17 pages, 7172 KiB

Open AccessArticle

Development of a Colloidal Gold-Based Immunochromatographic Strip Targeting the Nucleoprotein for Rapid Detection of Canine Distemper Virus

by Zichen Zhang, Zhuangli Bi, Qingqing Du, Miao Zhang, Linying Cai, Yiming Fan, Jingjie Tang, Mingxing Hu, Shiqiang Zhu, Aoxing Tang, Guijun Wang, Guangqing Liu and Yingqi Zhu

Biosensors 2025, 15(7), 432; https://doi.org/10.3390/bios15070432 - 4 Jul 2025

Viewed by 238

Abstract

Canine distemper, a fatal and highly transmissible disease caused by the canine distemper virus (CDV), poses a major threat to the companion animal industry. An urgent need exists for a rapid, specific, and simple method for the detection of this disease in order [...] Read more.

Canine distemper, a fatal and highly transmissible disease caused by the canine distemper virus (CDV), poses a major threat to the companion animal industry. An urgent need exists for a rapid, specific, and simple method for the detection of this disease in order to improve its prevention and control. In this research, two monoclonal antibodies (mAbs), 1D3E9 and 1H9B7, were prepared, both of which specifically recognize the nucleoprotein (N protein) of CDV, and an immunochromatographic assay for CDV detection was subsequently developed using these mAbs. The results showed that both mAbs belong to the IgG1 subclass with kappa light chains. 1D3E9 was found to recognize the linear epitope ⁴¹⁰AGPKQSQITFLH⁴²¹, while 1H9B7 targeted the epitope ⁴⁵⁰HFNDERFPGH⁴⁵⁹. The test strips exhibited high specificity and good stability for up to two months when stored at 4, 25, and 37 °C. The assay exhibited a sensitivity of 10^2.39 TCID₅₀/0.1 mL. When compared with RT-PCR for detecting CDV in clinical samples, the concordance rate was 91.67%. Thus, this method shows great potential for facilitating rapid on-site detection of CDV and could be highly beneficial from the viewpoint of disease surveillance and control. Full article

(This article belongs to the Section Biosensors and Healthcare)

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14 pages, 2343 KiB

Open AccessArticle

A New Sensing Platform Based in CNF-TiO₂NPs-Wax on Polyimide Substrate for Celiac Disease Diagnostic

by Evelyn Marín-Barroso, Maria A. Ferroni-Martini, Eduardo A. Takara, Matias Regiart, Martín A. Fernández-Baldo, Germán A. Messina, Franco A. Bertolino and Sirley V. Pereira

Biosensors 2025, 15(7), 431; https://doi.org/10.3390/bios15070431 - 4 Jul 2025

Viewed by 296

Abstract

Celiac disease (CD), a human leukocyte antigen-associated disorder, is caused by gluten sensitivity and is characterized by mucosal alterations in the small intestine. Currently, its diagnosis involves the determination of serological markers. The traditional method for clinically determining these markers is the enzyme-linked [...] Read more.

Celiac disease (CD), a human leukocyte antigen-associated disorder, is caused by gluten sensitivity and is characterized by mucosal alterations in the small intestine. Currently, its diagnosis involves the determination of serological markers. The traditional method for clinically determining these markers is the enzyme-linked immunosorbent assay. However, immunosensors offer sensitivity and facilitate the development of miniaturized and portable analytical systems. This work focuses on developing an amperometric immunosensor for the quantification of IgA antibodies against tissue transglutaminase (IgA anti-TGA) in human serum samples, providing information on a critical biomarker for CD diagnosis. The electrochemical device was designed on a polyimide substrate using a novel solid ink of wax and carbon nanofibers (CNFs). The working electrode microzone was defined by incorporating aminofunctionalized TiO₂ nanoparticles (TiO₂NPs). The interactions and morphology of CNFs/wax and TiO₂NPs/CNFs/wax electrodes were assessed through different characterization techniques. Furthermore, the device was electrochemically characterized, demonstrating that the incorporation of CNFs into the wax matrix significantly enhanced its conductivity and increased the active surface area of the electrode, while TiO₂NPs contributed to the immunoreaction area. The developed device exhibited remarkable sensitivity, selectivity, and reproducibility. These results indicate that the fabricated device is a robust and reliable tool for the precise serological diagnosis of CD. Full article

(This article belongs to the Special Issue Advanced Electrochemical Biosensors and Their Applications)

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