Biosensors

15 pages, 9907 KiB

Open AccessArticle

A Facile Method for Synthesizing Cobalt Oxide Nanoparticles to Create a Highly Sensitive Non-Enzyme Glucose Sensor

by Zhanar K. Kalkozova, Ulpan A. Balgimbayeva, Maratbek T. Gabdullin, Lesya V. Gritsenko, Guoquan Suo and Khabibulla A. Abdullin

Biosensors 2025, 15(4), 235; https://doi.org/10.3390/bios15040235 - 7 Apr 2025

Abstract

In this study, an electrochemical non-enzymatic glucose sensor based on cobalt oxide was developed using a simple chemical bath deposition method. The as-synthesized material exhibited no significant sensitivity; the latter emerged only after subsequent electrochemical activation. To the best of our knowledge, this [...] Read more.

In this study, an electrochemical non-enzymatic glucose sensor based on cobalt oxide was developed using a simple chemical bath deposition method. The as-synthesized material exhibited no significant sensitivity; the latter emerged only after subsequent electrochemical activation. To the best of our knowledge, this is the first report demonstrating the successful application of electrochemical activation to achieve enhanced sensitivity. An X-ray diffraction analysis confirmed that a single-phase Co₂(OH)₂(CO₃) material was obtained immediately after synthesis, which was subsequently transformed into Co₃O₄ nanoparticles during electrochemical activation. SEM and TEM analyses revealed that the synthesized particles initially exhibited a nanorod structure, which evolved into a highly dispersed form after activation. The non-enzymatic glucose sensor based on the electrochemically activated material demonstrated excellent glucose sensitivity of 33,245 µA mM⁻¹ cm⁻² within the linear range of 0–0.5 mM, with a detection limit (LOD) of 5 µM. The starting material remained stable for over 12 months under ambient storage conditions and regained its high sensitivity following electrochemical activation. Full article

(This article belongs to the Section Biosensor Materials)

► Show Figures

Figure 1

2 pages, 140 KiB

Open AccessCorrection

Correction: Tao et al. Development of a Label-Free Electrochemical Aptasensor for the Detection of Tau381 and its Preliminary Application in AD and Non-AD Patients’ Sera. Biosensors 2019, 9, 84

by Dan Tao, Bingqing Shui, Yingying Gu, Jing Cheng, Weiying Zhang, Nicole Jaffrezic-Renault, Shizhen Song and Zhenzhong Guo

Biosensors 2025, 15(4), 234; https://doi.org/10.3390/bios15040234 (registering DOI) - 7 Apr 2025

Abstract

In the original publication [...] Full article

11 pages, 3429 KiB

Open AccessArticle

A Sensitive and Fast microRNA Detection Platform Based on CRlSPR-Cas12a Coupled with Hybridization Chain Reaction and Photonic Crystal Microarray

by Bingjie Xue, Bokang Qiao, Lixin Jia, Jimei Chi, Meng Su, Yanlin Song and Jie Du

Biosensors 2025, 15(4), 233; https://doi.org/10.3390/bios15040233 (registering DOI) - 5 Apr 2025

Abstract

Changes in microRNA (miRNA) levels are closely associated with the pathological processes of many diseases. The sensitive and fast detection of miRNAs is critical for diagnosis and prognosis. Here, we report a platform employing CRISPR/Cas12a to recognize and report changes in miRNA levels [...] Read more.

Changes in microRNA (miRNA) levels are closely associated with the pathological processes of many diseases. The sensitive and fast detection of miRNAs is critical for diagnosis and prognosis. Here, we report a platform employing CRISPR/Cas12a to recognize and report changes in miRNA levels while avoiding complex multi-thermal cycling procedures. A non-enzyme-dependent hybridization chain reaction (HCR) was used to convert the miRNA signal into double-stranded DNA, which contained a Cas12a activation sequence. The target sequence was amplified simply and isothermally, enabling the test to be executed at a constant temperature of 37 °C. The detection platform had the capacity to measure concentrations down to the picomolar level, and the target miRNA could be distinguished at the nanomolar level. By using photonic crystal microarrays with a stopband-matched emission spectrum of the fluorescent-quencher modified reporter, the fluorescence signal was moderately enhanced to increase the sensitivity. With this enhancement, analyzable fluorescence results were obtained in 15 min. The HCR and Cas12a cleavage processes could be conducted in a single tube by separating the two procedures into the bottom and the cap. We verified the sensitivity and specificity of this one-pot system, and both were comparable to those of the two-step method. Overall, our study produced a fast and sensitive miRNA detection platform based on a CRISPR/Cas12a system and enzyme-free HCR amplification. This platform may serve as a potential solution for miRNA detection in clinical practice. Full article

(This article belongs to the Section Biosensors and Healthcare)

► Show Figures

Figure 1

35 pages, 5121 KiB

Open AccessReview

Aptamers as Diagnostic and Therapeutic Agents for Aging and Age-Related Diseases

by Tae-In Park, Ah Hyun Yang, Bashistha Kumar Kanth and Seung Pil Pack

Biosensors 2025, 15(4), 232; https://doi.org/10.3390/bios15040232 (registering DOI) - 5 Apr 2025

Abstract

In the 21st century, the demographic shift toward an aging population has posed a significant challenge, particularly with respect to age-related diseases, which constitute a major threat to human health. Accordingly, the detection, prevention, and treatment of aging and age-related diseases have become [...] Read more.

In the 21st century, the demographic shift toward an aging population has posed a significant challenge, particularly with respect to age-related diseases, which constitute a major threat to human health. Accordingly, the detection, prevention, and treatment of aging and age-related diseases have become critical issues, and the introduction of novel molecular recognition elements, called aptamers, has been considered. Aptamers, a class of oligonucleotides, can bind to target molecules with high specificity. In addition, aptamers exhibit superior stability, biocompatibility, and applicability, rendering them promising tools for the diagnosis and treatment of human diseases. In this paper, we present a comprehensive overview of aptamers, systematic evolution of ligands by exponential enrichment (SELEX), biomarkers associated with aging, as well as aptamer-based diagnostic and therapeutic platforms. Finally, the limitations associated with predicting and preventing age-related conditions are discussed, along with potential solutions based on advanced technologies and theoretical approaches. Full article

(This article belongs to the Special Issue Advanced Biosensors for Disease Screening, Monitoring, Diagnosis and Treatment)

► Show Figures

Figure 1

36 pages, 16146 KiB

Open AccessReview

Research Progress of Electrochemical Biosensors for Diseases Detection in China: A Review

by Haoran Cui, Xianglin Xin, Jing Su and Shiping Song

Biosensors 2025, 15(4), 231; https://doi.org/10.3390/bios15040231 (registering DOI) - 5 Apr 2025

Abstract

Disease diagnosis is not only related to individual health but is also a crucial part of public health prevention. Electrochemical biosensors combine the high sensitivity of electrochemical methods with the inherent high selectivity of biological components, offering advantages such as excellent sensitivity, fast [...] Read more.

Disease diagnosis is not only related to individual health but is also a crucial part of public health prevention. Electrochemical biosensors combine the high sensitivity of electrochemical methods with the inherent high selectivity of biological components, offering advantages such as excellent sensitivity, fast response time, and low cost. The generated electrical signals have a linear relationship with the target analyte, allowing for identification and concentration detection. This has become a very attractive technology. This review offers a summary of recent advancements in electrochemical biosensor research for disease diagnosis in China. It systematically categorizes and summarizes biosensors developed in China for detecting cancer, infectious diseases, inflammation, and neurodegenerative disorders. Additionally, the review delves into the fundamental working principles, classifications, materials, preparation techniques, and other critical aspects of electrochemical biosensors. Finally, it addresses the key challenges impeding the advancement of electrochemical biosensors in China and examines promising future directions for their development. Full article

(This article belongs to the Special Issue State-of-the-Art Biosensors in China (2nd Edition))

► Show Figures

Figure 1

11 pages, 1759 KiB

Open AccessArticle

A Label-Free CRISPR/Cas12a-G4 Biosensor Integrated with FTA Card for Detection of Foodborne Pathogens

by Anqi Chao, Qinqin Hu and Kun Yin

Biosensors 2025, 15(4), 230; https://doi.org/10.3390/bios15040230 (registering DOI) - 5 Apr 2025

Abstract

CRISPR/Cas-based diagnostics offer unparalleled specificity, but their reliance on fluorescently labeled probes and complex nucleic acid extraction limits field applicability. To tackle this problem, we have developed a label-free, equipment-free platform integrating FTA card-based extraction, CRISPR/Cas12a, and pre-folded G-quadruplex (G4)–Thioflavin T (ThT) signal [...] Read more.

CRISPR/Cas-based diagnostics offer unparalleled specificity, but their reliance on fluorescently labeled probes and complex nucleic acid extraction limits field applicability. To tackle this problem, we have developed a label-free, equipment-free platform integrating FTA card-based extraction, CRISPR/Cas12a, and pre-folded G-quadruplex (G4)–Thioflavin T (ThT) signal reporter. This system eliminates costly fluorescent labeling by leveraging G4-ThT structural binding for visible fluorescence output, while FTA cards streamline nucleic acid isolation without centrifugation. Achieving a limit of detection (LOD) to 10¹ CFU/mL for Escherichia coli O157:H7 in spiked food samples, the platform demonstrated 100% concordance with qPCR and standard fluorescent probe-based CRISPR/Cas12a system. Its simplicity, minimal equipment (portable heating/imaging), and cost-effectiveness make it a revolutionary tool for detecting foodborne pathogens in resource-limited environments. Full article

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

► Show Figures

Figure 1

21 pages, 2310 KiB

Open AccessArticle

Translation of COVID-19 Serology Test on Foil-Based Lateral Flow Chips: A Journey from Injection Molding to Scalable Roll-to-Roll Nanoimprint Lithography

by Pakapreud Khumwan, Stephan Ruttloff, Johannes Götz, Dieter Nees, Conor O’Sullivan, Alvaro Conde, Mirko Lohse, Christian Wolf, Nastasia Okulova, Janine Brommert, Richard Benauer, Ingo Katzmayr, Nikolaus Ladenhauf, Wilfried Weigel, Maciej Skolimowski, Max Sonnleitner, Martin Smolka, Anja Haase, Barbara Stadlober and Jan Hesse

Biosensors 2025, 15(4), 229; https://doi.org/10.3390/bios15040229 (registering DOI) - 4 Apr 2025

Abstract

Lateral flow tests (LFTs) had a pivotal role in combating the spread of the SARS-CoV-2 virus throughout the COVID-19 pandemic thanks to their affordability and ease of use. Most of LFT devices were based on nitrocellulose membrane strips whose industrial upscaling to billions [...] Read more.

Lateral flow tests (LFTs) had a pivotal role in combating the spread of the SARS-CoV-2 virus throughout the COVID-19 pandemic thanks to their affordability and ease of use. Most of LFT devices were based on nitrocellulose membrane strips whose industrial upscaling to billions of devices has already been extensively demonstrated. Nevertheless, the assay option in an LFT format is largely restricted to qualitative detection of the target antigens. In this research, we surveyed the potential of UV nanoimprint lithography (UV-NIL) and extrusion coating (EC) for the high-throughput production of disposable capillary-driven, foil-based tests that allow multistep assays to be implemented for quantitative readout to address the inherent lack of on-demand fluid control and sensitivity of paper-based devices. Both manufacturing technologies operate on the principle of imprinting that enables high-volume, continuous structuring of microfluidic patterns in a roll-to-roll (R2R) production scheme. To demonstrate the feasibility of R2R-fabricated foil chips in a point-of-care biosensing application, we adapted a commercial chemiluminescence multiplex test for COVID-19 antibody detection originally developed for a capillary-driven microfluidic chip manufactured with injection molding (IM). In an effort to build a complete ecosystem for the R2R manufacturing of foil chips, we also recruited additional processes to streamline chip production: R2R biofunctionalization and R2R lamination. Compared to conventional fabrication techniques for microfluidic devices, the R2R techniques highlighted in this work offer unparalleled advantages concerning improved scalability, dexterity of seamless handling, and significant cost reduction. Our preliminary evaluation indicated that the foil chips exhibited comparable performance characteristics to the original IM-fabricated devices. This early success in assay translation highlights the promise of implementing biochemical assays on R2R-manufactured foil chips. Most importantly, it underscores the potential utilization of UV-NIL and EC as an alternative to conventional technologies for the future development in vitro diagnostics (IVD) in response to emerging point-of-care testing demands. Full article

(This article belongs to the Special Issue Biosensing Technologies in Medical Diagnosis)

13 pages, 1977 KiB

Open AccessArticle

Stamp-Imprinted Polymer EIS Biosensor for Amyloid-Beta Detection: A Novel Approach Towards Alzheimer’s Screening

by Chloé E. D. Davidson and Ravi Prakash

Biosensors 2025, 15(4), 228; https://doi.org/10.3390/bios15040228 - 3 Apr 2025

Abstract

Surface-imprinted polymers (SIPs) represent an exciting and cost-effective alternative to antibodies for electrochemical impedance spectroscopy (EIS)-based biosensing. They can be produced using simple printing techniques and have shown high efficacy in detecting large biomolecules and microorganisms. Stamp imprinting, a novel SIP method, creates [...] Read more.

Surface-imprinted polymers (SIPs) represent an exciting and cost-effective alternative to antibodies for electrochemical impedance spectroscopy (EIS)-based biosensing. They can be produced using simple printing techniques and have shown high efficacy in detecting large biomolecules and microorganisms. Stamp imprinting, a novel SIP method, creates the target analyte’s imprint using a soft lithography mask of the analyte matrix, thereby reducing material complexities and eliminating the need for cross-linking, which makes the process more scalable than the conventional SIPs. In this work, we demonstrate a stamp-imprinted EIS biosensor using a biocompatible polymer, polycaprolactone (PCL), for quantifying amyloid beta-42 (Aβ-42), a small peptide involved in the pathophysiology of Alzheimer’s disease. The evaluated SIP-EIS biosensors showed a detection limit close to 10 fg/mL, and a detection range covering the physiologically relevant concentration range of the analyte in blood serum (from 10 fg/mL to 10 μg/mL). The device sensitivity, which is found to be comparable to antibody-based EIS devices, demonstrates the potential of SIP-EIS biosensors as an exciting alternative to conventional antibody-based diagnostic approaches. We also evaluate the viability of analyzing these proteins in complex media, notably in the presence of serum albumin proteins, which cause biofouling and non-specific interactions. The combination of high sensitivity, selectivity, and ease of fabrication makes SIP-EIS biosensors particularly suited for portable and point-of-care applications. Full article

(This article belongs to the Special Issue Recent Developments in Micro/Nano Sensors for Biomedical Applications)

► Show Figures

Figure 1

28 pages, 3972 KiB

Open AccessReview

Doping Detection Based on the Nanoscale: Biosensing Mechanisms and Applications of Two-Dimensional Materials

by Jingjing Zhao, Yu Wang and Bing Liu

Biosensors 2025, 15(4), 227; https://doi.org/10.3390/bios15040227 - 3 Apr 2025

Abstract

Doping undermines fairness in sports and threatens athlete health, while conventional detection methods like LC-MS and GC-MS face challenges such as complex procedures, matrix interferences, and lengthy processing times, limiting on-site applications. Two-dimensional (2D) materials, including graphene, MoS₂, and metal–organic frameworks [...] Read more.

Doping undermines fairness in sports and threatens athlete health, while conventional detection methods like LC-MS and GC-MS face challenges such as complex procedures, matrix interferences, and lengthy processing times, limiting on-site applications. Two-dimensional (2D) materials, including graphene, MoS₂, and metal–organic frameworks (MOFs), offer promising solutions due to their large surface areas, tunable electronic structures, and special interactions with doping agents, such as hydrogen bonding, π-π stacking, and electrostatic forces. These materials enable signal transduction through changes in conductivity or fluorescence quenching. This review highlights the use of 2D materials in doping detection. For example, reduced graphene oxide–MOF composites show high sensitivity for detecting anabolic steroids like testosterone, while NiO/NGO nanocomposites exhibit strong selectivity for stimulants like ephedrine. However, challenges such as environmental instability and high production costs hinder their widespread application. Future efforts should focus on improving material stability through chemical modifications, reducing production costs, and integrating these materials into advanced systems like machine learning. Such advancements could revolutionize doping detection, ensuring fairness in sports and protecting athlete health. Full article

(This article belongs to the Special Issue Organic Two-Dimensional Material: Synthesis and Biosensing Applications)

► Show Figures

Figure 1

14 pages, 2580 KiB

Open AccessArticle

Ternary-Emission Molecularly Imprinted Ratiometric Fluorescence Sensor and Kit for the Rapid and Visual Detection of Enrofloxacin

by Siwu Liu, Jingyi Yan, Dani Sun, Siyuan Peng, Jinhua Li and Huaying Fan

Biosensors 2025, 15(4), 226; https://doi.org/10.3390/bios15040226 - 2 Apr 2025

Abstract

In this study, a RGB based ternary-emission molecularly imprinted ratiometric fluorescence (MI-RFL) sensor was facilely constructed by using a post-imprinting mixing strategy for the sensitive detection of enrofloxacin (ENR). Upon excitation at 365 nm, the MI-RFL sensor exhibited significant emission peaks at 450, [...] Read more.

In this study, a RGB based ternary-emission molecularly imprinted ratiometric fluorescence (MI-RFL) sensor was facilely constructed by using a post-imprinting mixing strategy for the sensitive detection of enrofloxacin (ENR). Upon excitation at 365 nm, the MI-RFL sensor exhibited significant emission peaks at 450, 550, and 620 nm. As the ENR concentration increased, the blue fluorescence generated by ENR in the sensing system gradually intensified, while the red and green fluorescence emitted by the quantum dots in the molecularly imprinted polymers (MIPs) was significantly quenched. Sensing conditions were systematically investigated, including the excitation wavelength, mixing ratio of red/green MIPs, the pH of the buffer solution, and the reaction time. Under the optimal conditions, the developed sensor showed a good linear relationship within the range of 0.25–4 ppm along with obvious color change, with a low detection limit of 0.134 ppm. High selectivity was also attained with an imprinting factor up to 11.65. When applied to real samples of seawater and seafood, the sensor showed good recovery rates of 94.3–126.4% and accuracy with a relative standard deviation of less than 3.97%. Furthermore, the sensor-based kit was easily fabricated and, thus, naked-eye detection of ENR was realized onsite. This study can provide a universal approach for the rapid and visual detection of ENR in complicated matrices. Full article

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

► Show Figures

Figure 1

12 pages, 5945 KiB

Open AccessArticle

Sea Urchin-like Magnetic Microbeads-Based Electrochemical Biosensor for Highly Sensitive Detection of Metabolites

by Bin Chen, Xiaosu Yuan, Enze Tian, Yunjie Tan, Le Li and Ru Huang

Biosensors 2025, 15(4), 225; https://doi.org/10.3390/bios15040225 - 2 Apr 2025

Abstract

Analyzing metabolite levels in bodily fluids is essential for disease diagnosis and surveillance. Electrochemical biosensors are ideal for monitoring metabolite levels due to their high sensitivity, rapid response, and low cost. The magnetic microbeads-based electrode functionalization method further promotes the automation development of [...] Read more.

Analyzing metabolite levels in bodily fluids is essential for disease diagnosis and surveillance. Electrochemical biosensors are ideal for monitoring metabolite levels due to their high sensitivity, rapid response, and low cost. The magnetic microbeads-based electrode functionalization method further promotes the automation development of electrochemical biosensors by eliminating the tedious electrode polishing process. In this study, we presented sea urchin-like magnetic microbeads (SMMBs) and constructed an SMMB-based electrochemical biosensor. The specific morphology of SMMBs provides a larger specific surface area and abundant enzyme binding sites, thereby expanding the active reaction interface on the electrode and improving the sensitivity of the biosensor. Experiment results demonstrated that the SMMB-based electrochemical biosensor achieves μM level detection sensitivity for glucose. Furthermore, by replacing the anchored oxidase on SMMBs, the biosensor can be extended to detect other metabolites, such as cholesterol. In summary, the SMMBs provide a new path to handily construct electrochemical biosensors and hold a great potential for metabolite detection and further development. Full article

(This article belongs to the Special Issue Applications of Advanced Electrochemical (Bio)sensors in Environment, Food, and Medicine)

► Show Figures

Figure 1

17 pages, 4127 KiB

Open AccessArticle

A Neuroelectronic Interface with Microstructured Substrates for Spiral Ganglion Neurons Cultured In Vitro: Proof of Concept

by Boris Delipetar, Jelena Žarković Krolo, Ana Bedalov and Damir Kovačić

Biosensors 2025, 15(4), 224; https://doi.org/10.3390/bios15040224 - 1 Apr 2025

Abstract

In this study, we present a proof-of-concept neuroelectronic interface (NEI) for extracellular stimulation and recording of neurophysiological activity in spiral ganglion neurons (SGNs) cultured in vitro on three-dimensional, micro-patterned substrates with customized microtopographies, integrated within a 196-channel microelectrode array (MEA). This approach enables [...] Read more.

In this study, we present a proof-of-concept neuroelectronic interface (NEI) for extracellular stimulation and recording of neurophysiological activity in spiral ganglion neurons (SGNs) cultured in vitro on three-dimensional, micro-patterned substrates with customized microtopographies, integrated within a 196-channel microelectrode array (MEA). This approach enables mechanotaxis-driven neuronal contact guidance, promoting SGN growth and development, which is highly sensitive to artificial in vitro environments. The microtopography geometry was optimized based on our previous studies to enhance SGN alignment and neuron-electrode interactions. The NEI was validated using SGNs dissociated from rat pups in the prehearing period and cultured for seven days in vitro (DIV). We observed viable and proliferative cellular cultures with robust neurophysiological responses in the form of local field potentials (LFPs) resembling action potentials (APs), elicited both spontaneously and through electrical stimulation. These findings provide deeper insights into SGN behavior and neuron-microenvironment interactions, laying the groundwork for further advancements in neuroelectronic systems. Full article

(This article belongs to the Special Issue Microelectrode Array for Biomedical Applications)

► Show Figures

Figure 1

12 pages, 4942 KiB

Open AccessArticle

Intermolecular Structure Conversion-Based G4-TDF Nanostructures Functionalized μPADs for Fluorescent Determination of Potassium Ion in Serum

by Mengqi Wang, Xiuli Fu, Yixuan Liu, Zhiyang Zhang, Chenyu Jiang and Dean Song

Biosensors 2025, 15(4), 223; https://doi.org/10.3390/bios15040223 - 31 Mar 2025

Abstract

Herein, we proposed a versatile G-quadruplex (G4)-tetrahedral DNA framework (G4-TDF) nanostructure functionalized origami microfluidic paper-based device (μPADs) for fluorescence detection of K⁺ by lighting up thioflavin T (ThT). In this work, TDF provided robust structural support for G-rich sequence in well-defined orientation [...] Read more.

Herein, we proposed a versatile G-quadruplex (G4)-tetrahedral DNA framework (G4-TDF) nanostructure functionalized origami microfluidic paper-based device (μPADs) for fluorescence detection of K⁺ by lighting up thioflavin T (ThT). In this work, TDF provided robust structural support for G-rich sequence in well-defined orientation and spacing to ensure high recognition efficiency, enabling sensitive fluorescence sensing on origami μPAD. After introducing ThT, the G-rich sequences extended from TDF vertices formed a parallel G4 structure, showing weak fluorescence signal output. Upon the presence of target K⁺, this parallel G4 structure transitioned to antiparallel G4 structure, leading to a significantly increase in fluorescence signal of ThT. Benefiting from the outstanding fluorescence enhancement characteristic of the G4 structure for ThT and excellent specificity of the G4 structure to K⁺ plus satisfactory recognition efficiency with the aid of TDF, this origami paper-based fluorescence sensing strategy exhibited an impressive detection limit as low as 0.2 mM with a wide range of 0.5–5.5 mM. This innovative G4-TDF fluorescence sensing was applied for the first time on μPAD, providing a simple, effective, and rapid method for K⁺ detection in human serum with significant potential for clinical diagnostics. Full article

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

► Show Figures

Figure 1

49 pages, 23097 KiB

Open AccessReview

A Review on Optical Biosensors for Monitoring of Uric Acid and Blood Glucose Using Portable POCT Devices: Status, Challenges, and Future Horizons

by Kermue Vasco Jarnda, Heng Dai, Anwar Ali, Prince L. Bestman, Joanna Trafialek, Garmai Prosperity Roberts-Jarnda, Richmond Anaman, Mohamed Gbanda Kamara, Pian Wu and Ping Ding

Biosensors 2025, 15(4), 222; https://doi.org/10.3390/bios15040222 - 31 Mar 2025

Abstract

The growing demand for real-time, non-invasive, and cost-effective health monitoring has driven significant advancements in portable point-of-care testing (POCT) devices. Among these, optical biosensors have emerged as promising tools for the detection of critical biomarkers such as uric acid (UA) and blood glucose. [...] Read more.

The growing demand for real-time, non-invasive, and cost-effective health monitoring has driven significant advancements in portable point-of-care testing (POCT) devices. Among these, optical biosensors have emerged as promising tools for the detection of critical biomarkers such as uric acid (UA) and blood glucose. Different optical transduction methods, like fluorescence, surface plasmon resonance (SPR), and colorimetric approaches, are talked about, with a focus on how sensitive, specific, and portable they are. Despite considerable advancements, several challenges persist, including sensor stability, miniaturization, interference effects, and the need for calibration-free operation. This review also explores issues related to cost-effectiveness, data integration, and wireless connectivity for remote monitoring. The review further examines regulatory considerations and commercialization aspects of optical biosensors, addressing the gap between research developments and clinical implementation. Future perspectives emphasize the integration of artificial intelligence (AI) and healthcare for improved diagnostics, alongside the development of wearable and implantable biosensors for continuous monitoring. Innovative optical biosensors have the potential to change the way people manage their health by quickly and accurately measuring uric acid and glucose levels. This is especially true as the need for decentralized healthcare solutions grows. By critically evaluating existing work and exploring the limitations and opportunities in the field, this review will help guide the development of more efficient, accessible, and reliable POCT devices that can improve patient outcomes and quality of life. Full article

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

► Show Figures

Figure 1

20 pages, 1451 KiB

Open AccessReview

Microbial Transcription Factor-Based Biosensors: Innovations from Design to Applications in Synthetic Biology

by Kyeongseok Song, Haekang Ji, Jiwon Lee and Youngdae Yoon

Biosensors 2025, 15(4), 221; https://doi.org/10.3390/bios15040221 - 31 Mar 2025

Abstract

Transcription factor-based biosensors (TFBs) are powerful tools in microbial biosensor applications, enabling dynamic control of metabolic pathways, real-time monitoring of intracellular metabolites, and high-throughput screening (HTS) for strain engineering. These systems use transcription factors (TFs) to convert metabolite concentrations into quantifiable outputs, enabling [...] Read more.

Transcription factor-based biosensors (TFBs) are powerful tools in microbial biosensor applications, enabling dynamic control of metabolic pathways, real-time monitoring of intracellular metabolites, and high-throughput screening (HTS) for strain engineering. These systems use transcription factors (TFs) to convert metabolite concentrations into quantifiable outputs, enabling precise regulation of metabolic fluxes and biosynthetic efficiency in microbial cell factories. Recent advancements in TFB, including improved sensitivity, specificity, and dynamic range, have broadened their applications in synthetic biology and industrial biotechnology. Computational tools such as Cello have further revolutionized TFB design, enabling in silico optimization and construction of complex genetic circuits for integrating multiple signals and achieving precise gene regulation. This review explores innovations in TFB systems for microbial biosensors, their role in metabolic engineering and adaptive evolution, and their future integration with artificial intelligence and advanced screening technologies to overcome critical challenges in synthetic biology and industrial bioproduction. Full article

(This article belongs to the Special Issue Microbial Biosensor: From Design to Applications)

► Show Figures

Figure 1

26 pages, 3050 KiB

Open AccessReview

Advancements in Circulating Tumor Cell Detection for Early Cancer Diagnosis: An Integration of Machine Learning Algorithms with Microfluidic Technologies

by Ling An, Yi Liu and Yaling Liu

Biosensors 2025, 15(4), 220; https://doi.org/10.3390/bios15040220 - 29 Mar 2025

Abstract

Circulating tumor cells (CTCs) are vital indicators of metastasis and provide a non-invasive method for early cancer diagnosis, prognosis, and therapeutic monitoring. However, their low prevalence and heterogeneity in the bloodstream pose significant challenges for detection. Microfluidic systems, or “lab-on-a-chip” devices, have emerged [...] Read more.

Circulating tumor cells (CTCs) are vital indicators of metastasis and provide a non-invasive method for early cancer diagnosis, prognosis, and therapeutic monitoring. However, their low prevalence and heterogeneity in the bloodstream pose significant challenges for detection. Microfluidic systems, or “lab-on-a-chip” devices, have emerged as a revolutionary tool in liquid biopsy, enabling efficient isolation and analysis of CTCs. These systems offer advantages such as reduced sample volume, enhanced sensitivity, and the ability to integrate multiple processes into a single platform. Several microfluidic techniques, including size-based filtration, dielectrophoresis, and immunoaffinity capture, have been developed to enhance CTC detection. The integration of machine learning (ML) with microfluidic systems has further improved the specificity and accuracy of CTC detection, significantly advancing the speed and efficiency of early cancer diagnosis. ML models have enabled more precise analysis of CTCs by automating detection processes and enhancing the ability to identify rare and heterogeneous cell populations. These advancements have already demonstrated their potential in improving diagnostic accuracy and enabling more personalized treatment approaches. In this review, we highlight the latest progress in the integration of microfluidic technologies and ML algorithms, emphasizing how their combination has changed early cancer diagnosis and contributed to significant advancements in this field. Full article

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

► Show Figures

Figure 1

21 pages, 4710 KiB

Open AccessArticle

An Amplitude Analysis-Based Magnetoelastic Biosensing Method for Quantifying Blood Coagulation

by Xi Chen, Qiong Wang, Jinan Deng, Ning Hu, Yanjian Liao and Jun Yang

Biosensors 2025, 15(4), 219; https://doi.org/10.3390/bios15040219 - 29 Mar 2025

Abstract

Blood coagulation tests are crucial in the clinical management of cardiovascular diseases and preoperative diagnostics. However, the widespread adoption of existing detection devices, such as thromboelastography (TEG) instruments, is hindered by their bulky size, prohibitive cost, and lengthy detection times. In contrast, magnetoelastic [...] Read more.

Blood coagulation tests are crucial in the clinical management of cardiovascular diseases and preoperative diagnostics. However, the widespread adoption of existing detection devices, such as thromboelastography (TEG) instruments, is hindered by their bulky size, prohibitive cost, and lengthy detection times. In contrast, magnetoelastic sensors, known for their low cost and rapid response, have garnered attention for their potential application in various coagulation tests. These sensors function by detecting resonant frequency shifts in response to changes in blood viscosity during coagulation. Nevertheless, the frequency-based detection approach necessitates continuous and precise frequency scanning, imposing stringent demands on equipment design, processing, and analytical techniques. In contrast, amplitude-based detection methods offer superior applicability in many sensing scenarios. This paper presents a comprehensive study on signal acquisition from magnetoelastic sensors. We elucidate the mathematical relationship between the resonant amplitude of the response signal and liquid viscosity, propose a quantitative viscosity measurement method based on the maximum amplitude of the signal, and construct a corresponding sensing device. The proposed method was validated using glycerol solutions, demonstrating a sensitivity of 13.83 V⁻¹/Pa^0.5s^0.5Kg^0.5m^−1.5 and a detection limit of 0.0817 Pa^0.5s^0.5Kg^0.5m^−1.5. When applied to real-time monitoring of the coagulation process, the resulting coagulation curves and maximum amplitude (MA) parameters exhibited excellent consistency with standard TEG results (R² values of 0.9552 and 0.9615, respectively). Additionally, other TEG parameters, such as R-time, K-time, and α-angle, were successfully obtained, effectively reflecting viscosity changes during blood coagulation. Full article

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

► Show Figures

Figure 1

46 pages, 10314 KiB

Open AccessReview

Recent Advances in Enzymatic Biofuel Cells to Power Up Wearable and Implantable Biosensors

by Zina Fredj, Guoguang Rong and Mohamad Sawan

Biosensors 2025, 15(4), 218; https://doi.org/10.3390/bios15040218 - 28 Mar 2025

Abstract

Enzymatic biofuel cells (EBFCs) have emerged as a transformative solution in the quest for sustainable energy, offering a biocatalyst-driven alternative for powering wearable and implantable self-powered biosensors. These systems harness renewable enzyme activity under mild conditions, positioning them as ideal candidates for next-generation [...] Read more.

Enzymatic biofuel cells (EBFCs) have emerged as a transformative solution in the quest for sustainable energy, offering a biocatalyst-driven alternative for powering wearable and implantable self-powered biosensors. These systems harness renewable enzyme activity under mild conditions, positioning them as ideal candidates for next-generation biosensing applications. Despite their promise, their practical deployment is limited by challenges such as low power density, restricted operational lifespan, and miniaturization complexities. This review provides an in-depth exploration of the evolving landscape of EBFC technology, beginning with fundamental principles and the latest developments in electron transfer mechanisms. A critical assessment of enzyme immobilization techniques, including physical adsorption, covalent binding, entrapment, and cross-linking, underscores the importance of optimizing enzyme stability and catalytic activity for enhanced bioelectrode performance. Additionally, we examine advanced bioelectrode materials, focusing on the role of nanostructures such as carbon-based nanomaterials, noble metals, conducting polymers, and metal–organic frameworks in improving electron transfer and boosting biosensor efficiency. Also, this review includes case studies of EBFCs in wearable self-powered biosensors, with particular attention to the real-time monitoring of neurotransmitters, glucose, lactate, and ethanol through sweat analysis, as well as their integration into implantable devices for continuous healthcare monitoring. Moreover, a dedicated discussion on challenges and trends highlights key limitations, including durability, power management, and scalability, while presenting innovative approaches to address these barriers. By addressing both technical and biological constraints, EBFCs hold the potential to revolutionize biomedical diagnostics and environmental monitoring, paving the way for highly efficient, autonomous biosensing platforms. Full article

(This article belongs to the Special Issue Advances in Flexible Bioelectronics and Intelligent Biosensing Systems)

► Show Figures

Graphical abstract

17 pages, 4174 KiB

Open AccessArticle

Ultra-Sensitive Biosensors for Medical Applications Based on Nanomechanics: From Detection of Synthetic Biomolecules to Analysis of Sepsis in Pediatric Patients

by François Huber, Hans Peter Lang, Andrea Marten, Julia Anna Bielicki, Ernst Meyer and Christoph Gerber

Biosensors 2025, 15(4), 217; https://doi.org/10.3390/bios15040217 - 28 Mar 2025

Abstract

Recent advancements in nanomechanical microcantilever biosensors open new possibilities for clinical applications, permitting precise analysis of molecular interactions. The technology enables tracking gene expression, molecular conformational changes, antibody binding and antibiotic resistance. In particular, hybridization of DNA or RNA extracted from biopsies and [...] Read more.

Recent advancements in nanomechanical microcantilever biosensors open new possibilities for clinical applications, permitting precise analysis of molecular interactions. The technology enables tracking gene expression, molecular conformational changes, antibody binding and antibiotic resistance. In particular, hybridization of DNA or RNA extracted from biopsies and whole blood from patients has led to significant advancements in diagnostics of critical medical conditions, e.g., cancer, bacteraemia and sepsis, utilizing rapid, sensitive, and label-free detection. Direct diagnosis from patient samples is a decisive advantage over competitive methods circumventing elaborate and time-consuming purification, amplification and cultivation procedures prior to analysis. Here, recent developments are presented from simple DNA hybridization of synthesized oligonucleotides to RNA material obtained from patients’ blood samples, highlighting technological advancements in diagnostic applications, such as detection of pathogens and disease biomarkers. We envisage our method to be a significant input to rapid, early and sensitive diagnosis directly from patients’ blood without requirements for amplification or cultivation. This would represent a paradigm shift in diagnostics, as no competing method currently exists. Full article

(This article belongs to the Special Issue Microbial Biosensor: From Design to Applications)

► Show Figures

Graphical abstract

Journal Description

Biosensors

Latest Articles

Journal Menu

Journal Browser

Highly Accessed Articles

Latest Books

E-Mail Alert

News

Topics

Conferences

Special Issues

Topical Collections

Further Information

Guidelines

MDPI Initiatives

Follow MDPI