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Biosensors
Volume 15
Issue 8
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Biosensors, Volume 15, Issue 8 (August 2025) – 85 articles

Cover Story (view full-size image): What if you could measure urine leakage and pinpoint its exact triggers like running, sudden movements, or simply standing from a chair. Urinary incontinence affects millions of women, often forcing them to give up activities they love due to fear or stigma. Traditional tools rarely capture leakage during real-life activities. This study introduces a wearable uroflowmeter with a miniaturized sensor under the urethral meatus and a waist unit tracking body movements. Clinical feasibility studies showed it can measure urine flow and leakage volume while capturing activity data in real time. By linking leakage events to specific actions, it eliminates errors found in bladder diaries and enables objective, convenient monitoring outside clinics. Its results can provide real-life insights to personalize treatment and transform incontinence care. View this paper
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19 pages, 2301 KiB  
Article
Engineered TtgR-Based Whole-Cell Biosensors for Quantitative and Selective Monitoring of Bioactive Compounds
by Kyeongseok Song, Haekang Ji, Jiwon Lee, Geupil Jang and Youngdae Yoon
Biosensors 2025, 15(8), 554; https://doi.org/10.3390/bios15080554 - 21 Aug 2025
Abstract
TtgR, a transcriptional repressor from Pseudomonas putida, plays a key role in regulating multidrug resistance by controlling the expression of genes in response to various ligands. Despite its broad specificity, TtgR represents a promising candidate for the development of transcription factor (TF)-based [...] Read more.
TtgR, a transcriptional repressor from Pseudomonas putida, plays a key role in regulating multidrug resistance by controlling the expression of genes in response to various ligands. Despite its broad specificity, TtgR represents a promising candidate for the development of transcription factor (TF)-based biosensors. In this study, we utilized TtgR and its native promoter region (PttgABC) as genetic components to construct TF-based biosensors in Escherichia coli. By coupling TtgR and PttgABC with egfp, we developed a biosensor responsive to diverse flavonoids. To enhance the selectivity and specificity of the biosensor, we genetically engineered a TtgR-binding pocket. Engineered TtgR variants exhibited altered sensing profiles, enabling the development of biosensors with tailored ligand responses. Computational structural analysis and ligand docking provided insights into the interaction mechanisms between TtgR variants and flavonoids. Notably, biosensors based on wild-type TtgR and its N110F mutant were capable of quantifying resveratrol and quercetin at 0.01 mM with >90% accuracy. Although the precise molecular mechanisms involved remain unclear and further optimization is needed, the biosensors developed herein demonstrate strong potential for applications in numerous fields. This study lays the foundation for future research that could extend the utility of TtgR-based biosensors to synthetic biology, metabolic engineering, and beyond. Full article
(This article belongs to the Special Issue Biosensing Applications for Cell Monitoring)
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15 pages, 1830 KiB  
Article
A Novel Sensitive Recombinase-Aided Amplification Integrated Test Strip for Pseudomonas fluorescens in Milk via Dual Gene Probes
by Guangying Zhang, Lili Zhang, Jingqin Ye, Dongshu Wang and Ying Lu
Biosensors 2025, 15(8), 553; https://doi.org/10.3390/bios15080553 - 21 Aug 2025
Viewed by 3
Abstract
Pseudomonas fluorescens is the main spoilage bacterium in milk, and its proliferation is one of the factors leading to the deterioration of the quality of raw milk. In this study, a rapid detection system for P. fluorescens was developed based on recombinase-aided amplification [...] Read more.
Pseudomonas fluorescens is the main spoilage bacterium in milk, and its proliferation is one of the factors leading to the deterioration of the quality of raw milk. In this study, a rapid detection system for P. fluorescens was developed based on recombinase-aided amplification combined with a test strip (RAA-TS), which contained a double test line (DTL) targeting the virulence gene aprX of P. fluorescens and the housekeeping gene gyrB of Pseudomonas. Visual observation could detect gyrB (50 CFU/mL) and aprX (250 CFU/mL) within 90 min, including sample pretreatment and RAA reaction and detection steps. No cross-reactions were observed with Pseudomonas or other bacteria (n = 19). The quantitative detection limits (LOD) of gyrB and aprX for P. fluorescens in milk were 37 CFU/mL and 233 CFU/mL, respectively. Compared with polymerase chain reaction-agarose gel electrophoresis (PCR-AGE), the sensitivity of the developed RAA-TS-DTL system was increased by approximately four times. Furthermore, it could detect live P. fluorescens in milk when combined with optimized sample pretreatment by propidium monoazide (PMAxx). Its consistency with the traditional culture method in the detection of P. fluorescens spiked in milk samples (n = 25) was 100%. The developed RAA-TS-DTL had the advantages of high accuracy and short time consumption. Thus, it provides a new way or tool for the rapid screening or detection of P. fluorescens in milk. Full article
(This article belongs to the Special Issue Novel Nanomaterials and Nanotechnology: From Fabrication Methods and Improvement Strategies to Applications in Biosensing and Biomedicine (2nd Edition))
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15 pages, 1141 KiB  
Article
Enhanced Transdermal Delivery of Lidocaine Hydrochloride via Dissolvable Microneedles (LH-DMNs) for Rapid Local Anesthesia
by Shengtai Bian, Jie Chen, Ran Chen, Shilun Feng and Zizhen Ming
Biosensors 2025, 15(8), 552; https://doi.org/10.3390/bios15080552 - 21 Aug 2025
Viewed by 61
Abstract
Microneedles represent an emerging transdermal drug delivery platform offering painless, minimally invasive penetration of the stratum corneum. This study addresses limitations of conventional lidocaine hydrochloride formulations, such as slow onset and poor patient compliance, by developing lidocaine hydrochloride-loaded dissolvable microneedles (LH-DMNs) for rapid [...] Read more.
Microneedles represent an emerging transdermal drug delivery platform offering painless, minimally invasive penetration of the stratum corneum. This study addresses limitations of conventional lidocaine hydrochloride formulations, such as slow onset and poor patient compliance, by developing lidocaine hydrochloride-loaded dissolvable microneedles (LH-DMNs) for rapid local anesthesia. LH-DMNs were fabricated via centrifugal casting using polyvinyl alcohol (PVA) as the matrix material in polydimethylsiloxane (PDMS) negative molds, which imparts high mechanical strength to the microneedles. Biocompatibility assessments showed negligible skin irritation, resolving within 3 min. And drug-loading capacity reached 24.0 ± 2.84 mg per patch. Pharmacodynamic evaluation via mouse hot plate tests demonstrated significant analgesia, increasing paw withdrawal latency to 36.11 ± 1.62 s at 5 min post-application (p < 0.01). The results demonstrated that the LH-DMNs significantly elevated the pain threshold in mice within 5 min, surpassing the efficacy of conventional anesthetic gels and providing a rapid and effective solution for pain relief. These findings validate the system’s rapid drug release and efficacy, positioning dissolvable microneedles as a clinically viable alternative for enhanced transdermal anesthesia. Full article
(This article belongs to the Special Issue Advanced Microfluidic Devices and MEMS in Biosensing Applications)
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17 pages, 3406 KiB  
Article
Biosensor for Bacterial Detection Through Color Change in Culture Medium
by Aramis A. Sánchez, Grettel Riofrío, Darwin Castillo, J. P. Padilla-Martínez and Vasudevan Lakshminarayanan
Biosensors 2025, 15(8), 551; https://doi.org/10.3390/bios15080551 - 20 Aug 2025
Viewed by 86
Abstract
Rapid and accurate bacterial detection is essential in medicine, the food industry, and environmental monitoring. This work presents the development of an optical sensor based on color changes in the culture medium that leverages the optical interaction of bacterial metabolic products. The proposed [...] Read more.
Rapid and accurate bacterial detection is essential in medicine, the food industry, and environmental monitoring. This work presents the development of an optical sensor based on color changes in the culture medium that leverages the optical interaction of bacterial metabolic products. The proposed prototype operates on the principle of optical transmittance through mannitol salt agar (ASM), a selective medium for Staphylococcus aureus. As bacterial growth progresses, the medium undergoes changes in thickness and, primarily, color, which is optically measurable at specific wavelengths depending on the type of illumination provided by the simplified light-emitting diodes (LEDs). The sensor demonstrated the ability to detect bacterial growth in approximately 90–120 min, offering a significant reduction in detection time compared to traditional incubation methods. The system is characterized by its simplicity, sensitivity, low reagent consumption (up to 140 fewer reagents per test), and potential for real-time monitoring. These findings support the viability of the proposed sensor as an efficient alternative for early pathogen detection in both clinical and industrial applications. Finally, a proposal for simplifying the sensor in a system composed of a light-emitting diode and a light-dependent resistor is presented. Full article
(This article belongs to the Special Issue Advanced Optics and Photonics in Biosensing Applications)
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17 pages, 3307 KiB  
Article
Electrode-Free ECG Monitoring with Multimodal Wireless Mechano-Acoustic Sensors
by Zhi Li, Fei Fei and Guanglie Zhang
Biosensors 2025, 15(8), 550; https://doi.org/10.3390/bios15080550 - 20 Aug 2025
Viewed by 84
Abstract
Continuous cardiovascular monitoring is essential for the early detection of cardiac events, but conventional electrode-based ECG systems cause skin irritation and are unsuitable for long-term wear. We propose an electrode-free ECG monitoring approach that leverages synchronized phonocardiogram (PCG) and seismocardiogram (SCG) signals captured [...] Read more.
Continuous cardiovascular monitoring is essential for the early detection of cardiac events, but conventional electrode-based ECG systems cause skin irritation and are unsuitable for long-term wear. We propose an electrode-free ECG monitoring approach that leverages synchronized phonocardiogram (PCG) and seismocardiogram (SCG) signals captured by wireless mechano-acoustic sensors. PCG provides precise valvular event timings, while SCG provides mechanical context, enabling the robust identification of systolic/diastolic intervals and pathological patterns. A deep learning model reconstructs ECG waveforms by intelligently combining mechano-acoustic sensor data. Its architecture leverages specialized neural network components to identify and correlate key cardiac signatures from multimodal inputs. Experimental validation on an IoT sensor dataset yields a mean Pearson correlation of 0.96 and an RMSE of 0.49 mV compared to clinical ECGs. By eliminating skin-contact electrodes through PCG–SCG fusion, this system enables robust IoT-compatible daily-life cardiac monitoring. Full article
(This article belongs to the Special Issue Smart, Connected, and Portable Biosensors and Bioelectronics for Advancing Human Healthcare, Disease Diagnosis, and Therapeutics (2nd Edition))
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13 pages, 2147 KiB  
Article
Preliminary Study Using Wearable Near-Infrared Spectroscopy for Continuous Monitoring of Hemodynamics Through the Carotid Artery
by Nisha Maheshwari, Alessandro Marone, Lokesh Sharma, Stephen Kim, Albert Favate and Andreas H. Hielscher
Biosensors 2025, 15(8), 549; https://doi.org/10.3390/bios15080549 - 20 Aug 2025
Viewed by 190
Abstract
Non-invasive, continuous monitoring of carotid artery hemodynamics may provide valuable insights on cerebral blood perfusion (CBP). Near-infrared spectroscopy (NIRS) is a non-invasive modality that may be a good candidate for real-time carotid artery monitoring. We designed a wearable NIRS system to monitor the [...] Read more.
Non-invasive, continuous monitoring of carotid artery hemodynamics may provide valuable insights on cerebral blood perfusion (CBP). Near-infrared spectroscopy (NIRS) is a non-invasive modality that may be a good candidate for real-time carotid artery monitoring. We designed a wearable NIRS system to monitor the left and right radial and carotid arteries in 20 healthy subjects. The changes in total hemoglobin concentration (HbT) and tissue oxygen saturation (StO2) in all 80 arteries were continuously monitored in response to changes in oxygen supply. Wilcoxon non-parametric equivalence testing was used to compare changes in the radial (reference) and carotid arteries. The system-derived HbT and StO2 trends matched the expected physiological responses over time in the radial and carotid arteries. The mean peak-to-peak amplitude [uM] of HbT during sustained deep breathing was practically equivalent between the left radial (0.9 ± 0.8) and left carotid (1.6 ± 1.1) arteries (p = 0.01). The mean peak-to-peak amplitude [%] of StO2 was practically equivalent between the left radial (0.3 ± 0.2) and left carotid (0.3 ± 0.2) arteries (p < 0.001) and the right radial (0.4 ± 0.5) and right carotid (0.5 ± 0.4) arteries (p = 0.001). These findings indicate that NIRS may be a good option for monitoring the carotid arteries to track changes in CBP. Full article
(This article belongs to the Special Issue Wearable Sensors and Biosensors for Physiological Signals Measurement)
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49 pages, 10149 KiB  
Review
A Review of Machine Learning-Assisted Gas Sensor Arrays in Medical Diagnosis
by Yueting Yu, Xin Cao, Chenxi Li, Mingyue Zhou, Tianyu Liu, Jiang Liu and Lu Zhang
Biosensors 2025, 15(8), 548; https://doi.org/10.3390/bios15080548 - 20 Aug 2025
Viewed by 83
Abstract
Volatile organic compounds (VOCs) present in human exhaled breath have emerged as promising biomarkers for non-invasive disease diagnosis. However, traditional VOC detection technology that relies on large instruments is not widely used due to high costs and cumbersome testing processes. Machine learning-assisted gas [...] Read more.
Volatile organic compounds (VOCs) present in human exhaled breath have emerged as promising biomarkers for non-invasive disease diagnosis. However, traditional VOC detection technology that relies on large instruments is not widely used due to high costs and cumbersome testing processes. Machine learning-assisted gas sensor arrays offer a compelling alternative by enabling the accurate identification of complex VOC mixtures through collaborative multi-sensor detection and advanced algorithmic analysis. This work systematically reviews the advanced applications of machine learning-assisted gas sensor arrays in medical diagnosis. The types and principles of sensors commonly employed for disease diagnosis are summarized, such as electrochemical, optical, and semiconductor sensors. Machine learning methods that can be used to improve the recognition ability of sensor arrays are systematically listed, including support vector machines (SVM), random forests (RF), artificial neural networks (ANN), and principal component analysis (PCA). In addition, the research progress of sensor arrays combined with specific algorithms in the diagnosis of respiratory, metabolism and nutrition, hepatobiliary, gastrointestinal, and nervous system diseases is also discussed. Finally, we highlight current challenges associated with machine learning-assisted gas sensors and propose feasible directions for future improvement. Full article
(This article belongs to the Special Issue AI-Enabled Biosensor Technologies for Boosting Medical Applications)
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46 pages, 4692 KiB  
Review
Protecting Firefighters from Carcinogenic Exposure: Emerging Tools for PAH Detection and Decontamination
by Morteza Ghafar-Zadeh, Azadeh Amrollahi Biyouki, Negar Heidari, Niloufar Delfan, Parviz Norouzi, Sebastian Magierowski and Ebrahim Ghafar-Zadeh
Biosensors 2025, 15(8), 547; https://doi.org/10.3390/bios15080547 - 20 Aug 2025
Viewed by 91
Abstract
Polycyclic aromatic hydrocarbons (PAHs) are increasingly recognized as a major contributor to the occupational cancer risk among firefighters. In response, the National Fire Protection Association (NFPA) and other regulatory bodies have recommended rigorous decontamination protocols to minimize PAH exposure. Despite these efforts, a [...] Read more.
Polycyclic aromatic hydrocarbons (PAHs) are increasingly recognized as a major contributor to the occupational cancer risk among firefighters. In response, the National Fire Protection Association (NFPA) and other regulatory bodies have recommended rigorous decontamination protocols to minimize PAH exposure. Despite these efforts, a critical gap persists: the absence of real-time, field-deployable devices capable of detecting these invisible and toxic compounds during firefighting operations or within fire stations. Additionally, the lack of effective and optimized methods for the removal of these hazardous substances from the immediate environments of firefighters continues to pose a serious occupational health challenge. Although numerous studies have investigated PAH detection in environmental contexts, current technologies are still largely confined to laboratory settings and are unsuitable for field use. This review critically examines recent advances in PAH decontamination strategies for firefighting and explores alternative sensing solutions. We evaluate both conventional analytical methods, such as gas chromatography, high-performance liquid chromatography, and mass spectrometry, and emerging portable PAH detection technologies. By highlighting the limitations of existing systems and presenting novel sensing approaches, this paper aims to catalyze innovation in sensor development. Our ultimate goal is to inspire the creation of robust, field-deployable tools that enhance decontamination practices and significantly improve the health and safety of firefighters by reducing their long-term risks of cancer. 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)
17 pages, 1969 KiB  
Article
Towards an Implantable Aptamer Biosensor for Monitoring in Inflammatory Bowel Disease
by Yanan Huang, Wenlu Duan, Fei Deng, Wenxian Tang, Sophie C. Payne, Tianruo Guo, Ewa M. Goldys, Nigel H. Lovell and Mohit N. Shivdasani
Biosensors 2025, 15(8), 546; https://doi.org/10.3390/bios15080546 - 19 Aug 2025
Viewed by 205
Abstract
Inflammatory bowel disease (IBD) is a relapsing–remitting condition resulting in chronic inflammation of the gastrointestinal tract. Present methods are either inadequate or not viable for continuous tracking of disease progression in individuals. In this study, we present the development towards an implantable biosensor [...] Read more.
Inflammatory bowel disease (IBD) is a relapsing–remitting condition resulting in chronic inflammation of the gastrointestinal tract. Present methods are either inadequate or not viable for continuous tracking of disease progression in individuals. In this study, we present the development towards an implantable biosensor for detecting interleukin-6 (IL-6), an important cytokine implicated in IBD. The optimised sensor design includes a gold surface functionalised with a known IL-6-specific aptamer, integrating a recognition sequence and an electrochemical redox probe. The IL-6 aptasensor demonstrated a sensitivity of up to 40% and selectivity up to 10% to the IL-6 target in vitro. Sensors were found to degrade over 7 days when exposed to recombinant IL-6, with the degradation rate rapidly increasing when exposed to intestinal mucosa. A feasibility in vivo experiment with a newly designed implantable gut sensor array confirmed rapid degradation over a 5-h implantation period. We achieved up to a 93% reduction in sensor degradation rates, with a polyvinyl alcohol–methyl acrylate hydrogel coating that aimed to reduce nonspecific interactions in complex analytes compared to uncoated sensors. Degradation was linked to desorption of the monolayer leading to breakage of gold thiol bonds. While there are key challenges to be resolved before a stable implantable IBD sensor is realised, this work highlights the potential of aptamer-based biosensors as effective tools for long-term diagnostic monitoring in IBD. Full article
(This article belongs to the Special Issue Advanced Biosensors for Disease Screening, Monitoring, Diagnosis and Treatment)
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18 pages, 2079 KiB  
Article
An Amperometric Enzyme–Nanozyme Biosensor for Glucose Detection
by Asta Kausaite-Minkstimiene, Aiste Krikstaponyte, Nataliya Stasyuk, Galina Gayda and Almira Ramanaviciene
Biosensors 2025, 15(8), 545; https://doi.org/10.3390/bios15080545 - 19 Aug 2025
Viewed by 245
Abstract
Amperometric biosensors, due to their high sensitivity, fast response time, low cost, simple control, miniaturization capabilities, and other advantages, are receiving significant attention in the field of medical diagnostics, especially in monitoring blood glucose levels in diabetic patients. In this study, an amperometric [...] Read more.
Amperometric biosensors, due to their high sensitivity, fast response time, low cost, simple control, miniaturization capabilities, and other advantages, are receiving significant attention in the field of medical diagnostics, especially in monitoring blood glucose levels in diabetic patients. In this study, an amperometric glucose biosensor based on immobilized enzyme glucose oxidase (GOx) and bimetallic platinum cobalt (PtCo) nanoparticles was developed. The PtCo nanoparticles, deposited on a graphite rod electrode, exhibited peroxidase-like catalytic properties and were able to electrocatalyze the reduction of H2O2. After immobilization of the GOx, an amperometric signal generated by the biosensor was directly proportional to the glucose concentration in the range of 0.04–2.18 mM. The biosensor demonstrated a sensitivity of 19.38 μA mM−1 cm−2, with a detection limit of 0.021 mM and a quantification limit of 0.064 mM. In addition to this analytical performance, the biosensor exhibited excellent repeatability (relative standard deviation (RSD) was 4.90%); operational and storage stability, retaining 98.93% and 95.33% of its initial response after 26 cycles of glucose detection and over a 14-day period, respectively; and anti-interference ability against electroactive species, as well as exceptional selectivity for glucose and satisfactory reproducibility (RSD 8.90%). Additionally, the biosensor was able to detect glucose levels in blood serum with a high accuracy (RSD 5.89%), indicating potential suitability for glucose determination in real samples. Full article
(This article belongs to the Special Issue Recent Advances in Glucose Biosensors)
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17 pages, 1576 KiB  
Article
Design of an MIP-Based Electrochemical Sensor for the Determination of Paracetamol in Pharmaceutical Samples
by José Alberto Cabas Rodríguez, Fernando Javier Arévalo and Adrian Marcelo Granero
Biosensors 2025, 15(8), 544; https://doi.org/10.3390/bios15080544 - 19 Aug 2025
Viewed by 215
Abstract
Paracetamol (PAR) is a common antipyretic and analgesic extensively used to treat cold and flu symptoms. It has been proven to be effective in headaches and relieving fever and pain. It is usually found as an over-the-counter drug, which has been associated with [...] Read more.
Paracetamol (PAR) is a common antipyretic and analgesic extensively used to treat cold and flu symptoms. It has been proven to be effective in headaches and relieving fever and pain. It is usually found as an over-the-counter drug, which has been associated with an increase in cases of poisoning due to overdose. Therefore, the development of new analytical tools for the detection of PAR at low concentrations in different samples is necessary. In this work, a Molecularly Imprinted Polymer (MIP)-based electrochemical sensor was designed for the selective and sensitive determination of PAR using a glassy carbon electrode (GCE) modified with a polymeric film obtained through the electropolymerization of o-aminophenol. A complete characterization based on electrochemical techniques, such as electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV), and scanning electron microscopy (SEM) was used to examine all steps involved in the construction of the MIP-based electrochemical sensor. In addition, all parameters affecting the MIP were optimized. As a result, the MIP-based electrochemical sensor showed a very low limit of detection (LOD) of 10 nM, with an analytical sensitivity of (3.4 ± 0.1) A M⁻¹. In addition, construction of the MIP-based electrochemical sensor showed highly reproducibility, expressed in terms of a variation coefficient lower than 4%. The MIP-based electrochemical sensor was successfully used in an assay for the determination of PAR in pharmaceutical products. The performance of the MIP-based electrochemical sensor was compared to High Performance Liquid Chromatography (HPLC) for the determination of PAR in pharmaceutical samples, showing excellent agreement between the two methodologies. A very important aspect of the developed sensor was its reusability for at least twenty times. The MIP-based electrochemical sensor is a reliable analytical tool for the determination of PAR. Full article
(This article belongs to the Special Issue Electrochemical Biosensor Applications in Agriculture, Environment and Health Systems)
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28 pages, 3851 KiB  
Review
Technological Advances and Medical Applications of Implantable Electronic Devices: From the Heart, Brain, and Skin to Gastrointestinal Organs
by Jonghyun Lee, Sung Yong Han and Young Woo Kwon
Biosensors 2025, 15(8), 543; https://doi.org/10.3390/bios15080543 - 18 Aug 2025
Viewed by 336
Abstract
Implantable electronic devices are driving innovation in modern medical technology and have significantly improved patients’ quality of life. This review comprehensively analyzes the latest technological trends in implantable electronic devices used in major organs, including the heart, brain, and skin. Additionally, it explores [...] Read more.
Implantable electronic devices are driving innovation in modern medical technology and have significantly improved patients’ quality of life. This review comprehensively analyzes the latest technological trends in implantable electronic devices used in major organs, including the heart, brain, and skin. Additionally, it explores the potential for application in the gastrointestinal system, particularly in the field of biliary stents, in which development has been limited. In the cardiac field, wireless pacemakers, subcutaneous implantable cardioverter-defibrillators, and cardiac resynchronization therapy devices have been commercialized, significantly improving survival rates and quality of life of patients with cardiovascular diseases. In the field of brain–neural interfaces, biocompatible flexible electrodes and closed-loop deep brain stimulation have improved treatments of neurological disorders, such as Parkinson’s disease and epilepsy. Skin-implantable devices have revolutionized glucose management in patients with diabetes by integrating continuous glucose monitoring and automated insulin delivery systems. Future development of implantable electronic devices incorporating pressure or pH sensors into biliary stents in the gastrointestinal system may significantly improve the prognosis of patients with bile duct cancer. This review systematically organizes the technological advances and clinical outcomes in each field and provides a comprehensive understanding of implantable electronic devices by suggesting future research directions. Full article
(This article belongs to the Section Biosensors and Healthcare)
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19 pages, 3233 KiB  
Article
A Galactose-Functionalized Pyrrolopyrrole Aza-BODIPY for Highly Efficient Detection of Eight Aliphatic and Aromatic Biogenic Amines: Monitoring Food Freshness and Bioimaging
by Yujing Gan, Bingli Lu, Jintian Zhong, Xueguagn Ran, Derong Cao and Lingyun Wang
Biosensors 2025, 15(8), 542; https://doi.org/10.3390/bios15080542 - 18 Aug 2025
Viewed by 224
Abstract
The detection of aliphatic and aromatic biogenic amines (BAs) is important in food spoilage, environmental monitoring, and disease diagnosis and treatment. Existing fluorescent probes predominantly detect aliphatic BAs with single signal variation and low sensitivity, impairing the adaptability of discriminative sensing platforms. Herein, [...] Read more.
The detection of aliphatic and aromatic biogenic amines (BAs) is important in food spoilage, environmental monitoring, and disease diagnosis and treatment. Existing fluorescent probes predominantly detect aliphatic BAs with single signal variation and low sensitivity, impairing the adaptability of discriminative sensing platforms. Herein, we present a visual chemosensor (galactose-functionalized pyrrolopyrrole aza-BODIPY, PPAB-Gal) that simultaneously detects eight aliphatic and aromatic BAs in a real-time and intuitive way based on their unique electronic and structural features. Our findings reveal that the dual colorimetric and ratiometric emission changes are rapidly produced in presence of eight BAs through a noncovalent interaction (π–π stacking and hydrogen bond)-assisted chromophore reaction. Specifically, other lone-pair electrons containing compounds, such as secondary amines, tertiary amines, NH3, and thiol, fail to exhibit these changes. As a result, superior sensing performances with distinctly dual signals (Δλab = 130 nm, Δλem = 150 nm), a low LOD (~25 nM), and fast response time (<2 min) were obtained. Based on these advantages, a qualitative and smartphone-assisted sensing platform with a PPAB-Gal-loaded TLC plate is developed for visual detection of putrescine and cadaverine vapor. More importantly, we construct a connection between a standard quantitative index for the TVBN value and fluorescence signals to quantitatively determine the freshness of tuna and shrimp, and the method is facile and convenient for real-time and on-site detection in practical application. Furthermore, since the overexpressed spermine is an important biomarker of cancer diagnosis and treatment, PPAB-Gal NPs can be used to ratiometrically image spermine in living cells. This work provides a promising sensing method for BAs with a novel fluorescent material in food safety fields and biomedical assays. Full article
(This article belongs to the Special Issue Applications of Biosensors in Medicine, the Food Industry, and Disease Diagnosis)
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12 pages, 2134 KiB  
Article
Fluorescence Imaging-Activated Microfluidic Particle Sorting Using Optical Tweezers
by Yiming Wang, Xinyue Dai, Qingtong Jiang, Hangtian Fan, Tong Li, Xiao Xia, Yipeng Dou and Yuxin Mao
Biosensors 2025, 15(8), 541; https://doi.org/10.3390/bios15080541 - 18 Aug 2025
Viewed by 238
Abstract
The precise and efficient sorting of microscopic particles is critical in diverse fields, including biomedical diagnostics, drug development, and environmental monitoring. Fluorescence imaging-activated sorting refers to a strategy where fluorescence images are used to dynamically identify target particles and trigger selective manipulation for [...] Read more.
The precise and efficient sorting of microscopic particles is critical in diverse fields, including biomedical diagnostics, drug development, and environmental monitoring. Fluorescence imaging-activated sorting refers to a strategy where fluorescence images are used to dynamically identify target particles and trigger selective manipulation for sorting purposes. In this study, we introduce a novel microfluidic particle sorting platform that combines optical tweezers with real-time fluorescence imaging for detection. High-speed image analysis enables accurate particle identification and classification, while the optical trap is selectively activated to redirect target particles. To validate the system’s performance, we used 10 µm green and orange fluorescent polystyrene particles. The platform achieved a sorting purity of 94.4% for orange particles under continuous flow conditions. The proposed platform provides an image-based sorting solution, advancing the development of microfluidic systems for high-resolution particle sorting in complex biological and environmental applications. Full article
(This article belongs to the Special Issue Microfluidics for Sample Pretreatment)
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27 pages, 5309 KiB  
Review
The Potential of Nanopore Technologies in Peptide and Protein Sensing for Biomarker Detection
by Iuliana Șoldănescu, Andrei Lobiuc, Olga Adriana Caliman-Sturdza, Mihai Covasa, Serghei Mangul and Mihai Dimian
Biosensors 2025, 15(8), 540; https://doi.org/10.3390/bios15080540 - 16 Aug 2025
Viewed by 494
Abstract
The increasing demand for high-throughput, real-time, and single-molecule protein analysis in precision medicine has propelled the development of novel sensing technologies. Among these, nanopore-based methods have garnered significant attention for their unique capabilities, including label-free detection, ultra-sensitivity, and the potential for miniaturization and [...] Read more.
The increasing demand for high-throughput, real-time, and single-molecule protein analysis in precision medicine has propelled the development of novel sensing technologies. Among these, nanopore-based methods have garnered significant attention for their unique capabilities, including label-free detection, ultra-sensitivity, and the potential for miniaturization and portability. Originally designed for nucleic acid sequencing, nanopore technology is now being adapted for peptide and protein analysis, offering promising applications in biomarker discovery and disease diagnostics. This review examines the latest advances in biological, solid-state, and hybrid nanopores for protein sensing, focusing on their ability to detect amino acid sequences, structural variants, post-translational modifications, and dynamic protein–protein or protein–drug interactions. We critically compare these systems to conventional proteomic techniques, such as mass spectrometry and immunoassays, discussing advantages and persistent technical challenges, including translocation control and signal deconvolution. Particular emphasis is placed on recent advances in protein sequencing using biological and solid-state nanopores and the integration of machine learning and signal-processing algorithms that enhance the resolution and accuracy of protein identification. Nanopore protein sensing represents a disruptive innovation in biosensing, with the potential to revolutionize clinical diagnostics, therapeutic monitoring, and personalized healthcare. Full article
(This article belongs to the Special Issue Advances in Nanopore Biosensors)
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22 pages, 4664 KiB  
Article
Numerical Study of a Novel Kagome-Inspired Photonic Crystal Fiber-Based Surface Plasmon Resonance Biosensor for Detection of Blood Components and Analytical Targets
by Ayushman Ramola, Amit Kumar Shakya, Ali Droby and Arik Bergman
Biosensors 2025, 15(8), 539; https://doi.org/10.3390/bios15080539 - 15 Aug 2025
Viewed by 226
Abstract
This numerical study introduces a surface plasmon resonance (SPR)-based biosensor utilizing a kagome lattice-inspired hollow core photonic crystal fiber (PCF) for the highly sensitive detection of various blood biomarkers and analytical components. The sensor is designed to detect key blood biomarkers such as [...] Read more.
This numerical study introduces a surface plasmon resonance (SPR)-based biosensor utilizing a kagome lattice-inspired hollow core photonic crystal fiber (PCF) for the highly sensitive detection of various blood biomarkers and analytical components. The sensor is designed to detect key blood biomarkers such as water, glucose, plasma, and hemoglobin (Hb), as well as analytical targets including krypton, sylgard, ethanol, polyacrylamide (PA), and bovine serum albumin (BSA), by monitoring shifts in the resonance wavelength (RW). A dual-polarization approach is employed by analyzing both transverse magnetic (TM) and transverse electric (TE) modes. The proposed sensor demonstrates exceptional performance, achieving maximum wavelength sensitivities (Sw) of 18,900 nm RIU−1 for TM pol. and 16,800 nm RIU−1 for TE pol. Corresponding peak amplitude sensitivities (SA) of 71,224 RIU−1 for TM pol. and 58,112 RIU−1 for TE pol. were also observed. The peak sensor resolution (SR) for both modes is on the order of 10−6 RIU, underscoring its high precision. Owing to its enhanced sensitivity, compact design, and robust dual-polarization capability, the proposed biosensor holds strong promise for point-of-care diagnostics and real-time blood component analysis. Full article
(This article belongs to the Special Issue Surface Plasmon Resonance-Based Biosensors and Their Applications)
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15 pages, 2365 KiB  
Article
Development of a Novel Aptamer-Antibody Sandwich Chemiluminescent Biosensor and Its Application in the Detection of Aflatoxin B1
by Zhike Zhao, Jianghao Feng and Caizhang Wu
Biosensors 2025, 15(8), 538; https://doi.org/10.3390/bios15080538 - 15 Aug 2025
Viewed by 195
Abstract
In addressing the challenges posed by high costs, low accuracy, and cumbersome operations in mycotoxin detection, a novel aptamer-antibody sandwich chemiluminescent biosensor for detecting aflatoxin B1 (AFB1) was developed. The indirect competition between AFB1, aflatoxin B1-ovomucoid [...] Read more.
In addressing the challenges posed by high costs, low accuracy, and cumbersome operations in mycotoxin detection, a novel aptamer-antibody sandwich chemiluminescent biosensor for detecting aflatoxin B1 (AFB1) was developed. The indirect competition between AFB1, aflatoxin B1-ovomucoid complete antigen (AFB1-OVA), and rabbit anti-ovomucoid (OVA) antibody results in the formation of a sandwich complex. This sandwich assay is linked to a horseradish peroxidase-labeled antibody, which catalyzes luminol chemiluminescence for the indirect detection of AFB1. The biosensor was designed to operate with high precision, low cost, and a low detection limit for AFB1, which is contingent upon experimental conditions such as pH, reagent concentration, temperature, and incubation time. The optimization of pH, aptamer concentration, competitive incubation time, competitive incubation temperature, and HRP-labeled antibody concentration was instrumental in achieving these objectives. Experimental findings demonstrated that the sensor’s detection limit was 0.067 ng/mL, exhibiting excellent linearity (R2 = 0.99679) within the concentration range of 0.25–10 ng/mL. The recovery rate of spiked samples ranged from 94.4% to 108.05%. This sensor boasts a low detection limit, straightforward operation, and minimal cost, thus offering a novel solution for developing cost-effective, high-precision mycotoxin detection methods. Full article
(This article belongs to the Section Optical and Photonic Biosensors)
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16 pages, 2774 KiB  
Article
Enzyme-Free Monitoring of Glucose Using Molecularly Imprinted Polymers and Gold Nanoparticles
by Ana Rita Aires Cardoso, Pedro Miguel Cândido Barquinha and Maria Goreti Ferreira Sales
Biosensors 2025, 15(8), 537; https://doi.org/10.3390/bios15080537 - 15 Aug 2025
Viewed by 178
Abstract
This work describes a non-enzymatic electrochemical glucose biosensor combining for the first time molecularly imprinted polymers (MIPs) for glucose concentration and gold nanoparticles (AuNPs) on screen-printed carbon electrodes (SPEs), where both MIPs and AuNPs were assembled in situ. Electrochemical impedance spectroscopy (EIS) was [...] Read more.
This work describes a non-enzymatic electrochemical glucose biosensor combining for the first time molecularly imprinted polymers (MIPs) for glucose concentration and gold nanoparticles (AuNPs) on screen-printed carbon electrodes (SPEs), where both MIPs and AuNPs were assembled in situ. Electrochemical impedance spectroscopy (EIS) was used to evaluate the analytical performance of the sensor, which has a linear range between 1.0 µM and 1.0 mM when standard solutions are prepared in buffer. Direct measurement of glucose was performed by chronoamperometry, measuring the oxidation current generated during direct glucose oxidation. The selectivity was tested against ascorbic acid and the results confirmed a selective discrimination of the electrode for glucose. Overall, the work presented here represents a promising tool for tracking glucose levels in serum. The use of glucose MIP on the electrode surface allows the concentration of glucose, resulting in lower detection limits, and the use of AuNPs reduces the potential required for the oxidation of glucose, which increases selectivity. In addition, this possible combination of two analytical measurements following different theoretical concepts can contribute to the accuracy of the analytical measurements. This combination can also be extended to other biomolecules that can be electrochemically oxidised at lower potentials. Full article
(This article belongs to the Special Issue Molecularly Imprinted Polymers in Biosensors: Assembly, Characterization and Applications)
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13 pages, 7712 KiB  
Article
Bifunctional TiO2@AgNP Superstructures as a SERS-Sensing Platform for Identifying Flavonoids in Chinese Herbal Medicine
by Yulin Li, Jubo Li, Haisu Wang, Shaorui Qi, Zhehao Zhang, Yaqiu Wang, Ying Wang and Wei Ji
Biosensors 2025, 15(8), 536; https://doi.org/10.3390/bios15080536 - 15 Aug 2025
Viewed by 275
Abstract
Acanthopanax senticosus is an essential medicinal herb in traditional Chinese medicine, with its pharmacological properties largely attributed to bioactive flavonoids. The types and amounts of these flavonoids act as vital quality markers for both the raw materials and the resultant products. In this [...] Read more.
Acanthopanax senticosus is an essential medicinal herb in traditional Chinese medicine, with its pharmacological properties largely attributed to bioactive flavonoids. The types and amounts of these flavonoids act as vital quality markers for both the raw materials and the resultant products. In this work, we introduce a TiO2@AgNP nanocomposite designed as a surface-enhanced Raman scattering (SERS) sensor aimed at the preliminary quantification and identification of flavonoids. This is achieved by leveraging the effective molecular adsorption properties of TiO2 alongside the ‘hot spots’ generated by AgNPs. By optimizing SERS performance through adjustment of the molar ratio between TiO2 and Ag, we can quantitatively evaluate four flavonoids—luteolin, kaempferol, quercetin, and rutin—with low detection concentrations of 10−6 M, 10−5 M, 5 × 10−6 M, and 10−6 M, respectively. Additionally, we observe a nearly linear relationship between the SERS signals and the flavonoid concentrations, allowing for dual or multiplex analysis of these compounds. Furthermore, we successfully differentiated Acanthopanax senticosus samples from six different geographical regions in China based on the detection of significant flavonoid constituents. This serves as a proof of concept for practical applications that can enhance the identification and distinction of traditional Chinese medicine, as well as assess quality and medicinal efficacy. Full article
(This article belongs to the Special Issue Surface-Enhanced Raman Scattering in Biosensing Applications)
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24 pages, 3609 KiB  
Review
Droplet-Based Microfluidics in Single-Bacterium Analysis: Advancements in Cultivation, Detection, and Application
by Haiyan Ma, Yuewen Zhang, Ren Shen and Yanwei Jia
Biosensors 2025, 15(8), 535; https://doi.org/10.3390/bios15080535 - 15 Aug 2025
Viewed by 425
Abstract
Microorganisms exhibit remarkable diversity, making their comprehensive characterization essential for understanding ecosystem functioning and safeguarding human health. However, traditional culture-based methods entail inherent limitations for resolving microbial heterogeneity, isolating slow-growing microorganisms, and accessing uncultivated microbes. Conversely, droplet-based microfluidics enables a high-throughput and precise [...] Read more.
Microorganisms exhibit remarkable diversity, making their comprehensive characterization essential for understanding ecosystem functioning and safeguarding human health. However, traditional culture-based methods entail inherent limitations for resolving microbial heterogeneity, isolating slow-growing microorganisms, and accessing uncultivated microbes. Conversely, droplet-based microfluidics enables a high-throughput and precise platform for single-bacterium manipulation by physically isolating individual cells within microdroplets. This technology presents a transformative approach to overcoming the constraints of conventional techniques. This review outlines the fundamental principles, recent research advances, and key application domains of droplet-based microfluidics, with a particular focus on innovations in single-bacterium encapsulation, sorting, cultivation, and functional analysis. Applications such as antibiotic susceptibility testing, enzyme-directed evolution screening, microbial interaction studies, and the cultivation of novel bacterial species are discussed, underscoring the technology’s broad potential in microbiological research and biotechnology. Full article
(This article belongs to the Special Issue Biosensors Based on Microfluidic Devices—2nd Edition)
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16 pages, 1307 KiB  
Article
Kinetic Analysis of SARS-CoV-2 S1–Integrin Binding Using Live-Cell, Label-Free Optical Biosensing
by Nicolett Kanyo, Krisztina Borbely, Beatrix Peter, Kinga Dora Kovacs, Anna Balogh, Beatrix Magyaródi, Sandor Kurunczi, Inna Szekacs and Robert Horvath
Biosensors 2025, 15(8), 534; https://doi.org/10.3390/bios15080534 - 14 Aug 2025
Viewed by 538
Abstract
The SARS-CoV-2 spike (S1) protein facilitates viral entry through binding to angiotensin-converting enzyme 2 (ACE2), but it also contains an Arg–Gly–Asp (RGD) motif that may enable interactions with RGD-binding integrins on ACE2-negative cells. Here, we provide quantitative evidence for this alternative binding pathway [...] Read more.
The SARS-CoV-2 spike (S1) protein facilitates viral entry through binding to angiotensin-converting enzyme 2 (ACE2), but it also contains an Arg–Gly–Asp (RGD) motif that may enable interactions with RGD-binding integrins on ACE2-negative cells. Here, we provide quantitative evidence for this alternative binding pathway using a live-cell, label-free resonant waveguide grating (RWG) biosensor. RWG technology allowed us to monitor real-time adhesion kinetics of live cells to RGD-displaying substrates, as well as cell adhesion to S1-coated surfaces. To characterize the strength of the integrin–S1 interaction, we determined the dissociation constant using two complementary approaches. First, we performed a live-cell competitive binding assay on RGD-displaying surfaces, where varying concentrations of soluble S1 were added to cell suspensions. Second, we recorded the adhesion kinetics of cells on S1-coated surfaces and fitted the data using a kinetic model based on coupled ordinary differential equations. By comparing the results from both methods, we estimate that approximately 33% of the S1 molecules immobilized on the Nb2O5 biosensor surface are capable of initiating integrin-mediated adhesion. These findings support the existence of an alternative integrin-dependent entry route for SARS-CoV-2 and highlight the effectiveness of label-free RWG biosensing for quantitatively probing virus–host interactions under physiologically relevant conditions without the need of the isolation of the interaction partners from the cells. Full article
(This article belongs to the Special Issue In Honor of Prof. Evgeny Katz: Biosensors: Science and Technology)
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15 pages, 1615 KiB  
Article
Simultaneous Routing with Washing Droplets Based on Shape-Dependent Velocity Model in MEDA Biochips
by Chiharu Shiro, Hiroki Nishikawa, Xiangbo Kong, Hiroyuki Tomiyama and Shigeru Yamashita
Biosensors 2025, 15(8), 533; https://doi.org/10.3390/bios15080533 - 14 Aug 2025
Viewed by 183
Abstract
Micro Electrode Dot Array (MEDA) biochips have recently attracted considerable attention in the biochemical and medical industries. MEDA biochips manipulate micro droplets for biochemical experiments such as DNA analysis. Droplets on MEDA biochips are moved using the Electrowetting on Dielectric (EWOD) effect, but [...] Read more.
Micro Electrode Dot Array (MEDA) biochips have recently attracted considerable attention in the biochemical and medical industries. MEDA biochips manipulate micro droplets for biochemical experiments such as DNA analysis. Droplets on MEDA biochips are moved using the Electrowetting on Dielectric (EWOD) effect, but a portion of a droplet may remain on a cell after passing through, contaminating the cell. Other droplets cannot pass through a contaminated cell. In previous studies, contaminated cells were considered unavailable for droplet routing. As the number of contaminated cells increases, droplets may be prevented from moving to the desired position. Therefore, we propose a method for simultaneous routing of target functional and washing droplets based on a shape-dependent velocity model. In a simulation, the proposed method reduced the routing time by about 10% compared with an existing method. Full article
(This article belongs to the Special Issue Microfluidics for Biomedical Applications (3rd Edition))
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16 pages, 6084 KiB  
Article
First Design of a Contact Lens for Diagnosis of Dehydration
by Kundan Sivashanmugan, Reece E. Albert and Joseph R. Lakowicz
Biosensors 2025, 15(8), 532; https://doi.org/10.3390/bios15080532 - 14 Aug 2025
Viewed by 266
Abstract
Dehydration is a serious medical problem for elderly patients and young children. The most widely used diagnostics are measurements of sodium ion (Na+) and potassium ion (K+) in blood serum. Dehydration is difficult to diagnose even by trained health [...] Read more.
Dehydration is a serious medical problem for elderly patients and young children. The most widely used diagnostics are measurements of sodium ion (Na+) and potassium ion (K+) in blood serum. Dehydration is difficult to diagnose even by trained health care professionals because the body compensates to maintain the appearance of skin. These measurements required a blood draw because specific tests are generally not available for only Na+ and K+. The blood samples are analyzed by an electrolyte panel (EP) or a basic metabolic panel (BMP). Most hospitals limit EP and BMP to one per day to control costs. More frequent measurements of Na+ and K+ are needed, especially during rehydration. We designed a dehydration contact lens that can provide the Na+ and K+ concentrations as needed or for continuous monitoring. The measurements are obtained from the fluorescent lifetime or wavelength-ratiometric intensities of the Na+- and K+-sensitive fluorophores. The dehydration contact lens does not contain electronic components and are inexpensive to prepare. Full article
(This article belongs to the Special Issue Advanced Fluorescence Biosensors)
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15 pages, 3400 KiB  
Article
Ti3C2TX MXene/Polyaniline-Modified Nylon Fabric Electrode for Wearable Non-Invasive Glucose Monitoring in Sweat
by Lichao Wang, Meng Li, Shengnan Ya, Hang Tian, Kerui Li, Qinghong Zhang, Yaogang Li, Hongzhi Wang and Chengyi Hou
Biosensors 2025, 15(8), 531; https://doi.org/10.3390/bios15080531 - 14 Aug 2025
Viewed by 369
Abstract
Sweat-based electrochemical sensors for wearable applications have attracted substantial interest due to their non-invasive nature, compact design, and ability to provide real-time data. Remarkable advancements have been made in integrating these devices into flexible platforms. While thin-film polymer substrates are frequently employed for [...] Read more.
Sweat-based electrochemical sensors for wearable applications have attracted substantial interest due to their non-invasive nature, compact design, and ability to provide real-time data. Remarkable advancements have been made in integrating these devices into flexible platforms. While thin-film polymer substrates are frequently employed for their durability, the prolonged buildup of sweat on such materials can disrupt consistent sensing performance and adversely affect skin comfort over extended periods. Therefore, investigating lightweight, comfortable, and breathable base materials for constructing working electrodes is essential for producing flexible and breathable sweat electrochemical sensors. In this study, nylon fabric was chosen as the base material for constructing the working electrode. The electrode is prepared using a straightforward printing process, incorporating Ti3C2TX MXene/polyaniline and methylene blue as modification materials in the electronic intermediary layer. The synergistic effect of the modified layer and the multi-level structure of the current collector enhances the electrochemical kinetics on the electrode surface, improves electron transmission efficiency, and enables the nylon fabric-based electrode to accurately and selectively measure glucose concentration in sweat. It exhibits a wide linear range (0.04~3.08 mM), high sensitivity (3.11 μA·mM−1), strong anti-interference capabilities, and high stability. This system can monitor glucose levels and trends in sweat, facilitating the assessment of daily sugar intake for personal health management. Full article
(This article belongs to the Section Biosensor and Bioelectronic Devices)
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11 pages, 1327 KiB  
Article
All-in-One Sustainable Thread Biosensor for Chemiluminescence Smartphone Detection of Lactate in Sweat
by Emanuela Maiorano, Maria Maddalena Calabretta, Eugenio Lunedei and Elisa Michelini
Biosensors 2025, 15(8), 530; https://doi.org/10.3390/bios15080530 - 13 Aug 2025
Viewed by 289
Abstract
Thanks to their low-cost, portability, and sustainability, microfluidic thread-based analytical devices (μTADs) are emerging as an attractive analytical platform for wearable biosensing. While several μTADs, mainly based on colorimetric and electrochemical detection methods, have been developed, achieving the needed sensitivity and accuracy for [...] Read more.
Thanks to their low-cost, portability, and sustainability, microfluidic thread-based analytical devices (μTADs) are emerging as an attractive analytical platform for wearable biosensing. While several μTADs, mainly based on colorimetric and electrochemical detection methods, have been developed, achieving the needed sensitivity and accuracy for these biosensors continues to present a significant challenge. Prompted by this need we investigated for the first time the implementation of chemiluminescence (CL) as a detection technique for μTADs. Exploiting the lactate oxidase-catalyzed reaction coupled with the enhanced luminol/H2O2/horseradish peroxidase CL system, we developed a cotton-thread-based chemiluminescent device enabling the detection of lactate with a limit of detection of 0.25 mM in a 2 µL volume of artificial sweat at pH 6.5 within 3 min. The use of recycled grape skin as support made the device sustainable, while the smartphone detection allowed a simple and quantitative readout for the end-user. Using a smartphone as a detector, the analytical performance was evaluated in different conditions and in the presence of potential interferents, showing suitability for monitoring lactate levels in physiological conditions, such as for monitoring anaerobic thresholds in endurance training. Full article
(This article belongs to the Special Issue Advanced Biosensing and Bioimaging by Nanomaterials and Machine Learning)
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13 pages, 2094 KiB  
Article
Laser-Assisted Visible-Light Polymerization for Rapid Synthesis of Molecularly Imprinted Polymers
by Wissal Mrabet, Abdelhafid Karrat and Aziz Amine
Biosensors 2025, 15(8), 529; https://doi.org/10.3390/bios15080529 - 13 Aug 2025
Viewed by 315
Abstract
The demand for rapid, energy-efficient, and low-toxicity methods for synthesizing molecularly imprinted polymers (MIPs) is increasing, particularly for applications in environmental monitoring and green chemistry. In this context, the present work focuses on the development of a novel laser-assisted method for MIP synthesis, [...] Read more.
The demand for rapid, energy-efficient, and low-toxicity methods for synthesizing molecularly imprinted polymers (MIPs) is increasing, particularly for applications in environmental monitoring and green chemistry. In this context, the present work focuses on the development of a novel laser-assisted method for MIP synthesis, employing a visible laser (450 nm) and erythrosine B as a green photoinitiator. This visible-light approach enables fast and spatially controlled polymerization while avoiding the drawbacks of conventional methods (thermal heating, UV synthesis), such as the use of toxic initiators like AIBN and the need for UV shielding. MIPs were synthesized for bisphenol A and sulfamethoxazole, two emerging contaminants of significant environmental concern. The synthesis process was optimized for rapidity and scalability, and the resulting MIPs were integrated into a paper-based analytical device (MIP-PAD) for smartphone-assisted, on-site detection. The developed sensors exhibited excellent analytical performance, with recovery rates of 98.6% in tap water and 90.2% in river water and relative standard deviations (RSDs) below 1.88%. This study demonstrated a green, efficient, and highly controllable laser-assisted polymerization technique, offering a promising alternative to conventional MIP synthesis methods. Full article
(This article belongs to the Special Issue Molecularly Imprinted Polymers in Biosensors: Assembly, Characterization and Applications)
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12 pages, 2021 KiB  
Article
Dual-Mode Optical Detection of Sulfide Ions Using Copper-Anchored Nitrogen-Doped Graphene Quantum Dot Nanozymes
by Van Anh Ngoc Nguyen, Trung Hieu Vu, Phuong Thy Nguyen and Moon Il Kim
Biosensors 2025, 15(8), 528; https://doi.org/10.3390/bios15080528 - 13 Aug 2025
Viewed by 340
Abstract
We present a dual-mode optical sensing strategy for selective and sensitive detection of sulfide ions (S2−), employing copper-anchored nitrogen-doped graphene quantum dots (Cu@N-GQDs) as bifunctional nanozymes. The Cu@N-GQDs were synthesized via citric acid pyrolysis in the presence of ammonium hydroxide (serving [...] Read more.
We present a dual-mode optical sensing strategy for selective and sensitive detection of sulfide ions (S2−), employing copper-anchored nitrogen-doped graphene quantum dots (Cu@N-GQDs) as bifunctional nanozymes. The Cu@N-GQDs were synthesized via citric acid pyrolysis in the presence of ammonium hydroxide (serving as both nitrogen source and reductant) and copper chloride, leading to uniform incorporation of copper oxide species onto the N-GQD surface. The resulting nanohybrids exhibit two synergistic functionalities: intrinsic fluorescence comparable to pristine N-GQDs, and significantly enhanced peroxidase-like catalytic activity attributed to the anchored copper species. Upon interaction with sulfide ions, the system undergoes a dual-optical response: (i) fluorescence quenching via Cu-S complexation, and (ii) inhibition of peroxidase-like activity due to the deactivation of Cu catalytic centers via the interaction with S2−. This dual-signal strategy enables sensitive quantification of S2−, achieving detection limits of 0.5 µM (fluorescence) and 3.5 µM (colorimetry). The sensor demonstrates excellent selectivity over competing substances and high reliability and precision in real tap water samples. These findings highlight the potential of Cu@N-GQDs as robust, bifunctional, and field-deployable nanozyme probes for environmental and biomedical sulfide ion monitoring. Full article
(This article belongs to the Special Issue Advanced Optics and Photonics in Biosensing Applications)
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15 pages, 2864 KiB  
Article
Rapid Detection of Staphylococcus aureus in Milk Samples by DNA Nanodendrimer-Based Fluorescent Biosensor
by Mukaddas Mijit, Dongxia Pan, Hui Wang, Chaoqun Sun and Liang Yang
Biosensors 2025, 15(8), 527; https://doi.org/10.3390/bios15080527 - 12 Aug 2025
Viewed by 328
Abstract
Staphylococcus aureus is the primary pathogen responsible for mastitis in dairy cows and foodborne illnesses, posing a significant threat to public health and food safety. Here, we developed an enhanced sensor based on solid-phase separation using gold-magnetic nanoparticles (Au@Fe3O4) [...] Read more.
Staphylococcus aureus is the primary pathogen responsible for mastitis in dairy cows and foodborne illnesses, posing a significant threat to public health and food safety. Here, we developed an enhanced sensor based on solid-phase separation using gold-magnetic nanoparticles (Au@Fe3O4) and signal amplification via dendritic DNA nanostructures. The substrate chain was specifically immobilized using thiol–gold coordination, and a three-dimensional dendritic structure was constructed through sequential hybridization of DNAzymes, L chains, and Y chains, resulting in a 2.8-fold increase in initial fluorescence intensity. Upon specific cleavage of the substrate chain at the rA site by S. aureus DNA, the complex dissociates, resulting in fluorescence intensity decay. The fluorescence intensity is negatively correlated with the concentration of Staphylococcus aureus. After optimization, the biosensor maintains a detection limit of 1 CFU/mL within 3 min, with a linear range extended to 1–107 CFU/mL (R2 = 0.998) and recovery rates of 85.6–102.1%, significantly enhancing resistance to matrix interference. This provides an innovative solution for rapid on-site detection of foodborne pathogens. Full article
(This article belongs to the Special Issue The Application of Biomaterials in Electronics and Biosensors)
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18 pages, 2250 KiB  
Article
Fumonisin B Determination in Maize Products from Belize Using an Immunosensor Based on Screen-Printed Carbon Electrodes
by Beatriz Pérez-Fernández, Britt Marianna Maestroni, Carlotta Cozzani, Colette Eusey, Natalie Gibson, Alfredo de la Escosura-Muñiz and Christina Vlachou
Biosensors 2025, 15(8), 526; https://doi.org/10.3390/bios15080526 - 12 Aug 2025
Viewed by 392
Abstract
A competitive electrochemical immunosensor, using screen-printed carbon electrodes (SPCEs), was developed for the determination of total fumonisins (sum of FB1, FB2 and FB3) extracted with a simple solvent extraction and dilution method, without clean up, from maize flour and maize tortillas. The optimized [...] Read more.
A competitive electrochemical immunosensor, using screen-printed carbon electrodes (SPCEs), was developed for the determination of total fumonisins (sum of FB1, FB2 and FB3) extracted with a simple solvent extraction and dilution method, without clean up, from maize flour and maize tortillas. The optimized biosensor has a linear range of 0.25 to 50 µg/L with 3% and 2% reproducibility for FB1 and (FB1 + FB2), respectively, and a linear range of 0.25 to 10 µg/L with 2% reproducibility for (FB1 + FB2 + FB3). The limits of detection and quantification in PBS buffer for total fumonisins are 0.12 µg/L and 0.39 µg/L, respectively. These values in the maize matrix are 6.07 µg/kg and 20.25 µg/kg, respectively. In addition, the stability and the selectivity of the sensor were studied. The immunosensor was validated with liquid chromatography–tandem mass spectrometry. This novel biosensor is more rapid, simpler and cheaper than current methods, and can also be used at the point of need. Full article
(This article belongs to the Special Issue Applications of Cutting-Edge Biosensors in Environment, Food and Healthcare Field)
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24 pages, 2773 KiB  
Article
Highly Sensitive SOI-TFET Gas Sensor Utilizing Tailored Conducting Polymers for Selective Molecular Detection and Microbial Biosensing Integration
by Mohammad K. Anvarifard and Zeinab Ramezani
Biosensors 2025, 15(8), 525; https://doi.org/10.3390/bios15080525 - 11 Aug 2025
Viewed by 265
Abstract
We present a highly sensitive and selective gas sensor based on an advanced silicon-on-insulator tunnel field-effect transistor (SOI-TFET) architecture, enhanced through the integration of customized conducting polymers. In this design, traditional metal gates are replaced with distinct functional polymers—PPP-TOS/AcCN, PP-TOS/AcCN, PP-FE(CN)63− [...] Read more.
We present a highly sensitive and selective gas sensor based on an advanced silicon-on-insulator tunnel field-effect transistor (SOI-TFET) architecture, enhanced through the integration of customized conducting polymers. In this design, traditional metal gates are replaced with distinct functional polymers—PPP-TOS/AcCN, PP-TOS/AcCN, PP-FE(CN)63−/H2O, PPP-TCNQ-TOS/AcCN, and PPP-ClO4/AcCN—which enable precise molecular recognition and discrimination of various target gases. To further enhance sensitivity, the device employs an oppositely doped source region, significantly improving gate control and promoting stronger band-to-band tunneling. This structural modification amplifies sensing signals and improves noise immunity, allowing reliable detection at trace concentrations. Additionally, optimization of the subthreshold swing contributes to faster switching and response times. Thermal stability is addressed by embedding a P-type buffer layer within the buried oxide, which increases thermal conductivity and reduces lattice temperature, further stabilizing device performance. Experimental results demonstrate that the proposed sensor outperforms conventional SOI-TFET designs, exhibiting superior sensitivity and selectivity toward analytes such as methanol, chloroform, isopropanol, and hexane. Beyond gas sensing, the unique polymer-functionalized gate design enables integration of microbial biosensing capabilities, making the platform highly versatile for biochemical detection. This work offers a promising pathway toward ultra-sensitive, low-power sensing technologies for environmental monitoring, industrial safety, and medical diagnostics. Full article
(This article belongs to the Special Issue Microbial Biosensor: From Design to Applications—2nd Edition)
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