Biosensors

31 pages, 8523 KB

Open AccessReview

Optical and Electrochemical Biosensors Using Electrochemically Etched Porous Silicon

by Teodora Despotovski Kiš, Marko Radović, Brankica Kartalović and Nikola Knežević

Biosensors 2026, 16(9), 498; https://doi.org/10.3390/bios16090498 (registering DOI) - 6 Sep 2026

Versatile nanostructured materials based on electrochemically etched porous silicon (pSi) are being developed, which have tuneable pore morphology and unique optical and electrochemical properties that enable their effective biosensing applications. It has been shown that fabrication parameters critically influence pore formation and sensor [...] Read more.

Versatile nanostructured materials based on electrochemically etched porous silicon (pSi) are being developed, which have tuneable pore morphology and unique optical and electrochemical properties that enable their effective biosensing applications. It has been shown that fabrication parameters critically influence pore formation and sensor performance, yet challenges remain in reproducible synthesis, structural stability and device integration. Here we review the electrochemical etching synthesis of pSi and recent advances in pSi-based optical and electrochemical biosensors for detecting bacteria, biomolecules, and viruses. We highlight strategies such as surface functionalisation, incorporation of nanomaterials, and integration with microfluidic and lab-on-a-chip technologies that enhance sensitivity and response times by addressing mass transfer limitations. These developments highlight pSi’s potential as a low-cost, adaptable biosensing material with applications in clinical diagnostics and environmental monitoring, while mapping future directions to overcome current fabrication and stability challenges. Full article

(This article belongs to the Special Issue Development and Application of Functional Nanomaterial-Based Biosensors)

27 pages, 2570 KB

Open AccessReview

Photoacoustic Imaging for Liver Disease: The Systems and the Molecules

by Bowen Jiang, Zhixian Lin and Xiaoquan Yang

Biosensors 2026, 16(9), 497; https://doi.org/10.3390/bios16090497 (registering DOI) - 5 Sep 2026

Abstract

Liver disease represents a significant global health burden, and its effective management relies on early, accurate diagnosis. Established assessments for liver diseases, ranging from invasive biopsies to conventional noninvasive imaging (e.g., ultrasound, MRI, and CT), are often limited by inadequate specificity, potential safety [...] Read more.

Liver disease represents a significant global health burden, and its effective management relies on early, accurate diagnosis. Established assessments for liver diseases, ranging from invasive biopsies to conventional noninvasive imaging (e.g., ultrasound, MRI, and CT), are often limited by inadequate specificity, potential safety risks, or unsuitability for dynamic tracking. Photoacoustic imaging (PAI), a hybrid modality that combines optical absorption contrast with deep ultrasonic detection, offers an attractive solution for noninvasive, high-sensitivity, and high-specificity imaging in deep organs such as the liver. This review summarizes recent advances in photoacoustic imaging for liver pathophysiology, beginning with the evolution of imaging systems and extending to the diverse molecules employed for preclinical studies and early clinical trials. Specifically, novel reconstruction algorithms improved the spatial resolution and acquisition speed by up to threefold, Monte Carlo-based fluence compensation increased the deep-tissue signal-to-background ratio by approximately 50%, and a 7-azaindole-modified probe exhibited one-magnitude-higher superoxide-triggered activation than conventional hemicyanine dyes. Furthermore, we discuss key challenges and future perspectives, highlighting the translational potential of PAI as an emerging liver imaging modality. Full article

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

► Show Figures

Figure 1

21 pages, 4557 KB

Open AccessFeature PaperArticle

Wearable Inertial Sensor-Based Detection of Exercise-Induced Mobility Adaptations in Older Women: A Randomized Controlled Trial

by Mauricio Barramuño-Medina, Pablo Valdés-Badilla, Pablo Aravena-Sagardia, Jordan Hernandez-Martínez, Edgar Vásquez-Carrasco, Wilson Pastén-Hidalgo, Cristian Sandoval-Vásquez and Germán Gálvez-García

Biosensors 2026, 16(9), 496; https://doi.org/10.3390/bios16090496 (registering DOI) - 5 Sep 2026

Abstract

Wearable inertial sensors have become tools for objectively assessing mobility in older people. This study analyzed whether wearable inertial sensors could detect exercise-induced mobility changes and compared the effects of multicomponent training (MCT) and elastic band training (EBT) on mobility and physical function [...] Read more.

Wearable inertial sensors have become tools for objectively assessing mobility in older people. This study analyzed whether wearable inertial sensors could detect exercise-induced mobility changes and compared the effects of multicomponent training (MCT) and elastic band training (EBT) on mobility and physical function in older women. Forty-two participants were randomly allocated to either the MCT (n = 21) or EBT (n = 21) group, where 38 (EBT: n = 19; MCT: n = 19) completed the 16-week intervention. Outcomes included instrumented Timed Up-and-Go (iTUG) assessed with a wearable inertial sensor, the Senior Fitness Test, maximal isometric handgrip strength, conventional TUG, anthropometric measurements, health-related quality of life, and blood biomarkers. Data were analyzed using age-adjusted linear mixed-effects models. The iTUG showed shorter completion time (p < 0.001), reduced middle-turn duration (p = 0.004), and increased cadence (p = 0.007). Significant time effects were also observed for chair stand (p = 0.011), arm curl (p < 0.001), and conventional TUG (p = 0.009). No significant group × time interactions were detected. After adjustment for multiple comparisons, no significant changes were observed in anthropometric measures, health-related quality of life, or blood biomarkers. Wearable inertial sensors detected training-related mobility changes, and both exercise programs improved physical function and mobility without between-group differences. Full article

(This article belongs to the Special Issue Advances and Challenges in Wearable Biosensors for Human Activity Monitoring)

► Show Figures

Figure 1

20 pages, 16343 KB

Open AccessArticle

Geometry-Tunable Nanoneedle Arrays Reveal Membrane Penetration Mechanics for Intracellular Delivery

by Xuanhe Zhang, Zheng Wang, Yiqing Chen, Lele Song, Yuan Ma and Jiadao Wang

Biosensors 2026, 16(9), 495; https://doi.org/10.3390/bios16090495 - 4 Sep 2026

Abstract

Nanoneedle arrays provide a promising interface for intracellular delivery, yet scalable control of array geometry and membrane penetration mechanics remains insufficiently understood. Here, we developed a rapid and scalable strategy for fabricating geometry-tunable silicon nanoneedle arrays. One-step SF₆/O₂ etching produced [...] Read more.

Nanoneedle arrays provide a promising interface for intracellular delivery, yet scalable control of array geometry and membrane penetration mechanics remains insufficiently understood. Here, we developed a rapid and scalable strategy for fabricating geometry-tunable silicon nanoneedle arrays. One-step SF₆/O₂ etching produced ordered arrays with center-to-center spacing of 1–5 μm, whereas pseudo-Bosch etching produced high-aspect-ratio (HAR) nanoneedles. Using a microwell-assisted cell-on-probe atomic force microscopy platform, we quantified the first penetration force, penetration probability, and number of penetration events at the single-cell level. For one-step-etching arrays, increasing spacing from 1 to 5 μm reduced the first penetration force from 34.87 ± 2.90 to 4.05 ± 0.30 nN and increased the penetration probability from 0.21 ± 0.03 to 0.87 ± 0.04. A phenomenological inverse-square model captured the force–spacing relationship, supporting an array-level load-sharing mechanism. Under identical vibration-assisted microfluidic conditions, the FITC-dextran-positive fraction increased from 22.8% for 1 μm arrays to 77.1% for 5 μm arrays, whereas 1 μm HAR arrays achieved 28.8%. These results identify array spacing as a key factor governing single-cell penetration and delivery and provide a mechanistic basis for nanoneedle-based biosensor and cell-interface design. Full article

(This article belongs to the Collection Microfluidic Sensing for Biomedical Applications)

► Show Figures

Figure 1

24 pages, 4435 KB

Open AccessArticle

Design and Performance Analysis of an SPR Sensor for Milk Adulteration Monitoring

by John Germán Vera Luzuriaga, Marco Guevara, Diana Coello-Fiallos and Cristian Vacacela Gomez

Biosensors 2026, 16(9), 494; https://doi.org/10.3390/bios16090494 - 4 Sep 2026

Abstract

Hydrogen peroxide (H₂O₂) may be illegally added to milk to delay visible spoilage, producing concentration-dependent changes in its refractive index. This study numerically evaluates the optical response of a B-sil/Al/Al₂O₃/WS₂ surface plasmon resonance (SPR) [...] Read more.

Hydrogen peroxide (H₂O₂) may be illegally added to milk to delay visible spoilage, producing concentration-dependent changes in its refractive index. This study numerically evaluates the optical response of a B-sil/Al/Al₂O₃/WS₂ surface plasmon resonance (SPR) configuration to these refractive-index variations. The angular SPR response was calculated at λ = 633 nm using the transfer matrix method under TM-polarized illumination. The B-sil/Al/Al₂O₃/WS₂ architecture was established through sequential evaluation of prism material, Al thickness, Al₂O₃ thickness, and 2D interfacial material, followed by assessment of its response to H₂O₂-associated refractive-index changes in milk. The final structure consisted of 70 nm Al, 25 nm Al₂O₃, and 0.80 nm WS₂. Across the simulated H₂O₂ conditions, the resonance angle shifted from 85.65° to 86.11°, while the angular sensitivity ranged from 383.82 to 406.45°/RIU. The best balance among the evaluated metrics was obtained for H₂O₂-C2, with a sensitivity of 406.45°/RIU, QF of 4.65 RIU⁻¹, FoM of 436.48 RIU⁻¹, LoD of 1.23 × 10⁻⁵, and CSF of 436.56. The WS₂-containing interface produced calculated angular shifts for small refractive-index variations in the milk sensing medium. Comparison with reported SPR systems for milk-related sensing showed a comparable angular sensitivity range, while QF and detection accuracy were limited by the broad resonance profile. These results characterize the theoretical optical response of the B-sil/Al/Al₂O₃/WS₂ multilayer under H₂O₂-associated refractive-index changes but do not establish chemical selectivity toward H₂O₂. Experimental implementation would require an appropriate selective filtering or recognition strategy, together with validation of matrix effects and practical sensing performance. Full article

(This article belongs to the Special Issue Biosensors for Environmental Monitoring and Food Safety—2nd Edition)

► Show Figures

Figure 1

12 pages, 2379 KB

Open AccessArticle

Two Signals from One Event: Exploiting Intrinsic Dual-Functional Selenium Nanomaterials for Signal-On Chiroptical and Colorimetric Sensing of Free Thiols

by Jiayang Gao and Xinling Liu

Biosensors 2026, 16(9), 493; https://doi.org/10.3390/bios16090493 - 3 Sep 2026

Abstract

Rapid identification of free thiols is essential in pharmaceutical quality control and food safety. Herein, we demonstrate the sensing concept of “two signals from one event” by exploiting the intrinsic dual functionality of selenium (Se) nanomaterials to construct a signal-on, dual-mode sensing platform [...] Read more.

Rapid identification of free thiols is essential in pharmaceutical quality control and food safety. Herein, we demonstrate the sensing concept of “two signals from one event” by exploiting the intrinsic dual functionality of selenium (Se) nanomaterials to construct a signal-on, dual-mode sensing platform for free thiols. The single event is thiol-triggered seeded growth: free thiols interact with L-cysteine-modified Se seeds, driving seed fusion and crystallization into chiral trigonal Se structures. This same event yields two readouts simultaneously: a colorimetric response arising from particle size enlargement (UV-Vis red-shift) and a turn-on circular dichroism (CD) signal from long-range chiral ordering. The method achieves a detection threshold of 10 μmol/L for various free thiols and can be completed within 60 min from seed preparation to signal readout without complex instrumentation. It serves as a general indicator of total free thiols rather than distinguishing individual thiol species. Above the threshold, concentration-dependent color deepening and spectral redshifts provide semi-quantitative estimation of the concentration range. Its practicality was validated by detecting D-penicillamine in commercial tablets. This strategy offers an approach for on-site free thiol screening and highlights the potential of chiral inorganic nanomaterials in multi-mode sensing via chiral transfer and amplification. Full article

(This article belongs to the Special Issue Fundamental Innovation and Device Engineering of Biosensors Driven by Advanced Functional Materials)

► Show Figures

Figure 1

44 pages, 6275 KB

Open AccessArticle

Modeling and Experimental Validation for Detecting Indoor Respiratory Droplet

by Fuqiang Hu, Pengfei Zhang, Yusheng Sun, Xiaofang Wang and Pengfei Lu

Biosensors 2026, 16(9), 492; https://doi.org/10.3390/bios16090492 - 3 Sep 2026

Abstract

Precise quantification of respiratory pathogen transmission is urgently needed to underpin disease surveillance and support diagnostic decision-making in indoor healthcare settings. Although numerical simulations are widely used to study macro-scale transmission, the key physical parameters governing droplet dynamics remain insufficiently understood. This study [...] Read more.

Precise quantification of respiratory pathogen transmission is urgently needed to underpin disease surveillance and support diagnostic decision-making in indoor healthcare settings. Although numerical simulations are widely used to study macro-scale transmission, the key physical parameters governing droplet dynamics remain insufficiently understood. This study develops a multi-scale transmission model to evaluate the effects of droplet evaporation, sedimentation, and ventilation on viral transmission. Based on the Wells evaporation–sedimentation theory, a time-varying model is formulated incorporating droplet size distribution, environmental humidity, and ventilation conditions, with analytical expressions derived for concentration distributions across different respiratory activities (breathing, speaking, coughing, and sneezing). Results show that droplet size is decisive for transmission distance and lower relative humidity significantly extends sedimentation range. Small coughing droplets can travel up to 2.5 m, while the bimodal sneezing distribution (1.5 µm and 74 µm) generates high-concentration zones up to 2 m. To validate the model, a molecular communication testbed is developed as a biosensing-oriented platform integrating transmitters, receivers, and configurable ventilation modules with real-time sensing capabilities, enabling systematic verification under varied breathing modes, humidity, and ventilation conditions. Experimental results show strong agreement with theoretical predictions. This framework provides a quantitative basis for biosensing-enabled environmental monitoring and diagnostic-oriented risk assessment, informing ventilation optimization and infection control measures in indoor environments. Full article

(This article belongs to the Special Issue Biosensing Technologies in Medical Diagnosis—2nd Edition)

18 pages, 4489 KB

Open AccessArticle

Periodontal Disease Diagnosis by a Chemically Etched Single-Mode Fiber-Optic Biosensor for Label-Free Detection of Matrix Metalloproteinase-8 (MMP-8)

by Rigoberto Tovar, Jr., Sarkis Sozkes and Marzhan Sypabekova

Biosensors 2026, 16(9), 491; https://doi.org/10.3390/bios16090491 - 3 Sep 2026

Abstract

A miniature label-free biosensor based on a chemically etched single-mode optical fiber (SMF) is reported for the detection of matrix metalloproteinase-8 (MMP-8), a salivary biomarker of active periodontitis with a clinical decision threshold of 20 ng/mL. Fibers etched in 48% hydrofluoric acid to [...] Read more.

A miniature label-free biosensor based on a chemically etched single-mode optical fiber (SMF) is reported for the detection of matrix metalloproteinase-8 (MMP-8), a salivary biomarker of active periodontitis with a clinical decision threshold of 20 ng/mL. Fibers etched in 48% hydrofluoric acid to a waist diameter of 16.0 ± 1.4 µm gave a mean refractive index (RI) sensitivity of 376.8%/RIU and an RI limit of detection (LOD) of 5.9 × 10⁻⁴ RIU. Fibers were tested with MMP-8 spiked into phosphate-buffered saline (PBS) and into saliva over 0–200 ng/mL using a post-rinse protocol with per-fiber matrix subtraction. Dose–responses followed a Langmuir isotherm (Kd = 7.1 ng/mL in PBS, 12.7 ng/mL in saliva), with cohort LODs of 0.043 and 0.52 ng/mL, both well below the threshold. MMP-9 (100 ng/mL) and human serum albumin (1 mg/mL) gave negligible responses (≤2.7%, versus 68.2% for MMP-8 at 100 ng/mL); antibody immobilization was confirmed by confocal immunofluorescence. A commercial sandwich ELISA on the same spike series gave a matched-matrix LOD of 41.1 ng/mL, nearly two orders of magnitude higher. This performance requires no metal coating, nanostructuring, label, or signal amplification, only a single wet-etching step on stock telecommunications fiber. Full article

(This article belongs to the Special Issue Emerging Trends in Optical Fiber Biosensing Based on Micro- and Nanostructures and Materials)

► Show Figures

Figure 1

16 pages, 15459 KB

Open AccessArticle

Portable Paper-Based Colorimetric Biosensor for Rapid Screening of Organophosphate Exposure via Acetylcholinesterase Activity and RGB Image Analysis

by Carlos E. Zambra, Jorge Morales-Ferreiro, Francisca Herrera Vielma and Jessica Zúñiga-Hernández

Biosensors 2026, 16(9), 490; https://doi.org/10.3390/bios16090490 - 3 Sep 2026

Abstract

Background: Rapid screening of acetylcholinesterase (AChE) inhibition is essential for monitoring exposure to organophosphate compounds, particularly in field settings where access to laboratory infrastructure is limited. This study aimed to develop a portable paper-based colorimetric biosensor for the semi-quantitative detection of AChE activity [...] Read more.

Background: Rapid screening of acetylcholinesterase (AChE) inhibition is essential for monitoring exposure to organophosphate compounds, particularly in field settings where access to laboratory infrastructure is limited. This study aimed to develop a portable paper-based colorimetric biosensor for the semi-quantitative detection of AChE activity in blood samples. Methods: The biosensor was based on a pH-dependent color change adapted from the modified Edson method. The platform was first optimized using experimental models and then evaluated in human capillary blood samples collected under real field conditions. Reference serum cholinesterase activity was determined by a certified clinical laboratory and used for comparison with the colorimetric response of the biosensor. RGB (red, green, and blue) image analysis was performed in a subset of samples to digitally characterize the chromatic response of the device. Results: Samples with preserved AChE activity showed a visible color shift associated with substrate hydrolysis, whereas samples with reduced or inhibited activity maintained darker blue-dominant tones. RGB analysis of human samples revealed significant associations between AChE activity and the R and G channels, supporting the ability of the platform to distinguish between chromatic patterns associated with different ranges of enzymatic activity. Conclusions: The proposed platform demonstrated the feasibility of translating a pH-based AChE assay into a portable paper-based format for semi-quantitative visual and RGB-assisted screening. Its evaluation in human samples demonstrated the feasibility of its use under field conditions as a proof-of-concept. Further studies are needed to optimize its analytical performance and validate its application in larger and more diverse populations. Full article

(This article belongs to the Section Environmental, Agricultural, and Food Biosensors)

► Show Figures

Graphical abstract

15 pages, 12446 KB

Open AccessArticle

A Robust Electrochemical Aptasensor Based on a AuNP/Chitosan Conductive Network for Saxitoxin Detection in Freshwater Samples

by Luyang Zhang, Zongyu Yan, Zaiyu Zhang, Ziran Wang and Guorui Zhao

Biosensors 2026, 16(9), 489; https://doi.org/10.3390/bios16090489 - 3 Sep 2026

Abstract

Saxitoxin (STX) is a highly potent marine biotoxin, and trace contamination in aquatic environments can pose serious risks to human health. Therefore, reliable detection of low-concentration STX is crucial for water safety monitoring. Here, we developed a robust electrochemical aptasensor based on a [...] Read more.

Saxitoxin (STX) is a highly potent marine biotoxin, and trace contamination in aquatic environments can pose serious risks to human health. Therefore, reliable detection of low-concentration STX is crucial for water safety monitoring. Here, we developed a robust electrochemical aptasensor based on a gold nanoparticle/chitosan (AuNP/CS) conductive network for STX detection in freshwater samples. The chitosan matrix provides a three-dimensional scaffold for aptamer immobilization, while interconnected AuNPs create efficient electron-transfer pathways across the sensing interface. This integrated architecture improves interfacial conductivity and supports stable target-induced aptamer recognition. The aptasensor exhibits a linear response from 1 to 1000 nM and a limit of detection of 0.74 nM, with an apparent dissociation constant K_d = 70.29 ± 29.2 nM, together with high batch-to-batch consistency and long-term stability, retaining 93% of its initial response after 25 days. In spiked freshwater samples, the aptasensor achieved recoveries ranging from 99.10% to 111.33%, demonstrating the practical potential of this platform for monitoring STX contamination in aquatic environments. Full article

(This article belongs to the Special Issue Aptamer-Based Biosensing: Innovations in Molecular Recognition, Signal Transduction, and Applications)

► Show Figures

Figure 1

17 pages, 5452 KB

Open AccessArticle

Mechanical Properties and Fabrication of Bioinspired Cactus Spine Microneedles

by Hongru Liu, Xiang Long, Qiumeng Sun, Shixiong Wu and Zhishan Yuan

Biosensors 2026, 16(9), 488; https://doi.org/10.3390/bios16090488 - 3 Sep 2026

Abstract

Microneedle-based transdermal drug delivery enables painless and efficient drug administration but is limited by insufficient mechanical strength and high insertion forces. Inspired by the efficient penetration capability of cactus spines, this study investigated the microstructure and biomechanics of natural cactus spines and bioinspired [...] Read more.

Microneedle-based transdermal drug delivery enables painless and efficient drug administration but is limited by insufficient mechanical strength and high insertion forces. Inspired by the efficient penetration capability of cactus spines, this study investigated the microstructure and biomechanics of natural cactus spines and bioinspired microneedles. Finite element analysis showed that a groove width of 50 μm produced the highest stress and strain. Solid bioinspired microneedles were fabricated by 3D printing, while dissolvable hyaluronic acid, chitosan, and gelatin microneedles were prepared using femtosecond laser-fabricated titanium molds and replica molding. Optimized laser parameters generated micropores approximately 500 μm deep. Mechanical tests showed insertion forces of 60–100 mN for solid microneedles, with the 50 μm groove design exhibiting the highest value. Among dissolvable microneedles, gelatin displayed the greatest mechanical strength, whereas hyaluronic acid demonstrated the best overall potential for transdermal drug delivery. Full article

(This article belongs to the Special Issue Recent Advances in Microneedle Array Electrodes in Biomedicine)

► Show Figures

Figure 1

23 pages, 5337 KB

Open AccessReview

Fetal Magnetocardiography Using Optically Pumped Magnetometers: A Literature Review

by Rok Hren, Urban Marhl, Tamás Dóczi, Erika Országh, Vojko Jazbinšek and Tilmann Sander

Biosensors 2026, 16(9), 487; https://doi.org/10.3390/bios16090487 - 2 Sep 2026

Abstract

Fetal magnetocardiography (fMCG) provides direct non-invasive assessment of fetal cardiac electrophysiology, enabling detailed evaluation of cardiac rhythm, conduction, and repolarization. However, the clinical adoption of conventional fMCG has been limited by its reliance on superconducting quantum interference device (SQUID) systems, which require cryogenic [...] Read more.

Fetal magnetocardiography (fMCG) provides direct non-invasive assessment of fetal cardiac electrophysiology, enabling detailed evaluation of cardiac rhythm, conduction, and repolarization. However, the clinical adoption of conventional fMCG has been limited by its reliance on superconducting quantum interference device (SQUID) systems, which require cryogenic cooling and specialized infrastructure. Optically pumped magnetometers (OPMs) have emerged as a promising cryogen-free alternative with the potential to broaden access to fetal electrophysiological assessment. This review summarizes the technological evolution and early clinical evaluation of OPM-based fMCG through an analysis of original in vivo human studies published up to June 2026. Twelve eligible studies were identified and synthesized narratively. Advances in sensor design, magnetic shielding, acquisition strategies, and signal-processing algorithms have enabled SQUID-comparable signal quality and cardiac interval measurements while substantially reducing cryogenic and infrastructure requirements. OPM-fMCG has demonstrated the potential to assess fetal cardiac time intervals, heart rate variability, fetal movement, and clinically important arrhythmias, including congenital long QT syndrome, atrioventricular block, and supraventricular and ventricular tachyarrhythmias. However, the available evidence remains dominated by small, single-centre studies, with relatively few fetuses affected by clinically significant arrhythmias. Prospective multicenter clinical validation, protocol standardization, independent replication, and regulatory evaluation are therefore required before OPM-fMCG can be integrated into routine diagnostic pathways for pregnancies requiring advanced fetal electrophysiological assessment. Full article

(This article belongs to the Special Issue Biosensors for Physiological Signal Monitoring)

► Show Figures

Figure 1

25 pages, 4106 KB

Open AccessArticle

Wearable and Invisible ECG Quality and Usability Assessment in Cockpit Monitoring

by Mariangela Pinnelli, Ana Sofia Antunes Calado, Tiago Filipe Rodrigues Fernandes, Paulo Sérgio de Brito André, Emiliano Schena, Carlo Massaroni and Hugo Plácido da Silva

Biosensors 2026, 16(9), 486; https://doi.org/10.3390/bios16090486 - 2 Sep 2026

Abstract

Continuous physiological monitoring can support pilot-state assessment, but routine cockpit use requires sensing approaches that are both unobtrusive and physiologically reliable. Wearable ECG (wECG) provides stable cardiac recordings through skin-contact electrodes, whereas cockpit-integrated invisible ECG (iECG) can reduce user burden by acquiring signals [...] Read more.

Continuous physiological monitoring can support pilot-state assessment, but routine cockpit use requires sensing approaches that are both unobtrusive and physiologically reliable. Wearable ECG (wECG) provides stable cardiac recordings through skin-contact electrodes, whereas cockpit-integrated invisible ECG (iECG) can reduce user burden by acquiring signals through instrumented controls. However, iECG depends on intermittent hand contact and may show incomplete ECG morphology even when cardiac timing information is still preserved. This study proposes a window-based framework to assess the quality and task-specific usability of simultaneous wECG and iECG acquired during simulated flight. ECG data were collected in an Airbus A320 simulator from 14 volunteers, including experienced pilots and novices. The framework combines contact availability, R-peak reliability, PQRST morphology, and complementary signal quality indices into graded usability classes for heart rate (HR)-oriented monitoring. The iECG channel remained accessible for most of the analyzed recording time, with 93.8% of windows showing full or partial contact. Several windows classified as low quality by individual SQIs were retained as HR-usable when contact and R-peak timing remained reliable, indicating that single-metric rejection can be overly conservative for external-contact ECG. HR agreement supported the physiological relevance of the proposed classes: concordant wECG–iECG windows showed a mean absolute error (MAE) of 1.1 bpm, compared with 7.1 bpm for discordant windows. Bland–Altman analysis for iECG windows classified as usable for HR estimation showed a small mean bias of 1.4 bpm. These findings indicate that incomplete ECG morphology does not necessarily imply loss of HR usability, and that contact-aware, task-specific classification can preserve useful physiological information from unobtrusive cockpit interfaces. Full article

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

► Show Figures

Figure 1

23 pages, 3452 KB

Open AccessArticle

A Portable Colorimetric Biosensor Platform for Urinary Colorectal Cancer Biomarker Testing in Low-Resource Settings

by Prashanthi Kovur, Scott MacKay, Songtian Bai, James Cook, Claudia Torres-Calzada, Dipanjan Bhattacharyya, Upasana Singh and David S. Wishart

Biosensors 2026, 16(9), 485; https://doi.org/10.3390/bios16090485 - 2 Sep 2026

Abstract

Early detection of colorectal cancer (CRC) is challenging in low-resource settings because access to colonoscopy and centralized laboratory testing is limited. Urine-based metabolite biomarkers offer a non-invasive alternative for CRC triage, but translating a laboratory assay into a point-of-care (PoC) system requires standardized [...] Read more.

Early detection of colorectal cancer (CRC) is challenging in low-resource settings because access to colonoscopy and centralized laboratory testing is limited. Urine-based metabolite biomarkers offer a non-invasive alternative for CRC triage, but translating a laboratory assay into a point-of-care (PoC) system requires standardized fluid handling, operator-independent timing, field-compatible reagents, and quantitative calibration. Here, we present a low-cost, semi-automated PoC platform integrating a validated, sequential, three-metabolite CRC-biomarker assay with robotic fluid handling, a motorized chromatographic module, an optical reader, Bluetooth electronics, and tablet-guided control. The platform measures urinary diacetylspermine and hippuric acid, with creatinine serving as a normalization reference, and reports absolute quantitative concentrations. Automated dilution, tube positioning, timed incubation, controlled column elution, and software-guided transfer reduce operator-dependent variation. Using pooled urine samples spiked at clinically relevant concentrations, the creatinine assay showed a strong quadratic response (0–50 mM, R² = 0.998), as did the diacetylspermine assay (0–4 μM, R² = 0.979), while the hippuric acid assay showed a linear response of R² = 0.989. The RGB sensor tracked the concentration-dependent trend observed with a laboratory microplate reader (R² = 0.968–0.999). Reagents reformulated as lyophilized or pre-weighed, vacuum-sealed kits withstood accelerated heat and humidity (45 °C/70% RH) testing and international shipping to the pilot site very well. At approximately USD 490 for the complete instrument (including tablet) and roughly USD 7.65 in consumables per screening test, the platform offers a practical, quantitative, and portable route for decentralized CRC screening. Full article

(This article belongs to the Special Issue Biosensors for Disease Analysis)

► Show Figures

Figure 1

17 pages, 2979 KB

Open AccessArticle

Monitoring EML4-ALK Biomarkers via a Microfluidic Assay for Treatment Efficacy Assessment

by Shaked Doron, Lev Brio, Matan Krasner, Efrat Barbiro-Michaely and Doron Gerber

Biosensors 2026, 16(9), 484; https://doi.org/10.3390/bios16090484 - 2 Sep 2026

Abstract

Monitoring prognostic biomarkers is essential for evaluating cancer treatment efficacy in real time. Here, we present a rapid, proof-of-concept microfluidic assay for cancer biomarker quantification and functional therapy evaluation. The assay requires only 5 µL of sample, eliminates tedious sample manipulation, and uses [...] Read more.

Monitoring prognostic biomarkers is essential for evaluating cancer treatment efficacy in real time. Here, we present a rapid, proof-of-concept microfluidic assay for cancer biomarker quantification and functional therapy evaluation. The assay requires only 5 µL of sample, eliminates tedious sample manipulation, and uses commercial antibodies to track both biomarker concentration and functional activity. We demonstrated the successful detection of VEGF and EML4-ALK proteins in both lung cancer cell culture supernatant and serum-spiked samples, achieving a detection sensitivity 15 times greater than standard ELISA using the same antibody pairs for the respective antigens. Crucially, we showcase the platform’s distinct applicability to functional assays by monitoring dynamic phosphorylation changes in EML4-ALK following treatment with the tyrosine kinase inhibitor alectinib, successfully capturing a significant, rapid decrease in phosphorylation levels. At this preclinical stage, the platform demonstrates analytical and functional feasibility for highly sensitive and rapid biomarker monitoring, providing a foundation for future validation in patient-derived ALK-positive samples for therapeutic-response assessment. Full article

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

► Show Figures

Figure 1

39 pages, 7001 KB

Open AccessReview

Microfluidic-Integrated CRISPR-Cas Biosensor for Marine Pollutant and Pathogen Monitoring: A Review

by Natalia Binti Ali, Yuting Xiao, Kuiyu Jin, Yixuan Wang and Youquan Zhao

Biosensors 2026, 16(9), 483; https://doi.org/10.3390/bios16090483 - 1 Sep 2026

Abstract

Marine ecosystems face escalating threats from heavy metals, harmful algal bloom toxins, pathogens, and antibiotic resistance genes, yet conventional detection methods remain laboratory-dependent and incapable of real-time, multiplexed field monitoring. CRISPR-Cas diagnostics, leveraging programmable Cas12a/Cas13a trans-cleavage for attomolar-level sensitivity, offers a transformative [...] Read more.

Marine ecosystems face escalating threats from heavy metals, harmful algal bloom toxins, pathogens, and antibiotic resistance genes, yet conventional detection methods remain laboratory-dependent and incapable of real-time, multiplexed field monitoring. CRISPR-Cas diagnostics, leveraging programmable Cas12a/Cas13a trans-cleavage for attomolar-level sensitivity, offers a transformative solution when integrated with microfluidic platforms that provide the automation and miniaturisation required for field deployment. This review systematically examines this emerging convergence across four marine target classes: heavy metals, biotoxins, pathogens, and resistance genes alongside integration architectures, signal readout strategies, and comparative performance benchmarking. We identify that only a small fraction of reported platforms have been validated in authentic seawater, with cross-class multiplexing, biofouling resistance during autonomous deployment, and regulatory standardisation remaining largely unaddressed. By synthesising this rapidly developing literature and articulating these unresolved challenges, this review provides a foundational reference and research agenda for translating microfluidic-CRISPR biosensors from laboratory proof-of-concept to operational marine environmental surveillance. Full article

(This article belongs to the Special Issue CRISPR/Cas-Based Biosensing Systems: Development and Applications—2nd Edition)

► Show Figures

Figure 1

25 pages, 843 KB

Open AccessReview

Nanocarbon as a Quantum Material for Biointerfaces and Magnetic Platforms in Theranostic Biomedicine in Oncology: A Critical Review

by Priscila M. Galdino, Barbara R. Geraldino, Nilséia A. Barbosa and Fernando M. Araújo-Moreira

Biosensors 2026, 16(9), 482; https://doi.org/10.3390/bios16090482 - 1 Sep 2026

Abstract

Nanostructured carbon materials are low-dimensional systems relevant to oncology biosensing, with their utility arising from an electronic structure coupled to defect and edge states, a charge-transfer behavior and optical response that report molecular binding, an interfacial chemistry governing contact with the analyte, and, [...] Read more.

Nanostructured carbon materials are low-dimensional systems relevant to oncology biosensing, with their utility arising from an electronic structure coupled to defect and edge states, a charge-transfer behavior and optical response that report molecular binding, an interfacial chemistry governing contact with the analyte, and, in selected cases, magnetic properties enabling manipulation and readout. In functional terms, these behaviors trace to specific quantum-relevant features—quantum confinement, edge and defect states, and the resulting size-dependent optical and charge-transfer responses—rather than to a generic quantum-material designation. This critical review treats nanocarbons as engineered biointerfaces whose performance is set by how the carbon surface behaves in biological fluid, how recognition chemistry is anchored, and how the binding event is transduced, with magnetic responsiveness, stability, reproducibility, and fabrication control as decisive constraints. The analysis separates three material classes—non-magnetic nanocarbon sensors, hybrid carbon–magnetic systems, and defect-associated or potentially metal-free magnetic carbons—while grading evidence as direct, adjacent, comparator-derived, or prospective. Directly, graphene, carbon nanotubes, carbon dots, graphene quantum dots, and magnetic carbon hybrids serve in electrochemical, optical and fluorescent, field-effect, and magnetic-assisted formats. Clinical translation, however, remains constrained by biofouling, protein-corona formation, matrix interference, unstable functionalization, batch variability, incomplete standardization, and scarce validation in real samples and patient cohorts. Metal-free or defect-associated magnetic carbons therefore warrant caution, remaining prospective platforms until the preservation of magnetic response, reproducible functionalization, matrix compatibility, safety, and measurable analytical advantage are directly demonstrated. Full article

(This article belongs to the Special Issue Nano-Carbons in Biosensors)

► Show Figures

Figure 1

16 pages, 6384 KB

Open AccessArticle

Interval-Level Validation of a Wearable Dry-Electrode ECG Biosensor Platform: A Proof-of-Concept Study

by Avshalom Shaffer, Daniel Possti, Yizhaq Shmayahu, Deganit Barak-Shinar, Roy Beigel, David Hochstein, Rona Haker, Yael Hanein, Hila Meiri, Oliana Vazhgovsky and Shai Tejman-Yarden

Biosensors 2026, 16(9), 481; https://doi.org/10.3390/bios16090481 - 1 Sep 2026

Abstract

Wearable dry-electrode electrocardiographic (ECG) systems may enable longer and more comfortable rhythm monitoring, but their interval-level measurement fidelity requires validation against reference acquisition systems. In this single-center proof-of-concept study, 20 participants (10 healthy volunteers and 10 cardiology patients) underwent simultaneous ECG recordings with [...] Read more.

Wearable dry-electrode electrocardiographic (ECG) systems may enable longer and more comfortable rhythm monitoring, but their interval-level measurement fidelity requires validation against reference acquisition systems. In this single-center proof-of-concept study, 20 participants (10 healthy volunteers and 10 cardiology patients) underwent simultaneous ECG recordings with a U.S. Food and Drug Administration (FDA)-cleared wearable dry-electrode platform (X-trodes System M) and a wired reference system (MP150 with ECG100C module, Biopac Systems). Three-minute paired segments were recorded and underwent temporal synchronization, bandpass filtering, baseline correction, automated discrete-wavelet peak detection in NeuroKit2 (version 0.2.10), and standardized manual adjudication. After predefined exclusions for temporal alignment and P-wave detection quality, agreement was assessed in nine cardiac and ten healthy participants for RR intervals and in seven cardiac and eight healthy participants for P-to-R peak intervals. RR interval agreement was excellent in the healthy and cardiac cohorts, with a mean bias of 0.4 ± 3.1 ms and 0.1 ± 4.6 ms and mean absolute error (MAE) of 0.97 ms and 1.28 ms, respectively. Intraclass correlation coefficient (ICC) was over 0.99 for both cohorts. P-to-R peak interval agreement was strong, with an MAE of 1.76 ms and 7.14 ms and ICC of 0.96 and 0.98, respectively. These findings provide preliminary evidence of interval-level agreement for the X-trodes wearable dry-electrode ECG biosensor platform under controlled, short-duration daytime conditions. Because the matched interval pairs were clustered within a small number of participants, the findings should be regarded as proof-of-concept evidence supporting larger ambulatory validation studies rather than as definitive clinical validation. Full article

(This article belongs to the Special Issue AI-Based Biosensors and Biomedical Imaging)

► Show Figures

Figure 1

23 pages, 3399 KB

Open AccessArticle

Behavioral Dynamics of Zebrafish Under Hydrodynamic Stimuli Induced by Magnetic Microactuator in Microfluidics

by Dineshkumar Loganathan, Pu-Hsiang Wang and Chia-Yuan Chen

Biosensors 2026, 16(9), 480; https://doi.org/10.3390/bios16090480 - 1 Sep 2026

Abstract

Behavioral investigation in zebrafish is essential for understanding adaptive responses, where learning represents a key process influenced by external stimuli. The applied stimulus plays a critical role in shaping such responses, therefore making physiologically relevant stimulation strategies important. Hydrodynamic stimuli represent one such [...] Read more.

Behavioral investigation in zebrafish is essential for understanding adaptive responses, where learning represents a key process influenced by external stimuli. The applied stimulus plays a critical role in shaping such responses, therefore making physiologically relevant stimulation strategies important. Hydrodynamic stimuli represent one such modality, providing a natural and non-invasive means of activating mechanosensory responses in aquatic organisms, thereby enabling behavioral manipulation in microfluidic environments. To address this, a microfluidic assay was developed to generate controlled hydrodynamic environments by employing multiple S-shaped magnetic microactuators (SMMAs). Further, motions of these SMMAs were independently controlled to produce spatiotemporally varying vortical flow fields, enabling flow-induced transportation of zebrafish larvae. Flow dynamics were characterized by employing micro-particle image velocimetry (µPIV). Compared to the control condition, transportation time under microactuator-assisted guidance was significantly reduced, with a maximum improvement of 94.3% observed for a representative target zone. Building on this validated transport capability, training-dependent behavioral adaptation was quantified using latency under repeated hydrodynamic-training, where a reduction of 82.7% was achieved. Post-training assessment further demonstrated short-term retention of the acquired behavioral response followed by progressive extinction. These findings demonstrate that the proposed paradigm serves as a foundational behavioral assay leveraging hydrodynamic cues for studying adaptive responses in microfluidics. Full article

(This article belongs to the Section Environmental, Agricultural, and Food Biosensors)

► Show Figures

Figure 1

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