Search Results (582)

Filamentous fungi are increasingly recognized as versatile biological platforms for the development of advanced (bio)sensing technologies, owing to their extensive secretory capacity, material-forming ability, and intrinsic bioelectrical activity. This review critically surveys recent progress in fungal-based sensing within a multiscale framework spanning molecular, material, computational, and ecological domains, with particular emphasis on developments reported over the past five years. Key advances involving secretome-derived biomolecules, mycogenic nanomaterials, mycelium-based living materials, and fungal electrophysiology are discussed alongside emerging approaches for environmental monitoring that integrate sensor networks, imaging platforms, and data-driven analytics. Collectively, these works demonstrate that fungal systems can enhance biosensor sensitivity, selectivity, and sustainability, while enabling unconventional paradigms of signal transduction, material-integrated sensing, and biologically mediated computation. At larger spatial and temporal scales, mycelial growth dynamics and electrical activity provide measurable responses to mechanical, chemical, and environmental perturbations, supporting early applications in wearable devices, structural materials, and ecosystem monitoring. Despite significant progress, challenges remain in reproducibility, long-term stability, mechanistic understanding, and scalable device integration. Overall, the evidence reviewed highlights filamentous fungi as biologically adaptive and ecologically embedded systems with substantial potential to support next-generation (bio)sensing technologies, while underscoring the need for integrative approaches that combine biological insight with materials science, electronics, and artificial intelligence. Full article

The sensitive detection of microRNA-21 (miR-21), a key biomarker for various cancers, is crucial for early diagnosis, yet conventional methods often face limitations in sensitivity and operational complexity. Here, we report a label-free biosensor based on a suspended graphene field-effect transistor (GFET) for the direct electrical detection of miR-21. The suspended architecture isolates the graphene channel from substrate-induced interference, resulting in enhanced carrier mobility and reduced electrical noise. After surface functionalization with a specific probe, the GFET demonstrated a clear concentration-dependent response to target miR-21. The binding events were transduced into a monotonic increase in relative resistance (ΔR/R₀) and a positive shift of the Dirac point (V_Dirac), achieving a detection limit in the femtomolar (fM) range. These results establish the suspended GFET as a highly sensitive and robust platform for quantifying nucleic acid biomarkers, holding significant potential for biomedical research and point-of-care diagnostics. Full article

Terahertz (THz)-based metasurface biosensors have garnered considerable interest owing to their strong electromagnetic (EM) resonance-based sensing methods. Nonetheless, the majority of published designs exhibit constrained optical transparency and angular sensitivity, hence limiting their integration with optoelectronic systems and reducing sensing reliability at oblique angles. This study introduces a graphene-based optically transparent terahertz metasurface that demonstrates wide-angle stability for biosensing applications to address these challenges. The proposed metasurface utilizes a patterned graphene resonator integrated with an optically transparent silicon dioxide (SiO₂) dielectric substrate and a conductive indium–tin–oxide (ITO) ground configuration, enabling efficient THz absorption at the resonant frequency while maintaining optical transparency. Due to its structural symmetry, the suggested structure exhibits polarization insensitivity and angular stability up to 60° for both transverse electric (TE) and transverse magnetic (TM) modes. Furthermore, the comprehensive operating mechanism is explained by impedance matching theory, surface current distribution, and analysis of electric field distributions. A thorough numerical analysis of the proposed metasurface was conducted by incorporating analytes with varying refractive indices using CST Microwave Studio, demonstrating its effective sensing capabilities, with a sensitivity of 0.69 THz/RIU and a quality factor of 24.67. A comparative examination with existing designs reveals that the proposed device, due to its optical transparency, angular stability, and high sensitivity, demonstrates significant potential for terahertz biosensing applications. Full article

Field-effect transistor (FET) biosensors enable label-free and real-time electrical transduction; however, their practical deployment is often constrained by the need for bulky benchtop instrumentation to provide stable biasing, low-noise readout, and data processing. Here, we report a portable extended-gate FET (EG-FET) integrated sensing system that consolidates the sensing interface, analog front-end conditioning, embedded acquisition/control, and user-side visualization into an end-to-end prototype suitable for on-site operation. The system couples a screen-printed Au extended-gate electrode to a MOSFET and employs a low-noise signal-conditioning chain with microcontroller-based digitization and real-time data streaming to a host graphical interface. As a proof-of-concept, enterohemorrhagic Escherichia coli O157:H7 was selected as the target. A bacteria-specific immunosensing interface was constructed on the Au extended gate via covalent immobilization of monoclonal antibodies. Measurements in buffered samples produced concentration-dependent current responses, and a linear calibration was experimentally validated over 10⁴–10¹⁰ CFU/mL. In specificity evaluation against three common foodborne pathogens (Staphylococcus aureus, Salmonella typhimurium, and Listeria monocytogenes), the sensor showed a maximum interference response of only 13% relative to the target signal (ΔI/ΔImax) with statistical significance (p < 0.001). Our work establishes a practical hardware–software architecture that mitigates reliance on benchtop instruments and provides a scalable route toward portable EG-FET sensing for rapid, point-of-need detection of foodborne pathogens and other biomarkers. Full article

Graphene oxide (GO) and reduced graphene oxide (rGO) have solidified their role as cornerstone nanomaterials in the pursuit of sustainable technology. This review synthesizes recent advances in harnessing the unique properties of GO and rGO such as their tunable surface chemistry and exceptional electrical conductivity for applications spanning environmental remediation and energy storage. In the environmental domain, they function as superior adsorbents and catalysts for the removal of hazardous pollutants. Concurrently, in the energy sector, their integration into supercapacitors and battery electrodes significantly enhances energy and power density. The adaptability of these materials also facilitates the creation of highly sensitive sensors and biosensors. However, the transition from laboratory research to widespread industrial application is hindered by challenges in scalable production, environmental health and safety concerns, and long-term stability. This review enhances the understanding of GO and rGO’s diverse applications and paves the way for future sustainable technologies in energy and environmental sectors. Full article

Yeast biosensors represent a promising biotechnological innovation for ensuring the safety and quality of fermented beverages such as beer, wine, and kombucha. These biosensors employ genetically engineered yeast strains to detect specific contaminants, spoilage organisms, or hazardous compounds during fermentation or the final product. By integrating synthetic biology tools, researchers have developed yeast strains that can sense and respond to the presence of heavy metals (e.g., lead or arsenic), mycotoxins, ethanol levels, or unwanted microbial metabolites. When a target compound is detected, the biosensor yeast activates a reporter system, such as fluorescence, color change, or electrical signal, providing a rapid, visible, and cost-effective means of monitoring safety parameters. These biosensors offer several advantages: they can operate in real time, are relatively low-cost compared to conventional chemical analysis methods, and can be integrated directly into the fermentation system. Furthermore, as Saccharomyces cerevisiae is generally recognized as safe (GRAS), its use as a sensing platform aligns well with existing practices in beverage production. Yeast biosensors are being investigated for the early detection of contamination by spoilage microbes, such as Brettanomyces and lactic acid bacteria. These contaminants can alter the flavor profile and shorten the product’s shelf life. By providing timely feedback, these biosensor systems allow producers to intervene early, thereby reducing waste and enhancing consumer safety. In this work, we review the development and application of yeast-based biosensors as potential safeguards in fermented beverage production, with the overarching goal of contributing to the manufacture of safer and higher-quality products. Nevertheless, despite their substantial conceptual promise and encouraging experimental results, yeast biosensors remain confined mainly to laboratory-scale studies. A clear gap persists between their demonstrated potential and widespread industrial implementation, underscoring the need for further research focused on robustness, scalability, and regulatory integration. Full article

Electric field-assisted local functionalization of materials is a resist-free technique generally applied at the nanoscale, which has been understood within the paradigm of the water meniscus. Using a home-made prototype the authors applied this technique at scales compatible with the biosensor industry (tens of microns). However, interpreting these results requires a different paradigm. The expansion of the oxidized region over time in two-dimensional materials under a localized electric field is modeled from first physical principles. Boltzmann statistics is applied to the oxyanion incorporation at the perimeter of the oxidized zone, and a new general relation between oxide radius and time is formulated. It includes the reduction in the energy barrier due to the field effect and its dependence on the oxide radius. To gain insight into this dependence whatever the layers structure, 2D material involved, or electrical operating conditions, simple structures based on multilayer stacks representing the main constituents are proposed, where the Poisson equation is solved using finite element calculations. This enables to derive energy barriers for oxyanion incorporation at varying spot radii which are consistent with those resulting from fitting experimental data. The reasonable agreement obtained provides researchers with a new tool to predict the evolution of local functionalization of 2D layers as a function of the following fabrication parameters: time, applied voltage, and relative humidity, solely based on materials properties. Full article

Recent studies show that titanium (Ti)-based alloys combine established mechanical strength, corrosion resistance, and biocompatibility with emerging electrical and electrochemical properties relevant to bioelectronics. The main goal of the present manuscript is to give a wide-ranging overview on the use of Ti-alloys in electronics and biomedicine, focusing on a comprehensive analysis and synthesis of the existing literature to identify gaps and future directions. Concurrently, the identification of possible correlations between the effects of the manufacturing process, alloying elements, and other degrees of freedom influencing the material characteristics are put in evidence, aiming to establish a global view on efficient interdisciplinary efforts to realize high-added-value smart devices useful in the field of biomedicine, such as, for example, implantable apparatuses. This review mostly summarizes advances in surface modification approaches—including anodization, conductive coatings, and nanostructuring that improve conductivity while maintaining biological compatibility. Trends in applications demonstrate how these alloys support smart implants, biosensors, and neural interfaces by enabling reliable signal transmission and long-term integration with tissue. Key challenges remain in balancing electrical performance with biological response and in scaling laboratory modifications for clinical use. Perspectives for future work include optimizing alloy composition, refining surface treatments, and developing multifunctional designs that integrate mechanical, biological, and electronic requirements. Together, these directions highlight the potential of titanium alloys to serve as foundational materials for next-generation bioelectronic medical technologies. Full article

Non-invasive glucose monitoring remains a significant challenge in diabetes management, with existing approaches often limited by poor accuracy, high cost, or patient discomfort. Microwave-based biosensors offer a promising label-free alternative by exploiting the dielectric contrast between glucose and water. This paper presents a compact, dual-band concentric square-shaped split-ring resonator (SRR-type) biosensor fabricated on a low-cost FR-4 substrate for aqueous glucose detection. The sensor leverages electric field confinement in inter-ring gaps to transduce glucose-induced permittivity changes into measurable shifts in resonance frequency and reflection coefficient. Experimental results demonstrate a linear, monotonic response across the clinical range up to 250 mg/dL, with a frequency-domain sensitivity of 1.964 MHz/(mg/dL) and amplitude-domain sensitivity of 0.0332 dB/(mg/dL), achieving high coefficients of determination (R² = 0.9956 and 0.9927, respectively). The design achieves a normalized size of 0.137 λ_g², combining high sensitivity and compact size within a scalable platform. Operating in the UWB-adjacent band (2.76–3.25 GHz), the proposed biosensor provides a practical, reproducible, and PCB-compatible solution for next-generation label-free glucose monitoring. Full article

A piezoelectric ultrasonic transducer has been developed to detect flow rate, occlusion, and bubble formation in a portable peritoneal dialysis system. This transducer works by utilizing the piezoelectric effect to convert electrical energy into ultrasonic waves and detect the reflected waves through the tube wall. In addition, organic thin film transistors (OTFTs) were tested at annealing temperatures of 75 °C, 100 °C, and 125 °C to evaluate the effect of temperature on mobility and on/off ratio. The best results were obtained at 100 °C with a mobility of 0.816 cm²/Vs and an on/off ratio of 1.4 × 10³ correlated with grain size. This study aims to report the fabrication process and initial characterization of the OTFT device as a first step towards the development of a portable biosensor that can be integrated into a point-of-care system. The transducer is designed for use in PeritoCare^® (Bangi, Malaysia), a portable peritoneal dialysis system developed by Universiti Kebangsaan Malaysia (UKM). The integration of piezoelectric transducers and OTFTs into the PeritoCare^® system enables the development of a more flexible, efficient, and mobile peritoneal dialysis system for young, active end-stage renal disease (ESRD) patients. Full article

Sensors in plant and crop monitoring play a key role in improving agricultural efficiency by enabling the collection of data on environmental conditions, soil moisture, temperature, sunlight, and nutrient levels. Traditionally, wide-scale wireless sensor networks (WSNs) gather this information in real-time, supporting the optimization of cultivation processes and plant management. Our paper proposes a novel “plant-to-machine” interface, which uses a plant-based biosensor as a primary data source. This model allows for direct monitoring of the plant’s physiological parameters and environmental interactions via Electrical Impedance Spectroscopy (EIS), aiming to reduce the reliance on extensive sensor networks. We present simple data-gathering hardware, a non-invasive single-wire connection, and a machine learning-based framework that supports the automatic analysis and interpretation of collected data. This approach seeks to simplify monitoring infrastructure and decrease the cost of digitizing crop monitoring. Preliminary results demonstrate the feasibility of the proposed model in monitoring plant responses to sunlight exposure. Full article

Impedance biosensors are manufactured on glass slides using a semiconductor process to monitor cell growth and cell–drug reactions in real time, and the results are compared with biological assay results to confirm the validity of impedance measurement method. Approximately 10,000 cells per well were cultured for 48 h, after which 6.67 μg/mL puromycin was injected to observe apoptosis over the following 48 h. A frequency sweep from 1 kHz to 1 MHz was performed to determine the optimal frequency range, identifying 367–440 kHz as the most sensitive for detecting impedance changes. Impedance was measured every 10 min for 96 h. Capacitance gradually increased during cell proliferation, while after drug administration, a transient increase occurred within 9 h, followed by a rapid decline, indicating cell death within 24 h. The sensor utilized Electrical Cell–substrate Impedance Sensing (ECIS) to detect real-time changes in cell status without the need for staining or destruction. Comparison with conventional biological assays such as MTS and FACS confirmed that the impedance biosensor provided higher sensitivity and quantitative accuracy in monitoring both cell proliferation and apoptosis. This study demonstrates that the developed biosensor enables label-free, non-invasive, and continuous monitoring of cellular behaviors with acceptable coincidence with 3 different biological assay results. Impedance biosensor presents a promising alternative to conventional biological assays and offers potential applications in drug screening, cytotoxicity evaluation, and real-time biological monitoring. Full article

In recent years, the amount of mercury discharged by human activities has continued to increase. Most of the mercury in surface water settles into the sediment, where it can be directly or indirectly transformed into mercury ion (Hg²⁺) compounds (such as dimethylmercury) under the action of microorganisms. Hg²⁺ display high toxicity and bioaccumulation in food, such as fish and rice, and thus the contamination of mercury ion is a serious concern for human health. Practical Hg²⁺ detection methods are usually limited by the sensitivity and selectivity of the used methods, such as colorimetric determination and fluorescence biosensor based on the solution phase. Therefore, it is urgent to develop Hg²⁺ detection methods in the practical environment with high sensitivity and selectivity. DNA is low-cost, relatively stable, and has been used for different fields. In this study, DNA for Hg²⁺detection was absorbed on the surface of single-walled carbon nanotubes (SWNTs) by using 1,5-diaminonaphthalene (DAN) based on field-effect transistor (FET) biosensors. The interaction between DNA and Hg²⁺ can be directly converted into electrical signals based on the SWNTs biosensors. The experimental results showed that the limit of detection (LOD) of Hg²⁺ without the phase-locked amplifier was about 42.6 pM. The function of the phase-locked amplifier is to achieve fast detection of the biosensor with strong anti-noise ability. Intriguingly, the sensitivity of the biosensor combined with a phase-locked amplifier to detect Hg²⁺ was further improved to be 5.14 pM compared with some current methods of biosensors. Furthermore, this biosensor has an excellent selectivity and practical detection in tap water, which demonstrates its high performance and low cost in practical application in Hg²⁺ detection. These results show this method for Hg²⁺ detection using SWNTs biosensors with a phase-locked amplifier is promising. Full article

Accurate, non-invasive glucose monitoring remains a major challenge in biomedical sensing. We present a high-sensitivity planar microwave biosensor that progresses from a 2-cell hexagonal array to an 8-cell hexagonal array, and finally to a 16-cell double-honeycomb (DHC-CSRR) architecture to enhance field confinement and resonance strength. Full-wave simulations using Debye-modeled glucose phantoms demonstrate that the optimized 16-cell array on a Rogers RO3210 substrate substantially increases the electric field intensity and transmission response |S₂₁| sensitivity compared with FR-4 and previous multi-CSRR designs. In vitro measurements using pharmacy-grade glucose solutions (5–25%) and saline mixtures with added glucose, delivered through an acrylic channel aligned to the sensing region, confirm the simulated trends. In vivo, vector network analyzer (VNA) tests were conducted on four human subjects (60–150 mg/dL), comparing single- and dual-finger placements. The FR-4 substrate (${\mathsf{\epsilon }}_{\mathrm{r}}$ = 4.4) provided higher frequency sensitivity (2.005 MHz/(mg/dL)), whereas the Rogers RO3210 substrate (${\mathsf{\epsilon }}_{\mathrm{r}}$ = 10.2) achieved greater amplitude sensitivity (9.35 × 10⁻² dB/(mg/dL)); dual-finger contact outperformed single-finger placement for both substrates. Repeated intra-day VNA measurements yielded narrow 95% confidence intervals on |S₂₁|, with an overall uncertainty of approximately ±0.5 dB across the tested glucose levels. Motivated by the larger |S₂₁| response on Rogers, we adopted amplitude resolution as the primary metric and built a compact prototype using the AD8302-EVALZ with a custom 3D-printed enclosure to enhance measurement precision. In a cohort of 31 participants, capillary blood glucose was obtained using a commercial glucometer, after which two fingers were placed on the sensing region; quadratic voltage-to-glucose calibration yielded R² = 0.980, root–mean–square error (RMSE) = 2.316 mg/dL, overall accuracy = 97.833%, and local sensitivity = 1.099 mg/dL per mV, with anthropometric variables (weight, height, age) showing no meaningful correlation. Clarke Error Grid Analysis placed 100% of paired measurements in Zone A, indicating clinically acceptable agreement with the reference meter. Benchmarking against commercial continuous glucose monitoring systems highlights substrate selection as a dominant lever for amplitude sensitivity and positions the proposed fully non-invasive, consumable-free architecture as a promising route toward portable RF-based glucose monitors, while underscoring the need for larger cohorts, implementation on flexible biocompatible substrates, and future regulatory pathways. Full article

The demand for low-cost, portable, and sensitive analytical devices has fueled the development of 3D-printed biosensors. This study evaluates the effect of silk fibroin incorporation on the electrical properties of graphite-PLA electrodes manufactured via 3D printing. Electrochemical Impedance Spectroscopy (EIS) method was utilized to assess capacitive–resistive behavior under dry conditions, and with PBS buffer, at fibroin concentrations of 0%, 0.04%, 0.4%, and 4%. Fibroin modulated impedance magnitude values without a clear trend, indicating the presence of additional influencing factors. The results promote better understanding of biofunctionalization effects in 3D-printed electrodes and support their potential for biomedical, environmental, and industrial sensing applications. Full article