Vasa Radonic

A whole bacterial cell immunosensing method based on extended-gate field-effect transistor (EGFET) is presented for the first time in this report. Herein, a commercial n-type MOSFET is modified into an EGFET by extending the gate to the biosensing layer via a simple signal line. As a biosensing layer, a gold electrode functionalized with antibodies is fabricated to confer specificity to Escherichia coli (E. coli). The transistor’s transfer and output characteristics I-V curves were acquired with a commercial parameter analyzer, and the sensor response is characterized by observing how the channel current counters to different concentrations of bacteria bound to the biosensing layer. The EGFET immunosensor demonstrates the detection limit of ≤1.5 CFU mL^-1, linearity (R² > 0.98) within the range of concentrations from 1.5×10¹ to 1.5×10⁸ CFU mL^-1. The specificity is confirmed with two non-target bacteria species (Klebsiella aerogenes and Bacillus subtilis). The developed whole-cell, label-free immunosensor has the potential to be adapted as a point-of-care diagnostic device as a practical, low-cost alternative to conventional laboratory-bound methods.

The controlled assembly of high-quality Ti3C2Tx MXene monolayers remains a key challenge for their integration into electronic and optoelectronic devices. Here, we report a green and scalable route for the fabrication of morphology-controlled MXene monolayers by combining minimally intensive layer delamination (MILD) synthesis with a modified Langmuir-Blodgett (MLB) technique. The MLB method provides a simple, cost-effective, and environmentally friendly platform for transferring Ti3C2Tx monolayers from the air-water interface onto SiO2/Si substrates without the need for complex instrumentation. By systematically tuning key processing parameters such as ultrasonication time, subphase pH, and spreading volume, precise control over sheet size, well-defined morphology, uniformly distributed and flat sheets was achieved. The morphology, structure, chemical, and optical properties of Ti3C2Tx sheets were investigated using atomic force microscopy (AFM), scanning electron microscopy (SEM), X-Ray Difraction (XRD), Raman spectroscopy, and ultraviolet–visible spectrophotometry (UV-Vis), confirming the formation of high-quality monolayers and their controlled assembly. Bottom-gated field-effect transistor (FET) devices fabricated from the resulting Ti3C2Tx monolayer sheets exhibit high electrical conductivity (up to ~8700 S/cm) with n-type carrier transport and electron mobilities in the range of 10-30 cm2/V·s under ambient conditions, with a device yield exceeding 70%. These results demonstrate reproducibility and stable performance, highlighting the suitability of this approach for nanoelectronic applications. Notably, systematic studies integrating green synthesis, scalable interfacial assembly, and morphology control of MXene monolayers remain limited. This work provides a versatile and environmentally friendly strategy for engineering high-quality assembly of MXene monolayers, paving the way for their broader application in next-generation electronic, sensing, and energy devices.

Biosensors as advanced analytical tools have found various applications in food safety, healthcare, and environmental monitoring in rapid and specific detection of target analytes in small liquid samples. Up to now, planar electrochemical electrodes have shown the highest potential for biosensor applications due to their simple and compact construction and cost-effectiveness. Although a number of commercially available electrodes, manufactured from various materials on different substrates, can be found on the market, their high costs for single use and low reproducibility persist as major drawbacks. In this study, we present an innovative, cost-effective approach for the rapid fabrication of electrodes that combines lamination of 24-karat gold leaves with low-cost polyvinyl chloride adhesive sheets followed by laser ablation. Laser ablation enables the creation of electrodes with customizable geometries and patterns with microlevel resolutions. The developed electrodes are characterized by cyclic voltammetry and electrochemical impedance spectroscopy, scanning electronic microscopy, and 3D profiling. To demonstrate the manufacturing and biosensing potential, different geometries and shapes of electrodes were realized as the electrochemical transducing platform and applied for the realization of magnetic bead (MB)-labeled biosensors for quantitative detection of food-borne pathogens of Salmonella typhimurium (S. typhimurium) and Listeria monocytogenes (L. monocytogenes).

Biosensors are innovative and cost-effective analytical devices that integrate biological recognition elements (bioreceptors) with transducers to detect specific substances (biomolecules), providing a high sensitivity and specificity for the rapid and accurate point-of-care (POC) quantitative detection of selected biomolecules. In the meat production chain, their application has gained attention due to the increasing demand for enhanced food safety, quality assurance, food fraud detection, and regulatory compliance. Biosensors can detect foodborne pathogens (Salmonella, Campylobacter, Shiga-toxin-producing E. coli/STEC, L. monocytogenes, etc.), spoilage bacteria and indicators, contaminants (pesticides, dioxins, and mycotoxins), antibiotics, antimicrobial resistance genes, hormones (growth promoters and stress hormones), and metabolites (acute-phase proteins as inflammation markers) at different modules along the meat chain, from livestock farming to packaging in the farm-to-fork (F2F) continuum. By providing real-time data from the meat chain, biosensors enable early interventions, reducing the health risks (foodborne outbreaks) associated with contaminated meat/meat products or sub-standard meat products. Recent advancements in micro- and nanotechnology, microfluidics, and wireless communication have further enhanced the sensitivity, specificity, portability, and automation of biosensors, making them suitable for on-site field applications. The integration of biosensors with blockchain and Internet of Things (IoT) systems allows for acquired data integration and management, while their integration with artificial intelligence (AI) and machine learning (ML) enables rapid data processing, analytics, and input for risk assessment by competent authorities. This promotes transparency and traceability within the meat chain, fostering consumer trust and industry accountability. Despite biosensors’ promising potential, challenges such as scalability, reliability associated with the complexity of meat matrices, and regulatory approval are still the main challenges. This review provides a broad overview of the most relevant aspects of current state-of-the-art biosensors’ development, challenges, and opportunities for prospective applications and their regular use in meat safety and quality monitoring, clarifying further perspectives.

Microfluidic technology, which involves the manipulation of fluids in microchannels, faces challenges in channel design and performance optimization due to its complex, multi-parameter nature. Traditional design and optimization approaches usually rely on time-consuming numerical simulations, or on trial-and-error methods, which entail high costs associated with experimental evaluations. Additionally, commonly used optimization methods require many numerical simulations, and to avoid excessive computation time, they approximate simulation results with faster surrogate models. Alternatively, machine learning (ML) is becoming increasingly significant in microfluidics and technology in general, enabling advancements in data analysis, automation, and system optimization. Among ML methods, Bayesian optimization (BO) stands out by systematically exploring the design space, usually using Gaussian processes (GP) to model the objective function and guide the search for optimal designs. In this paper, we demonstrate the application of BO in the design optimization of the microfluidic systems, by enhancing the mixing performance of a micromixer with parallelogram barriers and a Tesla micromixer modified with parallelogram barriers. Micromixer models were made using Comsol Multiphysics software® and their geometric parameters were optimized using BO. The presented approach minimizes the number of required simulations to reach the optimal design, thus eliminating the need for developing a separate surrogate model for approximation of the simulation results. The results showed the effectiveness of using BO for design optimization, both in terms of the execution speed and reaching the optimum of the objective function. The optimal geometries for efficient mixing were achieved at least an order of magnitude faster compared to state-of-the-art optimization methods for microfluidic design. In addition, the presented approach can be widely applied to other microfluidic devices, such as droplet generators, particle separators, etc.

Biosensors are innovative and cost-effective analytical devices that integrate biological recognition elements (bioreceptors) with transducers to detect specific substances (biomolecules), providing high sensitivity and specificity for rapid and accurate Point-of-Care (POC) quantitative detection of selected biomolecules. In the meat production chain, their application has gained attention due to the increasing demand for enhanced food safety, quality assurance, food fraud detection and regulatory compliance demands. Biosensors can detect foodborne pathogens (Salmonella, Campylobacter, Shiga toxin-producing E. coli/STEC, L. monocytogenes), spoilage bacteria and indicators, contaminants (pesticides, dioxins, mycotoxins), antibiotics, antimicrobial resistance genes, hormones (growth promoters, stress hormones), metabolites (acute phase proteins as inflammation markers) at different modules along the meat chain, from livestock farming to packaging in farm-to-fork (F2F) continuum. By providing real-time data from the meat chain, biosensors enable early interventions, reducing health risks (foodborne outbreaks) associated with contaminated meat/meat products or substandard meat products. Recent advancements in micro and nanotechnology, microfluidics, and wireless communication have further enhanced the sensitivity, specificity, portability, and automation of biosensors, making them suitable for on-site, field applications. Integration of biosensors with blockchain and Internet of Things (IoT) systems allows acquired data integration and management, while integration with Artificial Intelligence (AI) and Machine Learning (ML) enables rapid data processing, analytics and input for risk assessment by competent authorities. This promotes transparency and traceability within the meat chain, fostering consumer trust and industry accountability. Despite biosensors’ promising potential, challenges such as scalability, reliability associated with the complexity of meat matrices and regulatory approval, are still the main challenges. This review provides a broad overview of the most relevant aspects of the current state-of-the-art biosensors` development, challenges and opportunities for prospective biosensors` application and its regular use in meat safety and quality monitoring and clarify further perspectives.

Although various sensors specifically developed for target analytes are available, affordable biosensing solutions with broad applicability are limited. In this study, a cost-effective biosensor for detecting human epidermal growth factor receptor 2 (HER2) was developed using custom-made gold leaf electrodes (GLEs). A novel strategy for antibody immobilization on a gold surface, for the first time mediated by protein L and HER2-specific antibody trastuzumab, was examined using commercial screen-printed gold electrodes and GLEs. A self-assembled monolayer of 11-mercaptoundecanoic acid (MUA) was formed on the gold surface, which was used to covalently immobilize protein L. Further binding of trastuzumab to the protein L was employed and HER2 detection was achieved through electrochemical impedance spectroscopy (EIS). The HER2 detection was examined in phosphate-buffered saline (PBS) and supplemented cell culture medium. The modified GLEs showed good specificity and high sensitivity of HER2 detection without any enrichment steps, achieving a limit of detection (LOD) of 1 ng mL^− 1 in PBS and 2.7 ng mL^− 1 in cell culture medium, making the proposed immunosensor a cost-effective and sensitive solution for detection in complex biological matrices.