Biosensors-Basel最新文献

In recent years, polymer-mediated signal amplification has drawn wide attention in bioelectronic sensing. With the rapid progress of biosensing and flexible electronics, polymers with excellent electron-ion transport properties, tunable molecular structures, and good biocompatibility have become essential materials for enhancing detection sensitivity and interfacial stability. However, current sensing systems still face challenges such as signal attenuation, surface fouling, and multi-component interference in complex biological environments, limiting their use in medical diagnosis and environmental monitoring. This review summarizes the progress of conductive polymers, molecularly imprinted polymers, hydrogels, and composite polymers in medical diagnosis, food safety, and environmental monitoring, focusing on their signal amplification mechanisms and structural optimization strategies in electronic transport regulation, molecular recognition enhancement, and antifouling interface design. Overall, polymers improve detection performance through interfacial electronic reconstruction and multidimensional synergistic amplification, offering new ideas for developing highly sensitive, stable, and intelligent biosensors. In the future, polymer-based amplification systems are expected to expand in multi-parameter integrated detection, long-term wearable monitoring, and in situ analysis of complex samples, providing new approaches to precision medicine and sustainable environmental health monitoring.

Background/objectives: Nanoparticles have emerged as indispensable tools in modern biomedicine, enabling precise diagnostics, targeted therapy, and controlled drug delivery. Despite their rapid progress, the translation of nanoparticle-based systems critically depends on the ability to detect, quantify, and track them across complex biological environments. Over the past two decades, a wide spectrum of detection modalities has been developed, encompassing optical, magnetic, acoustic, nuclear, cytometric, and mass spectrometric principles. Yet, no comprehensive framework has been established to compare these methods in terms of sensitivity, spatial resolution, and clinical applicability.

Methods: Here we show a systematic analysis of all broadly applicable nanoparticle detection strategies, outlining their mechanisms, advantages, and drawbacks, and providing illustrative examples of practical applications.

Results: This comparison reveals that each modality occupies a distinct niche: optical methods offer high sensitivity but limited penetration depth; magnetic and acoustic modalities enable repeated non-invasive tracking; nuclear imaging ensures quantitative, whole-body visualization; and invasive biochemical or histological assays achieve ultimate detection limits at the cost of tissue integrity. These findings redefine how each technique contributes to nanoparticle biodistribution and mechanistic studies, clarifying which are best suited for translational and clinical use.

Conclusions: Placed in a broader context, this review bridges fundamental nanotechnology with biomedical applications, outlining a unified methodological framework that will guide the rational design, validation, and clinical implementation of nanoparticle-based therapeutics and diagnostics. By synthesizing the field into a single comparative framework, it also provides an accessible entry point for newcomers in nanotechnology and related biomedical sciences.

The West Nile Virus (WNV), transmitted by Culex mosquitoes as a major vector, has been reported worldwide. Also, West Nile neuroinvasive disease (WNND) caused by WNV lineage 1a and 2 neuroinvasive infections has been constantly reported with high fatality rates. Nevertheless, there are no treatments and vaccinations, so diagnosis in the early stages is important. Recently, a molecular diagnostic technique using DNA endonuclease-targeted CRISPR trans reporter (DETECTR) with the CRISPR-Cas12a system integrated with isothermal nucleic acid amplification has newly emerged. In this study, we designed a 2-Step WNV DETECTR with reverse transcription-recombinase polymerase amplification (RT-RPA) for rapid and sensitive WNV diagnosis. It successfully detected down to 1.0 × 10² RNA copies for both WNV lineage 1a and 2 with demonstrating similar sensitivity to qRT-PCR without cross-reactivity to other viruses. Additionally, we designed a 1-Step WNV DETECTR, incorporating all processing steps into a single tube, capable of detecting down to 1.0 × 10³ RNA copies for both lineages. Furthermore, we developed a more streamlined method, the 1-Step with Filter WNV DETECTR, which achieved detection limits comparable to the 2-Step method, while reducing the processing time by 5 min. This study also explored the potential of the Punch-it™ NA-Sample Kit as an efficient alternative lysis method by comparing the detection differences across various lysis methods. Through this method, we achieved rapid and simple amplification and detection processes suitable for field diagnostics with high specificity and sufficient sensitivity. Therefore, DETECTR methods presented themselves as promising alternatives to conventional diagnostic tools, potentially overcoming financial and technical constraints in diverse medical settings.

Alzheimer's Disease (AD) is one of the most commonly seen neurodegenerative disorders, where early detection of its biomarkers is crucial for effective management. Conventional diagnostic methods are often expensive, time-consuming, and highly complex, which highlights an urgent need for point-of-care biosensing technology. In this work, we developed assays on three-dimensional (3D) graphene foam electrodes by functionalising them with a 1-Pyrenebutyric acid N-hydroxysuccinimide ester (Pyr-NHS) to enable effective antibody immobilisation for the detection of amyloid beta peptides (Aβ42 and Aβ40), key biomarkers for AD. Pyr-NHS linkers were used for stable functionalisation, followed by binding with Aβ42 and Aβ40 antibodies, and then bovine serum albumin (BSA) was employed as a blocking agent to minimise non-specific bindings on the electrode surface. Differential Pulse Voltammetry (DPV) measurements showed satisfactory stability over 12 days (RDS upper limit was <10%) and highly sensitive and specific detection of Aβ42 and Aβ40, with insignificant interference of tau217 protein. The biosensor exhibited a low limit of detection (LOD) with 252 aM for Aβ42 and 395 aM for Aβ40, covering 0.125 fM-1 nM and 0.125 fM-100 pM linear ranges, respectively. Further validation was conducted on spiked-diluted human plasma. This excellent analytical performance was attributed to the stable Pyr-NHS functionalisation, the 3D graphene foam enabling superior conductivity and a larger surface area on the working electrode, and the optimisation of antibody concentration for immobilisation. These promising results suggest that 3D graphene foam-based biosensors have considerable potential for early detection of AD biomarkers and developing cost-effective, portable, and reliable point-of-care devices.

The development of non-invasive sensors for individualised plant monitoring has become essential in smart farming to increase crop production. However current approaches are focused on the measurement of soil parameters instead, which cannot provide direct information about plant health. Moreover, equipment used for the direct monitoring of plant health are costly with complex operation, hindering their use by the wider community of farmers. This work reports for the first time the development of a flexible and highly transparent sensor, based on thin conductive PEDOT:PSS/PDMS hybrid films directly deposited onto leaves. The films were fabricated by aerosol deposition and could operate under two different modes. The first mode is used for the determination of plant dryness and concentration of ions. The second mode is used as a triboelectric generator to generate up to 7.2 µW cm^-2 electrical power through the friction of the sensors with a leaf. The device was assembled using a low-cost (GBP < 70) microcontroller incorporating environmental sensors, and an intuitive interface was designed for operation. The final sensor could determine the ionic strength at the millimolar level by means of the impedance of electrodes. This performance allowed the study of differences in ionic content and water availability in tomato leaves during day-night cycles. The high stability of the sensors also allowed the long-term monitoring of plant health. Using this technology, a decrease in the leaf ionic strength due to the lack of electrolytes was observed after watering with deionised water for 2 days. Upon supplementation with fertiliser, the recorded ionic strength and leaf water content were similar to the original values prior to the use of DI water, demonstrating the applicability of the device in the early detection of stress factors that could decrease crop production.

Contemporary biomedical diagnostics increasingly demand high sensitivity for pathogen detection and real-time health monitoring. In response to these requirements, screen-printed electrochemical sensors (SPEs) have emerged as a practical analytical platform owing to their low cost, portability, and compatibility with point-of-care and wearable systems. In the recent past, nanomaterials in two-dimensional format, especially MXenes, have gained much interest due to their high electrical conductivity, controllable surface chemistry, and biocompatibility, which can improve the performance and applicability of SPEs. The current review concentrates on the latest developments between 2020 and 2025, providing a critical assessment of research employing MXene-based nanomaterials for the modification and development of screen-printed electrode platforms. We provide an overview of fabrication techniques, printing methods, and surface modification methods, and proceed with an analysis of the electrochemical performance of MXenes and MXene-based heterostructures. Lastly, contemporary issues are considered, and opinions are suggested to facilitate the translation of MXene-functionalized SPEs to real biomedical diagnosis solutions.

(1) Background: This study aims to explore the changes in urinary metabolomic profile among trained young males following acute intermittent rowing training (AIRT), and to identify potential urinary biomarkers associated with exercise-induced muscle damage (EIMD). (2) Methods: 22 trained young males were recruited to perform AIRT. The changes in blood biochemical indexes associated with EIMD were analyzed. EIMD occurrence was evaluated using blood biochemical indexes, muscle function, and pain assessment. The changes in urinary metabolites were determined using untargeted metabolomic analysis. (3) Results: Four blood biochemical indices, including creatine kinase, lactate dehydrogenase, creatine kinase-MB, and hydroxybutyrate dehydrogenase, were significantly elevated immediately after AIRT. Furthermore, an obvious immune response appeared, and countermovement jump performance significantly decreased. Among 384 urinary metabolites, 33 were significantly upregulated, and 12 were downregulated immediately after AIRT. Upregulated metabolites were mainly involved in phenylacetate metabolism, ammonia recycling, the urea cycle, and glutathione metabolism. Four potential urinary biomarkers were identified, including 2'-Deoxycytidine, cytosine, Phenylacetaldehyde, and Pyridoxamine. (4) Conclusions: AIRT induced EIMD in all participants and significantly altered urinary metabolite profiles. The changes in urinary metabolites and pathways were due to the metabolic adaptation to oxidative stress, inflammatory responses, and ammonia metabolism imbalance. The selected four potential urinary biomarkers provide important evidence for the further development of a non-invasive, urine-based method for the immediate assessment of EIMD.

The four serotypes of dengue virus (DENV), types 1 to 4 (DENV-1 to DENV-4), exhibit approximately 60% identity in the encoded amino acid residues of viral proteins. Reverse transcription of RNA extracted from patient serum specimens followed by PCR amplification with serotype-specific probes is the current standard technique for DENV serotyping. However, this method is time- and cost-consuming, and rapid detection systems with low cost are desirable. Previously, we developed a prototype serotype-specific immunochromatography system. That system was composed of four strips with four corresponding distinct sample buffers, each specifically detecting a single DENV serotype. In the present study, we improved this system by combining pairs of strips into one lateral-flow cassette each, providing DENV-1 and DENV-2 detection in one device and DENV-3 and DENV-4 detection in a second device; this strategy successfully reduced the required sample volume. Furthermore, we were able to adjust the composition of the sample buffers such that a single sample buffer sufficed for all four DENV serotype detection reactions, allowing much easier handling of the devices. Evaluation of this new device against laboratory and clinical DENV isolates and clinical specimens from DENV-infected individuals showed sensitivity that was comparable to that of our previous version, yielding serotype specificity of 100%. These new devices are expected to be of use in the clinical setting, accelerating both prospective and retrospective epidemiological studies.

Fluorescence Anisotropy (FA) is a sensitive and efficient technique for quantifying biomolecular interactions, offering advantages such as minimal sample requirements and elimination of separation of bound from unbound species. Thus, it is well suited for aptamer-protein binding affinity studies. However, accurately determining equilibrium dissociation constants (K_D) in FA requires low concentrations of fluorescently labeled aptamers to prevent ligand depletion. A significant challenge arises at low aptamer concentrations due to an unexpected and physically nonmeaningful increase in apparent anisotropy, which impairs accurate data fitting. This anomalous increase in apparent anisotropy may arise from non-specific adsorption of aptamers to surfaces. In this study, we investigated the use of non-ionic surfactants to mitigate these effects and stabilize the anisotropy signal at low aptamer concentrations using the thrombin aptamer as a model system. We evaluated the impact of varying concentrations of two surfactants (Tween 20 and Triton X-100) on plots of anisotropy as a function of aptamer concentration and determined aptamer-protein binding affinities. Addition of 0.1% Tween 20 corrects the anomalous increase in anisotropy at low aptamer concentrations, enabling the use of aptamer concentrations as low as 5 nM in binding assays. Triton X-100 was less effective. By incorporating optimized concentrations of Tween 20, we demonstrated improved assay reproducibility and accuracy in K_D determination, expanding the dynamic range of usable aptamer concentrations in FA-based binding affinity studies. Similar benefits were observed with the clinically relevant aptamer s10yh2 and human serum albumin. These findings provide a practical strategy for enhancing the robustness of FA measurements and may be applicable to other aptamer-target systems and high-throughput assay formats.

The fluorescent dyes 9-aminoacridine (9-AA) and acridine orange (AO) are known mutagens that induce frameshift mutations in cells by intercalating between DNA bases. However, these chemicals can also affect other cellular components, such as proteins. In this study, we tested the ability of 9-AA and AO to induce heat shock in bacteria using the following methods: lux-biosensors based on Escherichia coli cells with the luxCDABE genes transcriptionally fused to heat shock-specific inducible promoters, RT-qPCR, and nanoDSF. We demonstrated that acridine dyes not only induce mutagenesis but also cause heat shock in bacterial cells. AO significantly reduced the melting temperature of proteins and strongly activated σ^E- and σ³²-dependent promoters, but not PluxC, which is activated by elevated temperatures via a different mechanism. In contrast, 9-AA weakly denatured the proteins and induced the σ^E-dependent promoter; however, it activated the σ³²-dependent promoters and PluxC, supporting the hypothesis that the σ³² heat shock response system is activated via hairpin RNA denaturation by 9-AA. The study on the application of lux-biosensors was hampered by the high general toxicity and luminescence shielding effect of AO, and RT-qPCR's sensitivity was insufficient for detection of the response to 9-AA. Thus, methodologically, it is justified to conduct a comprehensive study of substances that cause heat shock or affect bioluminescence by both RT-qPCR and lux-biosensors.