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Avian influenza viruses (AIV) are capable of infecting a considerable proportion of the world's population each year, leading to severe epidemics with high rates of morbidity and mortality. The methods now used to diagnose influenza virus A include the Western blot test (WB), hemagglutination inhibition (HI), and enzyme-linked immunosorbent assays (ELISAs). But because of their labor-intensiveness, lengthy procedures, need for costly equipment, and inexperienced staff, these approaches are considered inappropriate. The present review elucidates the recent advancements in the field of avian influenza detection through the utilization of nanomaterials-based immunosensors between 2014 and 2024. The classification of detection techniques has been taken into account to provide a comprehensive overview of the literature. The review encompasses a detailed illustration of the commonly employed detection mechanisms in immunosensors, namely, colorimetry, fluorescence assay, surface plasmon resonance (SPR), surface-enhanced Raman spectroscopy (SERS), electrochemical detection, quartz crystal microbalance (QCM) piezoelectric, and field-effect transistor (FET). Furthermore, the challenges and future prospects for the immunosensors have been deliberated upon. The present review aims to enhance the understanding of immunosensors-based sensing platforms for virus detection and to stimulate the development of novel immunosensors by providing novel ideas and inspirations. Therefore, the aim of this paper is to provide an updated information about biosensors, as a recent detection technique of influenza with its details regarding the various types of biosensors, which can be used for this review.

A fast and non-separative screening strategy is presented for the analysis of five urinary metabolites of polycyclic aromatic hydrocarbons (PAHs), namely 2-naphthol, 1-acenaphthenol, 2-hydroxyfluorene, 9-phenanthrol and 1-hydroxypyrene. These hydroxylated derivatives (OH-PAHs) were subjected to enzymatic hydrolysis and were extracted from urine using a liquid-liquid extraction (LLE). The profile signals were obtained by direct injection of the sample into a programmed temperature vaporizer coupled to a quadrupole mass spectrometer via a deactivated fused silica tubing (PTV-qMS). Semi-quantitative determination was carried out by means of partial least squares regression (PLS1) using urine samples free of the analytes and spiked at several uncorrelated concentration levels. The multivariate calibration models worked satisfactorily, with errors ranging between 30 and 33 % for all the analytes except for 1-acenaphthenol that provided an error of 39 % when external validation set was considered. The repeatability and reproducibility, expressed as relative standard deviation (RSD), were ranged between 8-16 % and 11-18 %, respectively. The proposed method could be a useful tool for semi-quantification purposes of five OH-PAHs in urine samples, identifying positive samples for subsequent further chromatographic separation (confirmation), thus saving time and costs.

The separation of target microparticles using microfluidic systems owns extensive applications in biomedical, chemical, and materials science fields. Integration of microfluidic sorting systems employing dielectrophoresis (DEP) technology has been widely investigated. However, enhancing separation efficiency, purity, stability, and integration remains a pressing issue. This study proposes a stepwise multi-stage continuous DEP separation microfluidic chip with a microfilter structure. By leveraging a stepwise electrode configuration, a gradient electric field is generated to drive target microparticles along the electric field gradient, thereby enhancing separation efficiency. Innovative integration of a microfilter structure facilitates simultaneous filtration and improves flow field distribution, thus enhancing system stability. Through the synergistic effect of stepwise electrodes and the microfilter structure, superior coupling of electric and flow fields is achieved, consequently improving the sorting purity, separation efficiency, and system stability of the DEP-based microfluidic sorting system. Validation through simulation and separation of polystyrene microspheres demonstrates the excellent particle separation performance of the proposed system. It evidently shows potential for seamless extension to various biological microparticle sorting applications, harboring significant prospects in the biomedical domain field.

In recent years, hydrogel-based flexible sensors have garnered increasing attention in research. Ionic hydrogels, enriched with large amounts of ionic liquids, exhibit electrical conductivity, excellent electrochemical stability, anti-freezing, and antimicrobial properties. However, most ionic hydrogels suffer from poor mechanical properties, limiting their adaptability to more complex application scenarios. Integrating conductive polymers into hydrogels leads to desirable features such as increased specific surface area, soft and biocompatible interfaces, and high electrolyte permeability. In this study, we successfully prepared Fe^3+/Ap@PVA/PEDOT double-network hydrogel. Utilizing polyvinyl alcohol (PVA) as the primary matrix, we introduced PEDOT:PSS and FeCl₃ to confer conductivity to the hydrogel. The incorporation of amylopectin (Ap) further enhanced mechanical performance. The resulted hydrogel sensor exhibits outstanding mechanical properties, allowing for stretching up to 347 % and withstanding a tensile force of 505 kPa. In addition, it exhibits excellent antifreeze properties (can work at -30 °C), healability, water retention, and high sensitivity to stretching (GF = 4.72 at a 200 % strain ratio), compression (GF = 2.97 at a 12 % compressive ratio), and temperature (TCR = 2.46). These remarkable properties of the hydrogel make it possible in applications such as human motion monitoring, handwriting recognition, and temperature sensing.

This article reports a spectrofluorometric method for the determination of sunitinib (STB) drug based on molecularly imprinted nanofibers fabricated by the electrospinning method and modified by magnetic nanoparticles as sorbent. The characterization of magnetic molecularly imprinted nanofibers (MMINs) was carried out using X-ray diffraction (XRD), scanning electron microscope (SEM), and transmission electron microscopy (TEM), which confirmed the successful synthesis of MMINs with well-distributed magnetite nanoparticles. Drug adsorption and desorption were optimized and important parameters such as sample pH, nanofiber mass, adsorption and desorption time, eluent solvent and sample volume were analyzed. The results demonstrated that the MMINs act as a selective sorbent for STB and can be readily collected through an external magnetic field. Methanol was used as the best eluent solvent for STB desorption from MNIN. A linear correlation was observed between the STB concentrations and fluorescence intensities in the range of 0.01-15.0 mg L^-1. The detection limit for this method was 0.002 mg L^-1. The relative standard deviation (RSD) of 2.6 % for 1.0 mg L^-1 and 1.1 % for 10 mg L^-1 of STB (n = 3) were obtained, which indicates that the developed method is precise in determining STB. Human serum and capsule analysis show the applicability of the proposed sensor for real samples.

The plasma membrane involves in many important biological events such as cell fusion and programmed cell death, but most of current plasma membrane probes cannot meet the requirement of long-term specific anchoring to the plasma membrane. Herein, we propose a molecular side-chain engineering strategy to modulate the long-term imaging performance of fluorescent dyes to the plasma membrane by regulating the cell permeability and anchoring ability. A series of FMR dyes with different lengths of side chains were designed and synthesized, and their transmembrane behaviours and staining performance were evaluated in living HeLa cells. We found that short-chain and medium-chain FMR dyes have excellent cell permeability without the labeling ability to the plasma membrane while the long-chain FMR dyes specifically stain the plasma membrane and can be firmly anchored to the plasma membrane for a long period of time. These long-chain FMR dyes have high stain specificality to the plasma membrane, and C10-FMR can be anchored to the plasma membrane of living cells for 2 h, which enables it to continuously monitor dynamic changes of the plasma membrane. The three-dimensional precision imaging of various cells was achieved using C10-FMR, which provides an opportunity to obtain complete information on the three-dimensional spatial morphology of the plasma membrane. The PEG-induced cell fusion of chicken red blood cells and H₂O₂-induced apoptosis of HeLa cells were monitored by real-time tracking of dynamic changes of the plasma membrane during these processes, which provide solid examples to prove the usefulness of these fluorescent dyes as long-term imaging tools. This work validates the hypothesis that cell permeability of membrane dyes can be readily regulated by tuning the side chains, and provides the effective design strategy of fluorescent dyes for 3D and long-term dynamic tracking of the plasma membrane of diverse animal cells.