Analysis & sensing最新文献

Single domain antibodies (sdAbs) provide versatile binding reagents that offer advantages over conventional antibodies for use in immunoassays. SdAbs consist of the ~15 kDa variable heavy domain from the heavy chain-only antibodies found in camelids and can be engineered for integration in a variety of immunoassay formats. The Luminex MAGPIX instrument is a high-throughput platform that uses color-coded MagPlex beads to enable multiplexed immunoassays and is relatively fast and simple. We developed a MagPlex bead-based assay for the detection of influenza A virus (IAV), using sdAbs against IAV nucleoprotein (NP). To provide sensitive detection, the sdAbs were formatted into bivalent constructs; and the capture reagent was tailored to provide oriented immobilization on the bead. Using the best capture and reporter pair, we achieved detection of recombinant NP down to 1 ng/mL. Finally, we demonstrated that the developed immunoassay showed promise in detecting IAV in clinical samples.

An electrochemical sensing platform for the detection of paracetamol is proposed in this work. The sensor (Asp-MWCNTs/IL/ITO) is based on Indium Tin Oxide (ITO) electrode loaded with asparagine functionalised Multi Walled Carbon Nanotubes (MWCNTs) and Ionic Liquid (IL). Initially, in-silico studies were performed to check the favourable interaction of the drug with the nanocomposite. The potential energy surface of Asp-MWCNTs and paracetamol complexes were explored using density functional theory and single-point energy coupled cluster calculations. The analysis of non-covalent interactions showed hydrogen bonding interactions predominantly stabilising the complex. The interaction process between Asp-MWCNTs and paracetamol is spontaneous due to negative value of binding energy (−0.75 eV). The functionalised MWCNTs were characterised through different techniques. Asp-MWCNTs/IL/ITO electrode showed good sensitivity with a linear range from 20–300 μgL⁻¹ and limit of detection of 0.0194 μM for paracetamol in phosphate buffer as supporting electrolyte. The sensor showed excellent repeatability and reproducibility with a relative standard deviation of 1.45 % at 60 μgL⁻¹ concentration. The chemical functionalization resulted in providing extra stability as it retained 95 % of its signal response even after 45 days. The sensor's applicability was tested in real water samples with the help of spiking study which showed good recovery >95 %.”

Despite the soaring popularity of e-cigarettes among teenagers and young adults, our understanding of the full extent of their health hazards have remained limited. This is due to the vast complexities of e-cigarette aerosols and the difficulty in their full characterisation. Conventional mass spectrometry methods of e-cigarette analysis, though pioneering in driving political and medical discourse, have been limited in their capabilities to uncover all compounds in its emissions due to prominent limitations in experimental setup. To overcome this major hurdle, we have developed a setup for puff-by-puff analysis of electronic and conventional cigarette emissions by concentric dielectric barrier discharge ionisation mass spectrometry. In this pilot study, the simple setup of in-line dilution and high-resolution mass spectrometry analysis allowed us to directly uncover 225 compounds in e-cigarette puffs across a wide spectrum of chemical classes in two sequential 5-minute runs. These include acids, carbonyls, aromatic cyclics, heterocyclics, unsaturated and saturated hydrocarbons, alcohols, esters, alkaloids, sulfur-containing compounds, oxides, and nitriles. As a result, our setup provided a significant improvement in rapid compound identification, and demonstrated a much broader chemical landscape in e-cigarette emissions than previously reported.

Clostridioides difficile (CD) is a Gram-positive, anaerobic, and spore-forming bacillus that colonizes the human gut and causes a range of diseases, such as pseudomembranous colitis and antibiotic-associated diarrhea, that are generally known as CD infection (CDI). Rapid and accurate detection of CDI with high sensitivity and specificity is crucial for patient treatment, infection control, and epidemiological monitoring. Current diagnostic methods for CDI have several limitations, such as high cost, long turnaround time, suboptimal sensitivity, and the need for specialized equipment. Hence, novel detection methods that can overcome these limitations are needed. Functional nucleic acids (FNAs) are a promising class of molecular recognition element (MRE) that can be incorporated into biosensors for detecting infectious pathogens. Several FNAs have been developed for detecting CD. In this review, an overview of CD, CDI, and current diagnostic methods for CDI and their drawbacks are provided. Furthermore, the design principles and working mechanisms of FNAs as well as their applications for the detection of pathogenic bacteria, including CD, are discussed. The potential for developing point-of-care paper sensors using currently available CD-selective FNAs is also highlighted.

Effective glucose monitoring is critical for managing diabetes and preventing its associated complications. While commercial glucose monitoring devices predominantly rely on blood samples, emerging research focuses on detecting glucose in alternative biofluids, harnessing advanced nanomaterials. Among these, Metal-Organic Frameworks (MOFs), composed of metal ions and organic ligands, have garnered significant attention due to their unique properties, including tunable porosity, high surface area, and abundant active sites conducive to glucose interaction. MOFs present a versatile platform for glucose sensing, offering potential in both enzymatic and non-enzymatic detection methods. This review delves into the recent advancements in MOFs-based electrochemical glucose sensors, providing a comprehensive analysis of various MOFs and their composites as electrode materials. The discussion highlights the structural attributes, functionalization strategies, and electrochemical performance of MOFs in glucose sensing, emphasizing their role in the development of next-generation, non-invasive glucose monitoring technologies. The review provides a comprehensive overview on the application of MOFs and MOFs-based composites in both enzymatic and non-enzymatic electrochemical-based glucose sensing and highlights the synthesis, mechanism, functionalization and development in the detection strategy of MOFs in glucose sensing.

A detailed study on the dynamic response of mountable pressure sensors is presented, with a focus on foot pressure sensors integrated with carbon nanotube (CNT)-coated cotton fibers. The research explores the sensor‘s sensitivity to pressure changes, repeatability, hysteresis, and durability through rigorous modeling and experimental validation. Computational simulations using Python (NumPy library) and experimental data demonstrate the sensor‘s nonlinear conductance response to applied force, attributed to the varying contact area and number of contact points among the fibers. Long-term outdoor exposure tests confirm the material‘s resilience to environmental stressors, maintaining its electrical conductivity and structural integrity. The study also investigates the sensor‘s capability to monitor human activities, such as walking, running, stair climbing, and jumping, by analyzing force profiles and step rates. Additionally, the sensors effectively detect muscle movements during swallowing, coughing, and speech, with potential applications in health monitoring and artificial voice synthesis. The Minimum Redundancy Maximum Relevance (MRMR) algorithm is utilized to implement feature selection methods aimed at distinguishing between various activities, thereby demonstrating the sensor‘s potential for activity recognition. An estimation of harvested electric power using a piezoelectric sensor on the pressure sensors has been done, which can provide power to the different wearable devices attached to our body. This work contributes to the advancement of self-powered wearable pressure sensors to monitor real-time human activity, with implications for healthcare, sports performance, and assistive technologies.

Flexible biosensors play a crucial role for healthcare management and disease diagnosis. Electrochemical biosensors have attracted significant attention for wearable sensing applications owing to their numerous advantages, including high sensitivity and selectivity, inherent miniaturization and rapid response times. Challenges lie in the development of highly conductive and flexible electrodes that can be integrated with biorecognition components to engineer selective biosensor interfaces. Carbon nanotubes (CNTs) hold significant promise as materials for wearable flexible sensor fabrication. This review highlights recent strategies for fabricating conductive and flexible electrodes, whether in the form of films or fibers, based on CNTs and their composites. Additionally, the review explores emerging biosensing applications, including flexible sensors for the direct electrochemical detection of biomarkers, sensors functionalized with enzymes, antibodies, or DNA, and sensors interfaced with cells to monitor transient biochemical signals.

Time-gated or time-resolved FRET (TR-FRET) assays are important tools in biosensing, bioimaging, drug screening, and molecular diagnostics. Efficient TR-FRET assays require stable lanthanide complexes with high absorption cross sections, high quantum yields, and long photoluminescence lifetimes. Owing to their challenging synthesis, such complexes are relatively rare and new components are of potential interest when developing TR-FRET probes. Here, we evaluate the recently developed Tb complex CoraFluor-1 concerning its analytical performance in terbium-to-quantum dot FRET and terbium-to-gold nanoparticle NSET assays using the prototypical biological recognition system of streptavidin and biotin. Biological binding was quantifiable at sub-picomolar concentrations in small sample volumes, with broad applicability demonstrated across three commercial fluorescence plate readers used for time-resolved, spectrally-resolved, and clinical bioanalysis. Overall, CoraFluor-1 provided excellent analytical performance as both FRET and NSET donor, validating its potential for developing new TR-FRET probes for biosensing and bioimaging.

Formic acid (FA) is one of the very important organic acids that has been widely used in various industries. The highly corrosive FA can have severe adverse effects on the surrounding environment. Here, we developed an electrochemical sensor that utilizes the material properties of multi-walled carbon nanotubes (MWCNTs), and copper phthalocyanine (CuPc) for the real-time detection of FA gas. The response of FA has been compared with the responses of 9 common volatile organic compounds (VOCs). The chronoamperometry (CA) results revealed a high selectivity towards FA by showing an increase in the sensor current by about 25 %, in contrast to the decrease of the current in response to the other VOCs. The sensitivity of the CuPc device to FA was calculated to be 38.85 mAM⁻¹. Material characterization (SEM, EDX, FTIR, Raman, and UV-vis) also strongly suggests a protonation mechanism caused by the carboxylic acid group, which enhances the electrical conductivity.