Analysis & sensing最新文献

The accurate and selective detection of vitamins are very much needed in the food, and pharmaceutical industries and health care. In this study, a new sustainable disposable electrochemical platform was fabricated with nano silver/Cu₂O composite (nAg/Cu₂O) for sensing ascorbic acid (vitamin C). The modified electrode exhibited reduced resistance to charge transfer and improved electro active area. The analyte displayed excellent electrochemical activity on the surface of nAg/Cu₂O modified paper electrode and showed a concentration-dependent response between 0.05 to 500 μM with a detection limit (S/N=3), 0.04 μM. Furthermore, the anti-interference studies revealed that the nAg/Cu₂O nanocomposites have high selectivity towards ascorbic acid. Notably, the sensor based on nAg/Cu₂O showed exceptional stability and reproducibility, with a relative standard deviation for peak currents measuring approximately 7 % or less while testing for a week of time. The real-world application and analytical performance was realized by identifying ascorbic acid in commercial vitamin C tablets with satisfactory results.

Breath biomarker detection represents a transformative frontier in non-invasive diagnostics, offering rapid, real-time insights into health conditions ranging from metabolic disorders to cancer. Metal oxide nanostructures (MONs) have emerged as key materials in this research because of their large surface area, adjustable electrical characteristics, and sensitivity to gaseous biomarkers at trace quantities. This paper examines current advances in chemiresistive MON-based sensors, focusing on the importance of structural optimization, hybrid material systems, and functionalization strategies in improving performance. Exploring the study of complicated datasets, the prediction of biomarker signatures, and dynamic aims in tuning the quality of the sensors. Functionalization strategies also play a vital role in enhancing the performance of MON-based sensors. By modifying the surface chemistry of chemiresistive metal oxides, researchers can tailor the sensors to preferentially adsorb certain gaseous biomarkers while minimizing interference from other compounds present in breath. Future opportunities include the development of multimodal sensors, simplified and portable devices, and durable, reusable platforms capable of long-term operation in real-world environments. With the confluence of nanotechnology and data-driven analytics, MON-based breath sensors have the potential to transform customized healthcare by providing worldwide early detection, illness monitoring, and preventative medication.

As interest in monitoring the nutritional and antioxidant levels in fruits and vegetables grows, the need for efficient, non-invasive detection methods increases. In this work, a novel coated microneedle colorimetric sensing platform is designed to rapidly and sensitively detect total phenolic compounds (TPC) in fruits and vegetables, which is the key indicator of their nutritional and antioxidant properties. The platform utilizes a swollen microneedle structure to efficiently collect juice samples, enhancing detection efficiency through colorimetric analysis and eliminating the complexity of traditional methods. The microneedles are fabricated from a composite material consisting of 10,12-pentacosadiynoic acid (PCDA) and methacrylated gelatin (GelMA), with a secondary layer containing α-cyclodextrin to selectively bind polyphenols, thereby inducing a visible color change for the specific detection of TPC. The colorimetric response is directly correlated with the concentration of TPC, facilitating on-site analysis. Using phenol as a model molecule, the detection range of the system for phenol is 10–60 mM, with an LOD of 0.5 mM. Furthermore, a mobile application enables portable detection and analysis, reducing detection time from several hours to just 30 min. This technology offers a promising approach for the rapid, reliable monitoring of phenolic content in fresh produce, with potential applications in food quality control, nutritional analysis, and agricultural monitoring.

Metal-organic frameworks (MOFs) offer an impeccable platform for glucose sensing, contributing in both enzymatic- and non-enzymatic-based electrochemical detection. Comprising metal ions and organic ligands, MOFs with their exceptional properties including tunable porosity, high surface area, diverse structural configuration, strong adsorptive capacity, electrocatalytic behavior, and abundant active sites pave way for improving healthcare diagnostics. More in the Review by R. Ajay Rakkesh and co-workers.

Lanthanum ferrite has emerged as a promising material for the development of advanced sensor technologies due to its unique electrical, magnetic, and optical properties. This comprehensive review explores the recent advancements in lanthanum ferrite-based sensors, highlighted their potential applications in various fields, including gas sensing, humidity sensing, biomedical diagnostics and environmental monitoring. The review delves into the underlying principles of lanthanum ferrite sensors, their fabrication techniques, and the strategies employed to enhance their sensitivity, selectivity, and stability. Particular emphasis is placed on the integration of lanthanum ferrite with complementary materials and the utilization of advanced characterization techniques to unlock the full potential of these sensor systems. Current challenges and future research directions in this rapidly evolving field are also discussed, aiming to provide a roadmap for further developments and widespread adoption of lanthanum ferrite-based sensors.

Noble metal (gold and silver) nanoparticles have found a range of applications as sensors and biosensors. These applications utilize the nanoparticles’ tunable optical properties within the visible range of the electromagnetic spectrum, which originate from localized surface plasmon resonance. Recent applications have focused on analyte and bioanalyte detection through nanoparticle growth while successfully achieving low detection limits. This review focuses on theoretical and empirical models used to quantify and/or optimize the localized surface plasmon resonance response to nanoparticle growth, with representative examples from the literature. The effect of nanoparticle growth on the localized surface plasmon resonance signal in monometallic nanoparticles, bimetallic core-shell nanoparticles, and monometallic nanoshells will be discussed, including spherical, spheroidal and non-spheroidal nanoparticle shapes.

Hypoxia is a common feature in solid tumors that arises when there is insufficient oxygen available. This lack of oxygen causes molecular adaptations required for the tumor cells to survive. Additionally, oxygen-deprived cancer cells tend to become less responsive to conventional cancer therapies. Hence, hypoxia plays an important role in contributing to tumor aggressiveness and therapy resistance. Hypoxia-related markers are gaining interest as prognostic and predictive markers for tumor response and treatment strategies. However, the detection of hypoxia in the tumor microenvironment without employing any labeling strategies poses significant challenges. Here, we present a classification model based on lipidomic single-cell mass spectrometry imaging data to classify hypoxia in breast cancer xenografts. Our approach is based on a classification model built from the lipid profiles of single breast cancer cells cultured under various oxygen conditions. Lipidomic alterations caused by differences in available oxygen concentrations were subsequently used to classify and spatially determine hypoxic regions in breast cancer xenografts without the need for any labeling. This approach, using cells as hypoxia markers, contributes to a better understanding of tumor biology and provides a foundation for improving diagnostic and therapeutic strategies for cancer treatments.

Type-2 diabetes (T2D) is a growing global health crisis, with over 90% of diabetes cases attributed to this condition. Misfolding and aggregation of islet amyloid polypeptide (IAPP) is a hallmark of early T2D, contributing to pancreatic β-cell dysfunction. While significant progress has been made in developing sensors for amyloids implicated in neurodegeneration, fluorescent probes for detecting IAPP aggregates remain limited. We report a series of flavonoid derivatives designed for enhanced IAPP fibril detection. The probes feature modifications, including methoxy substitution at C7 and varying amines at C4, which enhance their binding affinity for IAPP fibrils compared to the widely used Thioflavin T (ThT). The leading probes, F4 and MF1, exhibited over 10-fold increased binding affinity compared to ThT, alongside ratiometric fluorescence due to excited-state intramolecular proton transfer. F4 and MF1 were applied to image IAPP aggregates in pancreatic β-cells and zebrafish tissue sections, where both probes demonstrated specific imaging of IAPP fibrils. These probes also demonstrated reduced fluorescence when IAPP monomers were incubated with inhibitors, indicating fibril disassembly. Our results position F4 and MF1 as promising tools for exploring the pathological role of IAPP aggregation in diabetes and for high-throughput screening of IAPP aggregation inhibitors.

The full 2D tandem mass spectrometry (MS/MS) data domain provides a rapid survey of the chemical components of complex plant extracts without subjecting them to prior chromatographic separation. Nano electrospray ionization (nESI), desorption electrospray ionization (DESI) and paper spray ionization are used to create an ion mixture representative of the chemical constituents of a plant extract, then mass-selective collision-induced dissociation (CID) is used to automatically record fragments from each precursor ion in the mixture. Signal extraction from the 2D data domain yields matching spectra to conventional product and precursor ion scans and displays distributions of compounds bearing a chosen functionality. These features and other manipulations of the 2D MS/MS data are demonstrated using crude extracts of Artemisia annua (Sweet wormwood). Similarities and differences in the secondary metabolites of plant species are established rapidly by inspection of the 2D MS/MS plots. The methodology is characterized by the high speed of data acquisition while the limited mass resolution still allows high speed snapshots of chemistry.

The construction of fluorescence sensor L1 for cyanazine (CNZ) by using calix[4]arene scaffold allied with 9-Aminoacridine moiety has been reported. The recognized triazine herbicide CNZ decreased the fluorescence intensity of L1 by exhibiting “turn-off” phenomenon having detection limit to be 7.79 μM obtained from emission study. The quenching response of L1: CNZ was observed between the range of 5–105 μM possessing binding constant calculated to be 9.201×10⁶ M⁻¹. The spiking experiment of CNZ into L1 has also been performed to evaluate potency of L1 using vegetables and cereals. Also, a paper-based device has been prepared in order to implement this strategy for on-spot monitoring of CNZ. The L1:CNZ binding has been confirmed by conducting electrochemical studies like cyclic voltammetry, differential pulse voltammetry, ¹H NMR, FT-IR, MALDI-TOF, ¹H NMR titration, PXRD investigation and computational analysis.