Analysis & sensing最新文献

A new sensing microtiter plate platform enables rapid, one-step, ratiometric fluorescence detection of H₂O₂ using Amplex Red in hydrogel membranes with Cy5-based reference nanoparticles. It offers 3-minute readouts and 10 times lower detection limit than commercial kits while minimizing preparation steps. With enzyme functionalization, the platform supports glucose and lactate detection, offering a simplified yet powerful alternative to multistep assays. More in the Research Article by Axel Duerkop and co-workers.

Plant health monitoring is vital to address global agricultural instability. The emerging non-destructive, portable, wearable chemical sensors provide valuable insights into plant health with faster detection and real-time data. The Review by Yifei Luo, Xiaodong Chen, and co-workers summarizes progress in plant chemical sensing, focusing on key chemicals, materials, and mechanisms, aiming to overcome challenges and advance in-field deployment of these essential tools.

Hydrogen peroxide (H₂O₂) is an important small metabolite often quantified with commercially available multistep fluorescence-based assays. A new microtiter plate (MTP)-based platform that allows a rapid, one-step assay with a ratiometric readout function is developed. Specifically, 10-Acetyl-3,7-dihydroxyphenoxazine (ADHP) in a polyurethane-based hydrogel sensor membrane is embedded. For a ratiometric set-up, the membranes are loaded with polystyrene nanoparticles containing a Cy5-based reference which allowed for the compensation for variations in membrane thickness. These knife-coated µm-thin films are mounted onto bottomless MTPs with double-sided adhesive tape. Optimized membranes provide measurement times of 3 min upon sample addition and a limit of detection (LOD) in phosphate-buffered saline that is 10x lower than that of the ADHP-using Amplex Red commercial kit of 100 nmol L⁻¹ H₂O₂. These ADHP hydrogels can be stored at room temperature for at least 22 months. Horseradish peroxidase (HRP) is nanospotted alone or together with either lactate oxidase or glucose oxidase for the detection of H₂O₂, lactate, and glucose, respectively. With 50 v% glycerol as cryoprotectant in the spotting solution, the HRP ADHP platform is stable for at least 13 weeks at –20 °C. Enhanced simplicity and comparable performance to multistep assays suggest that the platform can simplify MTP-based assays in the future.

Peptides and proteins with D-amino acids and other stereoisomers in their sequences are now considered to be widespread in different organisms. Their significance is attributed to the altered functions of these molecules, such as having some pathological significance or enhancing biological activity. Only slight shifts in structural and other biophysical parameters make their full characterization and complete distinction technically challenging for traditional tools like mass spectrometry (MS). Ion mobility (IM) spectrometry in conjunction with liquid chromatography (LC) adds an extra dimension to the separation in space as it depends on the mobility of ions, being determined by their overall shape and the orientation of the molecules. Thus, peptide isomers having measurable mobility and collisional cross-section values can thus be resolved by IM-MS. In addition, by combining with tandem MS techniques, IM-MS with adequate conformation-resolving capability is likely to localize the isomerization sites. This review briefly introduces the basic principles of conformation-based chiral separation through LC and capillary electrophoresis, in conjunction with IM-MS for enhanced peptide/protein stereoisomer differentiation, and then comprehensively summarizes the recent advancements in IM-MS-based peptide/protein stereoisomer analysis, focusing on the development of conformation-based chiral separation strategies, including instrumental modifications, chemical modifications, and computational tools.

With the increasing risk of global agricultural instability and the pressing need to enhance crop productivity, monitoring of plant health has become increasingly important. Chemical sensing of agricultural environmental factors and plant signaling molecules has been shown to provide valuable insights into plant growth and development. Recent advances in plant monitoring technologies have seen a shift toward nondestructive, portable, or wearable sensors, which offer advantages over traditional analytical instruments, such as faster detection with real-time monitoring capabilities. However, these emerging forms of chemical sensors have not been widely adopted. This review summarizes recent advancements in plant chemical sensing, highlighting key environmental chemicals and plant biomarkers for detection, sensing materials, and detection mechanisms. Finally, the challenges and outlook of chemical sensors for plant monitoring are discussed. Through the identification of the key challenges, it is hoped to advance the development of nondestructive chemical sensors and facilitate their deployment for in-field plant monitoring.

Knowledge about the molecular structure and interactions of intracellular dyes is important to understand their function and possible effects in the biological environment. Here we discuss vibrational spectra of LysoSensor (LSG), a fluorescent marker for the acidic lysosomal compartment in cells. Raman spectra of the molecule at concentrations typically applied in experiments with cell cultures were obtained by surface-enhanced Raman scattering (SERS) experiments at varying pH values, using biocompatible gold nanoprobes also used in live cell SERS. The signals in the SERS spectrum of LSG were assigned based on spectra collected from its aromatic constituents benzimidazole and naphthalimide under the same conditions. The data indicate a strong pH dependence of the spectra of benzimidazole that is less pronounced in the vibrational signature of the LSG molecule. Despite excitation of the SERS off-resonance with the dye molecule, spectra obtained with the biocompatible wavelength of 785 nm have better sensitivity towards pH-dependent structural changes, due to favorable electromagnetic enhancement of vibrational modes, than when using excitation at 633 nm. The characterization based on SERS will help to understand the interactions of LSG with the cellular environment and with other probes, which will be useful for the design of efficient labels for bioanalysis.

Many pharmacologically relevant drug targets are located inside cells, requiring small-molecule therapeutics to penetrate the plasma membrane faster than they are metabolically inactivated or expelled by efflux pumps. Accurate measurement of intracellular concentrations is crucial for correlating biochemical potency with cellular efficacy and optimizing ligands. Despite the critical importance of this metric, current methods for quantifying intracellular levels of nonfluorescent small molecules are technically demanding and limited in throughput, significantly restricting the ability of medicinal chemists to readily and routinely measure cellular drug concentration. Here, we introduce a straightforward, high-throughput time-resolved Förster resonance energy transfer assay platform based on CoraFluor technology, a class of highly luminescent terbium complexes, to readily quantify the abundance of biologically active small molecules in whole cell lysates. Our approach conceptually extends existing homogeneous ligand displacement assays and does not require any additional reagents or equipment, enabling the comprehensive biochemical and cellular characterization of small-molecule ligands.

This study focuses on the synthesis, characterization, and sensing capabilities of liquefied petroleum gas (LPG) using 5% and 10% silver-doped zinc ferrite thin films under ambient conditions. A highly efficient sensor for LPG concentrations below the lower explosive limit (LEL) has been developed using Ag decorated on a ZnFe₂O₄ surface. The ZnFe₂O₄, 5% Ag-ZnFe₂O₄, and 10% Ag-ZnFe₂O₄ sensing films are meticulously prepared utilizing a spin coater and subsequently characterized through various techniques to explore the parameters of significance, including surface morphology, porosity, chemical bonding, optical band gap, and crystallinity. Among the synthesized materials, the 10% Ag-ZnFe₂O₄ demonstrates exceptional porosity, specific surface area, and uniformity, due to its faceted surface morphology. The developed 10% Ag-ZnFe₂O₄ film-based sensor exhibits a rapid response to LPG concentrations at room temperature, attaining a peak response of 2.55 when subjected to exposure of 2000 ppm of LPG. The durations for response and recovery were ≈15 and 68 s, respectively. The limit of detection of ZnFe₂O₄, 5% Ag-ZnFe₂O₄%, and 10% Ag-ZnFe₂O₄ sensors are observed to be ≈288, 220, and 205 ppm, respectively. The findings underscore the significance of an optimized 10% Ag-ZnFe₂O₄ sensor for efficient and economical LPG detection in residential and commercial environments.

The deterioration of aquatic ecosystems now ranks among the most urgent planetary challenges, with cascading effects on species survival, human welfare, and socioeconomic progress. Surface-enhanced Raman scattering (SERS), owing to its exceptional sensitivity, molecular fingerprinting capability, and rapid response, has become a powerful analytical technique for detecting water pollutants. This article provides a comprehensive summary of recent improvements in the use of SERS for detecting water pollutants. To begin with, SERS substrates are categorized into three major types—metallic, semiconductor, and composite—based on their distinct enhancement mechanisms. Building upon this classification, their use in detecting a wide range of aquatic pollutants, including heavy metal ions, pathogenic microorganisms, organic compounds, and micro/nanoplastics, is examined. Strategies for substrate design, sensitivity enhancement methods, and practical detection performance in real-world samples are also systematically reviewed. Finally, the review discusses challenges in applying SERS to water pollution monitoring and outlines future research directions. This review aims to provide valuable insights for advancing SERS-based strategies in environmental monitoring and promoting their practical application in water pollution detection.