Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy最新文献

The study focuses on the synthesis of V₄O₇ microcubes for the non-enzymatic colorimetric determination of H₂O₂.Vanadium oxide nanostructures are known for their redox activity and layered structures, making V₄O₇ a valuable material for sensing applications. The characterization of the prepared sample was done using XPS, XRD, Raman spectroscopy, and SEM techniques. The V₄O₇ microcube showed a rapid response to H₂O₂ through direct color change without the need for peroxidase enzymes or TMB. Upon exposure to H₂O₂, the mixed valence V₄O₇ oxidized to produce V₂O₅, enabling sensitive detection of H₂O₂. The V₄O₇ sensing system exhibited a wide linear response range from 0.025 to 300 µM with a low detection limit of 7.6 nM for H₂O₂ detection. When combined with glucose oxidase, the system could detect glucose levels as low as 18 nM within a linear range of 0.05 µM to 300 µM. The proposed sensor demonstrated high selectivity and robust potential for sensing H₂O₂ in biological samples. The system offers advantages such as fast response, simple operation, naked-eye observation, and cost-effectiveness. The novel sensing system holds promise for visual detection in H₂O₂ diagnostic clinics, highlighting its potential for practical applications in healthcare settings.

The detection of pesticide residues in agricultural products is crucial for ensuring food safety. However, traditional methods are often constrained by slow processing speeds and a restricted analytical scope. This study presents a novel method that uses filter-array-based hyperspectral imaging enhanced by a dynamic filtering demosaicking algorithm, which significantly improves the speed and accuracy of detecting pesticide residues. Our approach enhances the spatial and spectral resolution of hyperspectral images, thereby providing a rapid and cost-effective alternative to conventional methods with an image integration time of 20 ms. Tested on both synthetic datasets and real agricultural samples, this technology demonstrates superior performance under high noise conditions and exceptional precision in spectral reconstruction at critical color edges. The practicality of this system is demonstrated by integrating a hyperspectral microfilter array with a smartphone's imaging sensor, thereby showcasing the feasibility of deploying this advanced detection technology in everyday portable devices for quick and convenient monitoring of pesticide residues.

An imbalance in iron homeostasis contributes to mitochondrial dysfunction, which is closely linked to the pathogenesis of various diseases. Herein, we developed a nanosensor for detecting mitochondrial ferrous ions in vitro and in vivo. A poly(N-isopropylacrylamine)-coacrylic acid nanohydrogel was synthesized, and ferrous ions were detected using the fluorescent probe FeRhonox-1 embedded within it. (3-Carboxypropyl)-triphenylphosphonium bromide was chemically conjugated to the hydrogel matrix to enable mitochondrial targeting. The developed nanosensor showed a narrow particle size distribution, high sensitivity and selectivity for ferrous ions, and low cytotoxicity, enabling the nanosensor to sense and image ferrous ions in mitochondria with high spatial resolution. Changes in ferrous ion concentrations in human umbilical vein endothelial cells were measured and imaged after lipopolysaccharide (LPS) or iron dextran treatment. Moreover, the nanosensor was successfully used for ferrous ion imaging in live mice. The in vivo results showed that LPS injection induced the accumulation of mitochondrial ferrous ions. The proposed nanosensor could serve as a powerful tool for monitoring ferrous ions in mitochondria, providing strong support for studying disorders of iron metabolism.

Applying antioxidant coating materials to prepare surface-enhanced Raman spectroscopy (SERS) sensing substrates can effectively enhance the sensitivity and stability for the analysis of molecules. In this study, we have leveraged SERS to develop an innovative sensor for the swift identification of Paraquat (PQ), enabling on-site detection of this herbicide. The newly devised sensor distinguishes itself through its exceptional oxidation resistance. This resistance is attributed to the physical properties of the nanoparticles, specifically the silver shell coating and loading on the molybdenum disulfide (MoS₂). By the creation of "hot spots" of the composite nanoparticles (Ag@AuBPs on flower-like MoS₂), the kit achieves a remarkably low detection limit as low as 1.0 × 10^-10 M for Paraquat in lake water, soil, and clothing samples, allowing for rapid and direct identification of PQ in complex environments.

Monitoring biomarker levels in body fluids is of great importance in clinical diagnosis. Herein, a robust 3D ZnMOF, {[Zn₂(BTPB)_0.5(bib)_1.5(μ₂-OH)]·2H₂O}_n, was fabricated based on the ligands of 1,4-bis(2,4,6-tricarboxylpyrid-5-yl)benzene (H₆BTPB) and 1,4-bis(imidazol-1-yl)benzene (bib). On the basis of its stable architecture and intrinsic luminescence, ZnMOF demonstrated remarkable potential as a bifunctional luminescent sensor for selective and sensitive detecting the biomarkers of 3-nitrotyrosine (3-NT) and 5-hydroxyindoleacetic acid (5-HIAA) in water and body fluids by employing distinct "turn-off" and "turn-on" responses. Additionally, the inherent sensing mechanism was further assessed from the viewpoints of spectral overlap and photo-induced electron transfer. This work manifested MOFs-based luminescent sensors are developing into an effective method for detecting biomarkers in body fluids with perfect practicality and compatibility.

Herein, we have used a simple synthetic strategy to access a novel non-sulfur fluorescent molecular probe coumarin and 1,8-napthyridine conjugated probe DNCS. The developed probe has great selectivity and sensitivity for detecting Hg²⁺ ions. Our photophysical properties evaluation for the synthesized probe with different metal ions (Ba²⁺, Al³⁺, Ca²⁺, Bi³⁺, Ce³⁺, Cd²⁺, Cu²⁺, Sr²⁺, Co²⁺, Fe²⁺, Cr³⁺, Fe³⁺, Mn²⁺, Hg²⁺, Zn²⁺, Pb²⁺, Ni²⁺, and Sn²⁺) unveiled the very selective and sensitive fluorescence sensing behavior with Hg²⁺ ions in the energy window of near UV and visible light radiation in an organic aqueous solvent mixture (EtOH and water). The limit of detection (LOD) of 9.04 x10^-5 M and binding constant of 2.56 × 10³ M^-1 were obtained for the probe DNCS with Hg²⁺ ions, and 1:1 stoichiometric complexation. Our bioimaging experiments demonstrated that the developed probe exhibited fluorescent sensing behaviors towards Hg²⁺ ions with HCT 116 cells. Moreover, the current studies present the electronic properties of the DNCS probe computed through DFT computation studies at the B3LYP/6-311G(d,p) level of theory. We are confident that the developed fluorescent probe has the potential for the efficient fluorometric detection of Hg²⁺ ions and plays a significant role in environmental and human health protection.

Excited-state intramolecular proton transfer (ESIPT) reactions are one of the fundamental energy transformation reactions in catalysis and biological process. The combining ESIPT with the twisted intramolecular charge transfer (TICT) brings the richness of optical, photoelectronic performances to certain functional compounds. Delineating the mechanism of ESIPT + TICT reactions and further understanding why a specific functional group dominates are fundamentally crucial for the design and application of the functionally photoelectric materials. In this paper, six 2-(2'-hydroxyphenyl) benzimidazole (HBIgens) derivatives involved in ESIPT + TICT were investigated by density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations to have an insight into the photophysical and photochemical process in acetonitrile. The optimized geometries indicated that the intramolecular hydrogen bonds (-O-H···N-) were enhanced in the corresponding first singlet, which provided the fundamentally outstanding prerequisites of the ESIPT reactions. By further charge analysis, it is indicated that the introduction of substitutes to the different positions would determine the Stokes' shifts, and the electron-adopting p-cyanophenyl group mainly contributed to the TICT structure. Constraint scanning the potential energy curves of both ground and first singlet excited states, the electron-adopting N,N-diethylamino group on the meta position could enhance the barrier and inhibit the ESIPT reaction. Furthermore, the nucleus independent chemical shift (NICS(1)_ZZ) values of phenol groups indicate the relationship between the reversal aromaticity and the barrier of ESIPT, both of which were proved to be negatively correlated in the ESIPT reaction. It is concluded that not only both types and positions of substituents can tune the excited-state proton transfer behaviors in HBIgen derivatives, but also the aromatic rule can easily be applied to elaborate the ESIPT reaction.

In this work, we explored the potential of the spot test combined with image analysis using smartphones as a rapid, simple, low-cost, and environmentally friendly method for identifying methadone concentration. Herein, a carbon-gold nanocomposite has been used to generate color variation at different concentrations of methadone. The data obtained from the digital image colorimetric method was compared with those from the UV-Vis spectroscopy as a standard technique. This method was also utilized for extensive optimization and validation procedures. Through image analysis, it can be obtained with the PhotoMetrix smartphone App. and single-variable calibration of collected images. This program computes and processes image histograms from the smartphone camera automatically to determine the concentration of methadone in biological samples. For further analysis, the multivariate calibration technique of PARAFAC can also be used on the images that were taken inside the MATLAB program.

This research delves into the holistic hydrothermal synthesis of VS₂ QDs and their subsequent utilization as a fluorescent probe for the subtle detection of ferric ions (Fe³⁺) in practical sample matrices. The detection paradigms harness a colorimetric sensing mechanism, amplified by smartphone-enabled analytical integration for improved precision and real-time monitoring. A comprehensive suite of analytical characterization techniques has been employed, revealing that the as-synthesized VS₂ QDs feature a surface densely populated with functional groups. While the VS₂ QDs showcase interactions with multifarious metal ions in aqueous media, they set forth a pronounced and selective fluorescent quenching response toward Fe³⁺ ions, markedly surpassing their interactions with other metal ions. The developed sensing probe exhibits a linear detection range spanning from 0 - 90 μM, with a LOD as low as 2.25 μM, also exhibits exceptional sensitivity (K_D ∼ 0.8 × 10⁴ M^-1) and remarkable selectivity for Fe³⁺ ions, harnessing the intrinsic photoluminescent characteristics of VS₂ QDs. In addition, a sophisticated portable smartphone platform, integrated with a radiometric fluorescence probe specifically tailored for in-situ detection of Fe³⁺ at the point of care, exhibits a LOD of approximately 5.05 μM, a value that resides below the prescribed safety threshold. Thus, the proposed probe stands to function as an exceptionally potent sensing apparatus for the precise quantification of Fe³⁺ in complex real-world samples.

Resonance Light Scattering (RLS) is a sensitive analytical technology hindered by its susceptibility to impurities in complex samples. This study introduces a combination of RLS with a high-efficiency sample preparation device, the Miniaturized Thermal-Assisted Purge-and-Trap (MTAPT), enhancing RLS's effectiveness in complex sample analysis. Specifically, we utilized MTAPT-RLS for the indirect screening of illegal hydrochloride drug additions in health products, based on three considerations: the transformation of bound HCl in hydrochloride drugs into volatile HCl under strong acid and heat; the minimal Cl content in health products for taste purposes; and the detectability of Cl ions by RLS upon the addition of AgNO₃ and a stabilizer. Employing RLS, this method quantifies Cl elements via fluorescence signals, achieving a linear response (R = 0.9984) across 5.0-80.0 μg/mL and a recovery rate of 94.1-114.0 % across three sample types. With a detection limit of 2.0 μg/mL, this approach exceeds traditional rapid detection methods in speed and sensitivity, offering substantial benefits for food safety monitoring. Additionally, we developed a smartphone-based detection system utilizing RGB signal changes captured by smartphone cameras, coupled with a custom app. This system shows a linear response (R = 0.9888) within the same concentration range and detection limit. Notably, the green light source provided the highest sensitivity, aligning with the RLS peak at approximately 520 nm. With its excellent portability, this method is well-suited for on-site rapid detection, independent of bulky analytical instruments.