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

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.

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.

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.

High copper levels pose a risk to environmental and human health due to their toxicity and widespread industrial application, in which abnormal copper levels are associated with various diseases both in neurodegenerative diseases and plant growth. Thus, a turn-on fluorescent probe BBYD-Cu, based on donor-acceptor type structure, was designed and synthesized with easy preparations. BBYD-Cu can specifically recognized Cu²⁺ by 2-picolinic ester group, then released the fluorophore to enhance the fluorescent signals. With a detection limit of 31 nM, it displays extremely sensitive and precise Cu²⁺ detection. In addition, BBYD-Cu has the advantages of fast response speed (within 3 min), excellent selectivity and strong anti-interference ability for Cu²⁺. Significantly, the BBYD-Cu demonstrates superior detection and imaging performance even in intricate real-world environmental samples, biological nerve cells and plant soybean sprout root tissue.

The power conversion efficiency (PCE) of ternary all-small-molecule organic solar cells (T-ASM-OSCs) differs significantly from that of the polymer systems (2 %), and the role of third component remains unclear. The electron donor of coumarin derivatives with simple structure and strong and broad light absorption has high PCE for T-ASM-OSCs composed of non-fullerene acceptors (Y6 and DBTBT-IC). Here, we calculated the electronic structure and interfacial properties of the binary C1-CN:Y6 and ternary C1-CN:Y6:DBTBT-IC systems using molecular dynamic (MD) simulations and density functional theory (DFT) to explore the role of the third component (DBTBT-IC). The addition of the third component mainly facilitates the different stacking patterns of the host system in ternary OSCs, optimizes the charge transfer properties, enhances the light absorption, generates more CT pathways and significantly promotes the charge separation for unfavorable stacking patterns. While the guest system composed of C1-CN:DBTBT-IC also leads to the ternary system with more stable stacking patterns and low exciton binding energy. This work elucidates the role of the third component and the importance of interfacial molecular stacking, providing theoretical guidance for the selection and design of organic photovoltaic materials.

Nitric oxide (NO) is a key signaling molecule that regulates energy metabolism, apoptosis, and antioxidant balance within mitochondria. It is closely associated with the development of cardiovascular diseases, neurodegenerative diseases, and cancer. Therefore, developing fluorescent probes capable of accurately detecting NO levels in mitochondria is essential for understanding disease mechanisms and clinical diagnostics. In this study, we developed a novel fluorescent probe based on the isophorone fluorophore. This probe achieves high sensitivity and specific ratiometric detection of NO in mitochondria by regulating the intramolecular charge transfer (ICT) effect. The probe emits red fluorescence before reacting with NO, and the addition of NO triggers an amine-NO addition reaction that inhibits the ICT effect, resulting in a color change to yellow-green fluorescence. This ratiometric fluorescence response provides a new method for quantitatively detecting NO. Additionally, the probe has a significant Stokes shift and good ratiometric wavelength separation, enhancing detection accuracy. It localizes explicitly to mitochondria, directly reflecting changes in mitochondrial NO concentration. Experiments in HeLa cells and zebrafish models have demonstrated the potential application of the probe in diagnosing and studying NO-related diseases. This provides new strategies and tools for researching the biological functions of NO and the early diagnosis of related diseases.

Psychological stress is a major contributor to individual health disparities. Accurate and quantitative detection of stress markers is crucial preventing mental health related problems. Supramolecular chemistry is widely used in drug delivery, catalysis, sensors and other applications. However, due to the difficulty of host functionalization such as cyclodextrins and solid-state pillar[n], it is still a challenge to directly realize the detection of guests through host-guest recognition behavior. Here, we reported an atom transfer radical polymerization (ATRP) fluorescent biosensor for direct and selective detection of guest molecule stress marker cortisol, translating molecular recognition behavior into quantifiable detection signals. Realizes quantitative chemical detection and builds a portable and affordable sensing platform for quantitative detection of target molecules without complex cross-linking steps. Overcomes the disadvantages of traditional methods that require the use of antibodies or are difficult to functionalize during the host-guest recognition process. This ATRP fluorescent biosensor was fabricated by employing zinc phthalocyanine (ZnPc) as a photocatalyst under 630 nm wavelength radiation, β-CD-Br₁₅ as a macromolecular initiator, and fluorescein O-methacrylate (FMA-O) as a monomer for polymerization. The system provides ultra-high sensitivity for the detection of cortisol (limit of detection 0.47 ng/mL) and specificity for the detection of cortisol in the presence of interfering substances such as progesterone and urea. Selective and real sample experiments confirm the specificity and scalability of this mechanism can also be customized by the rational design of the host-guest complex to quantitatively detect various molecules. This study confirms the feasibility of using a cyclodextrin-centered macromolecular initiator as a capture and label-free fluorescent biosensor for cortisol, a stress biomarker.

Culture media are widely used for biological research and production. It is essential for the growth of microorganisms, cells, or tissues. It includes complex components like carbohydrates, proteins, vitamins, and minerals. The media's consistency is key for predictable outcomes in biology applications. However, traditional methods of analyzing media are costly and time-consuming by using chromatography or mass spectrometry. This study introduces an innovative approach using optimized convolutional neural networks (CNN) combined with Raman spectroscopy to identify culture media. Samples of culture media from different models and batches are prepared for identification experiment. Raman spectra of each culture media samples are captured with unique molecular vibrations and rotations by Raman spectrometer rapidly. After preprocessing of sample data, Raman spectra are input to CNN for identification training and validation. An optimized CNN with more layers is designed to enhance the identify ability for Raman spectra. In experiment, it compared the performance of PCA-SVM, the original CNN, and an optimized CNN for media identification. The PCA-SVM achieved high accuracy and precision rates of 99.19% and 98.39% respectively. The original CNN achieved an accuracy of 71.89% due to limited training dataset. The optimized CNN model achieved a perfect accuracy rate of 100% in identifying different culture media. To avoid overfitting risk, additional external test is performed with optimized CNN. The result confirmed that optimized CNN offering effectiveness in identifying media from different models and batches, with strong generalization ability. The findings in study may offer an efficient and cost-effective method for pharmaceutical companies, to ensure the consistency of culture media.