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

Real-time monitoring of viral particles can have a crucial impact on vaccine manufacturing and can alleviate public health challenges by supporting continuous supply. Spectroscopic methods such as Raman spectroscopy can provide rapid and non-invasive measurements. Here, we have developed a Raman spectroscopy-based tool to monitor the quality and quantity of viral particles in a continuous flow setup. We characterized the attenuated human cytomegalovirus (CMV) across a wide range of concentrations (1.45 × 10¹⁰ to 2.90 × 10¹¹ particles/mL) and flow rates (100 μm/s to 1000 μm/s) within a square quartz capillary. This process analytical technology (PAT) tool enables the detection of viral particles even at high flow rates such as 1000 μm/s. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and dynamic light scattering (DLS) demonstrated that the samples maintain their integrity even after laser exposure, reiterating the non-invasive nature of Raman spectroscopy. To the best of our knowledge, this is the first report on characterizing CMV particles using Raman spectroscopy, especially under flow conditions. We have also demonstrated the limit of detection (LOD_min) (2.01 × 10¹⁰ particles/mL) for CMV particles in continuous flow (1000 μm/s) (via the Raman spectroscopy method), addressing the effects of flow rate, concentration, and sample integrity. This technology could enable process control in the bio-manufacturing of vaccines.

The determination of the α-glucosidase (α-Glu) activity is crucial for the early screening of diabetes. However, traditional α-Glu detection methods mainly rely on a single-signal readout system, which is inevitably subjected to interference from a complicated detection environment. To address this practical issue, a fluorescence-colorimetric dual-mode sensor based on green-emitting nitrogen-doped carbon dots (GN-CDs) was designed for the sensitive and portable detection of α-Glu. The detection strategy of this sensor was based on the enzymatic reaction of α-Glu with the specific substrate p-nitrophenyl-α-D-glucopyranoside (PNPG) to generate p-nitrophenol (PNP), which not only displayed stronger absorbance at 400 nm but also could effectively quench the fluorescence of GN-CDs through the inner filter effect (IFE), thereby realizing the dual-mode detection of α-Glu. Through the mutual calibration of the double signals, the accuracy and anti-interference ability of α-Glu detection in complex environments were significantly improved, with the detection limits as low as 0.023 U/L in fluorescence mode and 0.045 U/L in colorimetric mode, respectively. Furthermore, portable α-Glu detection was successfully achieved by integrating GN-CDs loaded hydrogel microspheres and smartphone-based image analysis technology. Therefore, the developed dual-signal sensor provided an accurate and portable strategy for α-Glu detection, demonstrating great application potential in the sensing of diabetes-related biomarkers.

Fluorescence excitation-emission matrix (EEM) spectroscopy is a crucial analytical tool for characterizing dissolved organic matter in aquatic systems. The factorization of mixed spectral components within EEMs has long been the main subject of data interpretation, prompting widespread adoption of trilinear decomposition such as parallel factor analysis (PARAFAC). However, the requirements of multi-sample dataset and manual judgment pose limitations to PARAFAC analysis, particularly hindering the real-time and in-situ applications. This study introduces a rapid decomposition approach capable of automatically decomposing single EEM input into fluorescent components. The proposed approach, termed empirical initialization non-negative matrix factorization (EI-NMF), comprises three core steps: (1) chemical rank estimation via singular value decomposition (SVD), (2) empirical initialization based on statistical analysis, and (3) non-negative matrix factorization with multiplicative updates. Simulated data and natural water samples were used to verify the feasibility of proposed approach. Validation on simulated data yielded satisfactory results: EI-NMF achieved accurate chemical rank determination and component spectral recovery (Tucker congruence coefficients >0.9) relative to the true component spectra. Decomposition results of unseen natural samples further confirmed that EI-NMF can effectively processes single EEM inputs, yielding decomposition outcomes with excellent accuracy and chemical interpretability. This computationally efficient framework enables real-time decomposition of individual EEMs (processing time <0.1 s), offering significant potential for in situ monitoring of aquatic fluorescent components.

Organic photosensitizers (PSs) with organelle targeting and photodynamic therapy (PDT) performance have received extensive attention from scientific researchers. In this study, diphenylamine-xanthene compounds with aggregation-induced emission (AIE) properties were designed and synthesized. The different organelle-targeting performance of the photosensitizer was achieved by subtly regulating the functional group connected to the aldehyde group. These aggregation-induced emission luminogens (AIEgens) can not only specifically target organelles, but also effectively produce reactive oxygen species (ROS) under visible light irradiation. Mitochondria-targeting AIE compounds with cationic groups (OCH₃-AP) have better ROS generation capacity and cell phototoxicity than compound (OCH₃-AM) targeting lipid droplets (LDs). Through in vivo experiments, it was found that OCH₃-AP has a long retention ability in live tumor tissues and have potential application value in photodynamic cancer therapy.

To achieve rapid, non-destructive detection of food quality indicators, this study introduces a novel method that combines near-infrared (NIR) spectroscopy with the Extreme learning machine (ELM) model. Eight spectral preprocessing methods and three wavelength selection algorithms were evaluated for predicting total ginsenoside content (TGC) and protein content (PC), along with a comparative analysis of the ELM model's performance against support vector regression and random forest. Results showed that Savitzky-Golay smoothing with standard normal variate was the best preprocessing method, K-means clustering provided the optimal wavelength selection algorithm, and the ELM model demonstrated the best performance. Specifically, the ELM based on K-means method achieved optimal results: R² of 0.9431, RMSE of 0.2933 mg/g, rRMSE of 0.0824, RPD of 4.2386, and P-time of 4 × 10^-7 s for TGC; and R² of 0.9764, RMSE of 4.1361 mg/g, rRMSE of 0.0337, RPD of 6.1295, and P-time of 2 × 10^-7 s for PC. In summary, combining NIR spectroscopy with the ELM model and clustering-based wavelength selection algorithm offers a reliable and practical solution for rapid, non-destructive, and accurate detection of food quality indicators.

Rationale: Procaine HCl (PrHCl), a protic ionic liquid (PIL), exhibits intricate relaxation due to ionic and neutral species interactions. However, its glass-forming ability is limited. To overcome these limitations, this study explores the synthesis of a novel PIL, PrHIb, by replacing Cl^- with the bulky, asymmetric ibuprofen anion. This modification is expected to introduce steric hindrance, restrict molecular mobility, and decouple relaxation processes, thereby enhancing thermal stability, glass-forming ability, and pharmaceutical functionality.

Aim: To synthesize and characterize a novel protic ionic liquid, PrHIb, with a focus on relaxation dynamics, glass-forming ability, and dual therapeutic potential.

Method: PrHIb synthesis was validated by density functional theory (DFT), Fourier Transform Infrared Spectrscopy (FTIR), and Fourier Transform Raman Spectroscopy (FT-RS). The antibacterial and anti-inflammatory properties of PrHIb were evaluated. Thermal and molecular dynamics were studied by differential scanning calorimetry (DSC) and broadband dielectric spectroscopy (BDS). Molecular mobility was assessed to decipher the decoupling of ionic and neutral molecules. The polymer matrices were explored to enhance performance and applicability by restricting molecular mobility.

Results and discussion: DFT confirmed PrHIb formation as endothermic and non-spontaneous under standard conditions with positive enthalpy (∆H = -3.88× 10⁵ kcal/mol) and Gibbs free energy (∆G = -3.88× 10⁵ kcal/mol), while negative entropy (∆S = -56.43 cal/molK) reflects reduced system disorder. FTIR and FT-RS validated the incorporation of functional groups from procaine and ibuprofen. PrHIb exhibited enhanced antimicrobial efficacy against E. coli (62 %) and Pseudomonas (80 %) compared to PrHCl and retained strong anti-inflammatory activity (95 %). DSC and BDS studies confirmed glass-forming behavior, with a T_g of 266 K. Replacement of Cl^- with Ibu^- led to decoupled relaxation and the lack of secondary relaxation. Two distinct relaxations in M″(ω) were attributed to ionic conductivity and structural relaxation. All data were fit the Havriliak-Negami equation. Vogel-Fulcher-Tammann (VFT) showed high fragility (m = 102), indicating sharp viscosity changes near T_g. polyvinylpyrrolidone (PVP) confinement reduced fragility (m = 36), suppressed ionic hopping, and improved stability with a T_g of ∼269 K.

Conclusion: Replacing Cl^- with bulky, asymmetric Ib^- in PrHIb restricts molecular mobility, leading to decoupled relaxation processes and enhanced dynamic heterogeneity. Confinement in a PVP matrix further stabilizes PrHIb by reducing fragility and improving its glass-forming ability. These features, along with dual antimicrobial and anti-inflammatory activity, h

Kaempferol (3,4',5,7-tetrahydroxyflavone, KMP) and curcumin (diferuloylmethane, CUR) are naturally occurring polyphenolic compounds with broad therapeutic potential, including anticancer, antioxidant, and anti-inflammatory properties. Among their molecular targets, DNA plays a central role, particularly through interactions with non-canonical DNA structures such as G-quadruplexes (G₄) and i-motifs (C₄), which form in guanine- and cytosine-rich genomic regions, respectively. These structures regulate telomere maintenance, gene expression, and genomic stability, making them attractive drug targets. In this study, we investigate the binding behavior of KMP and CUR with G₄, C₄, and duplex calf thymus DNA (calf thymus (CT)-DNA) using an integrated spectroscopic and computational approach. Circular dichroism, UV-visible absorption, and fluorescence spectroscopy were used to monitor ligand-induced structural and photophysical changes. CUR exhibited pronounced solvatochromism, with emission maxima shifting according to solvent polarity and DNA topology and showed the strongest fluorescence enhancement in G₄ DNA. KMP displayed excited state intramolecular proton transfer (ESIPT), with the highest tautomeric emission observed in G₄ structures. However, G₄ also facilitated ground-state anion formation at the 3-OH group of KMP, which suppressed ESIPT by interfering with intramolecular hydrogen bonding between C(4) = O and 3-OH. ESIPT was least prominent in C₄, and moderate in duplex DNA, where anion formation was less favored. Displacement assays using ethidium bromide (EtBr) provided functional insight into the competitive binding dynamics, confirming groove and loop binding for both ligands in G₄ and C₄ DNA, while KMP also exhibited intercalative binding in duplex DNA. Molecular docking and molecular dynamics simulations corroborated these findings, revealing stable ligand-DNA complexes and specific interaction modes. This comprehensive approach highlights CUR as a polarity-sensitive reporter and KMP as a thermally and structurally responsive ESIPT fluorophore. Together, they represent promising tools for probing DNA topology and developing targeted molecular diagnostics or therapeutic strategies centered on nucleic acid structure recognition.

Traumatic brain injury (TBI) is a serious clinical and social problem. Millions of TBI cases, that require hospitalization and consequently burden social security systems, are reported each year. Analysis of the time course of changes that occur in the brain after primary injury may help indicate therapeutic goals and treatment directions that will minimize severe secondary effects of TBI. Existing animal models simulating the development of TBI in human are divided into two main groups, namely into diffuse and local models. Diffuse injury models are ideal for studying concussions and long-term effects of TBI, as they replicate global changes occurring in brain. Local injury models excel in examining focal brain damage and testing region-specific therapies, they also offer greater control and reproducibility. In our study local induction of TBI enabled better control of the extent of the damage and thus reduced the number of animals needed for the experiment. As part of the work, Fourier transform infrared microspectroscopy and complementary Raman microscopy were used to track the time course of biochemical changes that occur in the rat cerebral cortex as a result of its local mechanical damage. Comparative studies, carried out for the injury site and microscopically unaffected area of the cerebral cortex, indicated some anomalies in the accumulation and structure of organic compounds, including a reduction of the level of cholesterol/cholesterol esters (approx. 30 % in first two examined periods after TBI) and the compounds containing phosphate groups (approx. 25 %), as well as the conformational changes of proteins and lipids in the injury site comparing to unchanged cortex tissue. The comparison of the glial scar development in male and female rats showed only a very subtle differences between sexes. Among them it is necessary to mention the diminished unsaturation degree of lipids within the scar in case of female rats that was not found in males. The obtained results substantiated that vibrational microspectroscopy methods represent powerful, non-destructive tool of high-resolution biomolecular analysis of brain tissue. These techniques enable the identification of biochemical alterations linked to glial scarring following TBI, allow for the monitoring of the dynamics of this process, and provide insights into the sex-dependence of the recorded anomalies. This knowledge could prove instrumental in identifying potential diagnostic and prognostic biomarkers of TBI, as well as in the development of new therapeutic strategies for managing this condition.

Carbonized polymer dots (CPDs), a new nanofluorescent materials inheriting the advantages of CDs, have been widely studied for their excellent physicochemical stability and tunable fluorescence properties, and have extensive application in the fields of optoelectronic devices and environmental monitoring. In this study, nitrogen-doped CPDs (CMC-M-CPDs) were synthesized via hydrothermal reaction using carboxymethyl cellulose (CMC) and melamine (M), which allowed N doping to improve the luminescence of CPDs through cross-linking and reduction of the energy gap. Due to the excitation-dependent, the luminescence wavelength of CPDs can be tuned, so these CPDs exhibit two optimal emission centers in the fluorescence spectra, which originate from the carbon core and the surface, respectively. A significant quenching effect on the luminescence of CMC-M-CPDs at 457 nm and 515 nm was exhibited due to static quenching of Cr(VI). Therefore, dual-channel fluorescence detection of Cr(VI) can be achieved, allowing detection using both excitation wavelengths to be carried out concurrently and mutually verified in complex environments. This improves the accuracy of detection, with limits of detection (LOD) of 60.15 nM and 93.95 nM, respectively. The CMC-M-CPDs demonstrate excellent selectivity and anti-interference in the detection of Cr(VI), with a quenching response occurring within 1 s. This dual-channel fluorescent probe can also be applied for sensitive detection in tap water and Songhua River water. Furthermore, the fluorescence of quenched CPDs can be restored by adding ascorbic acid (AA), achieving a maximum recovery efficiency of 96.6 %.

Polarity, viscosity and peroxynitrite (ONOO^-) are key factors in determining mitochondrial function and activity, and real-time monitoring of these parameters is important for gaining insight into the physiological mechanisms involved. In this study, we developed a new multifunctional fluorescent probe CNB-2 for monitoring mitochondrial polarity, viscosity, and ONOO^- level fluctuations. CNB-2 demonstrated robust responses to polarity and viscosity, with its fluorescence intensity exhibiting a strong linear correlation to the logarithm of polarity parameters and viscosity, increasing significantly as these parameters rise. Notably, for ONOO^- detection, CNB-2 is characterized by rapid response, high selectivity, a low detection limit (51.3 nM), and a large Stokes shift (130 nm). Moreover, CNB-2 can be used for live cell imaging of mitochondrial polarity, viscosity, and ONOO^-, as well as monitoring of changes in ONOO^- concentration in real-time during ferroptosis. Therefore, the prepared probe CNB-2 provides a reliable tool for better understanding the mitochondrial microenvironment and a new way for diagnosing ferroptosis-related diseases.