Elsevier最新文献

Covalent functionalization is always known for superior colloidal stability, improved selectivity, fluorescence stability, and prevents aggregation of molecules, which reflects higher sensitivity and is preferred over non-covalent interactions. Herein, we have demonstrated one-step covalent functionalization of high-purity carbon nanodots (CNDs) with ligands such as glutathione (GSH) and cysteine (CYS) for the enhanced specificity towards arsenic detection. An improved detection limit of 0.26 ppt and 1.7 ppb for As (III) with GSH and CYS functionalized CNDs was observed while comparing with previous non-covalent thiol-based probes with a linear and non-linear Stern-Volmer plot meant for both static and dynamic quenching processes. The arsenic fluorescent probe was thoroughly characterized with spectroscopic and morphological studies. Further, an attempt was also made to develop a paper analytical device (PAD) for instrument free arsenic detection in water, and the real-world application is demonstrated by analyzing the tap water and groundwater samples from arsenic arsenic-affected area.

Prostate cancer (PCa) exhibits significant intra-tumor metabolic heterogeneity. In this study, we developed a multi-platform workflow combining pathological staining, matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI), and laser capture microdissection-assistant gas chromatography-tandem mass spectrometry (LCM-GC-MS/MS) to investigate the metabolic spatial heterogeneity of a specific PCa tissue. Four suspicious glandular regions were initially identified by histology and immunofluorescence. MALDI-MSI revealed three distinct metabolic patterns for further analysis. It was found that only one glandular region showed PCa metabolic features, enabling precise differentiation from other regions of interest. The information from LCM-GC-MS/MS complemented that from MSI by confirming and quantifying fatty acid alterations. This workflow broadened the spatial metabolic coverage and enhanced intra-tumor metabolic heterogeneity analysis in PCa.

This study presents the development and validation of an automated pressurized liquid extraction (PLE) method using the EXTREVA ASE system for the determination of 233 pesticide residues in coffee, a matrix considered challenging due to its complex composition. The method was evaluated at three fortification levels (10, 20, and 50 μg/kg), with nine replicates per level distributed over three days to assess inter-day reproducibility. At 20 and 50 μg/kg, all compounds met the established performance criteria of 70-120 % recovery and relative standard deviations (RSDs) below 20 %. At the 10 μg/kg level, only 12 compounds (5.2 %) were outside these criteria, primarily due to known issues such as co-elution with matrix components or the acidic nature of certain analytes. All analytes exhibited excellent linearity (R² ≥ 0.99) across a five-point procedural calibration from 0.005 to 0.1 mg/L (0.005, 0.01, 0.02, 0.05, 0.1 mg/L), confirming the method's suitability for quantitative analysis. Matrix effect evaluation showed that 44 % of analytes experienced low or negligible effects, 42 % moderate effects, and only 14 % were strongly affected. Real sample analysis confirmed the method's applicability for routine monitoring, while participation in the EUPT-FV-SC07 proficiency test for coffee demonstrated high analytical performance, with z-scores ranging from -0.7 to 0.3 and RSDs below 20 % for all compounds. Overall, this work provides a validated, reproducible and automation-ready solution for multiresidue pesticide control in complex matrices such as coffee, meeting regulatory standards and suited for high-throughput laboratories.

The adulteration of pure edible oils, particularly with cost-effective oils like palm oil, has become a significant concern due to its detrimental impact on oil quality and human health. This study examines how palm oil adulteration affects the dielectric, physical, and chemical properties of groundnut and sunflower oils. Additionally, this study explores the nutritional differences between pure and adulterated oils, highlighting potential risks to consumers. Microwave analysis showed decreased dielectric constant and loss in groundnut and sunflower oils after palm oil blending. Chemical parameters and fatty acid composition confirmed adulteration effects and potential health risks. To ensure the accuracy and reliability of our findings, we applied several chemometric methods, including Hierarchical Cluster Analysis (HCA), Principal Component Analysis (PCA), Multiple Linear Regression (MLR), and Artificial Neural Networks (ANN) to detect adulteration in oils. Among these, ANN and MLR were compared for predicting the dielectric constant. The results showed that ANN performed much better than MLR, explaining R² value of 0.94 in groundnut oil and 0.96 in sunflower oil, proving it to be a more accurate method for assessing oil quality. The features that made the ANN model work better were found using SHAP analysis. The result of the SHAP value shows that the refractive index (RF) in groundnut oil and the saponification (SAP) value in sunflower oil are the most influential predictors of dielectric constant, as both parameters vary significantly with adulteration. This finding demonstrates a powerful and accurate approach for detecting adulteration and assessing the quality of edible oils.

A conductive hydrogel with double network structure was prepared by embedding Ag nanoparticles onto polyvinylpyrrolidone through in situ reduction, and subsequently crosslinking the mixture with polyvinyl alcohol and sodium lignosulfonate. This unique architecture imparted the hydrogel with good mechanical properties and fatigue resistance. Notably, the hydrogel exhibited remarkable antibacterial efficacy, achieving inhibition rates of 99.9 % against E. coli and 95.8 % against S. aureus. Furthermore, the conductive network, formed through the synergistic interaction of free ions and AgNPs, significantly enhanced both the conductivity and durability of the hydrogel sensor. The results demonstrated that the sensor maintained stable sensitivity even after 1000 cycles of stretching at 3 % and 30 % strain. In practical applications, this hydrogel sensor was successfully employed for real-time monitoring of various human body parts, including fingers, elbows, knees and facial expressions, underscoring its significant potential in the fields of flexible electronics and wearable sensing technologies.

A sample pretreatment method based on extraction induced by emulsion breaking (EIEB) was developed for the determination of selenium in milk powder by inductively coupled plasma mass spectrometry (ICP-MS). Validation with a certified reference material confirmed the method's excellent accuracy (recoveries: 82.90-97.80 %), good precision (relative standard deviation, RSD = 1.68 %, n = 6), and favorable robustness (RSD = 22.03 %, n = 6). The limit of detection (LOD) was 2.2 μg/kg. Compared to microwave-assisted acid digestion, the EIEB approach reduced acid consumption by 80 % (1 mL vs. 5 mL), simplified the workflow, and eliminated the need for specialized equipment, while maintaining comparable analytical performance. Additionally, Triton X-100 was found to enhance selenium signal intensity, acting as a sensitizer in ICP-MS. Analysis of commercial milk powder samples showed selenium concentrations consistent with nutritional reference values. Overall, the EIEB-ICP-MS method provides a robust and sustainable alternative for selenium quantification in dairy products. Aligned with the principles of green analytical chemistry, it also holds promise for application in the analysis of other hydrophilic food matrices.

Cell-based therapies offer transformative potential for treating a range of diseases, however, maintaining desirable cell functions under environmental and biochemical stresses remains a major challenge. In the present study, silk ionomer nanoencapsulation using layer-by-layer (LbL) deposition was utilized as a versatile strategy to provide temporary cell protection from these stresses and preserve cell functions for downstream use. Using THP-1 immune cells, tunable encapsulation of the cells with up to 10 bilayers of silk was demonstrated. Characterization by quartz crystal microbalance (QCM-D) and atomic force microscopy (AFM) revealed nonlinear thickness growth (∼800 nm) and peak stiffness of 231 kPa above five bilayers, indicating a transition from rigid initial layer deposition, to softer outer layers. We demonstrate that the silk ionomer coatings preserved cellular functions, including differentiation into M1 and M2 macrophages, the associated cytokine profiles (TNF-α, IL-1β, IL-10, TGF-β), and expression of cell surface markers (CD68, CD206) when compared to the uncoated controls. Notably, these temporary coatings blocked antibody binding to CD14/CD68 receptors and also protected cells from shear stress during extrusion through a 34G needle at 200 μL/min, resulting in greater than a 70 % increase in cell survival compared to the uncoated cells during extrusion. These results establish silk ionomers as a robust biomaterials platform for enhancing the mechanical resilience and immune evasion of cells in advanced applications, such as for 3D bioprinting, adoptive immunotherapy, and regenerative transplantation.

Current injectable biomaterials for vocal fold disorders suffer from fast degradation and require frequent re-injection. Decellularized extracellular matrix (dECM) hydrogels are a tissue-derived, injectable biomaterial with intrinsic regenerative capacity. However, dECM hydrogels often exhibit mechanical instability and share the same problems with degradation as existing vocal fold biomaterials. In this work, we developed a composite dECM-alginate hydrogel with bioorthogonal click tetrazine ligation with improved stability, biocompatibility and regenerative capacity. dECM was extracted from two sources: tissue-specific vocal fold mucosa and scalable small intestinal submucosa for comparative analysis. Click dECM hydrogels from both sources were tunable and matched mechanical properties of native human vocal folds. The click dECM hydrogels showed capacity to resist contraction and modulate bioactive molecule secretion by fibroblasts, as well as stimulate the initial endothelial cell elongation phase of vasculogenesis. When injected subcutaneously into rats, both gels exhibit a strong initial immune response, followed by integration with the surrounding tissue by day 21. Overall, our click dECM hydrogels showed improved stability over previous dECM hydrogels and their performance was independent of tissue source.

Lactate, a crucial metabolic indicator, plays a vital role in diagnostics and treatment monitoring. Current lactate analysis often relies on enzymatic methods, employed in both clinical analyzers and point-of-care testing (POCT) devices. While these enzymatic assays offer selectivity and sensitivity, they suffer from limitations including higher costs, shorter lifetime, and reduced stability, particularly impacting POCT applications. This work introduces a novel POCT platform for lactate determination, utilizing a non-enzymatic approach. This analytical system is based on the photoreduction of iron(III)-lactate complexes, followed by detection of the resulting iron(II) with Ferrozine. Miniaturization of the system was achieved through two key innovations. First, the entire analytical procedure is conducted on 6 mm diameter reaction disks fabricated from cellulose and glass microfiber filters, facilitating easy storage and disposal while minimizing reagent and sample consumption (a few microliters). Second, an optoelectronic photometric system, incorporating an RGB LED emitter and a photodiode detector, enables both photoreduction (using blue light) and detection of the Fe(II)-Ferrozine complex (using green light). This POCT platform allows for rapid lactate determination in cerebrospinal fluid within 50 s, with analytical parameters supporting sample dilution up to even 100-fold.

Quantifying the fission product ¹⁴⁷Nd in nuclear debris samples is an important component of post-detonation nuclear forensics. The most accurate quantifications are obtained when Nd is purified from all other fission products, actinides, activation products, and environmental matrix contained within the debris. In this study, a recently developed method for Nd purification was tested, purifying ¹⁴⁷Nd from solutions of mixed fission products using high-speed counter-current chromatography (HSCCC). Importantly, the new method allowed for faster elution of Nd from the column as compared with established high performance liquid chromatography (HPLC) methods, and resulted in accurate/precise ¹⁴⁷Nd quantification by gamma-ray spectrometry. While the up-front equipment costs associated with HSCCC may be higher, its operational costs are on par with those of HPLC (solvents, extractants, power). Gas-flow proportional beta decay counting revealed contamination from the nearest neighbor lanthanide ¹⁴³Pr (a gamma-silent radioisotope) in the HSCCC-purified samples, but the activity contribution from ¹⁴⁷Nd could still be quantified. Remarkably consistent elution profiles were observed for the HSCCC method, spanning rare earth element (REE) loadings of more than 10 orders of magnitude (tracer to mmol quantities). The reliability and speed of the new method suggest utility for the rapid separation and quantification of ¹⁴⁷Nd in unknown samples.