Talanta Open最新文献

Globally, trace metals toxicity in wastewater poses health problems for humans even at truncated concentrations and warrants investigation. This review study focuses on the suitable cutting-edge advancements in nanotechnology-based electrochemical sensor technology for the apprehension of selected toxic metal ions such as arsenic(As), cadmium(Cd), chromium(Cr), lead(Pb), and uranium(Ur)) in wastewater samples. The discussion includes an examination of synthesis techniques for sensors based on Nanomaterials (NMs). Moreover, these electrochemical sensors are scrutinized to study the complex principles that describe their problem solving achievement, such as susceptibility, determination limit, duplicability, repeatability, and selectivity in wastewater matrices for trace metal detection. Most importantly, the discussion also considers the interactions between NMs, electrochemistry, and sensing mechanisms, providing a comprehensive view of the cooperative developments promoting improved advanced sensor technology. This review critically investigates the existing literature to assess and capture the progress landscape of nano-based electrochemical sensors. Ultimately, this review paper could significantly play a role towards the use of these attractive nano-based electrode materials in revamping paradigms for environmental monitoring and advancing precision in trace metal sensing in wastewater.

Paper-based microfluidics has emerged as a promising field with diverse applications ranging from medical diagnostics to environmental monitoring. Despite significant progress in research and development, the translation of paper-based prototypes into practical end-user devices remains limited. This limitation stems from challenges related to devices not being sufficiently portable and autonomous, which paper-based microfluidics is expected to overcome. Yet for this purpose, we note the lack of comprehensive numerical modeling tools capable of simulating the intricate physicochemical phenomena involved in order to optimize the development process; hence, in this study, we introduce porousMicroTransport, a novel simulation package integrated with the open-source platform OpenFOAM®, designed to address these challenges. porousMicroTransport offers efficient solvers for fluid flow and transport phenomena in microfluidic porous media, including capillarity models and (bio)chemical reactions. Moreover, under horizontal flow conditions, porousMicroTransport application field can be extended to any porous media. We demonstrate the software’s effectiveness in two example cases, showcasing its ability to accurately reproduce complex phenomena involved in paper-based devices. By virtue of being an easy-to-use and computationally efficient tool, porousMicroTransport facilitates the design and optimization of devices, potentially enabling more devices to meet the WHO’s REASSURED criteria for point-of-care testing. We anticipate that this tool will accelerate the development and deployment of robust and portable diagnostic devices, bridging the gap between research and practical applications.

Silver nanoparticles (AgNPs)-Chitosan (Chi) functionalized cysteine (cys)-SAM (self-assembled monolayer) based electrochemical, label free, ultrasensitive, non-invasive immunosensing nanomolecular platform has been fabricated for the detection of novel OC biomarker S-100. This has been achieved through bio-functionalization of AgNPs-Chi/cys/mini gold slides by covalent immobilization of anti-S100 antibodies. Cyclic voltammetric (CV) studies establish successful fabrication of anti-S100/AgNPs-Chi/Au nanomolecular platform. Differential pulse voltammetric (DPV) measurements reveal that anti-S100/Chi-AgNPs/Au is able to sense 50 fg mL^-1 – 500 ng mL^-1 of S100 in buffer and in spiked saliva samples within 120 s interaction time having improved favorable shelf life and specificity. The fabricated platform is very selective and able to detect S100 in OC patient/s saliva samples warrants realization of simple non-invasive electrochemical immunosensor for in situ or on-site applications (especially for remote areas) for early diagnosis of OC while offering bio-compatibility at low cost.

Although several luminescent-based nanostructured materials are used as cellular imaging probes, creating a biocompatible subcellular imaging probe can be challenging. Instantaneously, it is crucial and urgently needed for certain fluorescent nanoprobes to identify possibly harmful heavy metal ions. We present a straightforward one-pot preparation of bright orange emissive (quantum yield approximately 16 %) Nitrogen/Sulfur co-doped carbon dots (N/S CDs) from citric acid and methylene blue as raw materials that will serve as a specific Cr(VI) ions sensor and an effective mitochondrial labeling in cancer cells. They had several benefits including low ecological impact, facile synthesis, good water solubility, photostability, and high stability. We found that N/S CDs photoluminescence (PL) could be reduced when Cr(VI) ions were present near them, and the PL reduction occurred highly sensitively to the presence of Cr(VI) compared to other metal ions including Cr(III) ions. This specific reduction of PL was due to the non-fluorescent complex formation through the inner filter effect (IFE). The established fluorescence-based sensing technique could serve for Cr(VI) ion quantification with exceptional sensing efficiency in the wide linear range of 7 to 70 μM (R₂ = 0.9873), with the limit of detection of 53.5 nM. It was also revealed that the current fluorescent probe could be encouragingly utilized to quantify the concentration of Cr(VI) ions in various water specimens such as tap water. In addition, they were shown to function as a mitochondria-targeting nanoprobe in human cancer cells (ME 180 cells and Hela cells) for cell imaging. Concludingly, it was envisioned that these fluorescent nanoprobes could find a use in real-time monitoring of Cr(VI) ions in water-based ecosystems with ultrahigh sensitivity and cell image tracking via mitochondria labeling as biocompatible nanoprobes.

A novel fluorescent molecularly imprinted polymer membrane (FMIM) has been developed for the selective binding and qualitative detection of pepsin enzyme, a biomarker indicative of gastroesophageal reflux disease (GERD). This study utilises the high selectivity offered by molecular imprinting techniques to capture pepsin enzyme within complex biological matrices, such as human saliva. Additionally, fluorescent carbon dots integrated into the membrane matrix provide instant visual detection of pepsin. Various combinations of functional monomers and cross-linkers were systematically evaluated to investigate their impact on the binding capacity and mechanical stability of the resultant FMIMs. The optimum performance was achieved with a mixture of two hydrophilic monomers, namely N-(hydroxymethyl)acrylamide and acrylamide, in conjunction with N,N-methylenebis(acrylamide) as the cross-linking agent. The developed FMIM demonstrated a binding capacity of 21.56 mg g^-1, surpassing that of the fluorescent non-imprinted membrane (FNIM) at 8.49 mg g^-1. Moreover, the binding of FMIM to pepsin was tested against other competitor enzymes to verify its selectivity. Furthermore, comprehensive characterisation of both FMIM and FNIM was conducted using various analytical techniques to ensure their structural integrity and functionality. Ultimately, the developed FMIM exhibited effective binding of pepsin in standard solutions and samples, enabling enrichment and visual detection of the biomarker enzyme.

The 2018 Agricultural Improvement Act federally legalized the cultivation of hemp and manufacture and sale of cannabidiol (CBD). The overproduction of CBD led to a significant drop in price. To maintain profitability, manufacturers began producing synthetic and semi-synthetic cannabinoids, marketing them as “legal” and “hemp-derived” due to their synthesis from CBD. The cannabis industry is adaptable, and laboratories have struggled to keep up with the rapid emergence of new compounds. This has resulted in products with unlabeled or mislabeled cannabinoids, causing unexpected adverse events. A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the separation and quantitation of 21 cannabinoids. The method was applied in the analysis of 55 commercially available products. Results demonstrate significant issues with quality assurance and labeling in the unregulated cannabis market. Many products either did not contain the cannabinoids listed on their labels or contained cannabinoids that were not listed. When cannabinoids were present, their concentrations were often incorrect, with some products showing high concentrations that could pose a potential health risk. Moreover, safety, dosing, and other pharmacological data of these newly proliferated cannabinoids are lacking. Reports of adverse events are increasing to poison controls centers and emergency departments following cannabis product use. Often, the actual cannabinoids involved in the case reprots are not determined. It is critical to develop more comprehensive testing methodologies to determine the content of cannabis products and to implement stronger quality assurance measures and regulations to protect the public from low-quality and potentially dangerous products.

Carbon Quantum Dots from Natural Sources (NACQDs) is a novel type of carbon-based material that have garnered significant attention due to their remarkable features, including luminescence, photostability, nanoscale size, water solubility, low toxicity, biocompatibility, and cost-effectiveness. The synthesis of NACQDs involves a diverse range of natural sources, such as fruits, foods, beverages, human and animal derivatives, vegetables, leaves, and waste materials. Various synthesis methods, including electrochemical approach, chemical oxidation, hydrothermal carbonization, ultrasonic techniques, microwave-assisted synthesis, solvothermal method, laser ablation technique, thermolysis, and atmospheric plasma-based synthesis, have been explored to tailor the size and properties of NACQDs. Characterization techniques like Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TЕM), ultraviolet absorption, fluorescence properties, and nuclear magnetic resonance (NMR) have provided invaluable insights into the physical and chemical characteristics of NACQDs. This review highlights the immense potential of NACQDs in metal ion sensing applications and underscores the need for further investigation to enhance their reproducibility and precise control over their properties. NACQDs hold great promise as versatile nanomaterials for metal ion sensing and are poised to revolutionize diverse fields, ranging from environmental monitoring to biomedical diagnostics and chemical analysis.

We used a microfluidic paper-based analytical device (μPAD) to investigate the influence that zinc reduction exerts on the determination of nitrite and nitrate ions in natural water samples. The μPAD consists of layered channels for the reduction of nitrate to nitrite with zinc powder and the subsequent detection of nitrite with Griess reagent. The amount of zinc, number of layers, and reaction time for the reduction were optimized to obtain an intense signal for nitrate. Initially, the sensitivity to nitrate corresponded to 55% that of nitrite, which implied an incomplete reduction. We found, however, that zinc decreased the sensitivity to nitrite in both the μPAD and spectrophotometry. The sensitivity to nitrite was decreased by 48% in spectrophotometry and 68% in the μPAD following the reaction with zinc. One of the reasons for the decreased sensitivity is attributed to the production of ammonia, as we elucidated that both nitrite and nitrate produced ammonia via the reaction with zinc. The results suggest that the total concentration of nitrite and nitrate must be corrected by constructing a calibration curve for nitrite with zinc, in addition to developing curves for nitrate with zinc and for nitrite without zinc. Using these calibration curves, the absorbance at different concentration ratios of nitrite and nitrate ions could be reproduced via calculation using the calibration curves with zinc for nitrite and nitrate. Eventually, the developed μPAD was applied to the determination of nitrite and nitrate ions in natural water samples, and the results were compared with those using a conventional spectrophotometric method. The results of the μPAD are in good agreement with those of conventional spectrophotometry, which suggests that the μPAD is reliable for the measurement of nitrite and nitrate ions in natural water samples.

Whiskey is a traditional distilled product produced on the island of Ireland that is currently experiencing a major expansion in export volume. Different styles of Irish whiskey exist, however only some very limited published information exists on the volatile congener profile of the different styles of Irish whiskey. Such information is potentially indispensable from a quality, flavour and authenticity perspective. As gas chromatography is the established analytical method of choice to identify volatile congeners, this study compared headspace-solid phase microextraction (HS-SPME) using conventional gas chromatography single quadrupole mass spectrometry, to HS-SPME and HS-SPME-Arrow using comprehensive two-dimensional gas chromatography (GC×GC) modulated using reverse flow in tandem with time-of-flight mass spectrometry (TOFMS) detection. Six representative Irish whiskey samples were evaluated consisting of new make spirit and mature whiskies representing Single Malts, Pot Stills and Blends. The number of volatile congeners identified in these samples by HS-SPME/HS-SPME Arrow GC×GC-TOFMS was approximately twice that detected by conventional HS-SPME GCMS. In total 145 unique individual volatile congeners, excluding ethanol were identified, with the majority consisting of esters, but also benzenes, alcohols, aldehydes, terpenoids, furans, ketones, alkanes, alkenes, norisoprenoids, acetals, acids, lactones and phenols. The use of HS-SPME Arrow GC×GC-TOFMS significantly enhances the number of volatile congeners that can be identified and therefore provides much more information that can convey insights into product quality, consistency, flavour and also for authentication purposes.

Rice is the most important staple crop for more than half of the world's population. As rice quality can deteriorate during storage, methods that can effectively classify rice according to its storage duration are essential. However, existing methods of assessing rice storage time are time-consuming, laborious, and incompatible with modern industrial processing technologies. Therefore, we investigated the ability of near-infrared spectroscopy combined with machine learning algorithms to distinguish rice storage duration. A total of 482 rice samples were analyzed, which included 74, 100, and 308 samples produced during 2015–2016, 2017–2018, and 2020–2021, respectively. Five pre-processing methods were initially applied to the spectra to enhance the accuracy of the discrimination model. Subsequently, two-dimensional correlation spectroscopy and competitive adaptive reweighted sampling (CARS) were used to extract the characteristic spectra associated with storage time. Finally, three pattern recognition methods (K-nearest neighbor analysis, linear discriminant analysis, and least squares support vector machine (LS-SVM)) were compared for their effectiveness in constructing classification models. The results indicated that the best model for identifying the storage duration of rice was established after spectral pre-processing with the standard normal variate and first derivative, using the CARS algorithm to select feature wavelengths, and applying the LS-SVM modeling method, which together yielded correct identification rates of 99.72 % and 91.67 % for the calibration and validation sets, respectively. Thus, we propose near-infrared spectroscopy coupled with machine learning algorithms as an effective approach for classifying rice according to storage duration, which can facilitate evaluations of rice freshness in the market.