The synthesis of Pt doped WO3 nanosheets and application on colorimetric detection of cysteine by naked eye using response surface methodology for optimization

Detection of ag+ and cysteine using rapid synthesis of copper nanoclusters with dual ligands

In this work, the copper nanoclusters with red fluorescence (CuNCs@DAMP) were prepared with 4,6-diamino-2-mercaptopyrimidine (DAMP) as a ligand by a simple one-pot method, but the CuNCs@DAMP couldn't respond to silver ions (Ag+) and L-cysteine (Cys). Then glutathione (GSH) modified CuNCs@DAMP (GSH-CuNCs@DAMP) with short preparation time (10 min) was found that not only its maximum emission peak underwent a significant blue-shift (from 705 to 605 nm), but also it could selectively detect Ag+ and Cys with LOD (limit of detection) of 0.018 and 0.19 μM and the linear ranges of 0.05-10.0 and 0.6-73.0 μM. Meanwhile, the synthetic conditions of GSH-CuNCs@DAMP and the fluorescence quenching mechanisms of GSH-CuNCs@DAMP by Ag+ and Cys were studied intensively. Furthermore, the CuNCs was successfully employed to monitor Ag+ and Cys in real samples with good recoveries, which hinted that a simple, fast and sensitive method was provided for Ag+ and Cys assays.

Chemometrics and digital image colorimetry approaches applied to paper-based analytical devices: A review

Colorimetric paper-based analytical devices (CPADs) are cost-efficient and high-throughput technologies that use readily available materials for point-of-need (PON) applications by leveraging color changes in response to target analytes. However, the complexity of samples can limit the precision and accuracy of CPAD applications. Therefore, CPADs have been combined with chemometric approaches to enhance analytical performance and provide simple solutions to complex systems. The integration of formal optimization techniques, such as Design of Experiments (DoE), classification tools, quantification methods, and other advanced algorithms enables optimal experimental analytical conditions and extracting meaningful information from the complex colorimetric data generated by CPADs. These approaches facilitate robust calibration and prediction models, enabling reliable quantifications or sample differentiation. In addition, chemometrics combined with CPADs contributes to Green Analytical Chemistry once they have the potential to minimize the number of experiments, provide optimal designs and consumption of reagents, and decrease waste generation. The synergy between digital colorimetry using CPADs and smart devices with chemometric techniques holds great promise for portable analysis in resource-limited settings, with applications ranging from environmental monitoring to point-of-care diagnostics. Herein, we review recent advances in the development of CPADs, ranging from manufacturing methods to extraction of color patterns and data treatment using several chemometric tools, performance assessment, and potential transfer to onsite applications for relevant analytical problems.

Advancements in wearable technology for monitoring lactate levels using lactate oxidase enzyme and free enzyme as analytical approaches: A review

Lactate is a metabolite that holds significant importance in human healthcare, biotechnology, and the food industry. The need for lactate monitoring has led to the development of various devices for measuring lactate concentration. Traditional laboratory methods, which involve extracting blood samples through invasive techniques such as needles, are costly, time-consuming, and require in-person sampling. To overcome these limitations, new technologies for lactate monitoring have emerged. Wearable biosensors are a promising approach that offers non-invasiveness, low cost, and short response times. They can be easily attached to the skin and provide continuous monitoring. In this review, we evaluate different types of wearable biosensors for lactate monitoring using lactate oxidase enzyme as biological recognition element and free enzyme systems.