Quantification of glutathione in single cells from rat liver by microchip electrophoresis with chemiluminescence detection

Isolation, identification, and degradation mechanism by multi-omics of mesotrione-degrading Amycolatopsis nivea La24

Mesotrione is a herbicide used in agricultural production; however, its stability and long-term residues pose ecological risks to soil health and subsequent crops. In this research, the strain Amycolatopsis nivea La24 was identified as capable of completely degrading 50 mg∙L-1 mesotrione within 48 h. It exhibited a broad adaptability to various environment and could degrade three sulfonylurea herbicides (nicosulfuron, chlorimuron-methyl, and cinosulfuron). Non-target metabonomic and mass spectrometry demonstrated that La24 strain broke down the mesotrione parent molecule by targeting the β-diketone bond and nitro group, resulting in the production of five possible degradation products. The differentially expressed genes were significantly enriched in fatty acid degradation, amino acid metabolism, and other pathways, and the differentially metabolites in glutathione metabolism, arginine/proline metabolism, cysteine/methionine metabolism, and other pathways. Additionally, it was confirmed by heterologous expression that nitroreductase was directly involved in the mesotrione degradation, and NDMA-dependent methanol dehydrogenase would increase the resistance to mesotrione. Finally, the intracellular response of La24 during mesotrione degradation was proposed. This work provides insight for a comprehensive understanding of the mesotrione biodegradation mechanism, significantly expands the resources for pollutant degradation, and offers the potential for a more sustainable solution to address herbicide pollution in soil.

Electrophoretic Determination of L-Carnosine in Health Supplements Using an Integrated Lab-on-a-Chip Platform with Contactless Conductivity Detection

The health supplement industry is one of the fastest growing industries in the world, but there is a lack of suitable analytical methods for the determination of active compounds in health supplements such as peptides. The present work describes an implementation of contactless conductivity detection on microchip technology as a new strategy for the electrophoretic determination of L-carnosine in complex health supplement formulations without pre-concentration and derivatization steps. The best results were obtained in the case of +1.00 kV applied for 20 s for injection and +2.75 kV applied for 260 s for the separation step. Under the selected conditions, a linear detector response of 5 × 10-6 to 5 × 10-5 M was achieved. L-carnosine retention time was 61 s. The excellent reproducibility of both migration time and detector response confirmed the high precision of the method. The applicability of the method was demonstrated by the determination of L-carnosine in three different samples of health supplements. The recoveries ranged from 91 to 105%. Subsequent analysis of the samples by CE-UV-VIS and HPLC-DAD confirmed the accuracy of the obtained results.

Recent developments in capillary and microchip electroseparations of peptides (2019-mid 2021)

The review provides a comprehensive overview of developments and applications of high performance capillary and microchip electroseparation methods (zone electrophoresis, isotachophoresis, isoelectric focusing, affinity electrophoresis, electrokinetic chromatography, and electrochromatography) for analysis, microscale isolation, and physicochemical characterization of peptides from 2019 up to approximately the middle of 2021. Advances in the investigation of electromigration properties of peptides and in the methodology of their analysis, such as sample preparation, sorption suppression, EOF control, and detection, are presented. New developments in the individual CE and CEC methods are demonstrated and several types of their applications are shown. They include qualitative and quantitative analysis, determination in complex biomatrices, monitoring of chemical and enzymatic reactions and physicochemical changes, amino acid, sequence, and chiral analyses, and peptide mapping of proteins. In addition, micropreparative separations and determination of significant physicochemical parameters of peptides by CE and CEC methods are described.

An ultrasensitive chemiluminescent biosensor for tracing glutathione in human serum using BSA@AuNCs as a peroxidase-mimetic nanozyme on a luminol/artesunate system

In this work, a nanosensor chemiluminescent (CL) probe for sensing glutathione (GSH) was developed, for the first time, based on its inhibition of the intrinsic peroxidase-mimetic effect of BSA@AuNCs. The endoperoxide linkage of artesunate could be hydrolyzed by BSA@AuNCs resulting in the release of reactive oxygen species (ROS), and the consequent generation of strong CL emission. By virtue of the strong covalent interactions of -S⋯Au-, GSH could greatly suppress the peroxidase-mimetic effect of BSA@AuNCs, leading to a drastic CL quenching. The CL quenching efficiency increased proportionally to the logarithm of GSH concentration through the linearity range of 50.0-5000.0 nM with a limit of detection of 5.2 nM. This CL-based strategy for GSH tracing demonstrated the advantages of ultrasensitivity, high selectivity and simplicity. This strategy was successfully utilized to measure GSH levels in human serum with reasonable recovery results of 98.71%, 103.18%, and 101.68%, suggesting that this turn-off CL sensor is a promising candidate for GSH in biological and clinical samples.

Microfluidics as a Novel Tool for Biological and Toxicological Assays in Drug Discovery Processes: Focus on Microchip Electrophoresis

The last decades of biological, toxicological, and pharmacological research have deeply changed the way researchers select the most appropriate 'pre-clinical model'. The absence of relevant animal models for many human diseases, as well as the inaccurate prognosis coming from 'conventional' pre-clinical models, are among the major reasons of the failures observed in clinical trials. This evidence has pushed several research groups to move more often from a classic cellular or animal modeling approach to an alternative and broader vision that includes the involvement of microfluidic-based technologies. The use of microfluidic devices offers several benefits including fast analysis times, high sensitivity and reproducibility, the ability to quantitate multiple chemical species, and the simulation of cellular response mimicking the closest human in vivo milieu. Therefore, they represent a useful way to study drug-organ interactions and related safety and toxicity, and to model organ development and various pathologies 'in a dish'. The present review will address the applicability of microfluidic-based technologies in different systems (2D and 3D). We will focus our attention on applications of microchip electrophoresis (ME) to biological and toxicological studies as well as in drug discovery and development processes. These include high-throughput single-cell gene expression profiling, simultaneous determination of antioxidants and reactive oxygen and nitrogen species, DNA analysis, and sensitive determination of neurotransmitters in biological fluids. We will discuss new data obtained by ME coupled to laser-induced fluorescence (ME-LIF) and electrochemical detection (ME-EC) regarding the production and degradation of nitric oxide, a fundamental signaling molecule regulating virtually every critical cellular function. Finally, the integration of microfluidics with recent innovative technologies-such as organoids, organ-on-chip, and 3D printing-for the design of new in vitro experimental devices will be presented with a specific attention to drug development applications. This 'composite' review highlights the potential impact of 2D and 3D microfluidic systems as a fast, inexpensive, and highly sensitive tool for high-throughput drug screening and preclinical toxicological studies.

Recent Advances and Applications of Microfluidic Capillary Electrophoresis: A Comprehensive Review (2017-Mid 2019)

Microfluidic capillary electrophoresis (MCE) is the novel technique resulted from the CE mininaturization as planar separation and analysis device. This review presents and discusses various application fields of this advanced technology published in the period 2017 till mid-2019 in eight different sections including clinical, biological, single cell analysis, environmental, pharmaceuticals, food analysis, forensic and ion analysis. The need for miniaturization of CE and the consequence advantages achieved are also discussed including high-throughput, miniaturized detection, effective separation, portability and the need for micro- or even nano-volume of samples. Comprehensive tables for the MCE applications in the different studied fields are provided. Also, figure comparing the number of the published papers applying MCE in the eight discussed fields within the studied period is included. The future investigation should put into consideration the possibility of replacing conventional CE with the MCE after proper validation. Suitable validation parameters with their suitable accepted ranges should be tailored for analysis methods utilizing such unique technique (MCE).

Recent advances in single cell manipulation and biochemical analysis on microfluidics

Single cell analysis has become of great interest with unprecedented capabilities for the systematic investigation of cell-to-cell variation in large populations. Rapid and multi-parametric analysis of intercellular biomolecules at the single-cell level is imperative for the improvement of early disease diagnosis and personalized medicine. However, the small size of cells and the low concentration levels of target biomolecules are critical challenges for single cell analysis. In recent years, microfluidic platforms capable of handling small-volume fluid have been demonstrated to be powerful tools for single cell analysis. In addition, microfluidic techniques allow for precise control of the localized microenvironment, which yield more accurate outcomes. Many different microfluidic techniques have been greatly improved for highly efficient single-cell manipulation and highly sensitive detection over the past few decades. To date, microfluidics-based single cell analysis has become the hot research topic in this field. In this review, we particularly highlight the advances in this field during the past three years in the following three aspects: (1) microfluidic single cell manipulation based on microwells, micropatterns, droplets, traps and flow cytometric methods; (2) detection methods based on fluorescence, mass spectrometry, electrochemical, and polymerase chain reaction-based analysis; (3) applications in the fields of small molecule detection, protein analysis, multidrug resistance analysis, and single cell sequencing with droplet microfluidics. We also discuss future research opportunities by focusing on key performances of throughput, multiparametric target detection and data processing.

A novel microchip electrophoresis laser induced fluorescence detection method for the assay of T4 polynucleotide kinase activity and inhibitors

T4 polynucleotide kinase (T4 PNK) may catalyze the phosphorylation of 5'-hydroxyl termini in nucleic acids, which play a crucial role in DNA recombination, replication and damage repair. Here, a microchip electrophoresis laser induced fluorescence (MCE-LIF) method based on biochemical reaction was developed for the detection of T4 PNK activity and inhibitors. In this method, the single strand DNA (ssDNA) was hybridized with the 5-carboxyfluorescein (FAM) labeled single strand DNA (ssDNA-FAM) to form FAM labeled double-stranded DNA (dsDNA-FAM). In the presence of T4 PNK and adenosine triphosphate (ATP), T4 PNK catalyzes the transfer of γ-phosphate residues from ATP to the 5-hydroxyl terminal of dsDNA-FAM. The phosphorylated dsDNA-FAM can be gradually hydrolyzed by λexo to produce a FAM labeled single nucleotide fragment. Then the FAM labeled single nucleotide fragment and the unhydrolyzed dsDNA-FAM were separated by MCE, and two electrophoresis peaks appeared in the electrophoretogram. The detection of T4 PNK activity and inhibitors was realized by measuring the peak height of the FAM labeled single nucleotide fragment in electrophoretogram. This assay is very sensitive with a limit of detection of 0.002 U/mL, and it can be further used to screen the T4 PNK inhibitors.

A field amplification enhanced paper-based analytical device with a robust chemiluminescence detection module

A field amplification enhanced paper-based analytical device was established with a miniaturized optical detection module for chemiluminescence detection.