A capillary electrophoresis-based assay for carrier screening of the hotspot mutations in the CYP21A2 gene.

Molecular genetic analysis of the cytochrome P450 family 21 subfamily A member 2 (CYP21A2) gene is challenging owing to the highly homologous with its pseudogene. A reliable approach for the large-scale population screening of CYP21A2 is required. This study aimed to establish and evaluate a capillary electrophoresis-based assay for hotspot mutation carrier screening of the CYP21A2 gene. A total of 22 different variants in the CYP21A2 gene were detected by a capillary electrophoresis-based assay consisting of single nucleotide primer extension (SNaPshot) and high-throughput ligation-dependent probe amplification (HLPA) in the Chinese population, and the results were validated by alternative methods. Among the 5376 subjects, 1.51 % (81/5376) individuals were identified as CYP21A2 pathogenic variant carriers, with a carrier rate of 1/66. A total of 11 different variants were identified, of which c.293-13A/C > G (33.33 %) was the most common variant, followed by c.844C > T (19.75 %), c.518T > A (19.75 %), and Del/Con (16.05 %). There was a 100 % concordance between capillary electrophoresis and alternative method results. Furthermore, a total of 63 individuals (1.17 %, 63/5376) carried the c.955C > T (p. Q319∗) variant, among which 61 (61/63, 96.83 %) had a duplicated CYP21A2 gene and are therefore not carriers of a CYP21A2 allele. In conclusion, the capillary electrophoresis-based assay is an accurate and effective approach for genotyping the CYP21A2 gene and has the potential for the large-scale population screening of CYP21A2.

Stacking in electrophoresis by electroosmotic flow-assisted admicelle to solvent microextraction.

An in-line sample concentration method for capillary electrophoresis called admicelle to solvent microextraction was proposed. In this technique, analytes were trapped in the cetyltrimethylammonium bromide admicelles formed in situ on the negatively charged capillary surface. A solvent plug was then partially injected hydrodynamically to collapse the admicelles, which liberated and focused the analytes at the solvent front. Voltage was applied across the capillary, completing the stacking process. Various solvents, namely, methanol, ethanol, and acetonitrile, were investigated. The optimal solvent for solvent to admicelle microextraction was 30% acetonitrile in 24 mM sodium tetraborate (pH 9.2). Sample injection time and solvent to sample injection ratio were also optimised. For this demonstration, the optimum sample injection time and solvent to sample injection ratio were 320 s and 1:2, respectively. Using the optimum conditions, UV detection sensitivity was enhanced 132-176-fold for the model anions. The LOQ, %intra-/inter-day (n = 6/n = 12, 2 days) repeatability, and linearity (R2) of admicelle to solvent microextraction were 0.08-2 µg/mL, 1.9-3.9%, 2.8-4.9%, and 0.992, respectively. Admicelle to solvent microextraction was applied to the analysis of various fortified water samples, with good repeatability (%RSD = 0.5-3.6%), and no matrix interferences.

CE-MS and CE-MS/MS for the multiattribute analysis of monoclonal antibody variants at the subunit level.

The analysis of product-related substances and impurities is a critical step in the biopharmaceutical quality control of multiattribute monoclonal antibodies (mAbs), as posttranslational modifications or other variants can influence the product's biological activity. Many approaches are available for variant analysis; however, they are either variant-specific, mAb-specific, time-consuming, or require expensive equipment. Here, we present a generic capillary electrophoretic method based on a neutral-coated capillary which was coupled to mass spectrometry (MS) via the nanoCEasy interface for mAb variant analysis at the subunit level (enzymatically digested and reduced mAb). The method enabled the separation of several (i) size variants (e.g. glycosylation variants) and (ii) charge variants (e.g. c-terminal lysin clipping) as well as (iii) multiple other proteoforms (e.g. additional glycation) and (iv) incompletely reduced subunits. Separated variants were confirmed by MS/MS fragmentation even for small mass deviations like deamidation or open disulfide bridges. The system, initially developed for one mAb, was tested with nine other IgG1s to show the general applicability of the system. The presented multiattribute method enables fast and detailed characterization of mAb variants with little sample preparation and relatively simple separation equipment enabling the separation of a large set of mAb variants.

Reducing the water quenching processes using heavy water in capillary electrophoresis with fluorescence detection.

Water, ubiquitous in analytical methods, is renowned for its fluorescence quenching properties, influencing techniques like fluorescence spectrophotometry or techniques with fluorescence detection. This study explores the impact of water (H2O) substitution for heavy water (D2O) on the fluorescence behavior of anthraquinones and anthracyclines. Anthraquinones and anthracyclines play crucial roles in pharmacy, serving as essential components in various therapeutic formulations, particularly in cancer treatment and other pharmacological interventions. Capillary electrophoresis (CE) with heavy water as the background electrolyte (BGE) solvent offers superior sensitivity to the separation and detection of these analytes. Experimental results demonstrate the improved detection limits and separation efficiency of selected anthraquinones rhein (RH), aloe-emodin (AE), and anthracyclines doxorubicin (DOX), epirubicin (EPI) and daunorubicine (DAU) in heavy water-based buffers, highlighting the potential of heavy water in advancing analytical chemistry.

A simple method to remove polyimide coating from fused silica capillaries for capillary electrophoresis.

A simple and cost-effective method for making capillary electrophoresis (CE) detection windows is reported. A low-cost laser engraving machine equipped with a 450 nm high-power blue laser was used to remove the polyimide coating from the fused silica capillary by laser scanning the desired section. The entire process is automated and controlled in real time by software. This method can be easily adopted by many CE users for routine practice and is scalable for high-throughput production of detection windows across multiple capillaries.

Greening Separation and Purification of Proteins and Peptides.

The increasing awareness of environmental issues and the transition to green analytical chemistry (GAC) have gained popularity among academia and industry in recent years. One of the principles of GAC is the reduction and replacement of toxic solvents with more sustainable and environmentally friendly ones. This review gives an overview of the advances in applying green solvents as an alternative to the traditional organic solvents for peptide and protein purification and analysis by liquid chromatography (LC) and capillary electrophoresis (CE) methods. The feasibility of using greener LC and CE methods is demonstrated through several application examples; however, there is still plenty of room for new developments to fully realize their potential and to address existing challenges. Thanks to the tunable properties of designer solvents, such as ionic liquids and deep eutectic solvents, and almost infinite possible mixtures of components for their production, it is possible that some new designer solvents could potentially surpass the traditional harmful solvents in the future. Therefore, future research should focus mainly on developing new solvent combinations and enhancing analytical instruments to be able to effectively work with green solvents.

The method of capillary electrophoresis for quantitative determination of hydrophobized hyaluronic acid in its micellar forms.

Micelles based on hydrophobized hyaluronic acid (HA) are frequently used in targeted drug delivery systems. Capillary zone electrophoresis (CZE) was utilized for the quantitative determination of hydrophobized and native HA. A universal methodology was developed, suitable for the quantitative analysis of amphiphilic derivatives of hyaluronan (oleyl hyaluronan and hyaluronan conjugate with naphthalimide fluorophore) and native HA with varying molecular weights (15, 150, and 800 kDa). Furthermore, methodologies were proposed for the simultaneous quantification of a drug substance and oleyl hyaluronan in micellar forms based on the latter. The CE technique was applied for analyzing oleyl-hyaluronan-based micellar forms of two poorly soluble drug substances with oppositely charged ionic forms (loperamide and rifabutin). The examples contained in the study demonstrate a range of analytical sensitivity (LOD) for hyaluronan from 11 to 40 µg/mL and for the drug substance from 0.4 to 0.6 µg/mL. The study also showcases the accurate quantitative determination of rifabutin and loperamide in oleyl-hyaluronan-based micellar forms without the need for sample preparation. Thus, the proposed methodologies can be used to quantify native HA or its amphiphilic derivatives and simultaneously determine drug substances of various nature.

Molecular modeling study to unravel complexation of daclatasvir and its enantiomer by ß-cyclodextrins. Computational analysis using quantum mechanics and molecular dynamics.

A computational study was performed to unravel mechanisms underlying capillary electrophoresis enantioseparations of daclatasvir and its (R,R,R,R)-enantiomer with native and methylated ß-cyclodextrins (ß-CDs) as chiral selectors. Considering the enantioseparation results as benchmark, the structures of ß-CD and seven methylated ß-CDs were optimized by quantum mechanics, and their topography and computed molecular properties were compared. Furthermore, the electron charge density distribution of the macrocycles was also evaluated by calculating the molecular electrostatic potential of pivotal regions of native and methylated ß-CDs. The function of hydrogen bonds in the complexation process of daclatasvir and the CDs was derived from quantum mechanics analysis and confirmed by molecular dynamics, as orthogonal computational techniques. The presence of a round-shaped cavity in the CDs used as chiral selector appeared as a necessary requirement for the enantioseparation of daclatasvir and its (R,R,R,R)-enantiomer. In this regard, it was confirmed that the round shape of the CDs is sustained by hydrogen bonds formed between adjacent glucopyranose units and blocking rotation of the linking glycosidic bonds. The presence of hydroxy groups at the 6-position of the glucopyranose units and the concurrent absence of hydroxy groups at the 2-position were evidenced as important factors for enantioseparation of daclatasvir and its enantiomer by methylated ß-CDs.

Comparison of next generation sequencing (NGS) - (SNPs) and capillary electrophoresis (CE) - (STRs) in the genetic analysis of human remains.

A pilot study was performed using two different DNA technology platforms conducted by two laboratories to analyze DNA extracted from 83-year-old, human male skeletal remains from 16 individuals, of which there are no other viable means to identify these war victims. The workflow of the more recent developed ForenSeq Kintelligence Kit and next generation sequencing was compared to that of the standard capillary electrophoresis - short tandem repeat (STR) method (Power Plex ESX17 and Y23 Systems). The findings indicate that greater amount of useful genetic data can be gained with the Kintelligence system across the range of samples under study and particularly for samples in which partial or no STR profiles are obtained. SNP data are more likely to be obtained from degraded samples, like the ones analyzed in this study. Moreover, high volume SNP data are suitable for long distance kinship associations and genetic genealogy databases to develop more investigative leads for future kinship and missing persons cases, a process not feasible by STR typing.

Really the best of both? Application of an mRNA/miRNA multiplex assay to casework samples, animal samples, and a storage study.

The identification of body fluids is an important area of forensic genetics. In particular, the susceptibility to degradation of casework samples is of crucial importance, as the traces can often be exposed to different environmental conditions over a long period of time. RNAs especially are used as molecular markers for the identification of body fluids in forensics. Messenger RNAs (mRNAs) show an increased susceptibility to degradation, e.g. under humidity and UV radiation but are highly body fluid-specific. The shorter micro RNAs (miRNAs), however, are less susceptible to degradation, but only a few body fluid-specific markers could be investigated. In this study, a self-developed mRNA/miRNA multiplex assay for capillary electrophoresis from a preliminary study was further adapted and validated. The approach was applied to casework samples, animal samples, and a storage study. The advantages and disadvantages of the mRNA/miRNA assay were investigated in order to review a possible application for forensic casework. Some miRNA markers were also detected in animal samples, which once again underlines the possible non-specificity of miRNAs. In the storage study, the different markers were detected for different lengths of time depending on the body fluid examined. For almost all body fluids, the miRNA markers were still detectable after a period of 35 days under environmental conditions compared to the mRNA markers. The mRNA peaks were often already clearly reduced or no longer detectable after 14 days. The results show the advantage of the new mRNA/miRNA assay compared to established mRNA approaches, especially for older and degraded samples, but the assay has its limitations due to the limited number of specific miRNA markers.

Screening thrombin inhibitors from Yangxinshi tablets by online capillary electrophoresis-based immobilized enzyme microreactor and molecular docking.

INTRODUCTION: Yangxinshi tablet (YXST) is a effective traditional Chinese medicine in treating cardiovascular diseases such as heart failure and myocardial infarction. OBJECTIVES: This study aims to develop a method for screening thrombin inhibitors from YXST using an online immobilized enzyme microreactor (IMER) based on capillary electrophoresis (CE). MATERIALS AND METHODS: Thrombin (THR) was immobilized on the capillary's inner wall using polydopamine (PDA). The chromogenic substrate S-2238 was employed to assess thrombin (THR) activity and kinetic parameters. The stability and repeatability of the constructed thrombin-immobilized enzyme microreactor (THR-IMER) were evaluated over 40 runs, maintaining 85% of initial activity. The Michaelis-Menten constant (Km) for THR was determined to be 11.98 mM. The half-maximal inhibitory concentration (IC50) and inhibition constant (Ki) for argatroban on THR were calculated. Ten compounds in YXST were screened for THR inhibitory potency using the THR-IMER. RESULTS: Salvianolic acid B and caffeic acid were identified as potential THR inhibitors in YXST, with inhibition rates at 200 µg/mL of 55.06 ± 6.70% and 31.88 ± 4.79%, respectively, aligning with microplate reader assay results. Molecular docking analysis confirmed their interactions with key THR residues, verifying their inhibitory activity. CONCLUSION: The CE-based THR-IMER method was successfully developed for screening thrombin inhibitors from YXST, offering a reliable approach for identifying potential therapeutic compounds.

Stage-Specific Plasma Metabolomic Profiles in Colorectal Cancer.

Background/Objectives: The objective of this study was to investigate the metabolomic profiles of patients with colorectal cancer (CRC) across various stages of the disease. Methods: The plasma samples were obtained from 255 subjects, including patients with CRC in stages I-IV, polyps, and controls. We employed capillary electrophoresis time-of-flight mass spectrometry and liquid chromatography triple quadrupole mass spectrometry to analyze hydrophilic metabolites comprehensively. The data were randomly divided into two groups, and consistent differences observed in both groups were analyzed. Results: Acetylated polyamines, such as N1-acetylspermine and N1, N12-diacetylspermine, consistently showed elevated concentrations in stage IV compared to stages I-III. Non-acetylated polyamines, including spermine and spermidine, exhibited increasing trends from polyp to stage IV. Other metabolites, such as histidine and o-acetylcarnitine, showed decreasing trends across stages. While acetylated polyamines have been reported as CRC detection markers, our findings suggest that they also possess diagnostic potential for distinguishing stage IV from other stages. Conclusions: This study showed stage-specific changes in metabolic profiles, including polyamines, of colorectal cancer.

Analytical Methods to Evaluate RNA Circularization Efficiency.

Circular RNAs (circRNAs) have emerged as pivotal players in RNA therapeutics. Unlike linear counterparts, circRNAs possess a closed-loop structure, conferring them with enhanced stability and resistance to degradation. Ribozyme-based strategy stands out as the predominant method for synthetic circRNA production, by precisely cleaving and promoting the formation of a covalent circular structure. However, there is still a lack of analytical methods that can provide high-throughput and quantitative analysis to facilitate the circRNA vector engineering process. In the report, we detail analytical methods to characterize and evaluate ribozyme-based RNA circularization efficiency. Our approach will capture the attention of researchers interested in optimizing RNA circularization efficiency, as well as those focused on exploring key elements for ribozyme catalytic activity.

CE-UV method for the determination of catecholamine metabolites from baby pee-covered diapers.

A method has been developed for the analysis of vanillylmandelic acid, homovanillic acid, and 5-hydroxyindoleacetic acid from baby urine as biomarkers of neuroblastoma in infants. Disposable diapers were employed as sampling devices in order to guarantee a low invasiveness during this step. The proposed method consists on a simple extraction step with water from the used diaper followed by the measurement using capillary electrophoresis with UV detection. The Box-Behnken design (BBD) was utilized to optimize the process of extracting catecholamine metabolites from the examined samples. The variables of the sample preparation step were optimized and the method was validated obtaining limits of quantification of 1.65 µg mL-1, good intraday and inter-day precision with RSDs under 15 %. Finally the method was applied to real samples collected from the Department of Neonatology, University Clinical Centre (Gdansk, Poland). The greenness of the proposed method was also evaluated with different tools (i.e., AGREEPrep and GAPI) with satisfactory results, which allow to state that the method can be considered green. Moreover, its practicality was evaluated by application of BAGI tool, proving to be a practical and economical method to be applied in routine laboratories for determination of catecholamine metabolites in urine-type samples.

Clindamycin phosphate-based deep eutectic solvent as a chiral selector for enantioseparation of amino alcohol drugs in nonaqueous capillary electrophoresis.

Clindamycin phosphate (CP) exhibits good enantioselectivity for many basic drugs, but its separation effect for most amino alcohol drugs is not satisfactory. In this work, a deep eutectic solvent (DES) chiral selector based on CP was prepared for the first time and utilized as a single chiral selector in nonaqueous capillary electrophoresis (NACE) to separate twelve amino alcohol drugs. Compared with unmodified CP, the separations of model drugs in the DES chiral selector system were significantly improved. Most amino alcohol drugs could be completely separated, and the peak shapes were good. In addition, we used infrared spectroscopy and nuclear magnetic resonance method to study the specific separation mechanism and explored the reasons why DES chiral selector has better enantioselectivity. This work is the first to directly modify antibiotic chiral selector into DES, indicating a direction for us to develop novel chiral recognition materials.

Applications of Capillary Electrophoresis for the Detection of Adulterants in Dietary Supplements.

In recent years, the consumption of dietary supplements, particularly those incorporating plant-based ingredients, has increased greatly, driven by the perception of their natural origins and purported minimal health risks. However, one significant safety concern revolves around the adulteration of dietary supplements, wherein unscrupulous manufacturers may illegally incorporate pharmaceutical substances or their analogs into these products to achieve increased efficiency and bolster sales. This review assesses the role of capillary electrophoresis (CE) in ensuring the quality control of dietary supplement products over the past two decades. This study provides an overview of various applications of CE in analyzing dietary supplements, outlining the typical attributes of natural product analysis using CE. These analyses demonstrate the broad versatility of CE, exemplified by its diverse applications and detection modes. Moreover, the review highlights the growing prominence of CE as a separation technique in quality control, by comparison with more conventional methods like high-performance liquid chromatography (HPLC). Through this exploration, the review elucidates the pivotal role of CE in upholding the integrity and safety of dietary supplements, in connection with a landscape of evolving regulatory challenges and consumer demands.

Reshaping Capillary Electrophoresis With State-of-the-Art Sample Preparation Materials: Exploring New Horizons.

Capillary electrophoresis (CE) is a powerful analysis technique with advantages such as high separation efficiency with resolution factors above 1.5, low sample consumption of less than 10 µL, cost-effectiveness, and eco-friendliness such as reduced solvent use and lower operational costs. However, CE also faces limitations, including limited detection sensitivity for low-concentration samples and interference from complex biological matrices. Prior to performing CE, it is common to utilize sample preparation procedures such as solid-phase microextraction (SPME) and liquid-phase microextraction (LPME) in order to improve the sensitivity and selectivity of the analysis. Recently, there have been advancements in the development of novel materials that have the potential to greatly enhance the performance of SPME and LPME. This review examines various materials and their uses in microextraction when combined with CE. These materials include carbon nanotubes, covalent organic frameworks, metal-organic frameworks, graphene and its derivatives, molecularly imprinted polymers, layered double hydroxides, ionic liquids, and deep eutectic solvents. The utilization of these innovative materials in extraction methods is being examined. Analyte recoveries and detection limits attained for a range of sample matrices are used to assess their effects on extraction selectivity, sensitivity, and efficiency. Exploring new materials for use in sample preparation techniques is important as it enables researchers to address current limitations of CE. The development of novel materials has the potential to greatly enhance extraction selectivity, sensitivity, and efficiency, thereby improving CE performance for complex biological analysis.

Interactions of electrophoretically silent hemoglobin Hekinan II [HBA1:c.84G>T] with various forms of α-thalassemias and other hemoglobinopathies: novel insights into the molecular and hematological characteristics and genetic origins.

To determine the molecular basis, genotype - phenotype relationship, and genetic origin of Hemoglobin (Hb) Hekinan associated with several forms of α-thalassemia and other hemoglobinopathies for a better understanding of its diverse clinical phenotypes. Seventeen participants with suspected abnormal Hb were studied. Hb analysis was performed using high-performance liquid chromatography (HPLC) and capillary electrophoresis (CE). Mutational and α-haplotypic and structural analyses were conducted, and the effects of mutations on globin-chain stability were determined. All participants harbored Hb Hekinan II (HBA1:c.84 G>T) co-inherited with another α-globin gene anomaly. Three novel genotypes, (ααHekinan/αCSα), (ααHekinan/αCSα,ßA/ßE), and (ααHekinan/αCSα,ßE/ßE), were characterized. Despite being co-inherited with both α- and ß-Hb variants Hb Hekinan II led to minimal changes in erythrocyte parameters, suggesting a non-pathological nature. HPLC but not CE revealed a distinct small shoulder-like Hb pattern. Thai Hb Hekinan II was strongly associated with haplotype [+ - S + - - -] and the possibility of four different haplotypes, while two Burmese Hb Hekinan II were associated with haplotypes [± - S + - + -] and [± - S + - - -]. The novel genotypes identified provide a fresh perspective on Hb Hekinan II diversity. HPLC has superior identification capabilities for samples of Hb Hekinan II co-inherited with α-thalassemia. Thai and Burmese Hb Hekinan II have diverse origins.

Assessment of adeno-associated virus purity by capillary electrophoresis-based western.

A rigorous analytical assessment of recombinant adeno-associated virus (rAAV)-based drug products is critical for their successful development as clinical candidates. It is especially important to ascertain high purity while simultaneously ensuring low levels of impurities in the final drug product. One approach to evaluate the purity of rAAV drug products is to determine the relative stoichiometry of the three viral proteins (VPs) that comprise an rAAV capsid, and the levels of impurities in the final drug product. Here we present two capillary electrophoresis-western (CE-western) assays for quantifying (1) the relative stoichiometry of VP using the anti-AAV B1 antibody, and (2) residual levels of a baculovirus protein impurity, GP64, using the anti-GP64 antibody. In each assay, various purified samples from diverse AAV serotypes were analyzed to determine their VP ratio or GP64 levels. The ratio of VP3/VP1 in rAAV samples was correlated with biological activity, and the clearance of GP64 from the manufacturing process was demonstrated. The results obtained from both assays were further supported by liquid chromatography-mass spectrometry analyses. Overall, we report that CE-western is a high-throughput platform that utilizes low sample volumes for a rapid, sensitive, and robust assessment of the identity, composition, and purity of rAAV drug products.

Pilot Study for Deciphering Post-Translational Modifications and Proteoforms of Tau Protein by Capillary Electrophoresis-Mass Spectrometry.

Abnormal accumulation of tau protein in the brain is one pathological hallmark of Alzheimer's disease (AD). Many tau protein post-translational modifications (PTMs) are associated with the development of AD, such as phosphorylation, acetylation, and methylation. Therefore, a complete picture of the PTM landscape of tau is critical for understanding the molecular mechanisms of AD progression. Here, we offered a pilot study of combining two complementary analytical techniques, capillary zone electrophoresis (CZE)-tandem mass spectrometry (MS/MS) and reversed-phase liquid chromatography (RPLC)-MS/MS, for bottom-up proteomics of recombinant human tau-0N3R. We identified 50 phosphorylation sites of tau-0N3R in total, which is about 25% higher than that from RPLC-MS/MS alone. CZE-MS/MS provided more PTM sites (i.e., phosphorylation) and modified peptides of tau-0N3R than RPLC-MS/MS, and its predicted electrophoretic mobility helped improve the confidence of the identified modified peptides. We developed a highly efficient capillary isoelectric focusing (cIEF)-MS technique to offer a bird's-eye view of tau-0N3R proteoforms, with 11 putative tau-0N3R proteoforms carrying up to nine phosphorylation sites and lower pI values from more phosphorylated proteoforms detected. Interestingly, under native-like cIEF-MS conditions, we observed three putative tau-0N3R dimers carrying phosphate groups. The findings demonstrate that CE-MS is a valuable analytical technique for the characterization of tau PTMs, proteoforms, and even oligomerization.