ELECTROPHORESIS最新文献

Nonlinear electrophoresis (EP) has seen significant advancements over the past five decades, evolving into a potent electrokinetic phenomenon with transformative potential for analytical chemistry, particularly in the areas of bioanalysis and separations. This review chronicles the historical development of nonlinear EP, from its foundational Russian-language publications in the 1970s to its current applications enabling highly discriminatory separations of particles ranging from nanoparticles to large cells, exploiting subtle analyte differences. This review article is organized in three distinct eras: the 1970s, from 1980 to 2000, and from 2000 to the present. The latter is covered in terms of the advances in theory and modeling and the advances in experimental applications. The established regimes of classical nonlinear EP, currently utilized for electrophoretic separation of viruses, cells, and various micro- and nanoparticles, are discussed. Despite these breakthroughs, significant research opportunities remain, including the development of analytical expressions for dielectric particles at intermediate Peclet numbers (1 < Pe < 10), the application of AC signals for purely nonlinear separations, and understanding the migration of highly charged particles with thick electrical double layers. This article aims to provide experimentalists with a clear and accessible overview of the history and key advancements of nonlinear EP, highlighting its flexibility and positioning it as a major future player in bioanalytical chemistry.

The separation of live and dead cells is crucial for the diagnosis of early-stage diseases and efficacy test of drug screening, etc. We demonstrate the biological application of our recently developed AC insulator-based dielectrophoresis (AC iDEP) technique for the separation of live and dead yeast cells in a virtually infinitely long ratchet microchannel. This separation arises from the variation of surface charge and in turn electrokinetic velocity when yeast cells lose viability, as compared to the varying dielectrophoretic responses in conventional dielectrophoretic methods. The live and dead yeast cells can be focused toward the channel centerline and ratchet base, respectively, under AC voltages within a selected frequency and amplitude window. The performance of this cell viability-based AC iDEP separation is evaluated using the separation efficiency, which is reasonably predicted by a numerical model.

Non-invasive prenatal paternity testing (NIPPT) enables the genotyping of cell-free DNA (cfDNA) from maternal plasma through deep sequencing. Microhaplotypes (MHs) combine the advantages of short tandem repeats (STRs) and single-nucleotide polymorphisms (SNPs) and have attracted much attention in NIPPT. In this study, we optimized 45 MHs from our previous study and confirmed the effectiveness of the 45plex MH panel through different kinship inferences using real samples, including duos, trios, full siblings, and second-to-fifth-degree relatives, and excluding unrelated individuals. Furthermore, we tested 11 cfDNA and reference mother–child pairs in the first trimester (7 + 4–12 + 6 weeks) and 11 cfDNA and reference trios in the second trimester (18+ weeks). The R packages Familias and RelMix and the software EuroForMix were used for data interpretation. The results showed that MHs of cfDNA could be effectively detected using our sequencing and genotyping pipelines. We correctly determined paternity in 11 NIPPT cases, with Log₁₀LR > 10, which were significantly separated from real unrelated males. Our study indicates that this massively parallel sequencing (MPS)-based 45plex MH panel provides more robust relationship inference capabilities than standard STR systems, complements NIPPT, and may help solve relevant issues for relative DNA mixtures.

A simple and inexpensive method for integrating universal refractive index (RI) detection with existing capillary electrophoresis (CE) platforms utilizing epifluorescence detection is demonstrated. The approach uses the same epi-illumination laser source used for fluorescence detection to create a forward-scattered interference pattern for RI detection. The forward-scattered interferometry (FSI) approach only requires the addition of a bicell photodiode detector and mechanism for aligning it in the fringe pattern to add complementary universal RI detection with existing highly specific epi-fluorescence detection. FSI and fluorescence electropherograms illustrate the utility of measuring both channels simultaneously. Because both signals are generated from the same laser source focused into the same detection zone, the electropherograms are perfectly registered. The sample plug is directly detected with FSI in every separation, providing an intrinsic marker of the electroosmotic flow (EOF) without the need for neutral markers or separate measurements. Moreover, continuous EOF monitoring is also demonstrated using the introduction of thermal markers that are sensed in the FSI signal. Finally, it is shown that the FSI signal responds to both RI and the separation voltage, as has been shown previously for back-scatter interferometry (BSI) detection. This leads to enhanced signal-to-noise at elevated separation voltages, conditions that reduce analysis time and improve peak efficiency.

In dairy products, Bacillus subtilis (B. subtilis) is considered a harmful spoilage bacterium. Consequently, it is imperative to establish highly sensitive and selective approaches for detecting B. subtilis. In this article, quantification of B. subtilis via its 16S rRNA was first performed by microchip electrophoresis (MCE) combined with a dual nucleic acid recycling amplification strategy involving apyrimidinic endonuclease 1 (APE1)-mediated cycle and catalytic hairpin assembly (CHA). In APE1-mediated cycle, two specially designed probes containing apurinic/apyrimidinic sites (AP sites) capture B. subtilis 16S rRNA, and then APE1 cleaves the AP sites to release the recycled target RNA. Next, the product of APE1-mediated cycle triggers the CHA and generates the final product for further MCE detection. Under the optimal conditions, the limit of detection for B. subtilis was 29 CFU/mL (S/N = 3). The proposed strategy was successfully applied to the detection of B. subtilis in pasteurized milk and exhibited high speed, high sensitivity, and good specificity.

A novel post-modification strategy was developed for rapid functionalization of monoliths through amino-yne click chemistry. This approach enabled the conjugation of activated alkynes onto amino-functionalized organic-silica hybrid monolith surfaces under mild, catalyst-free conditions. Systematic investigation of critical reaction parameters was conducted to optimize the post-modification process. The morphological and structural characteristics of the prepared monolith were characterized by scanning electron microscopy (SEM) and nitrogen adsorption measurements. The successful grafting of functional groups onto the monolith surface was confirmed by contact angle analysis, Fourier transform infrared (FT-IR) spectroscopy, and x-ray photoelectron spectroscopy (XPS). The functionalized monolith demonstrated chromatographic selectivity for diverse analytes, including phenolic compounds and some weakly polar/nonpolar compounds (benzoin/benzoin methyl ether, styrene/p-chlorostyrene, and 1-naphthylethylamine/naphthalene). Furthermore, it was successfully applied to the quantitative analysis of honokiol in authentic magnolol samples, showcasing its potential for practical analytical applications.

Electric droplet sorting is widely applied in the screening of target molecules, cells, drugs, and microparticles. Previous studies have made several optimizations on the electrode materials, structures, and arrangements. However, voltages of over 1 kV are required to realize droplet sorting, which causes the undesired droplet splitting. In addition, great droplet deformation caused by the high voltage decreases the sorting accuracy and generates negative effects on the targets encapsulated within the droplets. In this study, we developed a low-voltage–driven droplet sorter (LV-DS) for droplet sorting with high stability and small deformation. Our LV-DS consisted of one square active and four triangular ground electrodes which were fabricated using liquid metal with higher stability and higher electrical conductivity than the previous electrode materials of low-melting alloy and salt water. Our LV-DS could realize the high-stability droplet sorting with small deformation at the voltage as low as 80 V. The results showed that our LV-DS presented great prospects in the high-stability droplet sorting with a low voltage. In addition, the advantage of small droplet deformation makes our LV-DS be attractive for the applications, such as droplet-based cell sorting with a high viability and droplet-based material screening with a small deformation.