ELECTROPHORESIS最新文献

DOI: 10.1002/elps.202400011

The cover image is based on the Article A dual-reference study design for understanding and improving AAV genome size analysis by Yali Sun and Zhi-xiang Lu, et al., https://doi.org/10.1002/elps.202400011. Created with BioRender.com.

A method was developed for studying mass transfer kinetics at lipid bilayers of liposomes. Elution peaks of coumarin were measured by liposome electrokinetic chromatography (LEKC). Four types of phospholipids having different alkyl chains were used for preparing liposomes, which were used as pseudo-stationary phases in LEKC systems. Rate constants of permeation across lipid bilayers of liposomes or of adsorption at lipid membranes were determined by analyzing the first absolute and second central moments of the elution peaks measured by LEKC. The rate constants of permeation or adsorption tend to decrease with an increase in the carbon number of the alkyl chains of phospholipids. It was demonstrated that the moment analysis of elution peak profiles measured by LEKC is effective for determining lipid membrane permeability or adsorption kinetics. Compared with other conventional techniques, the method has some advantages for studying mass transfer kinetics at lipid bilayers. Solute permeation across or solute adsorption at real lipid bilayers of liposomes is analyzed. The principle of the method is the analysis of separation behavior in LEKC, which is different from that of the other ones. It is expected that the method contributes to the kinetic study of mass transfer at lipid bilayers from various perspectives.

Exosomes have been identified as crucial mediators in numerous physiological and pathological processes, emerging as a focal point of scientific inquiry. This study aims to compare three methods for isolating exosomes from rat bone marrow mesenchymal stem cells: ultracentrifugation (UC), ultrafast separation system (EXODUS), and commercial precipitation kit (EXO-kit). First, the investigation compared exosomal morphology, particle size distribution, and expression of marker proteins. Subsequently, the RNA content, protein concentration, and purity of exosomes were evaluated. Finally, the impact of these exosomes on cellular metabolic viability and migration capacity was assessed. Results indicated that exosomes exhibited spherical or elliptical membrane structures, and most of the exosomes extracted by the three methods were in the range of 30to 200 nm. UC-extracted exosomes demonstrated the least impurities and clearest background, followed by EXODUS-extracted exosomes, and lastly EXO-kit-extracted exosomes. The EXO-kit-extracted exosomes yielded the highest RNA and protein content, whereas those isolated through UC exhibited superior purity. Furthermore, exosomes extracted from EXODUS and EXO-kit methods effectively enhanced the metabolic viability and migratory ability of osteoblast precursor cells compared to UC-extracted exosomes. In conclusion, each of the three methodologies presents advantages and limitations. Therefore, the selection of an appropriate exosome extraction technique should be based on specific experimental objectives and requirements.

The frequency dependence of electrokinetic particle trapping using large-area (>mm²) conductive carbon nanofiber (CNF) mat electrodes is investigated. The fibers provide nanoscale geometric features for the generation of high electric field gradients, which is necessary for particle trapping via dielectrophoresis (DEP). A device was fabricated with an array of microfluidic wells for repeated experiments; each well included a CNF mat electrode opposing an aluminum electrode. Fluorescent microspheres (1 µm) were trapped at various electric field frequencies between 30 kHz and 1 MHz. Digital images of each well were analyzed to quantify particle trapping. DEP trapping by the CNF mats was greater at all tested frequencies than that of the control of no applied field, and the greatest trapping was observed at a frequency of 600 kHz, where electrothermal flow is more significantly weakened than DEP. Theoretical analysis and measured impedance spectra indicate that this result was due to a combination of the frequency dependence of DEP and capacitive behavior of the well-based device.