Hydrogel-Inducing Graphene-Oxide-Derived Core-Shell Fiber Composite for Antibacterial Wound Dressing.

The study reveals the polymer-crosslinker interactions and functionality of hydrophilic nanofibers for antibacterial wound coatings. Coaxial electrospinning leverages a drug encapsulation protocol for a core-shell fiber composite with a core derived from polyvinyl alcohol and polyethylene glycol with amorphous silica (PVA-PEG-SiO2), and a shell originating from polyvinyl alcohol and graphene oxide (PVA-GO). Crosslinking with GO and SiO2 initiates the hydrogel transition for the fiber composite upon contact with moisture, which aims to optimize the drug release. The effect of hydrogel-inducing additives on the drug kinetics is evaluated in the case of chlorhexidine digluconate (CHX) encapsulation in the core of core-shell fiber composite PVA-PEG-SiO2-1x-CHX@PVA-GO. The release rate is assessed with the zero, first-order, Higuchi, and Korsmeyer-Peppas kinetic models, where the inclusion of crosslinking silica provides a longer degradation and release rate. CHX medicated core-shell composite provides sustainable antibacterial activity against Staphylococcus aureus.

Colocalization Analysis of Cytoplasmic Actin Isoforms Distribution in Endothelial Cells.

Actin cytoskeleton is an essential component of living cells and plays a decisive role in many cellular processes. In mammals, ß- and γ-actin are cytoplasmic actin isoforms in non-muscle cells. Despite minor differences in the amino acid sequence, ß- and γ-actin localize in different cell structures and perform different functions. While cytoplasmic ß-actin is involved in many intracellular processes including cell contraction, γ-actin is responsible for cell mobility and promotes tumor transformation. Numerous studies demonstrate that ß- and γ-actin are spatially separated in the cytoplasm of fibroblasts and epithelial cells; this separation is functionally determined. The spatial location of ß/γ-actin in endothelial cells is still a subject for discussion. Using super-resolution microscopy, we investigated the ß/γ-actin colocalization in endotheliocytes and showed that the ß/γ-actin colocalization degree varies widely between different parts of the marginal regions and near the cell nucleus. In the basal cytoplasm, ß-actin predominates, while the ratio of isoforms evens out as it moves to the apical cytoplasm. Thus, our colocalization analysis suggests that ß- and γ-actin are segregated in the endotheliocyte cytoplasm. The segregation is greatly enhanced during cell lamella activation in the nocodazole-induced endothelial barrier dysfunction, reflecting a different functional role of cytoplasmic actin isoforms in endothelial cells.