Electrospun poly(l-lactide-co-dl-lactide) nanofibrous scaffold as substrate for ex vivo limbal epithelial cell cultivation.

Ultrathin electrospun poly (l-lactide-co-dl-lactide) nanofibrous membranes coated with fibronectin were explored as scaffolds for the ex vivo cultivation of limbal epithelial cells (LECs) for the treatment of limbal stem cell deficiency. The developed scaffolds were compared with the "gold-standard" fibrin gel. The resulting membranes composed of nanofibers possessed a very low thickness of 4 µm and allowed very good optical transparency in the wet state. The fibronectin-coated nanofibrous scaffolds demonstrated LEC expansion and successful cultivation similar to that on fibrin gel. Unlike the regular cobblestone epithelial cell morphology on the fibrin gel, the nanofibrous scaffold presented a mostly irregular epithelial morphology with a shift to a mesenchymal phenotype, as confirmed by the upregulation of profibroblastic genes: ACTA2 (p = 0.023), FBLN1 (p < 0.001), and THY1 (p < 0.001). Both culture conditions revealed comparable expression of stem cell markers, including KLF4, ΔNp63α and ABCG2, emphasizing the promise of polylactide-based nanofibrous membranes for further investigations.

Poly[2-(dimethylamino)ethyl methacrylate-co-ethylene dimethacrylate]nanogel by dispersion polymerization for inhibition of pathogenic bacteria.

Bacterial infections and antimicrobial resistance are one of the major public health problems and various strategies to prevent potential threats have been developed. Protonated polymers were proven as efficient agents against several microbial pathogens. Poly[2-(dimethylamino)ethyl methacrylate] (PDMAEMA) linear polymer and its copolymers represent one example of functional materials which inhibit the growth of both harmful Gram-negative and Gram-positive bacteria. However, the antimicrobial effect of positively charged PDMAEMA particles has been never tested. In this report, we deeply studied several parameters of free-radical polymerization, including the effect of crosslinking monomer, medium composition, solvency and polarity, and type and concentration of initiator and stabilizer, to fabricate high-quality poly[2-(dimethylamino)ethyl methacrylate-co-ethylene dimethacrylate] (PDMAEMA-EDMA) nanogel. We successfully found that dispersion polymerization in water/2-methoxyethanol medium (80/20 w/w), initiated with 0.2 wt% potassium persulfate (KPS) and stabilized with 0.5 wt% poly(vinyl alcohol) (PVA), produced a well-defined and sub-micron 167 nm PDMAEMA-EDMA nanogel. Bactericidal activity of the quaternized PDMAEMA-EDMA nanogel was assessed via time-kill curve assay against two Gram-positive and Gram-negative pathogenic bacteria, namely Staphylococcus aureus (S. aureus) and Acinetobacter baumannii (A. baumannii). The results illustrated that the quaternized PDMAEMA-EDMA nanogel acted as an effective bactericidal agent against both tested bacteria.