Scaffolds with tuneable hydrophilicity from electrospun microfibers of polylactide and poly(ethylene glycol) mixtures: morphology, drug release behavior, and biocompatibility

Electrospun mats were obtained from different mixtures of polylactide (PLA) and poly(ethylene glycol) (PEG). Processing conditions were optimized for all compositions and the resulting micro/nanofiber morphologies (i.e., diameter size and surface texture) were characterized by scanning electron microscopy (SEM). NMR and FTIR spectroscopies were employed to verify the final compositions, and thermal properties were evaluated by DSC and TGA. XPS spectroscopy revealed that PEG was mainly deposited on the surfaces of the electrospun micro/nanofibers, leading to smooth textures. Interestingly, PLA/PEG scaffold solubility in ethanol was very different to that in water, since a significant amount of PEG was effectively retained in the PLA matrix after immersion in ethanol whereas only a low level of PEG was retained in the PLA matrix after immersion in water. The hydrophilicities of the scaffolds obtained from PLA/PEG mixtures were consequently higher than that of the PLA, even after exposure to water. As PEG can be used as a sacrificial polymer due to its high solubility in water, it was possible to increase the porosity of PLA/PEG scaffolds. PLA/PEG scaffolds loaded with triclosan (TCS) had very different release profiles in hydrophilic (e.g., PBS) and hydrophobic (e.g., Sörensen/ethanol 30:70 v/v) media, while differences were small between scaffolds with different PLA/PEG ratios. TCS-loaded scaffolds exhibited good antibacterial properties for all compositions and allowed the adhesion of epithelial cells (i.e., MDCK and VERO). Significant differences in cell proliferation were found between unloaded and TCS-loaded scaffolds due to the clear improvement in cell colonization observed with increasing PEG content.