Scaffolds constituted by mixed polylactide and poly(ethylene glycol) electrospun microfibers

Scaffolds comprising different ratios of poly(ethylene glycol) (PEG) and polylactide (PLA) electrospun fibers were prepared by using a single rotary collector. Electrospinning parameters and solution conditions were optimized to obtain continuous fibers and a homogeneous distribution of both polymers in the final scaffold. Short needle-collector distances allowed good overlapping of the two incident and independent jets. The composition of the scaffold was effectively tuned by varying the flow rate of the PLA solution. PEG and PLA fibers could be well distinguished in the scaffold because of their smooth and rough texture, respectively, and diameters in the nanometer and micrometer range. Greater sizes corresponded to polylactide and clearly depended on the flow rate. Drugs such as triclosan and polyhexamethylene biguanide hydrochloride, which have different hydrophilic/hydrophobic character and molecular size, were loaded into PLA microfibers by electrospinning. The high water solubility of PEG justified its use as a sacrificial polymer. Thus, it was possible to prepare scaffolds with tuned porosity (from 40 to 80 %) by water immersion of dual samples having different PEG content. Porosity greatly affected the release rate; specifically, a practically instantaneous or a sustained release was determined for triclosan in an appropriate medium. Drug loaded scaffolds had a clear bactericidal effect that was more effective for Gram-positive bacteria. Cell proliferation studies indicate that fibroblast colonization increased by 20-25 % in PLA/PEG scaffolds with high PEG contents compared to the control, whereas this effect was not observed for epithelial cells.