45S5 Bioglass® concentrations modulate the release of vancomycin hydrochloride from gelatin-starch films: evaluation of antibacterial and cytotoxic effects

The aim of this work was to evaluate the release profile of vancomycin hydrochloride (VC), as well as the degradation, in vitro antistaphylococcal effect and cytotoxicity in MG-63 osteoblast-like cells of gelatin-starch (GS) films added with different concentrations of microparticles of the bioactive glass 45S5 (m-BG). The biomaterials were obtained through the gel-casting method. Four different composites were prepared at four different weight percentages of m-BG: 0, 5, 10, and 15 %. Glutaraldehyde 0.25 wt% (GA) was used as the cross-linker. The composites were characterized by scanning electron microscopy and the in vitro degradation of the films was studied by measuring the water uptake and weight loss. The drug release kinetics was quantified spectrophotometrically. The inhibition zone test and the plate count method were used to evaluate the antibacterial activity of the samples. Three staphylococcus strains were evaluated: Staphylococcus aureus ATCC6538, S. aureus ATCC29213, and Staphylococcus epidermidis ATCC12228. Cytotoxicity effects were evaluated through the MTT assay. The addition of m-BG to GS films showed no effects on the amount of water uptake, but led to an increase in the weight loss over time, even with m-BG content. The release rate of VC was also affected by the increasing concentration of m-BG in the composite films. However, the antibacterial effects of the composites were not improved by this modulation. All composites strongly inhibited staphylococcal cells with similar strength. On the other hand, liquid extracts from the composites resulted in cytotoxic effects on MG-63 osteoblast-like cells due to the presence of GA, but not to the concentration of VC or m-BG.