Degradation of three dimensional poly(l-lactic acid) scaffolds modified by gelatin

In vitro degradation of poly(1-lactic acid) (PLLA) scaffolds modified by gelatin was carried out in 0.01 M NaOH solution at 37 degrees C for 5-6 days. The mass loss, pH value, viscosity-average molecular weight, morphology and thermal behavior during degradation were studied. The results showed that the prepared scaffolds were interpenetrating porous structure and the increased degradation time; both the viscous-average molecular weight and melting peak showed a clear upward trend, while the crystallinity and mass loss exhibited a downward trend. The semi-logarithmic linear relationship between the viscosity-average molecular weight and degradation time indicates an autocatalytic process. The mass of the PLLA scaffolds decreased by 10.33 % after 2 days of degradation and decreased by 86.19 % to the end of the experimental period. The decrease in the viscous-average molecular weight and a relatively little mass loss in the beginning of the degradation period indicate the bulk degradation. The gradual mass loss is indicated not only by the bulk degradation mechanism but also a surface erosion mechanism. The results obtained by the in vitro degradation in a NaOH solution at 37 degrees C can find useful applications in solving the biocompatibility of PLLA scaffolds.