Characterization of biodegradable poly(lactic acid) porous scaffolds prepared using selective enzymatic degradation for tissue engineering

In this study, poly(lactic acid) (PLA) scaffolds were prepared by selective enzymatic degradation using poly(3-hydrobutyrate- co -4-hydrobutyrate) [P(3HB- co -4HB)] depolymerase. The porous morphology and properties of the scaffolds were investigated to clarify whether the microstructure of the biomimetic extracellular matrix is suitable for cell proliferation and differentiation. When the P(3HB- co -4HB) composition of PLA/P(3HB- co -4HB) blends was changed from 50 wt% to 60 wt%, the mean pore diameter of the porous PLA scaffolds increased from 64.15 µm to 80.01 µm, the porosity significantly improved from 68.45% to 79.88%, and the compressive modulus decreased from 9.34 MPa to 6.94 MPa. PLA40 with 60% P(3HB- co -4HB) blending was used in in vitro degradation and mouse embryo fibroblast (MEF) cell culture tests. The results demonstrated that the PLA scaffolds were degraded completely into harmless products in simulated body fluid (SBF) solution at a slow degradation rate, and the weight loss of the scaffolds could reach 80% after 8 months of in vitro degradation. Meanwhile, the PLA scaffolds showed the largest swelling value of 157.4% after immersion in SBF solution for 14 days. Cell viability was determined through scanning electron microscopy (SEM) and 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2- H -tetrazolium bromide (MTT) tests. The results showed that the PLA scaffolds supported the attachment and growth of MEF cells. Compared with the PLA scaffolds without any modification, the PLA scaffolds modified by poly- l -lysine exhibited a better biocompatibility to MEF cells. These results indicate that selective enzymatic degradation has a potential application in scaffold manufacturing. SEM images of MEF cells on PLA scaffolds prepared by selective enzymatic degradation after 7 days of culture. The results demonstrated that MEF cells attached more easily to the surface than in the interior of the PLA scaffolds.