Shape memory process in resorbable polymers: effect on surface properties and cell adhesion

The objectives of this study were to confirm the shape memory behavior of two new bioresorbable terpolymers (L-lactide, glycolide, and trimethylene carbonate: L-PLGTMC and B-PLGTMC), to follow the influence of the shape memory process on their surface properties and to test their cytocompatibility using osteoblast-like cells. For this purpose, foils of both terpolymers were prepared. The terpolymers' ability to recover up to 92-93% of the memorized shape within 10 seconds was obtained. The influence of shape memory process on the surface properties was assessed by water contact angle (WCA) measurement and atomic force microscopy (AFM) and the results suggested that both terpolymers preserved the hydrophilicity after recovery and also that B-PLGTMC polymer was rougher than L-PLGTMC (about 9 folds more). The AFM pictures showed the presence of spherical shape hills on the B-PLGTMC foil surface which after the stretching procedure became oriented toward the direction of the applied load. The terpolymers were seeded on both sides (Top and Bottom faces) with human MG63 osteoblast-like cells. Cell viability was assessed after 1, 3 and 7 days, using MTT assay. Results revealed an increasing number of metabolically active cells with the incubation time, suggesting, together with nitric oxide (NO) level determination, the cytocompatibility of both terpolymers. Cell spreading and morphology were investigated by H&E staining and obtained results corresponded well with ones of MTT and NO.