Evaluation of RGD-grafted porous PLLA scaffold for chondrogenic differentiation of stem cells

Abstract

Biodegradable porous poly(L-lactic acid) (PLLA) scaffolds were prepared using gas foaming method. The PLLA scaffolds with a hydrophobic surface were subjected to Ar plasma treatment and in situ acrylic acid (AA) grafting to obtain hydrophilic PLLA scaffold (PLLA-PAA). Cell-adhesive RGD peptide was then immobilized onto the AA-grafted PLLA (PLLA-PAA-RGD). Once rabbit bone marrow-derived mesenchymal stem cells (BM-MSC) were isolated, MSCs were seeded into PLLA control, PLLA-PAA, and PLLA-PAA-RGD scaffold and cultured for up to 4 weeks in chondrogenic medium with the addition of 10 ng/ml transforming growth factor (TGF)-beta 1. Surface analysis of AA-grafted PLLA identified significant alterations of surface characteristics, including reduced contact angle and different atomic compositions. From WST-1 assay at 4 weeks, cells were found more proliferative in PLLA-PAA than the others. Upon the histological analysis of Safranin 0 staining, chondrogenic differentiation of MSCs appeared to be progressed more actively in PLLA-PAA. The effect of RGD immobilization on MSC differentiation was barely notable.