Hydrophilic poly (ethylene glycol) coating on PDLLA/BCP bone scaffold for drug delivery and cell culture

A well developed porous poly-D-L-lactide (PDLLA)/biphasic calcium phosphate (BCP) scaffold was coated with a hydrophilic poly (ethylene glycol) (PEG)/vancomycin composite for drug delivery and surface modification. The PDLLA/BCP scaffold, obtained by a salt-leaching method, possessed highly inter-connected pores (250–350 μm) and a high porosity (83.8%). The hydrophilic PEG was used to effectively entrap the drug inside the scaffold and to enhance the wettability of the hydrophobic surface of the PDLLA/BCP matrix. The scaffold with PEG/vancomycin coatings was fabricated by injecting the PEG/vancomycin composite solution into the pre-vacuumized scaffold. A standardized bacterial assay showed that the drug was still active after association with the bone scaffold. The in-vitro drug release study of vancomycin showed an initial burst release followed by a slower sustained release. The drug release behavior in vitro was investigated in detail by controlling the composite solution parameters: PEG molecular weight and PEG concentration. The release profiles showed that an increase in the PEG molecular weight and concentration resulted in a slower drug release rate. The water contact angles of the scaffold surface decreased after being coated with PEG. The in-vitro osteoblast culture experiment confirmed the biocompatibility of the scaffold for the growth of osteoblasts.