An ionically crosslinked hydrogel containing vancomycin coating on a porous scaffold for drug delivery and cell culture

The aim of this study was to prepare and characterize a scaffold with an ionically crosslinked hydrogel coating layer containing a water-soluble drug, vancomycin, via a novel drug loading method for sustained drug delivery and surface modification. The poly(d,l-lactide acid) (PDLLA)/biphasic calcium phosphate (BCP) scaffold with a highly inter-connected porous structure was fabricated by a particle-leaching/thermally induced phase separation (TIPS) method. The pre-vacuumized scaffold was immersed into an alginate/vancomycin solution. Following impregnation by the solution, the scaffold was removed and immersed in a CaCl2 solution for 30 min to allow gelation of the alginate solution. In this way, the drug was not exposed to organic solvents or detrimental temperature conditions and it could avoid loss of drug during the leaching process. The water contact angles of the scaffold surface decreased after being coated with the hydrogel. The in vitro drug release profile showed sustained release properties which were influenced by the alginate concentration and the dissolution medium. A standardized bacterial assay showed that the drug was still active after association with the scaffold by this gentle method of drug loading. The in vitro osteoblast culture experiments confirmed the biocompatibility of the scaffold for attachment and proliferation of osteoblasts.