Preparation and characterization of biodegradable poly(D,L-lactide) and surface-modified bioactive glass composites as bone repair materials.

In order to improve filler dispersion and phase compatibility between poly(D,L-lactide) (PDLLA) and inorganic bioactive glass (BG) particles, and to enhance the mechanical properties of PDLLA/BG composites, the silane coupling agent 3-glycidoxypropyltrimethoxysilane (KH570) was used to modify the surface of BG particles (represented by KBG). The structure and properties of PDLLA/BG and PDLLA/KBG composites were investigated by mechanical property testing and scanning electron microscopy (SEM). This study demonstrated that the Guth and Gold models can be combined to predict the Young's modulus of the composites. The Pukanszky modulus showed that the interaction parameter B of PDLLA/KBG composites was higher than that of the PDLLA/BG, which indicates that there is a higher interfacial interaction between the PDLLA and KBG. The composites were incubated in simulated body fluid (SBF) at 37 degrees C to study the in vitro degradation and bioactivity of the composites and to detect bone-like apatite formation on their surfaces.

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 CaCl(2) 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.