Fabrication and characterization of novel hybrid organic/inorganic microparticles to apply in bone regeneration.

The aim of this study was to fabricate and characterize the novel hybrid organic/inorganic microparticles (MPs) to apply in bone regeneration. These hybrid MPs were fabricated using a scale-up method we have developed to increase the yield of chitosan (CS) MPs. The MPs were based on the CS and consist of inorganic components such as dibasic calcium phosphate (CaHPO(4)) or calcium carbonate (CaCO(3)). Tripolyphosphate (TPP) has been used as a cross-linking agent to form cross-links between the amine groups in CS and phosphate groups in TPP. Four types of hybrid MPs were fabricated: CS; CS-10%CaHPO(4); CS-20%CaHPO(4); CS-10% CaCO(3). SEM images revealed that all types of MPs were approximately spherical in shape and most of them were with a diameter range of 30-60 microm. XRD reveals the evidence of having CaHPO(4) or CaCO(3) in the CS-10%CaHPO(4), CS-20%CaHPO(4), or CS-10%CaCO(3) MPs, respectively. All types of MPs have shown the existence of cross-links according to FTIR. We have studied the mesenchymal stem cell (MSC) attachment on the surfaces of all types of MPs compared to control wells at 4, 8, 25, and 48 h. The attached MSCs on all types of MPs were increased more than two-fold at 48 h compared with that of 4 h. These hybrid MPs have a great potential to apply as a bone-void filler or bone tissue engineering scaffold to treat the bone defects. (c) 2009 Wiley Periodicals, Inc.