Rapid biomineralization of chitosan microparticles to apply in bone regeneration.

The aim of this study was to prepare bone like mineral (BLM) layers rapidly on the exterior surfaces of chitosan (CS) microparticles (MPs). The CS MPs were fabricated using a scale-up double emulsification method. The CS MPs were in the spherical shape and the size of 30-60 microm. The MPs were then placed in 5x concentrated simulated body fluid (5 x SBF) and allowed to undergo biomineralization to form a BLM layers on the surface of CS MPs at 37 degrees C over a 24 h period. The BML layers on the exterior surface of CS MPs were characterized using wide angle X-ray diffraction (XRD), Fourier transform infrared microscopy (FTIR), and scanning electron microscopy (SEM). Insulin like growth factor-1 (IGF-1) was dissolved at a concentration of 1 microg/ml in 5 x SBF to incorporate into the BLM layer. The CS MPs (100 mg) were incubated in a sample of 4 ml of 5 x SBF containing IGF-1 at a concentration of 1 microg/ml for 24 h. The IGF-1 release from BML layers on CS MPs were studied by placing MPs in 4 ml of phosphate buffered saline (PBS) and incubating MPs at 37 degrees C for 30 days. Samples (100 microl) were taken over the course of the 30 days and analyzed using Enzyme-linked Immunosorbent assay (ELISA). The release IGF-1 from BML layers was in a burst manner followed by a sustained release during the 30-day period. This study suggests that the CS MPs have the potential to be used to help deliver therapeutic drugs to localized areas and hence increase and accelerate bone growth.