In vitro degradation of three-dimensional chitosan/apatite composite rods prepared via in situ precipitation.

Three-dimensional (3D) compact rods with multilayer structure made from chitosan (CHI) and apatite (Ap) have been prepared. The cytocompatibility assay revealed that the CHI/Ap composite could promote cell proliferation. In vitro degradation behaviors of the rods have been systematically investigated for up to 6 weeks in phosphate buffer saline (PBS) solution at 37°C.

Fabrication of chitosan/hydroxylapatite composite rods with a layer-by-layer structure for fracture fixation.

A composite rod for fracture fixation using chitosan (CHI)/hydroxylapatite (HA) was prepared by means of in situ precipitation, which had a layer-by-layer structure, good mechanical properties, and cell compatibilities. The CHI/HA composite rods were precipitated from the chitosan solution with calcium and phosphorus precursors, followed by treatment with a tripolyphosphate-trisodium phosphate solution (pH >13) to crosslink the CHI and to hydrolyze the calcium phosphates to nanocrystalline HA. The results of FTIR, XRD, and TEM measurements confirmed that HA had been formed within the CHI matrix.

Development of Fe3O4-poly(L-lactide) magnetic microparticles in supercritical CO2.

The Fe(3)O(4)-poly(L-lactide) (Fe(3)O(4)-PLLA) magnetic microparticles were successfully prepared in a process of solution-enhanced dispersion by supercritical CO(2) (SEDS), and their morphology, particle size, magnetic mass content, surface atom distribution and magnetic properties were characterized. Indomethacin (Indo) was used as a drug model to produce drug-polymer magnetic composite microparticles. The resulting Fe(3)O(4)-PLLA microparticles with mean size of 803 nm had good magnetic property and a saturation magnetization of 24.

Study of poly(L-lactide) microparticles based on supercritical CO2.

Poly(L-lactide) (PLLA) microparticles were prepared in supercritical anti-solvent process. The effects of several key factors on surface morphology, and particle size and particle size distribution were investigated. These factors included initial drops size, saturation ratio of PLLA solution, pressure, temperature, concentration of the organic solution, the flow rate of the solution and molecular weight of PLLA.