Properties and Osteogenicity of Two Calcium Sulfate Materials with Micro or Nano Morphology.

Calcium sulfate dihydrate (CaSO4 x 2H2O, CSD) was widely used as the artificial bone graft. In this study, two kinds of CSD materials were characterized with XRD, TG/DTA, FT-IR, and SEM. They were both composed of CSD. Spherical shape particles were observed for nano-CSD with diameters of 52-300 nm. The micro-CSD were thin sheet particles with dimensions of 5-10 μm. At 56 days post-implantation in vivo, nano-CSD had good tissue compatibility. A frequently used bioactive material DBM, which was the combination of nano-CSD (nano-CSD-DBM) and micro-CSD (micro-CSD-DBM) in a 1:1 weight ratio separately. Composite materials were implanted in intramuscular pockets in nude mouse model. New bone mineralization could be both observed in the surgery site. Collagen I was also widely distributed by immunohistochemistry assay. And new bone area of nano-CSD-DBM was 28 ± 4.6% at 4 weeks post-operation. But new bone area of micro-CSD-DBM was 16 ± 3.7% (less than nano-CSD-DBM). Nano-CSD showed increased degradation rate with obvious anginogenicity. And nano-CSD-DBM showed more excellent bone induction property as bone substitute implant.