Abstract
The in vivo reaction against nano-apatite is still not well understood. We self-prepared four samples using medical-grade collagen and commercial (40 nm) nano-apatite particles (n-HAp), namely (i) collagen sponge (sample C), (ii) n-HAp collagen composite sponge (sample AC), (iii) collagen sponge with basic fibroblast growth factor (b-FGF) (sample CF) and (iv) n-HAp collagen composite sponge with b-FGF (sample ACF); and implanted them in subcutaneous tissues of the back of mice for 1 and 2 weeks. Visual inspections and histological observations revealed that sample ACF caused most intensified angiogenesis with time, followed by sample CF and sample AC, while sample C caused little angiogenesis. More the angiogenetic, more the foreign body reactions. It was confirmed that n-HAp bound in collagen sponge was safe and bio-absorbable; and n-HAp had minor capability of angiogenesis, and if coupled with b-FGF, strong capability of angiogenesis at the implanted site in soft tissues. This biological property could be useful for re-generation of hard tissues as well as soft tissues in the future clinical applications.
