Amorphous Precursor-Mediated Calcium Phosphate Coatings with Tunable Microstructures for Customized Bone Implants

Calcium phosphate (CaP) is frequently used as coating for bone implants to promote osseointegration. However, commercial CaP coatings via plasma spraying display similar microstructures, and thus fail to provide specific implants according to different surgical conditions or skeletal bone sites. Herein, inspired by the formation of natural biominerals with various morphologies mediated by amorphous precursors, CaP coatings with tunable microstructures mediated by an amorphous metastable phase are fabricated. The microstructures of the coatings are precisely controlled by both polyaspartic acid and Mg2+. The cell biological behaviors, including alkaline phosphatase activity, mineralization, and osteogenesis-related genes expression, on the CaP coatings with different microstructures, exhibit significant differences. Furthermore, in vivo experiments demonstrate the osseointegration in different types of rats and bones indeed favors different CaP coatings. This biomimetic strategy can be used to fabricate customized bone implants that can meet the specific requirements of various surgery conditions.