Photosynthetic microporous bioactive glass ceramic beads for treating avascular osteonecrosis

Abstract

Bioactive glass (BG) ceramics have attracted considerable attention as ideal bone grafts for treating avascular osteonecrosis owing to similarities in biological function with that of native bone. Metal ion-doped BGs exhibit outstanding biocompatibility, controllable biodegradability, excellent osteoinductivity, and angiogenic ability. Moreover, effective oxygen generation can support the healing of osteonecrotic defects. In this study, we developed simple sol–gel, gel-casting, and surface modification methods to fabricate photosynthetic microporous BG ceramic beads with improved therapeutic efficacy for avascular osteonecrosis by combining the oxygen generation ability, osteoconductivity, osteoinductivity, and angiogenic ability. The BG ceramic beads exhibited interconnected microporous structures with uniform micropores and unequiaxed grains, and this microstructure was not affected by Sr- and Cu-co-doping. Conversely, Sr- and Cu-co-doping, epigallocatechin gallate immobilization, and thylakoid coating affected the in vitro biological activity of the BG ceramic beads. Biological activity assays revealed that the thylakoid-coated photosynthetic microporous BG (BG12ET) ceramic beads promoted osteoblastic cell proliferation and endothelial cell tube formation more effectively than other ceramic beads. Therefore, BG12ET ceramic beads incorporated with osteoinductive and angiogenic factors can potentially provide a new generation of bone grafts for synergistic osteonecrosis therapy.