Bioadaptable bone regeneration of Zn-containing silicocarnotite bioceramics with moderate biodegradation and antibacterial activity

Preparing novel bioceramics with bioadaptability of high osteogenesis and moderate degradation is particularly challenging. In this work, zinc containing silicocarnotite (Ca5(PO4)2SiO4, CPS) scaffolds (Zn-CPS) were applied as a potential novel therapy for bone defect since the good antibacterial capacity and biocompatibility of Zn. The effects of ZnO content on antibacterial capacity, protein adsorption, osteogenesis and degradation behavior of Zn-CPS bioceramics were investigated and the related mechanism was also discussed. The obtained Zn-CPS bioceramics showed enhanced antibacterial capacity, osteogenesis and degradation. In general, the antibacterial capacity and osteogenesis of Zn-CPS improved with the increase of ZnO content, while the degradation behavior of Zn-CPS exhibited different laws in vitro and in vivo. Specifically, after implantation for 12 weeks, the bone formation percent and degradation percent of 5Zn-CPS could up to 43.0% and 50.9%, indicating an excellent bioadaptability. Moreover, proteomics analysis of adsorbed proteins on Zn-CPS indicated that the addition of ZnO into CPS may activate PI3K-Akt signaling pathway to promote osteogenesis, and degradation contrast in vitro and in vivo also demonstrated that in vivo related factors, such as proteins, cells and enzymes played the crucial role in degradation. These findings imply that Zn-CPS bioceramics are promising materials for bone defect repair with infections.