Favorable osteogenic activity of iron doped in silicocarnotite bioceramic: In vitro and in vivo Studies

Background Calcium phosphate silicate (Ca5(PO4)2SiO4 or CPS) is a promising bioceramic for bone grafting. Iron (Fe) is a trace element in the human body that has been reported to enhance the mechanical strength of CPS ceramics. However, the exact biofunctions of Fe, combined with another human trace element, viz. silicon (Si), in CPS and the optimal dose for Fe addition must be further investigated. Methods In vitro: the morphology, structure and cell adhesion were observed by SEM; the ability to promote osteogenic differentiation and mineralization was explored by ALP and alizarin red staining; the expression of osteogenic-specific genes and proteins was detected by PCR, WB and immunofluorescence. In vivo: Further exploration of bone regeneration capacity by establishing a skull defect model. Results In vitro, we observed increased content of adhesion-related proteins and osteogenic-related genes expression of Fe-CPS compared with CPS, as demonstrated by immunofluorescence and polymerase chain reaction experiments, respectively. In vivo micro-computed tomography images, histomorphology, and undecalcified bone slicing also showed improved osteogenic ability of Fe-CPS bioceramics. Conclusion With the addition of Fe2O3, the new bone formation rate of the Fe-CPS scaffold after 12 weeks increased from 9.42% to 43.76%. Moreover, both in vitro and in vivo experimental outcomes indicated that Fe addition improved the CPS bioceramics in terms of their osteogenic ability by promoting the expression of osteogenic-related genes. Fe-CPS bioceramics can be employed as a novel material for bone tissue engineering on account of their outstanding new bone formation ability. The translational potential of this article This study suggests that Fe-CPS bioceramics can be employed as a novel material for bone tissue engineering on account of their outstanding new bone formation ability,which provides promising therapeutic implants and strategies for the treatment of large segmental bone defects.