Polymer-derived boron doped akermanite-octacalcium phosphate glass-ceramic scaffolds stimulate angiogenesis

Abstract

Angiogenesis is crucial in bone tissue engineering due to expediting the healing rate and remarkably enhancing the regeneration process. Further, vascular sprouting progression is controlled by cellular autocrine and paracrine secretion of growth factors. Boron ions significantly stimulate cells in terms of excessive angiogenic growth factors secretion, therefore, could lead to excessive angiogenesis, contingent upon receiving an appropriate dose of the ion. In the current work, akermanite-octacalcium phosphate glass-ceramics were elicited from polymeric precursors, the method of synthesis that is so-called polymer-derived ceramics (PDC), and boron-containing moieties were employed to dope this element in the structure. Synthesized glass-ceramics were subjected to in vitro studies, including osteoconduction via monitoring the precipitation of hydroxycarbonate apatite (HCA), cytocompatibility, angiogenic growth factor secretion, and alkaline phosphatase (ALP) activity. The optimized sample was implanted in mice models and monitored in an in vivo study. The samples containing 6 wt% of B2O3 showed less bioactivity and cell viability. In contrast, 3 wt% of B2O3 led to more controlled biodegradation of octacalcium phosphate and through moderating the rate of release, the risk of boron overdosing was restrained.