Iron Foam- Bio-cement Scaffolds for potential Biomedical ApplicationsThursday (27.09.2018) 12:00 - 12:15 S1/03 - 23 Part of:
Metal scaffolds with mechanical properties similar to humans have gained significant importance in the repair of bone defects. Iron has been used successfully in animal implantation studies with long degradation time frames. Bio-corrodible iron foams were coated with strontium and bisphosphonates in order to obtain a bioactive surface. The aim of the present study was to investigate role of open structure iron and iron based alloys in vivo as a bone replacement material, which provides osteoconductive surface on the one hand, and does not encumber the bone regeneration ability on the other. Moreover, the open foam structure mimics a bone-like structure which allows in-growth of new tissue and blood vessels. In order to evaluate the influence of alloying metal on bone regeneration, open cell iron foams were produced by powder-metallurgical technique and coated with strontium (FeSr) and bisphosphonates (FeBiP) which were then compared to plain iron foams (Fe) and empty defect. These were then substituted in a critical size metaphyseal defect in the femur of ovariectomized rats (n=60). After 6 weeks,microCt analysis revealed a statistically significant increased bone formation at the implant interface in FeSr compared to FeBiP (p=0.035) and Fe (p=0.002). Histomorphometric analysis revealed a statistically significant increase in bone formation at the tissue-implant interface with the addition of strontium carbonate and bisphosphonates respectively (p<0.01). This was further confirmed by immunohistochemistry data which also showed an increase in prominent bone formation markers viz. BMP2 and decrease in RANKL/OPG activity. Tof-Sims analysis also showed overlapping Ca signals with Fe for both SrCO3 and BiP thereby indicating tissue in-growth into the scaffolds. The results thus obtained demonstrate that doping of Sr and BiP on Fe results in higher surface activity thereby leading to enhanced bone formation. In addition osteocytes with regularly distributed canalicular system were found in the same regions. The study thus indicates alloying of Fe with Sr and BiP seems to be a promising way to optimize mechanical properties of iron on one hand and enhance bone formation with good biocompatibility and no inflammatory response on the other.