In this work, a titanium-doped hydroxyapatite (HAp) scaffold was produced from two different sources (natural eggshell and laboratory-grade reagents) to compare the efficacy of natural and synthetic resources of HAp materials on new bone regeneration. This comparative study also reports the effect of Ti doping on the physical, mechanical, and in vitro as well as in vivo biological properties of the HAp scaffold. Pellets were prepared in the conventional powder metallurgy route, compacted, and sintered at 900 °C, showing sufficient porosity for bony ingrowth. The physical-mechanical characterizations were performed by density, porosity evaluation, XRD, FTIR, SEM analysis, and hardness measurement. In vitro interactions were evaluated by bactericidal assay, hemolysis, MTT assay, and interaction with simulated body fluid. All categories of pellets showed absolute nonhemolytic and nontoxic character. Furthermore, significant apatite formation was observed on the Ti-doped HAp samples in the simulated body fluid immersion study. The developed porous pellets were implanted to assess the bone defect healing in the femoral condyle of healthy rabbits. A 2 month study after implantation showed no marked inflammatory reaction for any samples. Radiological analysis, histological analysis, SEM analysis, and oxytetracycline labeling studies depicted better invasion of mature osseous tissue in the pores of doped eggshell-derived HAp scaffolds as compared to the undoped HAp, and laboratory-made samples. Quantification using oxytetracycline labeling depicted 59.31 ± 1.89% new bone formation for Ti-doped eggshell HAp as compared to Ti-doped pure HAp (54.41 ± 1.93) and other undoped samples. Histological studies showed the presence of abundant osteoblastic and osteoclastic cells in Ti-doped eggshell HAp in contrast to other samples. Radiological and SEM data also showed similar results. The results indicated that Ti-doped biosourced HAp samples have good biocompatibility, new bone-forming ability, and could be used as a bone grafting material in orthopedic surgery.
Keywords: bone regeneration; eggshell HAp; in vitro; titanium.