Biphasic calcium phosphate (BCP) ceramics consisting of hydroxyapatite (HA) and tricalcium phosphate (TCP) has been used as a bone graft material during the last decade. In this paper, we report the bone in-growth induced by BCP ceramic in the experimentally created circular defects in the femur of dogs. This BCP ceramic consists of 55% hydroxyapatite (HA) and 45% b-tricalcium phosphate (TCP) prepared in situ by the microwave method. The defects were created as 4-mm holes on the lateral aspect of the femur of dogs and the holes were packed with the implant material. The defective sites were radiographed at a period of 4, 8, and 12 weeks postoperatively. The radiographical results showed that the process of ossification started after 4 weeks and the defect was completely filled with new woven bone after 12 weeks. Histological examination of the tissue showed the formation of osteoblast inducing the osteogenesis in the defect. The collageneous fibrous matrix and the complete Haversian system were observed after 12 weeks. The blood serum was collected postoperatively and biochemical assays for alkaline phosphatase activity were carried out. The measurement of alkaline phosphatase activity levels also correlated with the formation of osteoblast-like cells. This microwave-prepared BCP ceramic has proved to be a good biocompatible implant as well as osteoconductive and osteoinductive materials to fill bone defects.

The present study involves the development of citric acid-cross-linked carboxymethyl cellulose (C3CA) scaffolds by a freeze-drying process. Scaffolds were fabricated at different freezing temperatures of −20, −40, or −80 °C to investigate the influence of scaffold pore size on bone regeneration. All three scaffolds were porous in structure, and the pore size was measured to be 74 ± 4, 55 ± 6, and 46 ± 5 μm for −20, −40, and −80 °C scaffolds. The pores were larger in scaffolds processed at −20 °C compared to −40 and −80 °C, indicating the reduction in pore size of the scaffolds with a decrease in freezing temperature. The cytocompatibility, cell proliferation, and differentiation in C3CA scaffolds were assessed with the Saos-2 osteoblast cell line. These scaffolds supported the proliferation and differentiation of Saos-2 cells with significant matrix mineralization in scaffolds processed at −40 °C. Subcutaneous implantation of C3CA scaffolds in the rat model was investigated for its ability of vascularization and new matrix tissue formation. The matrix formation was observed at the earliest of 14 days in the scaffolds when processed at −40 °C while it was observed only after 28 days of implantation with the scaffolds processed at −20 and −80 °C. These results suggest that the citric acid-cross-linked CMC scaffolds processed at −40 °C can be promising for bone tissue engineering application.

Background The study aimed at the formulation of atorvastatin-loaded chitosan-hydroxyapatite composite bioscaffolds and determination of its wound-healing activity on animals. Hydroxyapatite was prepared from the biowaste eggshell cross-linked with calcium chloride and loaded with atorvastatin. The prepared bioscaffold was characterized for physicomechanical properties, morphological studies, differential scanning calorimetry, and in vitro drug release study. In vitro antibacterial activity was determined using the agar diffusion method, and in vivo wound-healing activity was evaluated using the excision wound-healing model. Results Results exhibited that bioscaffold containing 1:1 ratio of chitosan to hydroxyapatite (Hac1) with calcium chloride of 1.5 g (Hbc3) and loaded with atorvastatin (Hcc3) showed effective physicomechanical properties, i.e., thickness (60 μm), swelling behavior (68%), folding endurance (101), tensile strength (0.0283 Mpa), and burst time (1.9 s). Hcc3 scaffold was highly effective and exhibited the highest zone of inhibition against Bacillus subtilis (3.2 cm), Staphylococcus aureus (3.0 cm), Escherichia coli (3.5 cm), and Pseudomonas aeruginosa (2.7 cm). The group treated with Hcc3 scaffold was significant in healing wounds by showing 100% wound contraction. Conclusion It can be concluded from the study that atorvastatin-loaded chitosan-hydroxyapatite composite bioscaffolds may be a significantly more effective scaffold in healing excision wounds.

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