Preparation and characterization of four different compositions of calcium phosphate scaffolds for bone tissue engineering

Calcium phosphate ceramics rank among the materials showing the greatest promise for bone tissue engineering, due to their bone-like composition. In this study, porous calcium phosphate scaffolds were prepared from calcium-deficient hydroxyapatite (d-HAp) powders following the addition of stearic acid and sintering at 700, 1100, 1200 and 1400 °C for 3 h. The scaffolds produced in this study were characterized according to their morphology, properties and biodegradation. The results indicate an interconnected porous structure with pore sizes ranging from several microns to as large as 1000 μm. In the powders sintered at 700 °C (Sample H), only hydroxyapatite (HAp) phase was present; when heated to 1100 °C, β-TCP was observed with HAp (Sample BH); at 1200 °C, the phase compositions included β-TCP and α-TCP, as well as a small quantity of HAp (Sample ABH); and at 1400 °C, the phases of samples included mainly α-TCP and HAp (Sample AH). The degradation of the scaffolds was evaluated after immersion in distilled water for various periods of time. After soaking for 28 days, noticeable dissolution behavior was observed on the edges of the pores in the BH sample, while the H sample showed no significant difference in morphology. Obvious dissolution and precipitation were seen in the ABH and AH samples, and flake-like precipitates with α-TCP phase began appearing on the surface of the ABH and AH within 3 days after immersion.