Preparation and characterization of 3D printed hydroxyapatite-whisker-strengthened hydroxyapatite scaffold coated with biphasic calcium phosphate

This study investigates the in vitro degradation of calcium-deficient hydroxyapatite powder after heat treatment at different temperatures and analyzes the calculated phase composition, particle size distribution, degradation rate, and bioactivity of the powder after heat treatment. A mixture of hydroxyapatite and β-tricalcium phosphate (BCP) coatings was prepared on the surface of a 3D-printed hydroxyapatite-whisker-strengthened hydroxyapatite scaffold (HA_w/HA) by vacuum impregnation and ultraviolet light curing combined with an optimized heat treatment process. The performance of the coatings under different methods was characterized. The composite scaffolds with highly interconnected pores and excellent mechanical properties were prepared, and their biodegradation performance, bioactivity, osteoconductivity, and osteoinductivity of the scaffolds were improved. The results showed that calcium-deficient hydroxyapatite began to transform into BCP between 600 °C and 800 °C, and the powder treated at 800 °C has better bioactivity. The BCP coating prepared by light curing was more uniform, resulting in a higher interfacial bonding strength, and has better osteoconductivity and osteoinductivity than that prepared by vacuum impregnation.