Highly filled poly(l‐lactic acid)/hydroxyapatite composite for 3D printing of personalized bone tissue engineering scaffolds

The designing of new biodegradable polymer composites is one of the most promising areas of modern orthopedics and regenerative surgery. At present, a number of methods have been proposed for designing and processing biodegradable polymer composites via various 3D printing technologies; however, the homogeneity of filler distribution together with mechanical properties of scaffolds made of such composites are far from those required for clinical use. In this study, the method for producing biodegradable composite material based on poly(l‐lactic acid) (PLLA) solution in organic solvent and hydroxyapatite (HAp) powder was proposed. The influence of HAp weight fraction and additional annealing on PLLA matrix crystallinity was investigated. It was shown that crystallinity of PLLA decreases from 58.84 ± 1.21 to 17.33 ± 1.69 as HAp weight fraction increased from 0 to 50 wt%. However, HAp filler promoted PLLA crystallites growth according to the X‐ray powder diffraction analysis. The results of nanoindentation showed Young's modulus values of the 3D‐printed scaffolds with 50 wt% of HAp at the level of human femur and tibia.