Biodegradable polymer composites with osteogenic potential

The aim is to study the basic physico-mechanical properties of hydroxyapatite (HA) composites (up to 25-50 wt%) with polylactide (PLA-HA) and poly(e-caprolactone) (PCL-HA) prepared by melt compounding, as well as the osteogenic potential of PLA-HA in vivo. Materials and methods. All biodegradable polymer composites were prepared by hot melt compounding and studied by dielectric spectroscopy in frequency domain, optical microscopy, X-ray diffraction analysis and tensile tests. An ability of PLA-5 wt% HA composites prepared by 3D-printing to induce bone tissue growth in vivo was detected with the help of ectopic subcutaneous test in inbred mice. Results. Values of the real part of complex permittivity of PLA-HA and PCL-HA composites are increased by 15-30% compared to those for initial PLA and PCL, while tand loss factor does not exceed 0.02 for PLA-based composites and 0.2 for PCL-based composites. The crystallinity degree of PLA-HA composites is increased by 3 and 6 times with an increase of HA content from 25 to 50 wt% respectively compared to the indicator for PLA. The crystallinity degree of PCL-HA composites with 25 wt% HA is increased by 2 times compared to the value for PCL. It is due to the fact that HA powder particles play the role of additional nucleation centers. For all this, mechanical strength of composites diminished statistically. Even lowest HA content (5 wt%) in PLA-HA composites prepared by 3D-printing increased the incidence of ectopic osteogenesis by 40%. Conclusion. Designed biodegradable composites have a potential of practical use for bone tissue engineering.