Formation of a bioactive material for selective laser sintering from a mixture of powdered polylactide and nano-hydroxyapatite in supercritical carbon dioxide

Supercritical carbon dioxide (SC-CO₂) is used to prepare bioactive composites from powdered polylactide and nanosized hydroxyapatite for surface-selective laser sintering of three-dimensional tissue engineering structures. The mixture of powdered polylactide and nanosized hydroxyapatite and cannot be directly laser-sinter because of the impossibility of forming continuous filaments from sintered polymer particles. The use of composite particles for sintering formed in SC-CO₂ medium makes it possible to eliminate this shortcoming and to form continuous structures. Analysis of the composition and mechanical tests of such structures showed that the sintered composite obtained is fairly uniform, without destruction centers, capable of withstanding the same mechanical loads as the pure polymer, and therefore, suitable for use in tissue scaffold engineering.