Nanostructured PLLA−Hydroxyapatite Scaffolds Produced by a Supercritical Assisted Technique

Temporary bone scaffolds can surrogate the extracellular matrix to favor the regeneration of tissues and organs. It is very difficult to obtain the coexistence of the macro-, micro-, and nanostructural properties necessary to mimic the organization of the human bone. To obtain all of these characteristics, we tested a supercritical fluid assisted technique for the formation of PLLA/ceramic scaffolds using hydroxyapatite (HA) nanoparticles loaded at up to 50% by weight of the polymer to improve the biomimethism and the mechanical properties of the scaffolds. We produced poly( l -lactic acid) scaffolds in relatively short time (<30 h), with a porosity higher than 90% and with a high interconnectivity. An internal structure formed by very long nanofibers of 200−400 nm diameter and prefixed macroscopic shape and size was also obtained. A maximum compressive modulus of 123 kPa was obtained, and the solvent residue was lower than 5 ppm.