Preparation of designed poly(D,L-lactide)/nanosized hydroxyapatite composite structures by stereolithography.

The preparation of scaffolds to facilitate the replacement of damaged tissues and organs by means of tissue engineering has been much investigated. The key properties of the biomaterials used to prepare such scaffolds include biodegradability, biocompatibility and a well-defined three-dimensional 3-Dpore network structure. In this study a poly(D,L-lactide)/nanosized hydroxyapatite (PDLLA/nano-Hap) composite resin was prepared and used to fabricate composite films and computer designed porous scaffolds by micro-stereolithography, mixing varying quantities of nano-Hap powder and a liquid photoinitiator into a photo-crosslinkable PDLLA-diacrylate resin. The influence of nano-Hap on the rheological and photochemical properties of the resins was investigated, the materials being characterized with respect to their mechanical, thermal and morphological properties after post-preparation curing. In the cured composites stiffness was observed to increase with increasing concentration of nanoparticles. A computer designed construct with a pore network based on the Schwarz architecture was fabricated by stereolithography using PDLLA/nano-Hap composite resins.