Laser rapid prototyping for tissue engineering and regeneration

In present paper we describe the development of advanced laser stereolithography (LS) methodology based on photopolymerisation of a new liquid mixture of polyfunctional acrylic monomers and osteoinductive hydroxyapatite powder. Supercritical carbon dioxide treatment of LS samples introduced both surface and bulk microporosity for enhanced primary cell attachment and to remove toxic additives improving biocompatibility of the materials. The results of in vitro tests comprising human osteoblast cells attachment, spreading and proliferation on the implants demonstrate low level of their cytotoxicity and high level of biocompatibility. We also present a novel Surface Selective Laser Sintering (SSLS) technique for biodegradable polymer scaffolds fabrication from thermosensitive poly(D,L-lactic) - and poly(D,L-lactic-co-glycolic) acids - polymers, which have a wide spread occurrence in biomedical applications. Unlike conventional Selective Laser Sintering (where the powder particles melt because of their volumetric absorption of the laser radiation), in SSLS initiation of the sintering occur due to near IR laser beam absorption by a small amount (< 0.1wt.%) of biocompatible carbon black microparticles uniformly distributed along the polymer powder surface. This technique enable to prevent any significant changes in polymer initial structures and even incorporate bioactive enzymes into the samples. The results of our in vitro studies using 3T3 fibroblast, C2C12 myoblast and ovine meniscal chondrocyte cells cultures hold great promise for use of produced scaffolds and developed technique in tissue engineering.