Selective laser sintered nanocomposite scaffolds for bone tissue engineering

Abstract

In scaffold-based bone tissue engineering, 3D scaffolds play a very important role in bone tissue regeneration. They provide a suitable microenvironment for seeded cells to attach, migrate, proliferate and differentiate, leading to new bone formation. As bone is a natural nanocomposite consisting of nano-sized bone apatite and collagen fibrils, synthetic, polymer-based biodegradable composites containing osteoconductive calcium phosphate (Ca-P) nanoparticles are naturally appealing as scaffold materials. For fabricating tissue engineering scaffolds, two groups of technologies, viz., non-designed manufacturing techniques and designed manufacturing techniques, can be used. The rise in recent years of designed manufacturing techniques, i.e., the application of rapid prototyping (RP) technologies in the tissue engineering field, stems from several reasons: scientific, technological or economical. These advanced technologies have distinctive advantages over some commonly used chemical engineering methods in scaffold fabrication. In this talk, an overview on the use of advanced manufacturing technologies by various research groups for constructing tissue engineering scaffolds is firstly given. For illustrating the purpose, practice and results of using advanced technologies to produce multifunctional scaffolds, our own research in employing selective laser sintering (SLS), a well-established RP technology, to make osteoconductive and osteoinductive bone tissue engineering scaffolds is introduced. Scaffold models of required features can be designed using data from computer-based medical imaging techniques (e.g., MRI). Good-quality Ca-P/PHBV nanocomposite scaffolds can be formed via SLS after process optimization. rhBMP-2 can be incorporated on surface-modified nanocomposite scaffolds. It can be released from the scaffolds in a controlled manner and cause osteogenic differentiation of hUC-MSCs in vitro. Both osteoconductivity and osteoinductivity provided by rhBMP-2 incorporated nanocomposite scaffolds stimulate bone tissue regeneration in vivo.