3D printing of multifunctional tissue engineering scaffolds

Abstract

Tissue engineering has advanced significantly over the past three decades and many human body tissues may be regenerated successfully, providing desired functions in the human body. A few approaches are used for human tissue regeneration, which include cell-, factor- or scaffold-based tissue engineering. Using scaffolds to assist tissue regeneration has been the dominant approach. In scaffold-based tissue engineering, it is important to develop suitable scaffold materials and employ appropriate scaffold manufacturing technologies to make desirable scaffolds, which will lead to successful tissue regeneration. Many materials have been investigated for different scaffolds and scaffold fabrication techniques have been studied by numerous researchers. Materials for tissue engineering are generally biodegradable polymers and scaffolds are produced by either non-designed manufacturing techniques (e.g., solvent casting/porogen leaching) or designed manufacturing techniques. Using designed manufacturing, which includes a host of additive manufacturing technologies (the so-called “3D printing”), for scaffold fabrication has distinctive advantages and has therefore attracted great attention in the tissue engineering field. However, some 3D printing technologies impose stringent requirements for stock materials and studies have been conducted on preparing stock materials and on evaluating the physical and mechanical properties of scaffolds made of these stock materials. Furthermore, existing, general 3D printing technologies may not be suitable for constructing multifunctional tissue engineering scaffolds in which biological molecules or even live cells need to be incorporated. Hence, new 3D printing technologies specifically for handling delicate biomolecules and/or cells are urgently needed. Our group has investigated selective laser sintering (SLS), a well-established 3D printing technology, for making osteoconductive and osteoinductive scaffolds for bone tissue engineering. In this process, we developed nanocomposite materials as scaffold materials which provided osteoconductivity. For the novel scaffolds, we also incorporated a growth factor which provided osteoincuctivity. Our studies showed that bone tissue regeneration was greatly promoted with the SLS-formed multifunctional scaffolds. We have also developed a low-temperature, extrusion-based 3D printing technique for constructing relatively strong scaffolds with the incorporation of biomolecules or cells. Very promising results were obtained using this new 3D printing technology. This talk will give an overview of 3D printing and its application in tissue engineering. It will introduce our work in this area and discuss issues in scaffold design and 3D printing.