ABSTRACT
Tissue engineering can be de ned as the development of biological substitutes to restore, maintain, or improve tissue functions and is based on the application of principles and methods of engineering and life sciences toward a fundamental understanding of structure-function relationships in normal and pathological mammalian tissues. This is an emerging interdisciplinary area of research and technology that has the potential of revolutionizing our methods of health care treatment and dramatically improving the quality of life for millions of people throughout the world. Several approaches to tissue engineering have been established of which the most common approach is based on scaffold-guided tissue formation in vitro. A scaffold is a biodegradable and biocompatible three-dimensional (3-D) porous structure, which can support cell adhesion and growth. Typically cells are seeded onto biodegradable polymeric scaffolds, and the constructs in some way reform the intrinsic tissue structures [1]. The scaffold approach to tissue engineering rst emerged in the early 1990s, and since then much of the work has focused on scaffolds in the form of sponges or foams, which possess a random microstructure. More recently as a result of a hypothesis that
tissues must have a prearranged spatial architecture in order to function correctly, much attention has shifted to designer scaffolds. This hypothesis is based on the fact that a large number of organs possess a well-de ned internal structure, which is essential to their function. Thus, in order to realize 3-D constructs for tissue repair and reconstruction, it is necessary to guide cell growth on structures with an established topology, which replicates that of natural tissue. As a result, several different microfabrication techniques for biomaterial scaffolds have been developed. Most of these techniques arise from preexisting manufacturing methodologies such as photolithography, silicon micromachining, and the realization of pseudomechanical microcomponents. We can distinguish two groups of methodologies: one based on the realization of two-dimensional (2-D) structures and the other on the fabrication of 3-D scaffolds. In this chapter, we focus exclusively on 3-D methods borrowed from the well-established eld of computer-aided design/computer-aided manufacturing (CAD/CAM) and rapid prototyping (RP).
