Part 1: scaffolds and surfaces.

Abstract

Every day thousands of clinical procedures are performed to replace or repair tissues in the human body that have been damaged through disease or trauma. Current therapies are focused on the replacement of the damaged tissue by using donor graft tissues (autografts, allografts or xenografts). Problems associated with this approach include shortage of donors or donor sites, the volume of donor tissue that can be safely harvested, donor site pain and morbidity, the possibility of harmful immune responses, transmission of disease and rejection of grafts [22]. Rather than replace damaged tissues with grafts, tissue engineering, or regenerative medicine, aims to regenerate damaged tissues by developing biological substitutes that restore, maintain or improve tissue function [2,5]. In native tissues, cells are held within an extracellular matrix (ECM) which guides development and directs regeneration of the tissue, serves to organise cells in space and provides them with environmental signals to direct cellular behaviour. The goal of tissue engineering is to synthesise substitutes that mimic the natural ECM to help guide the growth of newfunctional tissue in vitro or in vivo. At a simplistic level, biological tissues consist of cells, signalling mechanisms and extracellular matrix. Tissue engineering technologies are based on this biological triad and involve the successful interaction between three components: (1) the scaffold that holds the cells together to create the tissue?s physical form, (2) the cells that create the tissue and, (3) the biological signalling molecules, such as growth factors, that direct the cells to express the desired tissue phenotype (Fig. 1). Tissue engineering is a multidisciplinary field that harnesses expertise and knowledge from the medical profession, materials scientists, engineers, chemists and biologists.