Design of nonwoven scaffold structures for tissue engineering of the anterior cruciate ligament

This work is concerned with improving the design of textile scaffolds used to tissueengineer anterior cruciate ligaments. Two important design criteria of a scaffold are internal structure and cell-fibre compatibility. This paper considers both of these criteria, providing a review of scaffold design and structural parameters, followed by experiments on the biocompatibility of various generic fibres. In this paper, the influence of surface area to volume ratio and polymer morphology on cell-surface interactions is discussed, together with a consideration of the effect of poresize and scaffold porosity on cell proliferation, migration and nutrient supply. Another structural factor discussed is the role of fibre orientation as a means of guiding and organising new tissue growth. It is possible to manipulate these scaffold parameters to produce a scaffold of optimal structural design for the tissue engineering of the anterior cruciate ligament. A review of current scaffold types classified according to manufacturing method is presented. These manufacturing methods include solvent casting/particulate leaching, three-dimensional printing and fibre bonding. Scaffolds in fibrous form include woven, knitted, braided, embroidered and more recently nonwoven. Biocompatibility tests performed by the authors study the reaction of fibroblast cells to the surface of different generic fibre types; including para-aramid, polyester, polypropylene, polyglycolic acid and viscose rayon. The results of these tests are discussed in relation to cell attachment and fibre morphology.