J. Biomater. Sci. Polymer Edn, Vol. 12, No. 1, pp. 107–124 (2001) Ó VSP 2001. Scaffold design and fabrication technologies for engineering tissues — state of the art and future perspectives DIETMAR W. HUTMACHER 1;2 1 Laboratory for Biomedical Engineering, Department of Mechanical Engineering, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260 2 Department of Orthopedic Surgery, National University Hospital, Lower Kent Ridge Road, Singapore 119260 Received 22 August 2000; accepted 16 October 2000 Abstract —Today, tissue engineers are attempting to engineer virtually every human tissue. Potential tissue-engineered products include cartilage, bone, heart valves, nerves, muscle, bladder, liver, etc. Tissue engineering techniques generally require the use of a porous scaffold, which serves as a three- dimensional template for initial cell attachment and subsequent tissue formation both in vitro and in vivo. The scaffold provides the necessary support for cells to attach, proliferate, and maintain their differentiated function. Its architecture denes the ultimate shape of the new grown soft or hard tissue. In the early days of tissue engineering, clinically established materials such as collagen and polyglycolide were primarily considered as the material of choice for scaffolds. The challenge for more advanced scaffold systems is to arrange cells/tissue in an appropriate 3D conguration and present molecular signals in an appropriate spatial and temporal fashion so that the individual cells will grow and form the desired tissue structures — and do so in a way that can be carried out reproducibly,economically, and on a large scale. This paper is not intended to provide a general review of tissue engineering,but specically concentrateon the design and processingof synthetic polymeric scaffolds. The material properties and design requirements are discussed. An overview of the various fabrication techniques of scaffolds is presented, beginning with the basic and conventional techniques to the more recent, novel methods that combine both scaffold design and fabrication capabilities. Key words: Tissue engineering; scaffolds; synthetic polymers; design and fabrication techniques. 1. INTRODUCTION In the 1980s Bell et al. were among the rst to tissue engineer bi-layered skin grafts. They showed that a collagen lattice seeded with autologous skin broblasts contracts and forms dermal tissue, and suspensions of epidermal cells applied to these lattices in vitro led to differentiation of the epidermal cells. This skin equivalent has been used clinically in the treatment of venous ulcers, acute wounds and split thickness donor sites. It was reported to have similar behavior to human