Fabrication of porous substrates: A review of processes using pore forming agents in the biomaterial field

This paper is a review of solid and casting manufacturing processes able to create porous materials, mainly in the biomaterial field. The considered methods are based on pore forming agents that are removed either by heating or by dissolution. All techniques lead to products presenting pores with amount, size, and shape are close to those of the initial pore formers. Porosities up to 90% with pores ranging from 1 to 2000 mu m are reported. Major differences concern macrointerconnections that are more frequently obtained using foams, or porogens which undergo a melting stage during firing. Casting methods combined with solid free form fabrication are promising for the design of porous network through the manufacturing of 3D scaffolds corresponding to the desired porosity. (C) 2007 Wiley-Liss, Inc.