Porous polymeric structures for tissue engineering prepared by a coagulation, compression moulding and salt leaching technique.

A technique for the preparation of porous polymeric structures involving coagulation, compression moulding and particulate leaching has been developed. The technique combines the advantages of thermal processing methods and particulate leaching. A high molecular weight polymer solution in an organic solvent containing dispersed water-soluble salt particles is precipitated into an excess of non-solvent. The polymer-salt composite is then processed by thermal processing methods into devices of varying shapes and sizes, which can subsequently be extracted to give the desired porous structures. The porosities of the scaffolds could be varied between 70% and 95% by adjusting the polymer to salt ratio and the pore size could be controlled independently by varying the leachable particle size. This versatility provides for the optimisation of scaffolds used in medicine and in tissue engineering. Compared with commonly used porosifying methods such as sintering, compression moulding combined with salt leaching, and freeze-drying, this process allows excellent control over pore size and porosity and yields scaffolds with a much more homogeneous pore morphology. We have prepared porous structures from several relevant polymers in the biomedical field: poly(D,L-lactide), poly(epsilon-caprolactone) and 1000PEOT70PBT30, a segmented poly(ether ester) based on polyethylene oxide and polybutylene terephthalate.