The morphology, mechanical properties and ageing behavior of porous injection molded starch-based blends for tissue engineering scaffolding

摘要

One important parameter in the tissue engineering of hard tissues is the scaffold. A scaffold is a support in which cells are seeded and thatshould create the adequate environment for the cells to attach and proliferate. Furthermore the scaffold should allow the flow of anappropriate culture media, providing nutrients to the cells and simultaneously removing the metabolites resulting from the cells activity. Oneof the possibilities is to obtain solid foamed structures that will enable the cells to attach, spread into the inner surfaces and start to produceextracellular matrix. Ideally, if the scaffold is produced from a biodegradable material, it should degrade at a pace that is in phase with theformation of the new tissue.In this work it was studied the production of porous structures from biodegradable polymers for use as scaffolds for bone tissueengineering. Two materials were studied, starch compounded with poly(ethylene-vinyl-alcohol) (SEVA-C) and starch with poly(lactic acid)(SPLA). The porous structures were obtained by injection molding with a blowing agent to control the porosity, interconnectivity anddegradation rate. In previous attempts, the current starch compounds proved to be very difficult to process by this method. This studyincludes the characterization of the mechanical properties, water absorption and of the degradation kinetics of the 3-D porous structures.Two starch-based biodegradable 3D porous structures were successfully processed in conventional injection molding and the foaming wasobtained by means of the use of a blowing agent. The mechanical properties are very promising as well as the improved degradation kineticswhen compared with the synthetic polymers alone, although the degree of porosity and of interconnectivity needs to be improved in furtherwork.