A new approach based on injection moulding to produce biodegradable starch-based polymeric scaffolds: morphology, mechanical and degradation behaviour

Abstract

One of the present challenges in polymer sca!old processing is the fabrication of three-dimensional (3D) architectures with an adequate mechanical performance to be used in the tissue engineering of hard tissues. This paper describes a preliminary study on the development of a new method to produce biodegradable sca!olds from a range of corn-starch-based polymers. In some cases, hydroxlapatite was also used as a einforcement of the biodegradable polymers. The developed methodology consists of a standard conventional injection moulding process, on which a solid blowing agent based on carboxylic acids is used to generate the foaming of the bulk of the moulded part. The proposed route allows for the production of sca!olds with a compact skin and a porous core, with promising mechanical properties. By using the developed method it is possible to manufacture biodegradable polymer sca!olds in an easy (melt-based processing) and reproducible manner. The sca!olds can be moulded into complex shapes, and the blowing additives do not a!ect the non-cytotoxic behaviour of the starch-based materials. The materials produced using this method were evaluated with respect to the morphology of the porous structure, and the respective mechanical properties and degradation behaviour. It was demonstrated that it is possible to obtain, by a standard melt based processing route, 3D sca!olds with complex shapes that exhibit an appropriate morphology, without decreasing signi"cantly the mechanical properties of the materials. It is believed that the optimisation of the proposed processing methodology may lead to the production of sca!olds that might be used on the regeneration of load-bearing tissues.