Developing a novel biocomposite on selective laser sintering for tissue engineering

Abstract

Tissue engineering (TE) is a rapidly developing field in science. It involves biological, medical and engineering expertises. The advancement in TE is likely to promote major improvements in the treatment of a variety of conditions, from those that are life threatening to those limiting patient's ability to enjoy life fully. A current technical and engineering challenge is to provide good scaffolds for TE. Highly porous 3-dimensional scaffolds primarily serve as cell transplant devices to facilitate structural and functional tissue unit formation of the newly transplanted cells. It is desirable for the scaffolds to degrade as the tissues regain their original strength and structure. Various conventional methods have been investigated to produce scaffolds. However, these approaches are limited in many areas, such as irregularity of pore sizes and the lack of spatial control of the interior architecture. There have been contamination issues raised concerning the use of potentially harmful solvents in the processing chain. Therefore rapid prototyping (RP) is employed to circumvent this problem. Selective Laser Sintering (SLS) is chosen as the preferred RP method due to its versatility in processing various polymeric materials and good stability of its products. Propriety SLS materials are non-biocompatible as they were conventionally invented for production of industrial parts. Suitable biomaterial powders that can be processed in SLS without allowing damages on the material properties need to be identified. SLS uses a laser heat source to fabricate parts. A theoretical study based on heat transfer phenomena during SLS process was carried out. The study identified the significant biomaterial and laser beam properties that influence the sintering result. The material properties were thermal conductivity, thermal diffusivity, surface reflectivity and absorption coefficient. The influential laser beam properties were laser power and scan speed, which were machine parameters that can be controlled by users. The identification of the important parameters has reduced the number of sintering trials needed to obtain favourable sintering results.