Production Design and Evaluation of Vascular Grafts made of Bacterial Cellulose
Examensarbete för masterexamen
In the Western societies, the largest cause of mortality is atherosclerotic vascular disease. Bypass surgery is one of the most common today treatments. However, bypass surgery in which smaller blood vessels are to be replaced often fails because of occlusion. To date, there is no clinically suitable bypass material, for smaller blood vessels based on synthetic fabrics. Cellulose can be biosynthesized extracellularly by a microbe called Acetobacter xylinum. Presently, Arterion AB utilizes a novel technique that consists of using bacterial cellulose as a raw material for producing small vascular grafts, which are to replace small-diameter vessels in bypass surgery. The current bioreactor set-up for the production of bacterial cellulose grafts is in pilot stage. The mass profiles of the produced grafts are not homogeneous alongside the graft. A request from the surgeons is that thicker ends are preferred, in order to sew the graft together with the native blood vessels more easily. The aim of this master thesis project is first to acquire a more homogeneous mass profile. Secondly to achieve a mass profile that suits the surgical requests. In order to analyze the produced grafts, radial tensile tests were performed along with scanning electron microscopy. In each produced graft several rings were cut out that represented the different areas of a produced graft to illustrate the mass profile of a single graft. In between each ring samples for the scanning electron microscopy were cut out as well. The project was divided into two improvement areas which in total resulted into three protocols that were evaluated. Two of these protocols resulted in a more homogeneous mass profile while the third protocol established a novel concept of a modified fermentation set-up.
Livsvetenskaper , Industriell bioteknik , Life Science , Industrial Biotechnology