Influence of cultivation conditions on mechanical and morphological properties of bacterial cellulose tubes
Journal article, 2007
Bacterial cellulose (BC) was deposited in tubular form by fermenting Acetobacter xylinum on top of silicone tubes as an oxygenated support and by blowing different concns. of oxygen, i.e., 21% (air), 35%, 50%, and 100%. Mech. properties such as burst pressure and tensile properties were evaluated for all tubes. The burst pressure of the tubes increased with an increase in oxygen ratio and reached a top value of 880 mmHg at 100% oxygen. The Young's modulus was approx. 5 MPa for all tubes, irresp. of the oxygen ratio. The elongation to break decreased from 30% to 10-20% when the oxygen ratio was increased. The morphol. of the tubes was characterized by SEM (SEM). All tubes had an even inner side and a more porous outer side. The cross section indicated that the tubes are composed of layers and that the amt. of layers and the yield of cellulose increased with an increase in oxygen ratio. We propose that an internal vessel wall with high d. is required for the tube to sustain a certain pressure. An increase in wall thickness by an increase in oxygen ratio might explain the increasing burst pressure with increasing oxygen ratio. The fermn. method used renders it possible to produce branched tubes, tubes with unlimited length and inner diams. Endothelial cells (ECs) were grown onto the lumen of the tubes. The cells formed a confluent layer after 7 days. The tubes potential as a vascular graft is currently under investigation in a large animal model at the Center of Vascular Engineering, Sahlgrenska University Hospital, Gothenburg.