Bacterial cellulose as a potential scaffold for tissue engineering of cartilage

Tissue constructs for cartilage with native mechanical properties have not been described to date. To address this need the bacterial cellulose (BC) secreted by Gluconacetobacter xylinus (=Acetobacter xylinum) was explored as a novel scaffold material due to its unusual material properties and degradability. Native and chemically modified BC materials were evaluated using bovine chondrocytes. The results indicate that unmodified BC supports chondrocyte proliferation at levels of approximately 50% of the collagen type II substrate while providing significant advantages in terms of mechanical properties. Compared to tissue culture plastic and calcium alginate, unmodified BC showed significantly higher levels of chondrocyte growth. Chemical sulfation and phosphorylation of the BC, performed to mimic the glucosaminoglycans of native cartilage, did not enhance chondrocyte growth while the porosity of the material did affect chondrocyte viability. The BC did not induce significant activation of proinflammatory cytokine production during in vitro macrophage screening. Hence, unmodified BC was further explored using human chondrocytes. TEM analysis and RNA expression of the collagen II from human chondrocytes indicated that unmodified BC supports proliferation of chondrocytes. In addition, ingrowth of chondrocytes into the scaffold was verified by TEM. The results suggest the potential for this biomaterial as a scaffold for tissue engineering of cartilage.