Template assisted synthesis of porous nanofibrous cellulose membranes for tissue engineering

Porous, nanofibrous bacterial cellulose (BC) membranes were produced by the bacterium Acetobacter xylinum. The bacterium was cultivated in an appropriate culture medium under static conditions. In situ pore formation was attained through the use of pin templates with diameters varying from 60 to 300 μm composed of polyestirene (ϕ = 300 μm) or optical fibers (ϕ = 60 μm), which were placed on culture medium with the pins immersed in the liquid. Cellulose biosynthesis occurred around the pins leaving tiny pores on the cellulose membrane. After removal of the template the biofilm was dried at 50 °C/24 h. Physico-chemical properties of BC membranes, like degree of crystallinity, swelling and tensile strength were not significantly altered after pore formation. Microstructure evaluation revealed that the film matrix is composed of long nanofibers isotropically distributed on its surface. Round-shaped pores with diameters varying between 60 and 300 μm, depending on the pin template used, were formed in the cellulose membranes. These pores exhibited no border failures that could start crack propagation along the film surface. Microporous membranes could be useful for applications in repairing tissues, which require high oxygenation rates or wound contracture delay.