Controllable Bio-manufacturing Of Bacterial Cellulose Nano-fibers

Bacterial cellulose is the only nano-size fibrous material in nature, and its forming mechanism and preparation technology is one of the frontier topics in materials science. In this study, a new manufacturing process for cellulose nano-fibers was proposed based on the advanced bio-manufacturing technology. Through the combination of biotechnology and nanotechnology and using acetobacter xylinum as a nano-size machine for molecular assembly, movement of microorganism in micro-or nano scale was induced via dynamic microflow-control, static molecular template and fine groove structures, and the alignment of secretive microfibril nano-fiber was regulated. Finally, three dimensional composites with specific regular patterns were automatically fabricated from the cellulose nano-fibers with the"bottom up"method. The main research contents and results are as follows:(1)Liquid difference was used to control the velocity of flow. Through the observation of the movement of acetobacter xylinum in micro channel, the liquid difference was determined to be less than 10 mm when the moving direction of acetobacter xylinum is the same as microflaw in channels and the organism can attach to the bottom of micro channel. It was also confirmed that the acetobacter xylinum can grow well in the micro-fluidic chip made of PDMS. All of those prove that using micro-fluidic chip can regulate oriented alignment of cellulose.(2)Molecular template with the intermissions of hydrophilic and hydrophobic fringes was made using microcontact printing techonology (μCP technology) and used to for static culture. Cellulose materials with strip or lattice patterns in micron scale have been obtained. Meanwhile, scanning electron microscopic observations revealed that this cellulose material intends to have an ordered alignment.(3)Solid medium and PDMS templates with fine grooves were make using soft etching technology. Using the static culture of solid medium template, a cellulose film with full pattern has been obtained. It has also been confirmed that acetobacter xylinum likes to grow attaching to side walls. In summary, a new method for ordered controlling the material assembly in nano scale has been established. This approach provides an important scientific basis for constructing multi-level and super-fine bionic medical materials or anisotropic multi-component precise photo-electronic materials.