We have developed a new biofabrication process in which the precise control of bacterial motion is used to fabricate customizable networks of cellulose nanofibrils. This work describes how the motion of Acetobacter xylinum can be controlled by electric fields while the bacteria simultaneously produce nanocellulose, resulting in networks with aligned fibers. Since the electrolysis of water due to the application of electric fields produces the oxygen in the culture media far from the liquid-air boundary, aerobic cellulose production in 3D structures is readily achievable. Five separate sets of experiments were conducted to demonstrate the assembly of nanocellulose by Acetobacter xylinum in the presence of electric fields in micro and macro environments. This work demonstrates a new concept of bottom up material synthesis by control of a biological assembly process. / Master of Science