Multifunctional bacterial cellulose and nanoparticle-embedded composites

Cellulose, a linear polymer of glucopyranose sugar molecules, is synthesized both by plants and bacteria. The plant-produced cellulose is present along with other compounds such as hemicelluloses and lignin, and has been used historically for a wide variety of applications ranging from paper-making to cosmetics. The cellulose produced by bacteria, on the other hand, is pure and difficult to make on a large scale as it requires special bacterial cultures. The cellulose fibres, however, have high strength compared to plant-produced cellulose because of the high degree of crystallinity, and hence have found a renewed interest. Cellulose alone with its limited physical properties, however, cannot satisfy the wide-ranging properties required in the case of modern devices. Hence it has been functionalized by incorporating nano and submicron particles of a variety of materials depending on the end application. The unique, relatively inert, porous network structure of cellulose facilitates this method of functionalization. This flexibility facilitates development of multifunctional composites and has been recently demonstrated by synthesizing composites for widely different areas ranging from biocompatible arterial grafts to biodegradable, electrically conducting paper. This review summarizes these recent developments and highlights the application potential of pure bacterial cellulose and functionalized bacterial cellulose.