Bacterial nanocellulose (BNC) is a natural hydrogel known for its shapability and potential applicability as a biomaterial, however challenges with post-processing procedures such as drying limit its current utility. Freeze-dried BNC (FD-BNC) made by freezing wet BNC in liquid nitrogen and lyophilizing the frozen materials retains a natural porous cellulose structure. However, the mechanical properties of FD-BNC are negatively affected by the rapid freezing process, often leaving macroscopic fractures on the material. Air-dried BNC (AD-BNC), made by allowing water to evaporate from the wet BNC membranes, is mechanically strong under tension, however evaporation results in the collapse of the cellulose structure.

This thesis presents a thorough evaluation of drying methodology for BNC grown in sheets and tubes, characterizing how commonly used drying methods affect the physical and mechanical properties of the membranes. To address the shortcomings of commonly used methods, a novel drying method in which BNC sheets and tubes are gradually-frozen at a controlled rate and subsequently lyophilized is introduced. These gradually-frozen BNC (GF-BNC) membranes exhibit an aligned porous microstructure and improved mechanical properties compared to FD-BNC when applied to both BNC sheets and BNC tubes.

To further examine the utility of BNC sheets as modifiable materials, gallic acid dissolved in glycerol (GG) was physically loaded into the membranes, creating GG-loaded AD-BNC (AD-GG-BNC), FD-BNC (FD-GG-BNC) and GF-BNC (GF-GG-BNC). Successful loading into FD-BNC and GF-BNC significantly increased the elasticity of the films, with GF-BNC and its GG loaded counterpart (GF-GG-BNC) achieving overall optimal mechanical properties. Antibacterial assays demonstrated the practical efficacy of GF-GG-BNC in inhibiting proliferation and biofilm formation in E. coli and S. aureus, while favorable antithrombotic behaviour prevented surface clot formation and red blood cell adhesion when compared to GF-BNC membranes.

This thesis characterizes existing and novel BNC drying methods and how they affect the morphological and mechanical properties of both BNC sheets and tubes. Further, the potential for dried BNC as multi-functional material is explored by analyzing the properties of GG-loaded BNC sheets. These combined findings highlight the potential of BNC-based biomaterials as functional implants for biomedical applications.