Nano-biomaterials application: Morphology and physical properties of bacterial cellulose/gelatin composites via crosslinking

Nano-scale bacterial cellulose (BC) provides a fine structural network; therefore, this study investigated alkaline treated BC/gelatin composites (ATBC/G) crosslinked with transglutaminase (ATBC/G/T), genipin (ATBC/G/G), or EDC (ATBC/G/E), to improve the mechanical strength and hydrophilic property of BC composites. The ATBC/G composites displayed increased gelatin content, moduli, and hardness with increased gelatin concentrations in the immersion solution. EDC most effectively improved the mechanical properties of ATBC/G composites. Gelatin entering ATBC network, fills the empty spaces and connects to the 3D structure of ATBC. The ATBC/G/E composites maintain a network structure under 10% gelatin concentrations because gelatin tightly attaches to the ATBC surface. The ATBC/G composite exhibited analogical crystal morphology of ATBC, however, increased gelatin concentrations in addition to the EDC treatment decreased crystallinity in the composites. The FTIR spectrograph of the ATBC/G composites revealed the OH groups of the composites tended to increase. Therefore, gelatin crosslinking disrupted the crystallization formed from the hydrogen bonds between cellulose molecules. Crosslinking can also enhance the rehydration ratio.