Functionalization of Bacterial Cellulose Filaments for Knitting Responsive Textiles

This study introduces a novel biofabrication strategy to create programmable, moisture‐responsive textiles from bacterial cellulose (BC) filaments, establishing a novel material platform that unites biological growth with textile engineering. By integrating BC fermentation, bioengineering, polymer science, and programmable knitting, we demonstrate how in situ and ex situ functionalization can transform microbial biopolymers into adaptive textile systems. BC filaments were produced from Komagataeibacter xylinus and mixed bacterial yeast cultures (SCOBY) using spiral molds and functionalized with chitosan and BslA in situ, and glycerol, NaOH, or chromoprotein ex situ. Comprehensive mechanical test was carried out with tensile test and physical tests with water contact angle and swelling. These characterizations identified combinations that yielded knittable hydrophilic and hydrophobic filaments with tunable flexibility, strength, and water‐responsiveness. Knitted hydrophilic BC filaments exhibited pronounced hygromorphic actuation, absorbing 49% water and swelling by 318% and enabling controlled shape transformation under moisture stimuli, while hydrophobic counterparts maintained dimensional stability. This research pioneers the use of biologically functionalized BC filaments for responsive textile fabrication, advancing sustainable smart materials that couple living‐inspired biofabrication with textile programmability, with potential applications in adaptive wearables, environmental sensing, and soft robotics.