Magnetically responsive and flexible bacterial cellulose membranes

Magnetically responsive and flexible bacterial cellulose (BC) membranes were successfully fabricated using a simple diffusion of a ferrofluid solution. BC hydrogels were either water-substituted by alcohol (BC-N) or freeze dried (BC-F) prior to their immersion in the ferrofluid. The presence of both crystalline BC and Fe3O4 phases, and the homogeneous distribution of nanoparticles (NPs) in BC nanofibrils were observed. Higher concentrations of Fe3O4 NPs were found in the BC-N samples than for the BC-F samples. Higher magnetization in the BC-N samples was observed compared to the BC-F samples. Mechanical properties tests showed the higher strength and Young's modulus for the BC-F samples was possibly due to their more compacted nanostructure compared to BC-N. Using this simple process, the magnetic BC membranes show elastic properties upon deformation, returning to their original shape without damage. Also, they were highly sensitive to external magnetic forces giving them potential for many applications.