Magnetically Tunable Hydrogel for Biofilm Control

Bacterial biofilm formation contributes to healthcare and energy challenges, and researchers are actively pursuing a range of strategies to restrict the spread of biofilms in an eco-friendly manner. Commonly used approaches in industry rely on physical removal and chemical techniques, frequently targeting mature biofilms. While effective, these methods often face implementation challenges in remote settings and can have off-target environmental impacts. As a result, an alternative strategy is to focus on controlling or limiting the biofilm formation and growth rates with remote stimuli. It has been shown that the mechanotransduction pathway intrinsic to bacteria responds to changes in the storage modulus of the growth surface, modifying the bacteria's motility and biofilm formation. We developed a material with magnetically tunable mechanical properties by intercalating magnetic nanoparticles into an agar gel matrix and investigated its ability to control <i>Escherichia coli</i> motility and biofilm growth. The initial storage modulus ranges from 0.5 to 2.5 kPa, depending on the material composition. Upon exposure to a 20 mT magnetic field using standard neodymium magnets, the modulus is dynamically and reversibly increased by approximately 30%. As a result of this increase, the expansion rate of the <i>E. coli</i> biofilm is reduced by approximately 40%. The simplicity of the manipulation of its mechanical property not only gives this biomaterial potential to further mechanosensing mechanism research but also proves to be an innovative strategy for remote and eco-conscious restriction of biofilm formation.