Dual-Responsive Bidirectional Actuator for Biofilm Disruption on Medical Surfaces

Biofilms, dense microbial communities embedded in extracellular polymeric substances, present persistent challenges in medical devices by conferring antibiotic resistance and fostering chronic infections. Conventional antimicrobial or enzymatic approaches often fail due to poor penetration into biofilm matrices. This work introduces a dynamic surface capable of mechanically disrupting biofilms, enabling on-demand cleaning of biomedical interfaces. Here, we present a dual-responsive bilayer actuator composed of a solvent-responsive hydrogel and a photoresponsive elastomer. The system harnesses solvent- and light-induced bidirectional bending for effective detachment of bacterial biofilms. The bilayer undergoes upward curvature upon exposure to solvent and reverses to downward curvature upon irradiation with green light (530 nm), demonstrating repeatable and directional actuation. We evaluate the removal of Escherichia coli and Staphylococcus aureus biofilms across 12, 24, and 48 h growth periods, comparing single and cyclic actuation modes. Quantitative analyses show that upward bending (θ∼ 156°) and downward bending (θ∼ -73.7°) each achieve significant detachment, while cyclic actuation further enhances removal efficiency (>70%), particularly for mature 48 h biofilms. Colony-forming unit assays validate the reduction in viable bacteria following the actuation. This study demonstrates the potential of dual-responsive actuators as biocompatible, nonchemical strategies for biofilm removal for next-generation antifouling medical device surfaces.