(175ax) Biofilm Removal Using Reversible Shape Memory Polymer

Bacteria can attach essentially to all surfaces and form biofilms that cause biofouling and biocorrosion of equipment and chronic infections in human. Despite the significance, eradicating established biofilms from surfaces is a challenging task because of the protection of the extracellular biofilm matrix and slow growth of biofilm cells. Both contribute to the extremely high levels of tolerance to antimicrobials. Recently, we reported that one-way shape memory polymer (SMP) can be programed to remove biofilms with on-demand triggering of shape recovery with 99.9% removal of 48 h Pseudomonas aeruginosa biofilms. We further demonstrated that such shape recovery can increase metabolic activities of the detached biofilm cells and sensitize these cells to conventional antibiotics. To further develop this technology and achieve repeated shape change and long-term biofilm control, we synthesized reversible shape memory polymer (rSMP) with varying molecular weight of poly(caprolactone dimethacrylate), PCLDMA, using 25 wt% of butyl acrylate (BA) as a linker and 1 wt% of benzoyl peroxide as a thermal initiator. Among the combinations of molecular weight tested, the 2:1 wt. ratio mixture of 15,000 g/mol PCLDMA and 2,000 g/mol PCLDMA showed a transition temperature close to body temperature (36.7°C), according to differential scanning calorimetry analysis. The synthesized rSMP showed good reversible shape recovery for more than 5 cycles. With 18% stretching, we observed 61.0±6.6% removal of 48 h P. aeruginosa PAO1 biofilm cells in each shape recovery during the first three cycles. After these three continuous cycles, a total of 94.3±1.1% biofilm cells were detached based on the test with three biological replicates. To our best knowledge, this is the first application of reversible SMP for biofilm control.