Enhanced plasmid loss in bacterial populations exposed to the antimicrobial compound irgasan delivered from interpenetrating polymer network silicone hydrogels

When exposing bacterial cells to the irgasan-impregnated IPNs for 24 h, we observed a modest (2.8-4.7%), but significant (P < 0.05), plasmid loss as well as an inhibition of bacterial growth, both gradually increasing with increasing impregnation concentration. Repeated exposure to irgasan-impregnated IPNs drastically increased the plasmid loss of up to 83%, but cells adapted over time, which indicated the limitations of this specific drug for future medical applications. This study, however, illustrates the ability of IPNs to release an impregnated compound into a liquid suspension to induce a significant biological impact on growing bacterial cells.