Substrate independent approach for immobilisation of quaternary ammonium compounds to surfaces to reduce bio-burden

Bacterial contamination of biomedical devices is an ongoing problem. One method to alleviate such contamination is the introduction of surface compounds onto devices which can kill bacteria on contact. Polymers containing quaternary ammonium groups are known for their antimicrobial properties. Here we report a substrate-independent two-step method for the immobilisation of quaternary ammonium groups onto any type of surface. To achieve this glycidlytrimethylammonium chloride was covalently bound to plasma polymerised allylmine interlayer. Changes in the membrane permeability of Escherichia coli were observed by BacLight LIVE\DEAD staining. 30% of E. coli grown on the treated surfaces showed high levels of membrane permeability within 4 hours. Importantly, there was no observable cytotoxic effect on human dermal fibroblasts.