Surfactant-doped PEDOT films as dual-function bioelectronic coatings with enhanced charge storage capacity and antibiofilm activity

Biofilm-associated infections pose a persistent challenge for medical devices, motivating the development of multifunctional coatings that combine electrochemical performance with antibacterial functionality. Conducting polymers such as poly(3,4-ethylenedioxythiophene) (PEDOT) are attractive for bioelectronic interfaces, yet pristine PEDOT provides limited control over bacterial adhesion and biofilm formation. Here, we report a dual-function coating based on PEDOT electropolymerized in the presence of the quaternary ammonium surfactant dodecyltrimethylammonium bromide (DTAB) on flexible ITO/PET substrates. DTAB incorporation markedly enhanced the charge storage capacity (142.7 ± 2.5 mC cm⁻²) relative to pristine PEDOT (73.4 ± 4.3 mC cm⁻²), accompanied by altered surface organization, wettability, and a pronounced increase in charge-transfer resistance, consistent with strengthened capacitive behaviour. PEDOT@DTAB films enabled electrically addressable antibacterial functionality through dual-mode DTAB release, achieving passive release of 30.6 ± 3.4 μg cm⁻² after 24 h and electrically triggered release up to 79.1 ± 5.5 μg cm⁻². Functionally, PEDOT@DTAB inhibited biofilm formation by 95.4 ± 2.2% for Shewanella oneidensis and 45.7 ± 2.1% for Pseudomonas aeruginosa, with corresponding reductions in bacterial viability. This work establishes DTAB-doped PEDOT as a versatile bioelectronic interface that couples high charge storage capability with electrically tunable antibiofilm activity, offering a promising strategy to mitigate biofilm-associated infections.