Smart Antibacterial Coatings: Harnessing Bacterial Redox Activity for Infection Control

ABSTRACT Medical device‐associated biofilms are the primary source of chronic infections, antibiotic resistance, and device failure, but currently available antibacterial coatings have limited activity against sustained colonization. Conducting polymers have attracted considerable interest for biomedical applications owing to their reversible redox behavior and ability to accommodate therapeutic agents. In this work, we report a redox‐active antibacterial coating based on poly(3,4‐ethylenedioxythiophene) (PEDOT) loaded with ceftazidime (CAZ), designed to link antibiotic release to bacterial electroactivity. A high charge storage capacity (14.6 ± 3.4 mC cm − 2 ) together with an increased charge transfer resistance (10.7 ± 0.5 kΩ) indicated successful incorporation of CAZ within PEDOT matrix. Negligible passive release of CAZ (1.2 ± 0.1 µg cm −2 ) was noted when compared with bacteria‐induced release in the presence of Shewanella oneidensis (44.4 ± 9.0 µg cm −2 ) and Pseudomonas aeruginosa (62.2 ± 2.8 µg cm −2 ), as well as electrically‐induced release (49.5 ± 5.9 µg cm −2 ). Spectroelectrochemical and impedance data revealed that the redox state of PEDOT was modulated in a species‐dependent manner. The presence of PEDOT@CAZ limited the viability of S. oneidensis and P. aeruginosa to 13% and 20%, respectively. These findings indicate that PEDOT@CAZ acts as an intelligent antibacterial surface, releasing antibiotics in response to bacterial activity.