Electrochemically Synthesized Multifunctional PEDOT–Ceftazidime Films for Electrically Triggered, Advanced Bacteria-Responsive Antibacterial Coatings

Poly(3,4-ethylenedioxythiophene) (PEDOT) films incorporating the broad-spectrum β-lactam antibiotic ceftazidime (CAZ) were successfully synthesized via electropolymerization onto ITO/PET substrates. Cyclic voltammetry confirmed effective CAZ entrapment, as evidenced by anodic/cathodic peak shifts and enhanced charge storage capacity (14.5 ± 3.3 mC/cm²). Electrochemical impedance spectroscopy revealed a significant increase in charge transfer resistance for PEDOT@CAZ (10,738 ± 508 Ω) compared to pristine PEDOT (494 ± 38 Ω), which was attributed to the insulating effect of CAZ domains and disruption of PEDOT's conjugated structure. Fourier transform infrared spectroscopy, scanning electron microscopy, and elemental analysis further verified the successful incorporation of CAZ into the PEDOT matrix. Surface characterization demonstrated high hydrophilicity (12 ± 0.9°) and increased surface roughness (2.10 ± 0.50 µm), which are conditions typically favourable for bacterial attachment but effectively counteracted by the antimicrobial properties of CAZ. Passive release of CAZ was minimal (1.2 ± 0.1 µg/cm²); however, electrochemically stimulated release significantly enhanced antibiotic delivery (49.5 ± 5.9 µg/cm²). Importantly, bacterial species Shewanella oneidensis and Pseudomonas aeruginosa actively reduced and oxidized the PEDOT matrix, triggering responsive antibiotic release. These findings demonstrate that PEDOT@CAZ films synergistically combine conductive polymer electroactivity with bacteria-responsive localized antibiotic release, highlighting their potential as dual-action antimicrobial coatings for biomedical applications. Future studies should expand this concept beyond ceftazidime to other antibiotics, antimicrobial peptides, and unconventional agents like quorum-sensing inhibitors or bacteriophages.