Winning the 'race for the surface': curcumin-loaded PEDOT coatings with enhanced biocompatibility and antibacterial capabilities.

Abstract

The continued growth of bioelectronics has created a pressing demand for the development of implant coatings that integrate balanced electrochemical performance, surface characteristics favouring cell adhesion, excellent biocompatibility, and effective antibacterial functionality. To meet these demands, we propose curcumin-modified conducting polymer coatings that simultaneously enhance biocompatibility, antibacterial activity, and preserve electrochemical functionality. In this study, poly(3,4-ethylenedioxythiophene) (PEDOT) coatings were modified by curcumin - a natural agent widely studied due to its antibacterial, anti-inflammatory and wound-healing properties. Curcumin was immobilised within PEDOT coatings by electropolymerization in different environments (acetonitrile, water) and in the presence of different electrolytes (tetrabutylammonium hexafluorophosphate, tetrabutylammonium tetrafluoroborate or phosphate-buffered saline). The results showed that addition of curcumin during the electrochemical polymerization leads to the formation of PEDOT coatings with good conductivity (impedance <1 MΩ at 1 kHz) and favourable wettability (contact angle ∼50°), ideal for cell anchoring. Detailed kinetic analysis revealed that the mechanism of curcumin release depends on the selection of electrolyte. While the AlamarBlue assay indicated the beneficial influence of curcumin on fibroblast viability, a distinct localized antibacterial effect against Pseudomonas aeruginosa was also observed on the surface. In conclusion, PEDOT-Curcumin multifunctional coatings are shown to successfully shift the "race for the surface" in favour of mammalian cells, offering a promising strategy for the fabrication of implant coatings.