Fabrication of antibacterial thermoplastic polyurethane coatings via suspension flame spray: A comparative study of chlorhexidine with varied solubility

Pathogenic microorganisms triggered huge health hazards and economic losses. This study reports a facile strategy of preparing antimicrobial coating of thermoplastic polyurethane (TPU) with chlorhexidine (CHX) and chlorhexidine gluconate (CHG) as the antimicrobial components. Morphological and physiochemical characterization revealed successful incorporation of CHX and CHG into the composite coatings, with CHX being predominantly distributed inside the TPU matrix and CHG dispersed both on the surface and within the TPU coatings. Time-course release analysis showed a significantly slower release of CHX than CHG from the composite coatings. The release of TPU-CHX and TPU-CHG composite coatings with different drug loadings displayed an opposite conversion trend between the Higuchi model and the Korsmeyer-Peppas model. Further antibacterial test showed that both TPU-CHX and TPU-CHG coatings reached over 99.9% bactericidal efficacy against both E. coli and S. aureus , with the TPU-CHG coatings generally outperforming the TPU-CHX coatings. The present study offers an economical and convenient route to prepare biomedical coatings for antibacterial applications.