Structures and Antibacterial Properties of PLA-based Ciprofloxacin Composite Films Deposited by Low-Electron Beam Dispersion

Abstract

Polylactic acid (PLA)-based ciprofloxacin (Cip) antibacterial films with mass ratio PLA:Cip=1:1 were prepared by low-electron beam dispersion (EBD). The molecular structure, chemical composition and morphology of PLA-based ciprofloxacin antibacterial films were investigated by XPS, FTIR, liquid NMR and SEM. The antibacterial activity of composite films was tested against E. coli ATCC 25922 and S. aureus ATCC 12600 using the agar diffusion method on the solid LB agar medium. XPS and FTIR analysis showed the presence of an antibacterial ingredient in the composite films. Using NMR, it has been shown that the molecular structure of a monolayer of ciprofloxacin is fully consistent with the molecular structure of the initial ciprofloxacin powders. High antibacterial activity of the composite films has been also established and the layers still possess antibacterial activity with regard to S. aureus even after 7 days of leaching in an isotonic solution. The thermal treatment indicates that the composite films can withstand temperatures of 180 °C and keep its structure unchanged.