Synthesis of a Novel Quinoline Skeleton Introduced Cationic Polyfluorene Derivative for Multimodal Antimicrobial Application.

A new functional polyfluorene derivative containing quinoline skeleton and quarternary ammonium group (QAG) modified side chains (PFPQ) was synthesized and characterized. The multimodal antimicrobial effect toward Gram-negative E. coli was achieved by the dark toxicity resulting from the quinoline skeleton, QAG, and light toxicity resulting from reactive oxygen species (ROS) produced by the main backbone of PFPQ under white light. The mechanism of interaction between PFPQ and bacteria was also demonstrated. PFPQ bound to E. coli mainly through electrostatic interactions causing nearly 50% bacterial death in the absence of light irradiation, and the huge capability of PFPQ to generate ROS under white light opened another bactericidal mode. The killing efficiency was more than 99% upon relatively mild irradiation under white light (400-800 nm) with a light dose of 18 J·cm(-2). PFPQ with the incorporation of quinoline into the backbones will provide a new versatile strategy to achieve the multimodal antimicrobial effect to fight against resistant bacteria.