Fluorescent Conjugated Polymer/Quarternary Ammonium Salt Co-assembly Nanoparticles: Applications in Highly Effective Antibacteria and Bioimaging.

Bacterial resistance is one of the very severe factors that threaten human health. It is of great significance to construct a simple, highly effective, biocompatible, and cost-efficient therapeutic route. In this paper, a new method was constructed to prepare cationic nanoparticles, and fluorescent conjugated polymer coassembly nanoparticles CA-CPNs were designed and synthesized on the basis of the model conjugated polymers, PFVBT, and the model quarternary ammonium salts, cationic surfactant cetyltrimethylammonium bromide CTAB. PFVBTs were designed and synthesized in only three steps. CTAB is commercially available. By the reprecipitation method, the PFVBTs form the core and CTAB forms a shell on the surface of CA-CPNs by hydrophobic interaction. Importantly, when incubated with bacteria, the positively charged CA-CPNs can combine with bacteria, physically destroy the bacterial membrane, and kill bacteria without the requirement of light or chemical energy. When 0.80 μg/mL CA-CPNs were incubated for 30 min with Escherichia coli , more than 91% bacteria were killed. Also, more than 96% Staphylococcus aureus were dead when incubated with 1.0 μg/mL CA-CPNs. In virtue of the bright red fluorescence, CA-CPNs were also successfully applied to image MCF-7 cell with good biocompatibility. Overall, a simple, cost-effective, and universal method was provided to prepare cationic fluorescent nanoparticles that are a promising nanomaterial for biomedical applications.