Biological Functionalization of Conjugated Polymer Nanoparticles for Targeted Imaging and Photodynamic Killing of Tumor Cells

Conjugated polymer nanoparticles composed of PFT/PS as a core and PEG-COOH on the surface were prepared by a reprecipitating method. The CPNs diaplay excellet properties such as good photostability, low cytotoxicity, and strong brightness, etc. The average diamater of CPNs is 30 nm with a spherical morphology. To realize specific imaging in different parts of tumor cells, the bare CPNs with the carboxyls on the surface were conjugated with antibody or peptide by a covalent mode. Studies display that CPNs modified with anti-EpCAM can recognize MCF-7 tumor cells and locate on the membrane, while CPNs conjugated with transcriptional activator protein (Tat) specifically locate in the cytoplasm of MCF-7 cells. On the basis of the ability of CPNs for producing reactive oxygen species (ROS) under light irradiation, photodynamic therapy for tumor cells was investigated. Due to the long distance and wide diffusion range, MCF-7 tumor cells with CPNs/anti-EpCAM have no obvious change with or without white light irradiation. However, CPNs/Tat exhibits higher killing ability for MCF-7 cells. Noticeably, multifunctional CPNs linked with anti-EpCAM and Tat simultaneously not only can specifically target MCF-7 tumor cells, but also may inhibit and kill these cells. This work develops a potential application platform for multifunctional CPNs in locating imaging, photodynamic therapy, and other aspects.