PEGylated polypyrrole–gold nanocomplex as enhanced photothermal agents against tumor cells

The development of dual-component photothermal agents is of great importance for effective photothermal tumor treatment. As an attractive component, gold (Au) nanoparticles (NPs) were found in possession of the capacity to enhance the photothermal conversion capacity of metal-based components. However, their interaction with organic polymer-based photothermal agents is rarely explored. Herein, a novel PEGylated polypyrrole–gold nanocomplex was fabricated as the photothermal agent for enhanced photothermal treatment against tumor cells. Using poly(ethyleneimine) (PEI) as the stabilizer, polypyrrole (PPy) NPs were formed in the presence of ferrous ions. After polyethylene glycol (PEG) modification and Au NP loading, PPy–PEI–PEG/Au NPs were formed. They owned desirable colloid stability and excellent photothermal stability. The loaded Au NPs could improve the photothermal conversion efficiency of PPy NPs through the potential coupling between the localized surface plasma resonance of Au NPs and the conductivity of PPy NPs. They were highly cytocompatible and could be internalized into tumor cells effectively. Under near-infrared light irradiation, effective tumor cell death could be achieved by PPy–PEI–PEG/Au NPs. This developed dual-component photothermal agent is promising in tumor treatment with high efficacy.