Facile synthesis of poly(quinone-amine) based multifunctional photothermal nanoparticles for antibacterial and antitumor therapy

Photothermal therapy, as a therapeutic modality that uses photothermal agent (PTA) to convert light energy into thermal energy, has a promising future in the fields of bacterial clearance and tumor growth suppression. Among the various PTAs, conjugated polymers (CPs) have been highly emphasized due to their excellent photothermal conversion efficiency. However, CPs often exhibit complex structures and require cumbersome synthesis steps, which often make it difficult to achieve fast and convenient production. Here, we report the rapid synthesis of benzoquinone diamine conjugated polymer (BDCPs) through a simple polymerization process using p-benzoquinone and thiourea as raw materials. It is shown that BDCPs have good absorption in the NIR region and can be rapidly warmed up under light, which possesses good photothermal conversion ability. In addition, BDCP nanoparticles (BDCPNs) obtained by straightforward modification of BDCPs with polyethylene glycol can be stably dispersed in aqueous solution for a long time and maintain impressive photothermal conversion (37.8%). Moreover, cellular experiments affirm the excellent biocompatibility of BDCPNs. Under 808 nm laser irradiation, BDCPNs demonstrate potent inhibitory effects against Staphylococcus aureus (85%) and Escherichia coli (80%), as well as tumor cells (tumor inhibition rate: 84%), highlighting their superior photothermal therapeutic effects. We anticipate that this research will serve as a valuable reference for the swift and straightforward synthesis of photothermal polymers, facilitating their subsequent cost-effective promotion and application.