A perylene diimide zwitterionic polymer for photoacoustic imaging guided photothermal/photodynamic synergistic therapy with single near-infrared irradiation

Phototherapy has great promise for precise cancer diagnosis and effective therapy, but the development of one multifunctional nanoplatform for synergistic photodynamic therapy (PDT) and photothermal therapy (PTT) at a single excitation wavelength remains a challenge. In this work, a perylene diimide zwitterionic polymer PDS-PDI was synthesized via atom transfer radical polymerization (ATRP). This polymer was designed for photoacoustic imaging (PAI) guided synergistic PDT and PTT with single 660 nm near-infrared (NIR) light irradiation. The prepared PDS-PDI polymer presents high photothermal conversion efficiency (η ≈ 40%) and efficient singlet oxygen quantum yield (ΦΔ ≈ 16.7%) under 660 nm laser irradiation. Polymer PDS-PDI also acts as a contrast agent for PAI, offering real-time monitoring in tumor sites. Additionally, in vitro and in vivo assays indicate that polymer PDS-PDI has good biocompatibility and effective tumor destruction ability under 660 nm laser irradiation. In brief, polymer PDS-PDI prepared in this study could be applied as a dual-mode phototherapeutic agent under single laser irradiation. © 2018 The Royal Society of Chemistry.