A heavy atom-free copolymer for light triggered photodynamic and photothermal therapy of human prostate cancer cells

In this paper, a heavy atom-free co-polymer (NDTT) with high singlet oxygen quantum yield (48.2%) has been designed and prepared. This polymer can be self-assembled to form uniform nanoparticles (NPs) in water. Such NPs still retain singlet oxygen generation ability with SOSG (singlet oxygen sensor green) as a probe and high photothermal conversion efficacy (35.2%). An in vitro MTT assay indicates that these NPs have a low half inhibitory concentration (IC50) of only 5.8 μg mL−1 on human prostate cancer (Du145). Moreover, in vivo investigation suggests that the growth of tumors of nude mice can be completely suppressed upon irradiation while those of the control and no illumination groups increase at a high speed, demonstrating the high phototoxicity as well as low dark toxicity of NDTT NPs. However, the normal organs, including the liver, lungs, spleen, heart and kidneys suffer from no damage, as indicated by the H&E stained pictures. Our results show that NDTT is a potential candidate for imaging guided photothermal and photodynamic synergistic therapy of prostate cancer clinically.