Photothermal Controlled Generation of Alkyl Radical from Organic Nanoparticles for Tumor Treatment.

The therapeutic properties of light are well known for photodynamic or photothermal therapy, which could cause irreversible photodamage to tumor tissues. Although photodynamic therapy (PDT) has been proved in the clinic, the efficacy is not satisfactory because of complicated tumor microenvironments. For example, the hypoxia in solid tumor has a negative effect on the generation of singlet oxygen. In order to address the hypoxia issues in PDT, leveraging alkyl radical is an available option due to the oxygen-independent feature. In this work, a new kind of organic nanoparticles (TPP-NN NPs) from porphyrin and radical initiator is developed. Under near infrared light irradiation, TPP-NN NPs will splitting and release alkyl radical, which could induce the obvious cytotoxicity whether in normal or hypoxia environment. The photothermal controlled generation of alkyl radical could significantly inhibit the growth of cervical cancer, and show the ignorable systemic toxicity. This activatable radical therapy opens up new possibilities for application of PDT in hypoxia condition.