Indocyanine green-loaded porphyrin covalent organic frameworks for photothermal cancer therapy

Abstract

Photothermal therapy (PTT) usually requires stable and biocompatible photothermal agents, and more importantly, the ability to initiate photothermal effects inside the tumor under excitation of a near-infrared light source. Here, porphyrin-based covalent organic framework nanoparticles (COF-OH NPs) were prepared as a platform to successively load with indocyanine green (ICG). Compared to free ICG, the as-prepared composites (denoted as ICG@COF NPs) exhibited better stability and a higher photothermal conversion efficiency (56.7%) under 808 nm laser irradiation. In vitro experiments showed that ICG@COF NPs had good biocompatibility and high photothermal effects, which could effectively eradicate tumor cells when exposed to laser irradiation. Moreover, the remarkable ability to ablate tumors was further verified in vivo with 4T1 tumor-bearing mice as the model. After 10 days of treatment with ICG@COF NPs and laser irradiation, the tumors in mice were almost completely regressed, and the biochemical parameters of mice did not exhibit any significant abnormalities, indicating the significant therapeutic effect and high safety of the composites. Therefore, the development of ICG@COF NPs opens a new avenue for photothermal agents and expands the utilization of covalent organic frameworks in the biomedical area.