The mitochondria-targeted and IR780-regulated theranosomes for imaging and enhanced photodynamic/photothermal therapy

Abstract

(a) A schematic of the system TPP-IR780/Ce6-TNS. (b) Illustration of the system TPP-IR780/Ce6-TNS to the tumor microenvironment.

Abstract

The applications of photodynamic therapy (PDT) are usually limited by the low tumor selectivity of photosensitizers. Herein, we report a near infrared (NIR) imaging multifunctional nanocarrier, so called “theranosome (TNS)”, which encapsulated both chlorin e6 (Ce6, photosensitizer) and IR780 iodide (IR780, photothermal and NIR imaging agent) to realize enhanced PDT efficacy. The phototoxicity of Ce6 was effectively restrained by IR780. Upon NIR laser irradiation at 808 nm, IR780 in the TNS could be degraded, while the phototoxicity of Ce6 could be recovered. In addition, we proved that attaching a triphenylphosphonium (TPP) group to the TNS (TPP-IR780/Ce6-TNS) could greatly facilitate its mitochondrial targeting ability so as to offer a remarkably improved PDT efficacy. This newly constructed TNS exhibited high toxicity to the tumor cells in vitro, indicating TNS was a promising nanocarrier used as a PTT combined activatable PDT.