Novel Application of NIR-I-Absorbing Quinoidal Conjugated Polymer as a Photothermal Therapeutic Agent

Abstract

Conjugatedpolymer nanoparticles (CP NPs) that couldabsorb thefirst near-infrared (NIR-I) window have emerged as highly desirabletherapeutic nanomaterials. Here, a quinoidal-conjugated polymer (QCP),termed PQ, was developed as a novel class of therapeutic agents forphotothermal therapy (PTT). Owing to its intrinsic quinoid structure,PQ exhibits molecular planarity and & pi;-electron overlap alongthe conjugated backbone, endowing it with a narrow band gap, NIR-Iabsorption, and diradical features. The obtained PQ was coated witha poly(ethylene glycol) (PEG) moiety, affording nanosized and water-dispersedPQ nanoparticles (PQ NPs), which consequently show a high photothermalconversion efficiency (PCE) of 63.2%, good photostability, and apparenttherapeutic efficacy for both in vitro and in vivo PTTs under an 808 nm laser irradiation. This studydemonstrates that QCPs are promising active agents for noninvasiveanticancer therapy using NIR-I light.