Cationic Polymer-Photothermal Agent Conjugates with Enhanced Light Absorption and Tumor Accumulation for Efficient...

The development of nanoanticancer agents has garnered significant interest, particularly for their application in the second near-infrared (NIR-II) phototherapy. Despite the promise that nanoparticles hold for tumor phototherapy, their limited light absorption efficiency and tumor accumulation ability substantially constrain their effectiveness in practical applications. This necessitates not only a profound comprehension of nanoparticle properties but also an intricate understanding of their targeting/delivery mechanisms. In this study, we showcase the impressive outcomes achieved by combining small molecular photothermal agents (PTAs) with cationic polymer (PWS5@NPs). By harnessing the exceptional NIR-II photothermal properties of aza-boron-dipyrromethene (aza-BODIPY) derivatives and the protonation/deprotonation characteristics of N,N-dimethyl acrylamide (PA1), we have successfully engineered multifunctional nanoparticles that facilitate efficient in situ enrichment of osteosarcoma via active endocytosis. Furthermore, molecular self-assembly reduces the size of the nanoparticles and diminishes the interactions between aza-BODIPY molecules within the polymer matrix, markedly improving the light absorption efficiency of the nanoparticles. This cationic polymer-photothermal agent conjugate design not only amplifies the fluorescence brightness of the nanoparticles but also enhances the photothermal therapy (PTT) efficacy against in situ osteosarcoma.