Supramolecular photothermal agents mediated by black hole hosts

Abstract

High-performance organic photothermal agents (PTAs) hinges primarily on manipulating non-radiative decay processes, which typically necessitates intricate and time-intensive molecular engineering. The main challenge is how to bring dye and quencher into close molecular contact at a sub-nanometer distance for effective quenching. A host-guest strategy is presented to fabricate supramolecular PTAs by non-radiative electron transfer. Through strong complexation of dye with a “black hole host”, quaternary-ammonium modified calix[4]arene tetraoctyloxy ether (QC4A-8C), photothermal performances of ten distinct dyes were optimized to an unprecedented degree. The potential of supramolecular PTAs in biological application was evaluated photothermal therapy in vitro and in vivo using zinc tetrasulfonate phthalocyanine@QC4A-8C. This study provides insights into leveraging existing dyes to augment photothermal effects through electron transfer, offering a streamlined pathway for the development of safe and efficient supramolecular PTAs.