A dual-functional benzobisthiadiazole derivative as an effective theranostic agent for near-infrared photoacoustic imaging and photothermal therapy

Abstract

Nanoparticles (NPs) with integrated functionalities of targeting, therapy, imaging contrast and biocompatibility have shown promise for application in improved disease diagnosis and therapy. Herein, we report a theranostic agent based on a narrow-bandgap small molecule, benzo[1,2-c;4,5-c′]bis[1,2,5]thiadiazole-4,7-bis(9,9-dioctyl-9H-fluoren-2-yl)thiophene (denoted as BBT-2FT), with the strong absorption of near-infrared (NIR) light. Colloidal nanoparticles composed of BBT-2FT showed a photoacoustic signal intensity ten times higher than that of blood, and high photothermal conversion efficiency (η = 40%) under the irradiation of 808 nm laser light, which killed over 90% of HeLa cells in 10 min.