Chaotropic Effect-Induced Self-Assembly of the Malachite Green and Boron Cluster for Toxicity Regulation and Photothermal Therapy.

Malachite green (MG), a toxic antibacterial agent, is widely used in the farming industry. Effectively regulating the biotoxicity of this highly water-soluble cationic dye is challenging. Here, we present a novel strategy to reduce the biotoxicity of MG through the self-assembly of MG and the closo -dodecaborate cluster ([B 12 H 12 ] 2- ) driven by the chaotropic effect. [B 12 H 12 ] 2- and MG in an aqueous solution can rapidly form an insoluble cubic-type supramolecular complex (B 12 -MG), and the original toxicity of MG is completely suppressed. Surprisingly, this supramolecular complex, B 12 -MG, has a strong UV-vis absorption peak at 600-800 nm and significant photothermal conversion efficiency under 660 nm laser irradiation. On this basis, B 12 -MG, the supramolecular complex, can be used as an efficient photothermal agent for antimicrobial photothermal therapy (PTT) both in vitro and in vivo . As a molecular chaperone of MG, [B 12 H 12 ] 2- not only can be applied as an antidote to regulate the biotoxicity of MG but also provides a novel method for the construction of photothermal agents for PTT based on the chaotropic effect.