Two-dimensional TiS2 nanosheets for in vivo photoacoustic imaging and photothermal cancer therapy

Abstract

Recently, transition metal dichalcogenides (TMDCs) have attracted significant attention in nanomedicine owing to their intriguing properties. In this study, TiS₂ nanosheets, a new TMDC nanomaterial, are synthesized by a bottom-up solution-phase method and then modified with polyethylene glycol (PEG), obtaining TiS₂-PEG with high stability in physiological solutions and no appreciable in vitro toxicity. Due to their high absorbance in the near-infrared (NIR) region, TiS₂-PEG nanosheets could offer a strong contrast in photoacoustic imaging, which uncovers the high tumor uptake and retention of these nanosheets after systemic administration into tumor-bearing mice. We further apply TiS₂-PEG nanosheets for in vivo photothermal therapy, which are able to completely eradicate the tumors in mice upon intravenous injection of TiS₂-PEG followed by NIR laser irradiation. Our work indicates that TiS₂ nanosheets with appropriate surface coating (e.g. PEGylation) would be a promising new class of photothermal agents for imaging-guided cancer therapy.