Glutathione-capped, renal-clearable CuS nanodots for photoacoustic imaging and photothermal therapy.

The development of functional nanomaterials that undergo renal clearance is of fundamental importance to their in vivo biomedical applications. In this work, we report a one-pot method for the preparation of ultrasmall copper sulfide nanodots capped with a small natural tripeptide glutathione (GSH-CuS NDs). The GSH-CuS NDs had a hydrodynamic diameter of 5.8 nm, smaller than the reported polymer-coated CuS NDs with similar core sizes, and exhibited strong optical absorption and conversion at the near-infrared (NIR) region, leading to a sufficient photohyperthermic effect under the irradiation of a 980 nm laser. In vivo studies showed that the GSH-CuS NDs could induce significant photoacoustic imaging signal enhancement and remarkable photothermal therapy efficacy. Importantly, biodistribution studies and MRI imaging showed that the GSH-CuS NDs could freely circulate in the blood pool without undesirable accumulation in the liver and spleen, and could be naturally removed from the body through renal clearance, making them attractive for practical theranostic applications.