An intelligent nanoplatform for imaging-guided photodynamic/photothermal/chemo-therapy based on upconversion nanoparticles and CuS integrated black phosphorus

The strategy of combining imaging and treatment has been shown as a widely studied and promising approach. In this work, we first integrated copper sulfide (CuS) nanoparticles and black phosphorus (BP) nanosheets with strong negative charges via mesoporous silica-coated upconversion nanoparticles (UCNPs). Synergistic treatment of photothermal, photodynamic and chemotherapy can be achieved after loading doxorubicin (DOX). The nanocomposites perform excellent antitumor efficiency under 808?nm near-infrared (NIR) light, and avoid the slightly lower efficiency and limited penetration depth of conventional ultraviolet and visible (UV-vis) light. In this system, the pore size of mesoporous silica and the large specific surface area of BP are advantageous for achieving high DOX loading capacity. Furthermore, the reduction in the red/green (R/G) ratio elicited by DOX release can be employed to determine the extent of DOX release by the fluorescence resonance energy transfer (FRET) process. CT/MR imaging induced by doping of rare earth ions imparts multimode imaging capabilities to nanosystem under 808?nm light irradiation, thereby enabling imaging-guided cancer treatment.