Kinetically and thermodynamically controlled one-pot growth of gold nanoshells with NIR-II absorption for multimodal imaging-guided photothermal therapy

Since the successful clinical trial of AuroShell for photothermal therapy, there is currently intense interest in developing gold-based core-shell structures with near-infrared (NIR) absorption ranging from NIR-I (650-900 nm) to NIR-II (900-1700 nm). Here, we propose a seed-mediated successive growth approach to produce gold nanoshells on the surface of the nanoscale metal-organic framework (NMOF) of UiO-66-NH2 (UiO = the University of Oslo) in one pot. The key to this strategy is to modulate the proportion of the formaldehyde (reductant) and its regulator / oxidative product of formic acid to harness the particle nucleation and growth rate within the same system. The gold nanoshells propagate through a well-oriented and controllable diffusion growth pattern (points -> facets -> octahedron), which has not been identified. Most strikingly, the gold nanoshells prepared hereby exhibit an exceedingly broad and strong absorption in NIR-II with a peak beyond 1300 nm and outstanding photothermal conversion efficiency of 74.0%. Owing to such superior performance, these gold nanoshells show promising outcomes in photoacoustic (PA), computed tomography (CT), and photothermal imaging-guided photothermal therapy (PTT) for breast cancer, as demonstrated both in vitro and in vivo.