Gold Nanotetrapods with Unique Topological Structureand Ultranarrow Plasmonic Band as Multifunctional Therapeutic Agents

Owing to their excellent surface plasmonic properties, Au nanobranches have drawn increasing attention in various bio-applications, such as contrast agents for photoacoustic imaging, nanomedicines for photothermal therapy, and carriers for drug delivery. The monodispersity and plasmonic band width of Au nanobranches are of great importance for the efficacy of those bio-applications. However, it is still a challenge to accurately synthesize size- and shape-controlled Au nanobranches. Here we report a facile seed-mediated growth method to synthesize monodisperse Au nanotetrapods (NTPs) with tunable and ultra-narrow plasmonic bands. The NTPs have a novel D2d symmetry with four arms elongated in four directions. The growth mechanism of NTPs relies on the delicate kinetic control of deposition and diffusion rates of adatoms. Upon laser irradiation, the PEGylated NTPs possess remarkable photothermal conversion efficiencies and photoacoustic imaging properties. The NTPs can be applied as a multifunctional ...