Gold nanocages for biomedical applications

Nanostructured materials provide a promising platform for early cancer detection and treatment. Here we highlight recent advances in the systhesis and use of Au nanocages for such biomedical applications. Gold nanosages represent a novel class of nanostructures, which can be prepared via a remark-ably simple route based on the galvanic replacement reaction betbeen Ag nanocubes and HAucl₄. The Au nanocages have a tunable surface plasmon resonance penk that extends into the near-infrared, where the optical attenution caused by blood and soft tissue is essentially negligible. They are also biocompatible and present a well-established surface for easy functionalization. We have tailored the scattering and absorption cross-sections of Au nanocages for use in optical coherence tomography and photothermal treatment, respectively. Our preliminary studies show greatly improved spectroscopic image contrast for tissue phantoms containing Au nanocages. Our most recent results also demonstrate the photothermal destruction of breast cancer cells in vitro by using immuno-targeted Au nanocages as an effective photo-thermal transducer. These experiments suggest that Au nanocages may be a new class of nanometersized agents for cancer diagnosis and therapy.