Optical Properties Of Gold Nanoparticles And Their Use In Cell Marker And Tumor Therapy

Gold nanoparticles have shown some special optical characters, Such as high absorption, brighter emission compare to bulk gold. A lot of evidences proved it because of the lightning rod effect and surface plasmon resonance induced local field enhancement.From the view of local field enhancement, we measured extinction and emission spectra of some different kinds of gold nanoparticles, compare their optical characters, try to find the key point to improve single photon fluorescence or two photon fluorescence of gold nanoparticles. We find that gold nanocubes show an extra high photoluminescence quantum yield (0.04) compare to other gold nanoparticles, while gold nanorods have an incredible high two-photon absorption cross section (1×109GM).Based on the high photoluminescence quantum yield of gold nanocubes, we have successfully use them in cell imaging of human liver cancer cells QGY and human embryo kidney cells293T under single photon exciting. On the contrast, we use gold nanorods in cell imaging under two-photon exciting due to its high two-photon absorption cross section. Besides we have compared the cell imaging with gold nanorods of different aspect ratio, confirmed its influence on two-photon exciting cell imaging.Since gold nanoparticles have a high absorption coefficient, it can be a great light absorption agency for photo-thermal therapy. We tried gold nanocubes and gold nanorods for photo-thermal therapy of QGY and293T cells with CW laser, both got a nice efficient. On top of it, we have tried photo-thermal therapy with near infrared femto-second laser, which turned gold nanorods into nanobomb, and shown a instant, high efficient, accurate killing of cancer cells.