Investigation of shell aggregate gold nanostructures

The unique optical properties of noble metal nanostructures have led to an increased interest into their potential uses for various biological applications. For many medical investigations, it would be beneficial to use near infrared (NIR) excitation as well as small gold nanospheres, which can easily reach the cytoplasm and cell nucleus. To fulfil both requirements simultaneously, this paper proposes a novel nanostructure, the "shell aggregate", which consists of small nanospheres aggregate around a core such as an intracellular organelle. The extinction efficiency of such monolayer and bilayer shell aggregates is thoroughly investigated with appropriate simulations. The extinction spectra appear to depend heavily on the distance between the small nanospheres. The monolayer shell aggregate could be a good candidate for use in various biological, intracellular, applications since it provides a reasonably tunable plasmon resonance wavelength while the small size of its components can be exploited for intracellular distribution.