Gold nanorods: Their properties and applications as biomarkers and photothermal therapeutic agents

Gold nanorods are fascinating due to their interesting optical properties in the visible (400-700 nm) and near infra-red (NIR) (∼800-1500 nm) region of the electromagnetic spectrum. These properties arise due to the collective oscillation of electrons, called plasmons or localized surface plasmons resonance (LSPR) upon interaction with light. By simply changing their aspect ratio, the absorption maxima of the nanorods may be tuned to a desired wavelength. Additionally, gold nanorods elastically scatter light and the scattered color (wavelength) is a function of the LSPR. These colors can be visualized under darkfield microscopy. In the current work both the absorption and scattering properties of gold nanorods are utilized to monitor cell-induced deformations in a biological medium and as photothermal therapeutic agents to destroy the multi drug resistant (MDR) bacteria, Pseudomonas aeruginosa. Results from this work will be discussed.