Laser-Activated Gene Silencing via Gold Nanoshell-siRNA Conjugates.

The temporal and spatial control over the delivery of materials such as siRNA into cells remains a significant technical challenge. We demonstrate the pulsed near-infrared (NIR) laser-dependent release of siRNA from coated 40 nm gold nanoshells. Tat-lipid coating mediates the cellular uptake of the nanomaterial at picomolar concentration, while spatiotemporal silencing of a reporter gene (green fluorescence protein) was studied using photomasking. The NIR laser-induced release of siRNA from the nanoshells is found to be power- and time-dependent, through surface-linker bond cleavage, while the escape of the siRNA from endosomes occurs above a critical pulse energy attributed to local heating and cavitation. NIR laser-controlled drug release from functional nanomaterials should facilitate more sophisticated developmental biology and therapeutic studies.