Hollow Gold Nanoshells for Gene and Drug Delivery

The temporal and spatial control over the delivery of materials such as siRNA or drugs 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 pM 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.