Intracellular light-induced release of signaling molecules from gold-coated liposomes

The combination of laser light and composite nanovesicles enables unique opportunities for precise delivery to, and on-demand release of molecular compounds within, single cells at high spatiotemporal resolution. Here, we demonstrate precise delivery and intracellular release of molecules from gold-coated liposomes via near infrared (NIR) light. The plasmon resonant gold shell provides a light-sensitive trigger for on-demand content release from thermosensitive liposomes. Two demonstrations of intracellular delivery and release from gold-coated liposomes are presented here. The first example uses microinjection to preload gold-coated liposomes into a single cell, followed by exposure to onresonant NIR laser light to trigger release of a fluorescent nuclear dye intracellularly. In the second delivery and release demonstration, gold-coated liposomes encapsulating inositol trisphosphate (IP3), a ubiquitous secondary messenger in cell signaling cascades, passively accumulate within cells via endocytosis. Exposure to on-resonant NIR laser wavelength of light induces rapid release of IP3 from the intracellular liposomes and subsequent activation of Ca2+ signaling at a single cell, monitored by changes in fluorescence intensity of a Ca2+-sensitive dye.