(133b) Controlled Trigger and Drug Release from a Liposomal Nanocarrier Modulated with NIR Light

Liposomes have been widely assessed as drug nanocarriers, however they face the inherent contradiction of minimizing non-specific drug release and initiating fast release at the targeted site. Encapsulated or tethered hollow gold nanoparticles (HGN) photo-activated with near infrared (NIR) light can be used as a novel mechanism to trigger and control the nanocarrier content release. NIR light is an appropriate triggering source as it can penetrate several centimeters with minimal thermal injury to normal tissues. HGN strongly absorb NIR light in the range of 700-900 nm, depending on their diameter-to-shell thickness ratio. Nanoparticles that exhibit strong absorption of NIR light, offer the opportunity to convert optical energy into thermal energy. The photo-thermal heating of the HGN, generated by short laser pulses, results in large temperature gradients that lead to the formation of transient vapor nanobubbles in aqueous solutions. The collapse of the nanobubbles induces the rupture of cell, endosome, or liposome membranes and the subsequent drug release with minimal damage to the surroundings. We systematically synthesized different sizes and shapes of HGN to absorb NIR light, these nanoparticles were irradiated with a pico-second pulsed laser. We show that we can selectively photoactivate HGN at specific wavelengths in the NIR region to remotely trigger the content release of a DPPC liposome loaded with an anticancer drug, cisplatin, in order to deliver the drug to an in vitro system of prostate cancer cells. Near-complete cell killing was observed after triggering the release. This study builds a better understanding of the novel mechanisms of controlled drug release with potential applications for in vivo models.