Researchers at the University of California, Santa Barbara, have developed a method of using hollow gold nanospheres (HGN) located within or tethered to liposomes, together with pulsed near infrared (NIR) laser irradiation, to create the rapid release of a therapeutic agent from liposomes to the targeted area. In situ tests have demonstrated that this method ruptures over 90% of the liposomes in approximately 10 seconds, without use of toxic reagents or the need to heat large scale areas.

File Number: 19354 

Web site: http://techtransfer.universityofcalifornia.edu/...

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Background
For many years, researchers have been seeking commercially viable methods to initiate a rapid release of encapsulated drugs at the site of disease through an external triggering mechanism. Liposomes have been intensively investigated for this application. Large scale hypothermia, ultrasound or visible light have been used to rupture liposomes to accomplish targeted delivery. Unfortunately, these methods are limited to easily accessible areas, such as the eyes and skin. Gold nanoshells grown around silica cores have also been used to selectively heat and kill tumor cells, but the maximum temperature reached by continuous heating is limited to 10-20 C above background and the entire region to be heated must be saturated with nanoshells, which is difficult to accomplish. Gold/silica core nanoparticles are also difficult to manufacture. Hollow gold nanoshells have also been explored, but current methods require the use of toxic reagents or high temperatures.