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Discovery

'Smuggling' drugs at the cellular level

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Image of delicate, nested microbubbles.

Liposomes, a fabricated lipid sac filled with water, are prime candidates for drug delivery because they can pass through the skin virtually unnoticed. Shown here are nested microbubbles that pop and split open the liposome to release medicine when exposed to sound or vibrations with an ultrasonic frequency. Drexel University researchers Steven Wrenn and Peter Lewin are trying to expand the possibilities of this system, called transdermal delivery.

Credit: Drexel University

 

Image of microbubbles

Drexel University researchers Steven Wrenn and Peter Lewin are trying to expand the possibilities of a drug delivery system that can penetrate the skin, called transdermal delivery. Microbubbles respond to ultrasound in two ways that are key to making the transdermal delivery. First, they can be pushed by ultrasound at an intensity gentle enough to keep the liposome intact. So, nesting the microbubbles inside a liposome is analogous to raising the sail on a boat to catch the wind. Secondly, when the intensity of the ultrasound is turned up a bit, it causes microbubbles to wobble like a spring and--if the intensity is high enough--pop. Wrenn's group has shown that these gas implosions in the vicinity of the liposome can rip it open, thus allowing disbursal of its contents. A significant advantage of their approach over current transdermal delivery methods is that it could easily be customized to work for a broad array of drugs and other biological products.

Credit: Drexel University