September 14, 2012
Ultrasound May Lead To Needle-Free Vaccinations
Lee Rannals for redOrbit.com — Your Universe Online
MIT researchers are working on a technique that will allow needle-free vaccinations by using ultrasound waves.
The team wrote in the Journal of Controlled Release that applying two separate beams of ultrasound waves can uniformly boost permeability across a region of skin more rapidly than using a single beam of ultrasound waves.
“This could be used for topical drugs such as steroids – cortisol, for example – systemic drugs and proteins such as insulin, as well as antigens for vaccination, among many other things,” Carl Schoellhammer, an MIT graduate student in chemical engineering and one of the lead authors of the paper, said in a press release.
As ultrasound waves travel through a fluid, they create bubbles that move chaotically, and once they reach a certain size, they become unstable and implode. Surrounding fluid rushes into the empty space, generating high-speed "microjets" of fluid that create microscopic abrasions on the skin.
Other research has scientists working on low-frequency ultrasound for transdermal drug delivery, because the high-frequency waves don't have enough energy to make the bubbles pop. However, those systems create abrasions in random spots across the treated area.
The MIT scientists found that by combining high and low frequencies, they were able to produce better results. The high-frequency ultrasound waves generate additional bubbles, and also limit the lateral movement of the bubbles. This helps to keep the bubbles contained in the desired treatment area, creating a more uniform abrasion.
“It´s a very innovative way to improve the technology, increasing the amount of drug that can be delivered through the skin and expanding the types of drugs that could be delivered this way,” said Samir Mitragotri, a professor of chemical engineering at the University of California at Santa Barbara, who was not part of the research team.
The team tested their new method on pig skin and found that it boosted permeability more than a single-frequency system. They first delivered the ultrasound waves, then applied either glucose or inulin to the skin. They found that glucose was absorbed 10 times better, and inulin four times better.
“We think we can increase the enhancement of delivery even more by tweaking a few other things,” Schoellhammer said in the release.
This system can be used to deliver any type of drug that is given by a capsule, potentially increasing the dosage that can be administered. It could also be used to deliver drugs for skin conditions like acne or psoriasis.
Ultrasound transdermal drug delivery also offers a new way for diabetics to control their blood sugar levels, without the use of a needle.
The researchers said that they have already shown through their work that it is possible to provide immunity from vaccinations in a pain-free, needle-free way.
They are working on a prototype for a handheld ultrasound device, and are working on ways to boost skin permeability even more.