Ultrasound is likely most often associated with sonograms, but some MIT engineers are poised to change that. By using two separate beams of inaudible sound waves (one at low-frequency, the other high) the team were able to increase the permeability of skin, in a bid to improve the efficiency of transdermal drug delivery. The technique works thanks to the waves exciting bubbles in a fluid (such as water), forcing them to swell and move chaotically. Once the bubbles reach a certain size they implode, sucking the su
