Penn State engineers have developed a prototype for an ultrasound insulin delivery system that is about the size and weight of a matchbook that can be worn as a patch on the body.
Dr. Nadine Barrie Smith, assistant professor of bioengineering, said, ‘The new Penn State ultrasound patch, which operates in the same frequency range as the large commercially available sonic drug delivery devices, is about an inch-and-a-half by an inch-and-a-half in size and weighs less than an ounce. Commercially available sonicators currently have a probe about eight inches long which weighs over two pounds.’
Experiments with human skin and with live rats are said to have shown that the new ultrasound patch delivers therapeutically effective doses of insulin.
The key to the new ultrasound patch is a ‘cymbal’ transducer developed by Dr. Robert Newnham, the Alcoa professor emeritus of solid state science. The transducer produces the sound waves that drive the medication through the skin and into the blood stream.
The cymbal transducer consists of a thin disk of piezoelectric ceramic material sandwiched between titanium end caps shaped like cymbals. Four of these transducers are used in the prototype.
A thin reservoir of insulin is placed in front of the cymbal transducer and when a current is applied, sound waves just above the level of human hearing push the medication through the skin and into the blood vessels.
Smith noted, ‘Our experiments with rats show that an exposure of 20 minutes produced the same result as a 60-minute exposure. So, we are hopeful that, eventually, we may be able to tune the system so that one to five minutes of exposure may be enough.’