Using Plasma to Make Skin ‘Thin’

Delivering drugs through needles presents risks of infection to patients, not to mention causing pain and discomfort. Oral delivery of drugs, on the other hand, can prove toxic for some in digestible form and can be less effective than more direct methods unless higher does are administered. Transdermal delivery, where the drug is absorbed into the blood stream through the skin, provides an ideal solution, offering painless and effective delivery.
 
Only a fraction of drugs currently on the market can be administered this way because skin, by its very nature, is difficult to permeate—a characteristic measured by its barrier function. More universal use of transdermal drug delivery demands a mechanism to reduce this barrier function, improving its permeability to drugs.
 
A research team from Shizuoka University in Japan has explored the permeability of skin and will present their work during the AVS 63rd International Symposium and Exhibition being held November 6-11, 2016, in Nashville, Tenn. As a means to interact with skin, the team used plasma, a state of matter where electrons have dissociated from their corresponding ions and exhibit more collective behavior. Using plasma, which conducts electricity, they successfully decreased its barrier function for transdermal drug delivery.
 
The team of researchers at Shizuoka University built upon this prior work proving that plasma can interact with skin in the desired way. Using both a plasma jet and a microplasma discharge method researchers investigated the barrier function of the stratum corneum, or outermost skin layer, of Yucatan micropig skin, chosen because of its similarities to human skin. The physical changes in the pig skin were studied microscopically. Specifically, they studied changes in the outer skin layer using Attenuated Total Reflectance—Fourier Transform InfraRed (ATR-FTIR) spectroscopy. ATR-FTIR spectra provide precise information about water, the lipid (fat) bilayer and proteins in the outermost layer of the skin, all factors directly related to its permeability.
 
The team found microplasma to be a good potential method for transdermal applications. “We compared the effects of plasma on conductive and non-conductive material,” explained M. Blajan, an applied physicist from Shizuoka University in Japan. “Placement of skin on the conductive material caused burned spots on the skin by the plasma jet, while treatment of the skin by microplasma showed little physical damage.” This work could be instrumental in developing a more effective means of drug delivery.