Tiny bottles and melting corks

Microscopic, bottle-like structures with corks that melt at precisely-controlled temperatures could potentially release drugs inside the body or fragrances onto the skin, according to a recently published study.

Typical drug delivery systems act more like sponges than bottles. For example, drugs are absorbed into polymer particles and then allowed to diffuse out over time. The researchers hope that the new system may allow for greater control of drug delivery. Cargo would stay inside the hollow polymer particle when plugged with a solid cork. When the cork is melted by body heat, the drugs would quickly flow out of the particle bottle.

"It's just like when you open wine, you remove the cork," said Younan Xia, a professor in the Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory University.

The melting corks are made of fatty acids, derived from natural oils and fats. The length of the hydrocarbon chains on these molecules can be made longer or shorter to increase or decrease, respectively, the temperature at which they melt. This way, the fragrances in deodorants, for example, would be released only when a person gets hot and sweaty.