Researchers have created a drug-filled microneedle skin patch that helps convert energy-storing fat, or white fat, into energy-burning fat, or brown fat – all the while boosting the body’s metabolism.

The team of researchers at Columbia University Medical Center and the University of North Carolina reported that their patch could one day be used to burn off pockets of fat or treat metabolic disorders, including obesity and diabetes. The study was published today in ACS Nano.

Scientists have long sought after a therapy that can take an adult’s white fat and turn it into brown fat, in the hopes of treating obesity and diabetes.

“There are several clinically available drugs that promote browning, but all must be given as pills or injections,” study co-leader Li Qiang said in prepared remarks. “This exposes the whole body to the drugs, which can lead to side effects such as stomach upset, weight gain, and bone fractures. Our skin patch appears to alleviate these complications by delivering most drugs directly to fat tissue.”

The drugs are loaded into nanoparticles and then piled into a centimeter-square skin patch. The skin patch has dozens of microneedles which pierce the skin painlessly, according to the researchers, and gradually deliver a drug.

“The nanoparticles were designed to effectively hold the drug and then gradually collapse, releasing it into nearby tissue in a sustained way instead of spreading the drug throughout the body quickly,” patch designer and study co-leader Zhen Gu added.

The system was tested in obese mice using one of two compounds known to trigger browning – rosiglitazone or beta-adrenergic receptor agonist. Researchers gave each mouse two patches. One patch was loaded with drug-carrying nanoparticles and one patch, on the other side of the mouse’s abdomen, had no drug in it at all. The scientists swapped out patches every three days for four weeks.

A group of control mice received two empty patches.

Mice treated with either drug had a 20% reduction in fat on the treated side of their abdomens compared to the untreated side. They also had lower fasting blood glucose levels than the control mice, according to the team.

Tests in lean mice showed that treatment with either drug boosted the animals’ oxygen consumption, signaling an increase in metabolic activity, by about 20% compared to control mice.

The team also conducted genetic analyses, showing that the treated side of the animals’ abdomen had more genes associated with brown fat than on the untreated side.

“Many people will no doubt be excited to learn that we may be able to offer a noninvasive alternative to liposuction for reducing love handles,” Qiang said. “What’s much more important is that our patch may provide a safe and effective means of treating obesity and related metabolic disorders such as diabetes.”

The researchers noted that the drug-device combo has not yet been tested in humans and that they are investigating which drugs would work best to promote localized browning in people.

See the best minds in medtech live at DeviceTalks Boston on Oct. 2.