Harnessing light and red blood cells to improve drug delivery

red blood cells
UNC researchers have figured out how to turn red blood cells into drug delivery machines.

Powerful drugs, such as chemotherapy to treat cancer, are often toxic when given systemically, because they invade healthy cells and diseased cells alike. Scientists at the University of North Carolina at Chapel Hill have been working on an innovative way to target drug delivery only to the tissues of the body that need to be treated, using a combination of red blood cells and light. And the technique is so promising they’re creating a company to further develop it.

Here’s how it works: A drug is attached to vitamin B12, along with a fluorescent molecule, and loaded into red blood cells, according to a press release from the university. Normally, each red blood cell circulates for up to four months. The UNC scientists figured out how to coax the cells to release the drug exactly when and where it's needed by shining a light on them.

It was far from an easy technical hurdle to clear, though. Long-wavelength light can penetrate deeply into the body, but it doesn’t carry enough energy to break bonds within cells. So they figured out how to get the fluorescent molecule that’s attached to the drug to act as an antenna of sorts, capturing the light and using it to separate the drug from the vitamin B12. Their work was published in the journal Angewandte Chemie.

David Lawrence, a professor in the Eshelman School of Pharmacy at UNC, believes the technique could reduce the amount of drug needed to treat a variety of diseases, and therefore cut the risk of side effects. Benefits “could include avoiding surgery and the risk of infection, making anesthesia unnecessary and allowing people to treat themselves by shining a light on a problem area, such as an arthritic knee,” Lawrence said in the release. In the case of cancer, he added, “it may be possible to significantly reduce or eliminate the side effects that commonly accompany cancer chemotherapy.”

Developing new ways to deliver drugs only where they’re needed is a major priority in scientific circles, especially in oncology. In 2015, researchers at the University of Manchester presented their work using heat and liposomes to deliver cancer drugs directly into tumor cells. At the Massachusetts Institute of Technology, scientists are working on an implantable device, made from the polymer PLGA, that delivers chemo directly into pancreatic tumors.

To further investigate the method of combining light with red blood cells to carry drugs to diseased tissues, UNC’s Lawrence has partnered with the university to found Iris BioMed. The startup will develop the drug delivery technology and test it in people.