Implantable LED device uses light to treat deep-seated cancers

Some types of light have proven to be effective, minimally invasive treatments for cancers on or near the skin when combined with a light-activated drug. But deep-seated cancers, surrounded by tissue, blood, and bone, were beyond the reach of light’s therapeutic effects.

To bring the benefits of light to these harder-to-reach tumors, engineers and scientists at the University of Notre Dame have developed a wireless, implantable LED device. This device, when combined with a photosensitive dye, not only destroys cancer cells but also mobilizes an immune response that targets the cancer. The research appears in Photodiagnostics and photodynamic therapy.

“Some colors of light penetrate tissue more deeply than others,” said Thomas O’Sullivan, assistant professor of electrical engineering and co-author of the paper. “It turns out that a type of light—in this case, green—that doesn’t penetrate as deeply has the ability to trigger a stronger response against cancer cells.”

Before light can effectively destroy cancer cells, the cells must be injected with a dye with light-absorbing molecules. The device is turned on, the dye converts light into energy, and that energy turns the cells’ oxygen toxic—in effect, the cancer cells turn on each other.

While other treatments also use oxygen produced by cells, this device causes a particularly unexpected form of cell death.

“Working together, biochemistry graduate student Hailey Sanders and electrical engineering graduate student SungHoon Rho were astute enough to notice that the treated cells swelled, a hallmark of a type of cell death, pyroptosis, that is particularly good at triggering an immune response,” said Bradley Smith, the Emil T. Hofman Professor of Science and a co-author of the paper.

“Our goal is to induce just a little bit of pyroptotic cell death, which then triggers the immune system to start attacking the cancer.”

In future studies, the device will be used in mice to test whether a tumor-killing response initiated in one tumor will cause the immune system to recognize and attack another tumor on its own.

O’Sullivan noted that the device, which is about the size of a grain of rice, can be injected directly into a tumor and activated remotely via an external antenna. The goal is to use the device not only to deliver treatment but also to monitor the tumor’s response, adjusting signal strength and timing as needed.