SCOTLAND-Organic light-emitting diodes (OLEDs) have garnered much attention in recent years due to their potential to revolutionize lighting and displays. Now a team of researchers in Scotland has demonstrated in a pilot study that OLEDs may one day change the way photodynamic therapy (PDT) is used to treat skin cancer. In addition to the treatment of skin cancers, the researchers believe that the technology could also be used in the cosmetic industry for anti-aging treatments or skin conditions such as acne.
Ifor Samuel, a physics professor at the University of St. Andrews (Fife, Scotland), and James Ferguson, head of the photobiology unit at Ninewells Hospital (Dundee, Scotland), have developed a lightweight, wearable OLED-based device-an optical bandage or patch of sorts-that is powered by a pocket-sized battery about the size of an iPod. According to Samuel and Ferguson, the new device improves upon established PDT methods by making it possible for patients to undergo treatment outside of the hospital environment.
Conventional therapies for non-melanoma skin cancer (which accounts for about 80% of all skin cancers) involve either surgical removal or PDT. In the latter, the patient must go to the hospital or doctor’s office where a photosensitizing cream is applied to the affected area. After waiting about three hours for the photosensitizer to metabolize to the active form, 580-640 nm light is applied for 20-30 minutes. Most lesions take at least two such treatments.
Samuel says the “optical patch” approach is much more convenient and comfortable than conventional methods because lower light levels are used (reducing pain), and the patient can move around during treatment. In addition, more patients can be treated, which also increases cost efficiencies.
“A key step was realizing that very high light intensities are not needed in PDT, and in fact realizing that very high light intensities have some adverse effects, such as pain and photo bleaching,” Samuel said. “And while PDT needs light in the drug it also needs oxygen to diffuse, and this might not always be present in high intensities. Our approach is lower power and is stretched out over three hours, which solves the problem of pain and gives more time for oxygen to reach the site. With current office- and hospital-based approaches-versus our portable system-you couldn’t do this because the patient would have to sit in one place for too long and the hospitals need greater throughput.”
“We decided to use OLEDs because they are a nice, thin light source that offer multiple colors and wavelengths,” Samuel said. “Also, they are basically an inexpensive light source which means the device can be disposable. The key thing is that the area to be treated is most often 1.5 cm in diameter (even smaller if caught early), so we chose to use a 2-cm diffuse light source that neatly covers the lesion. Also, most other light sources are point sources; even inorganic LEDs are close to being single-point light sources and thus would require a diffuser for this application, which would increase the thickness of the device.”
The patented technology was developed with support from Scottish Enterprise Proof of Concept funding and has been licensed to Lumicure, a spin-off established by Samuel and Ferguson that is currently in discussions with venture capitalists to raise equity funds to commercialize the product. From a commercial perspective, the market potential would appear to be quite large; roughly half of all Americans, for example, suffer from non-melanoma skin cancer at some point in their lifetime. Lumicure is currently collaborating with Osram to develop the system for commercial production.
-Kathy Kincade
