By Pat Anson, Editor
Researchers say a new type of implantable wireless device could revolutionize the treatment of chronic pain by using light to block pain signals before they reach the brain.
In animal studies at Washington University School of Medicine and the University of Illinois at Urbana-Champaign, researchers used implanted microLED devices to “light up” peripheral nerve cells in mice. Their study is published online in the journal Nature Biotechnology.
"Our eventual goal is to use this technology to treat pain in very specific locations by providing a kind of 'switch' to turn off the pain signals long before they reach the brain," said co-senior investigator Robert Gereau IV, PhD, a Professor of Anesthesiology and director of the Washington University Pain Center.
Unlike spinal cord stimulators, which also mask pain signals to the brain, the new devices are soft and stretchable, and can be implanted in parts of the body that move. Spinal cord stimulators have to be anchored to bone.
"When we're studying neurons in the spinal cord or in other areas outside of the central nervous system, we need stretchable implants that don't require anchoring," said Gereau.
Gereau and his colleagues are experimenting with mice that are genetically engineered to have light-sensitive proteins on some of their nerve cells. The wireless implants contain microLED lights that use “optogenetics” to activate specific nerve cells. The devices are thin, flexible, and minimally invasive because they can be implanted in soft tissue.
Earlier versions of the device used remote lighting and fiber optic delivery systems that were tethered to power sources and could not be fully implanted.
Because the new devices are small, flexible and can be held in place with sutures, they have potential uses in or around the bladder, stomach, intestines, heart or other organs, according to John Rogers, PhD, a professor of materials science and engineering at the University of Illinois.
"They provide unique, biocompatible platforms for wireless delivery of light to virtually any targeted organ in the body," said Rogers.
Rogers and Gereau designed the implants with an eye toward mass production of the devices so they could be available to other researchers. They’ve formed a company called NeuroLux to aid in that goal.
According to iData Research, the spinal cord stimulator (SCS) market was valued at $1.3 billion in 2014. The company estimates that less than 10% of potential patients are being treated with an SCS device.
Stimulators are often considered the treatment of last resort after opioid pain medication, physical therapy, steroid shots and other types of treatment fail. Many patients are reluctant to get SCS devices because the surgery is so invasive.