Electronic Pain Relief Patches

Millions of athletes and arthritis patients turn to disposable pain relief patches designed to soothe aching joints and muscles. The new development of a flexible smart patch could eventually enable users to wirelessly control the exact temperature of their heat therapy with their smartphones.

The smart patch relies upon the design of stretchable, flexible copper springs to conduct power to a series of tiny, interconnected heating pads. Engineers in Saudi Arabia hope their smart patch could eventually begin to replace the 4.2 billion chemical based patches sold for pain relief every year. But first, they want to introduce more flexible electronic components to replace the electronics hardware and battery in their current prototype.

Most flexible electronics have yet to become ordinary products sitting on store shelves. But Hussain has always wanted to apply the promise of flexible electronics to simple, inexpensive products that anyone could buy. His team is talking with a company that represents a major brand in thermal patches about the possibility of developing the lab prototype into a commercial product.

The idea began in Hussain’s personal life. In October 2012, he noticed the patches that his mother used to ease arthritis pain in her finger and knee joints. Such patches are chemical based, made in many sizes and shapes for different parts of the body, and can become expensive over time because they are single-use products. Something clicked in Hussain’s mind; why not make a flexible and stretchable heating patch that was reusable and cost less than the chemical-based patches?

To create the flexible patch, Hussain’s group turned to copper, because it’s common in electronics and inexpensive. But the researchers faced the challenge of making copper interconnects that could survive stretching and flexing beyond the metal’s normal yield strain of just 20 to 25 percent.

They eventually settled upon a known fractal pattern of repeating shapes each shape resembling a figure eight drawn in a single, unbroken line that never intersects itself. That pattern enabled the copper interconnects to survive stretching up to 800 percent beyond their starting size.