Development of a new type of prosthetic device that uses microfluidics-enabled soft robotics could reduce skin ulcerations and pain in people who have transtibial amputations.
“Rather than creating a new type of prosthetic socket, the typical silicon/fabric limb liner is replaced with a single layer of liner with integrated soft fluidic actuators as an interfacing layer,” said Carolyn Ren, PhD, one of the authors of the study describing the results. “These actuators are designed to be inflated to varying pressures based on the anatomy of the residual limb to reduce pain and prevent pressure ulcerations.”
The research team started with a recently developed device using pneumatic actuators to adjust the pressure of the prosthetic socket. The weight of the initial device limited its use in real-world situations.
To address this problem, the group developed a way to miniaturize the actuators. They designed a microfluidic chip with ten integrated pneumatic valves to control each actuator. The full system is controlled by a miniature air pump and two solenoid valves that provide air to the microfluidic chip. The control box is small and light enough to be worn as part of a prosthesis.
A prosthetist provided a detailed map of desired pressures for the prosthetic socket. The research team carried out extensive measurements of the contact pressure provided by each actuator and compared these to the desired pressure for a working prosthesis.
All ten actuators were found to produce pressures in the desired range, suggesting the new device will work well in the field. Future research will test the approach on a more accurate biological model.
The group plans additional research to integrate pressure sensors directly into the prosthetic liner, perhaps using newly available knitted soft fabric that incorporates pressure sensing material.
Editor’s note: This story was adapted from materials provided by the American Institute of Physics.
The open-access study, “Air microfluidics-enabled soft robotic transtibial prosthesis socket liner towards dynamic management of residual limb contact pressure and volume fluctuation,” was published in Biomicrofluidics.
