Lymphedema is common in breast cancer survivors due to the high risk of lymph node damage or removal during surgical procedures. As the nodes’ locations cause fluid and proteins to collect in the arm, compression sleeves are used to try to restore normal flow. Current techniques, however, are both costly and inconvenient.
Images of the lymphedema sleeve (left) and a diagram of its components (right). The microfluidic chip sequentially inflates and deflates balloons, creating pressure and pushing fluid through the arm. Image Credit: Carolyn Ren.
To overcome these issues, investigators from the University of Waterloo’s Microfluidics Laboratory, DIESEL Biomechanics Laboratory, Breast Rehab, and Myant, Inc. created a soft robotic sleeve controlled by a microfluidic chip that minimizes treatment cost, weight and power consumption.
The research was published in the journal Biomicrofluidics, published by AIP Publishing. The prototype is much more portable than previous devices, and the mechanisms behind it could be applied to other treatments like prosthetics.
Each of the 16 channels on the microfluidic chip acts as a pipeline. The channels have different resistances, just like pipelines with different diameters have varying flow speeds. Due to the different resistances, the flow through each channel takes longer, causing balloons in the sleeve to successively inflate and push fluid upwards, out of the arm.
Only two miniature valves are needed to replace eight bulky, energy-consuming valves in the design. The cost is reduced from thousands to hundreds of dollars as a result. In contrast to prior technology that demanded a wall outlet, it runs on a 3.7-volt lithium-ion battery inside a control box that weighs less than an iPhone 13.
My definition of wearable is you can wear it and do whatever you want, and not be plugged into a wall. Bringing in the microfluidics field, we wanted to make the system battery-powered but without compromising the performance.
Carolyn Ren, Study Author, University of Waterloo
The team evaluated and optimized the sleeve pressure to encourage fluid flow by placing a sensor between the sleeve prototype and the arm.
The investigators are currently recruiting for patient testing. They plan to develop a commercially viable product using their device patent.
Microfluidic chips can also be used in prosthetics for amputees who have lost their lower legs.
Walking causes pressure to be distributed unevenly around the leg, and the leg swells and shrinks throughout the day, but conventional prosthetic sockets cannot adjust to these changes. A lymphedema sleeve, for example, could dynamically apply the appropriate amount of pressure to the leg and inflate or deflate to change size on demand.
We look at these problems from different angle, but I think there are a lot more things microfluidics can contribute to these areas.
Carolyn Ren, Study Author, University of Waterloo
Journal Reference:
Gao, R. Z., et al. (2022) A novel air microfluidics-enabled soft robotic sleeve: Toward realizing innovative lymphedema treatment. Biomicrofluidics. doi.org/10.1063/5.0079898.