Ohio State engineers create a more efficient insulin pump

Diabetes is a complicated condition requiring medical devices and a multitude of medications. Keeping up with treatment can often be a burden for patients.

A team from The Ohio State University Department of Electrical and Computer Engineering (ECE) is doing its part to make treatment of Type 1 diabetes much more simple. They proposed a new kind of insulin pump – a device improving upon others currently on the market. Not only is it powered wirelessly, but it is much smaller in size.

In collaboration with Cornell University, the Ohio State team includes ECE Assistant Professors Liang Guo and Asimina Kiourti, Internal Medicine Assistant Professor Kathleen Dungan, and recent PhD graduate Brock DeLong as well as current PhD student and Graduate Research Associate Bingxi Yan. 

“All of our work could be a significant optimization or revolution based on the current pumps,” said Yan on behalf of the group. “The difference between commercially available pumps and our pump is the reduction in size and power consumption.”

Patients typically prefer smaller and lighter devices, he said, especially if it is implanted into the body. To accomplish this, the engineers explored radio frequency (RF) power to have it operate wirelessly.

If RF technology allows cellphones to charge wirelessly, he said, why can’t an insulin pump be powered the same way? The advancement eliminates the need for a bulky battery and creates a lifelong device.  

Since Yan’s research interests lie in electroactive polymers, also known as artificial muscles, he focused on a balloon design, or squeeze operation, in order to contain the insulin in a reservoir and release it as needed.

"The balloon is elastic and soft and could be squeezed easily. We wrapped the outer surface with artificial muscles, the polymers," Yan said. "So, when the polymers shrink in volume, it triggers a squeezing effect on the balloon and any liquid contained."

Because of a check valve, he said, the squeezer pushes the insulin in only one measurable direction. 

Other vital components of the pump include a silicon polymer catheter tip, accommodating a porous material similar to Teflon, as well as the external wireless RF powering unit. 

DeLong and Kiourti dealt with the electrical components of the device. They designed the wireless power harvesters. These actuate the pump from the outside, and do away with the need for implanted batteries inside the patient, which frequently require replacement and are susceptible to infection.  

Kiourti said the benefits of going battery-free are numerous.

“The patient wears a smart garment that sends a wireless RF signal toward the implanted insulin pump – this signal is very much like conventional Wi-Fi or Bluetooth signals that we are all very familiar with,” she said. “In turn, the pump captures this RF signal, converts it into a direct current, and uses this direct current signal for actuation. In this case, actuation means squeezing the pump to release insulin. For us, this is a huge step toward completely battery-less implants.”

As for Yan, he is currently working on the next manuscript for the device and plans to present the scientific results by September 2018.

The group is also considering adding some sensors to the pump to detect the levels of glucose and automatically determine the amount of insulin needed. The sensors are used in current pumps and help tremendously since the diabetic is not required to do calculations. 

Yan hopes to continue working on the pump post-graduation and plans on earning his PhD in the fall of 2018. 

He said working on the project allows him to understand how engineering can help society in many ways. 

“This is the first time I realized the materials can be converted into some real contribution, with medical applications and cutting-edge devices for patients,” Yan said.

by Lydia Freudenberg, Department of Electrical and Computer Engineering