April 4, 2022

Associate Professor and Woodruff Faculty Fellow, W. Hong Yeo, who serves as the Director of the IEN Center for Human-Centric Interfaces and Engineering at the Georgia Institute of Technology, is laying the groundwork for a range of devices that could make monitoring patient health much easier. For Yeo the mission is personal.

Yeo earned his undergraduate degree in South Korea before serving in the military as an ordnance officer close to the demilitarized zone. When his father passed away suddenly in his sleep from an undetected heart issue he decided to make a career change.

He was not diagnosed at all. He was healthy, and regular medical screening didn't find anything until he suddenly died during sleep. As a mechanical engineer and biomedical engineer, I thought I could do something about it. This sad story motivates me daily to come to the lab and do something positive because my research, developing medical devices, is going to be good for everybody.

Heart Monitor

Motivated by the passing of his father, Yeo and his group have developed a portable heart monitor with the goal of bringing reliable data to the home, at an affordable price. Typical hospital monitors use tabletop systems with multiple rigid sensors connected to the patient by an array of wires. In addition to being cumbersome and uncomfortable, any movements by the patient can cause noise, or artifacts, in the data. For research purposes those artifacts can be disastrous. In addition to the wires being sensitive to disruptions, they make heart monitoring a very stationary process.

Yeo’s device makes use of soft wireless sensors the subject can wear without worrying about portability or artifacts in data.

“It’s a single wireless device, integrated platform,” says Yeo. “It’s fully portable and can be used with any tablet or smart phone for monitoring purposes. It can be worn comfortably for at-home monitoring by anyone who may need to monitor a heart condition.”

Yeo’s hope is that the device could also limit trips to a doctor’s office for monitoring and testing purposes, saving both time and money. The Covid-19 pandemic has sped up the development and acceptance of virtual medicine and telehealth. With Yeo’s heart monitor a patient could remain at home and be monitored by their doctor remotely, meeting in person only when necessary.

Yeo and his team are developing a simple screen-printing method for the circuit boards and sensors that would enable large-scale production, reducing costs and making the device very affordable.

Sleep Monitoring Device

In a similar vein, Yeo is using his sensors for sleep monitoring. Current sleep evaluations conducted at hospitals are not able to properly capture a subject’s natural sleep patterns because of the inherently uncomfortable nature of the tests. Being in an unfamiliar environment like a sleep lab, connected to a wide range of equipment, combined with undiagnosed sleeping issues can understandably lead to abnormal sleep behavior. Any subsequent diagnosis then ends up being based on bad data that is not reflective of a normal sleep pattern. Yeo’s sleep monitor consists of a soft sticker with an embedded flexible sensor placed on a user’s chest or forehead that can be worn at home in a subject’s typical sleep environment, resulting in higher quality data collection. That improved data could ultimately lead to the development of a more accurate diagnosis and improved treatment for sleep disorders such as sleep apnea, which afflicts approximately 25% of men and 10% of women in America.

Brain-Machine Interface

The third device Yeo is working on is a brain monitor. Human hair limits contact between traditional rigid electrodes and the scalp. Yeo’s sensors are soft, flexible, and covered in tiny microneedles that can go around the hairs to maximize contact, lowering electrical impedance and capturing more accurate measurements.  Like Yeo’s other devices, the brain-machine interface system is wireless and mobile, and can deliver high-quality data via Bluetooth.

Yeo’s heart, sleep, and brain monitors need minimal regulatory approvals because they are all wearable devices that aren’t implanted in the body. With those projects going well he is taking on what could be a bigger challenge- developing an improved trackable stent.

Smart Medical Stent

A typical medical stent works to expand blood vessels in order to improve blood flow and remove clots. However, once the device is inserted it is difficult to tell where it ends up or if it is working properly. Yeo’s team has developed a smart stent with an embedded sensor and antenna that passively receives and returns a signal, without circuits and batteries, to a monitoring device like a smartphone or tablet.  Changes in signals can be used to monitor blood flow and blood pressure in real-time, completely wirelessly, letting clinicians know if the stent is accomplishing its objective, or if the patient is developing more clots. The proof of concept has made it through animal trials but as an implantable device will have to pass through very strict regulatory processes to be used in human medicine.

Commercialization

Yeo’s lab includes more than 20 graduate students, nine postdocs, and 20-25 undergraduates working on funded projects. In order to make sure they are approaching medical problems in the right way, he and his students work closely with colleagues at Emory University School of Medicine and Children’s Healthcare of Atlanta, providing a rich and collaborative interdisciplinary research environment. As much as Yeo enjoys the research, he wants to make sure people benefit from it.

Yeo is now working on starting a new company with his recent graduates to commercialize the aforementioned biomedical devices. Yeo is optimistic that this commercialization effort will help him get his research from the lab bench to the market in the near future, with the possibility of improving the quality of life for countless people. 

Related Publications

• "Strain-Isolating Materials and Interfacial Physics for Soft Wearable Bioelectronics and Wireless, Motion Artifact-Controlled Health Monitoring", Advanced Functional Materials
• "At-home wireless monitoring of acute hemodynamic disturbances to detect sleep apnea and sleep stages via a soft sternal patch", Science Advances
• "Wireless Soft Scalp Electronics and Virtual Reality System for Motor Imagery-Based Brain–Machine Interfaces", Advanced Science

This research was supported by the IEN Center Grant (CHCIE) from the Georgia Tech Institute for Electronics and Nanotechnology, the National Science Foundation/the Centers for Disease Control and Prevention (NRI-2024742), the National Institutes of Health (NIH R21AG064309), the American Heart Association (19IPLOI34760577), and the National Institutes of Health (R03EB028928).