Each year, more than 2 million people worldwide undergo open-heart surgery. This involves opening the chest and briefly stopping the heart. Getting those hearts pumping again can sometimes be risky, says Pengju Li. A molecular engineer, he designs bioelectronic devices at the University of Chicago in Illinois. This tech treats diseases by stimulating muscles and the nervous system with electricity.  

Doctors might restart hearts by compressing them with their hands. But that’s “very invasive and demands significant expertise,” says Li. Other times, surgeons use metal tongs and electrodes. These risk damaging sensitive tissue. Li’s team has designed a light-powered pacemaker that might one day help hearts find their rhythm after surgery.  

Traditional pacemakers use special wires called leads. These directly zap the heart. Li’s device instead relies on layers of silicon that form a flexible membrane. It generates electricity when exposed to light from an optical fiber. This membrane is about “100 times thinner than a human hair,” says Li.  

The device has already proven successful in rodents and pigs and holds promise for use in people. 

Li isn’t just working on hearts, however. His team also is designing devices that use electric zaps to treat nerve disorders. One of them is sleep apnea. That causes people to briefly stop breathing as they sleep.  

Here, Li shares his experiences and advice with Science News Explores. (This interview has been edited for content and readability.)   

What inspired you to pursue your career? 

In secondary school, I was really interested in chemistry. My grandfather is a chemistry teacher. He owns a personal collection of some legal chemicals. He taught me a lot about how to do experiments. That inspired me to pursue materials science at the National University of Singapore. 

I became interested in working on hearts by chance. After an internship at a tech company making semiconductors, I decided to pursue a Ph.D. The Pritzker School of Molecular Engineering at the University of Chicago caught my eye. It’s something that I really feel can change the world. I decided to go to a lab [run by Bozhi Tian] that worked with biointerface materials. These help seamlessly connect technology with the body. One example is the soft coatings on medical devices that make them safer and more comfortable. One of the lab members was very good at heart surgery and experiments. Seeing his work made me interested in combining the engineering of materials with biology. 

How do you get your best ideas? 

One of my strategies involves talking and collaborating with medical doctors. They know about medical devices. They understand what problems may occur during surgeries. I schedule regular meetings with them to share ideas on current medical problems. They might tell me about surgical equipment that needs improving. I can then design a device that meets their needs. 

How is the field of bioelectronics changing? 

Artificial intelligence is making big changes in the field. In the past, developing new materials often involved many people. We’d hire a lot of people to do tedious work, like testing and tweaking material recipes. Now we can automate that work with AI. Recent studies have shown how robots can automate experiments to identify potential medicines and test materials. They’re much faster than humans. 

We can also integrate AI into today’s electronic devices. Algorithms can analyze data collected from your body and point out possible issues. 

What challenges do younger patients in need of pacemakers face? 

Most people focus on heart disease in the elderly. Implanting traditional pacemakers in younger patients can be more challenging. Surgeons can implant these devices in adults by passing them through the blood vessels. But children have much smaller veins, preventing us from reaching the heart. This is also true for conditions where the heart is shaped differently than what we typically see.  

That’s why we need to develop less invasive methods. Our team has engineered a tool that delivers pacemakers through the ribs. Instead of cutting the ribs, we make a small incision between them. This then lets us implant pacemakers using catheters. 

What tips do you have for those interested in studying bioelectronics? 

During college, look at all the labs open to you. Learn about the work they are doing and talk to their lab members. That will help you focus on the research you are interested in. After that, you can pursue either a Ph.D. or a medical degree. Many college students in my lab decided to attend medical school for hands-on surgical training. 

Others chose to do both a Ph.D. program and medical school. Typically, they spend the first two years in medical-school coursework, followed by three to five years focusing on Ph.D. research and publishing papers. After that, they return to clinical training and hospital rotations before progressing to a residency.