Christopher Chen is the founding director of BU’s Biological Design Center and a National Academy of Inventors Fellow.

Health & Medicine

Curing Heart Attacks, Replacing Diseased Organs—Christopher Chen Is Engineering a Healthier Future

Healing from a knee injury sent the BU biomedical engineer on a winding road of discovery and innovation

Christopher Chen was a teenager when he first started thinking seriously about what makes the human body such an amazing machine. An avid runner and soccer player, Chen injured his knee, sidelining him from sports for a while. His knee eventually got better on its own, but during this time of convalescence, Chen mused about replacement surgery—even the best materials, developed with the most cutting-edge technology, would eventually break down. If he had needed a knee replacement, he’d need another surgery at some point, and maybe even another after that. 

Why, Chen wondered, doesn’t our cartilage wear down as fast? While the prevalence of knee and hip replacement surgeries in the United States shows that our cartilage certainly does break down, most people will go their entire lives without needing to replace any joints. What makes our biology more resilient than the metal and plastic replacements scientists have developed? 

“What I found very frustrating, or puzzling, about it is that all the materials that we make, they wear. The more you use them, the worse they get. That’s just the nature of engineered materials,” says Chen, now the William Fairfield Warren Distinguished Professor of Biomedical Engineering in Boston University’s College of Engineering. “But so many of our materials, like our joints, seem to not wear. Why they don’t is because cells inside those tissues are continuously producing new material to maintain these tissues.” 

This essential insight set Chen on a winding path of discovery. He’s collected degrees in biochemistry (Harvard University), mechanical engineering (Massachusetts Institute of Technology), and medical engineering and medical physics (Harvard-MIT Health Sciences and Technology program), as well as a medical doctorate (also Harvard). He holds more than 30 patents and was inducted into the National Academy of Inventors Fellowship; his work has spun off into three successful biomedical businesses; and his widely cited body of research has become foundational for anyone in the field of biomedical engineering.

Chen is the founding director of BU’s Biological Design Center, which aims to improve our understanding of how cells and biological systems work, and then find ways to control them for our benefit. That involves designing technologies that can improve human health and the environment: engineered blood vessels that help fight cardiovascular disease, artificial microbial communities that could herald more sustainable energy.

“I’m most interested in why cells cease to behave normally when they are taken out of the body, making it impossible to use them as models of human biology and disease,” Chen says. “Can we build and organize cells into tissue and organ-like structures so that they once again act like they do when in our bodies? One thing we are really interested in is that cells are always sort of paying attention to what’s going on around them.”

Testing Heart Attack Treatments—with Zero Risk to Patients

That cellular process—a cell senses the biological environment around it and then reacts to that environment—is what sets our cells apart from even the best facsimile. Chen and his colleagues want to understand that process because, from an engineering perspective, it would allow them to create engineered tissues that more closely mimic the dynamic, regenerative nature of our own tissues. 

“The way I think about my work now is that—and this is a little bit philosophical—we are building living tissues that allow researchers to experiment on humans without actually experimenting on humans. The way we learn is by experimenting. We try things, and then we figure out what works and what doesn’t work, and that’s just part of how we learn as a species,” Chen says. 

In practice, that approach works perfectly for, say, designing a new bicycle. Tweak the size of the wheels, or the angle of the handlebars, and give it a spin. In medicine, however, the approach falls flat, because no scientist wants to test out a risky experiment on a living human. 

“If I said to you, ‘Let’s try to learn how to ride a bicycle, but you’re going to ride on this thin path, on either side of which is lava, so if you fall, you die,’ I don’t think anyone in the world would ever learn how to ride a bicycle. You have to be able to try and tinker and fail and learn and iterate,” Chen says. 

So, in order to create novel solutions for something like heart attacks, Chen and his team are developing ways for them, and other scientists, to more safely try, and fail, and try again. They’ve developed a new way of studying the heart by building a miniature replica of a heart chamber from a combination of nanoengineered parts and human heart tissue grown from stem cells. It beats by itself, driven by the live heart tissue. 

This device could give researchers a more accurate view of how the organ works, allowing them to track how the heart grows in the embryo, study the impact of disease, and test the potential effectiveness and side effects of new treatments—all at zero risk to patients and without leaving a lab.

Another line of research, one which resulted in Chen cofounding the biotechnology company Satellite Bio, is the development of tissue implants that can help treat or replace diseased organs. The company, which secured more than $100 million in venture funding, aims to create tissue “patches” to support failing organs. Perhaps in the future, liver failure will mean little more than a surgery to patch the diseased liver, Satellite Bio imagines. 

In both cases, as well as in his work more broadly, Chen says, “What we’re building are little snapshots of human biology, capturing a key disease process in a moment or in a small group of cells. And that’s a small step, but over time, we will get better at creating these systems that the scientific community can use to get answers to important questions. What makes certain diseases happen? How do they go awry? What are the right interventions to stop them?”

“The Pressure Is Always There”

To ask Chen, his work, like his education, is simply a matter of following one question to the next. Why do medical devices break down, when our own tissue doesn’t? What are the cells in that tissue doing? How do they know to regenerate, and when to stop? As soon as he learns enough about one challenge, a new, deeper one presents itself—and, along with it, a new opportunity to find an answer.

The way he sees it, every day that goes by without a solution to some of the most intractable medical issues of our time—heart attacks, liver failure—is another day when thousands of people die from these health problems. 

“The pressure is always there. We all know people who were recently diagnosed with cancer, or had a heart attack, and you know that the current treatments are not going to work. At that moment, everybody’s asking themselves, ‘How long will it take for the next treatment to become available?’ And at that point, time matters a lot—six months, a year, two years, five years, 10 years. Until you are sick, you don’t necessarily think about time, but the moment that unfortunate event starts, time matters a lot,” Chen says. As researchers, he adds, “I think we’re always aware of that. That’s part of the work. The goal is not just to discover something important. The goal is to discover it as fast as you can.”

With less than a decade to go until he hits the official retirement age, Chen is starting to consider how much time he has left in his career to find those answers—and how best to help the next generation of scientists and researchers succeed in this challenging field, and in challenging times more generally. 

“I’m seeing so many people at this moment that are losing faith and maybe not wanting to work in science, because they’re not sure that the country cares about science. I’ve been thinking about how we give them the tools so that they can continue in the mission,” Chen says. “I’ve certainly reached a point in my career where I recognize that the most important discoveries take time and need legions of researchers to move the needle together. So, I’m thinking, how do I inspire my trainees and others to lean in?

“You start to think about the legacy that is beyond what your own lab is going to get done, and more about all the ripples of everything that you’ve worked on.” 

Chen’s research is primarily funded by the National Institutes of Health and the National Science Foundation, with additional support from Wellcome Leap and the Paul G. Allen Foundation.