Profusa Pioneers Injectable Biosensors

If you’re a fan of science fiction, you might remember the 1966 movie Fantastic Voyage where a team of doctors and their submarine are shrunk to microscopic size and injected into the body of an injured scientist. Their task: remove the blood clot and save his life.

Profusa, a biomedical startup in California, takes the premise of Fantastic Voyage out of the realm of science fiction and into the possible. Dr. Ben Hwang, chairman and CEO of Profusa, joined me to discuss their goal to create a line of injectable sensors that can be used to monitor blood chemistry, catch diseases, and more.

Hwang’s career is something of a fantastic voyage of his own. In the 1980s, he worked as a batboy for the Los Angeles Dodgers, a gig that led to a job at the stadium doing marketing and promotions. “I was having so much fun at Dodger Stadium that I just quit going to school,” he said.

In time, Ben got his GED and then attended Pasadena City College with the goal of going to medical school. Because Caltech was close by, Ben went there to look for a job washing test tubes. He met Leroy Hood, a towering figure in American biological sciences, and that professional connection inspired Hwang so much that he went on to earn a doctorate in biology at Johns Hopkins University.

“We think a technology like this is really well overdue,” Ben told me. “It’s an opportunity to apply all of the learnings the world has gathered over the past couple of centuries, and more specifically the past couple of decades, and bring them together to apply this kind of technology to healthcare.”

The idea itself has been around for some time. Profusa’s breakthrough is its development of in-body sensors that don’t trigger our body’s immune response to either reject a foreign body or coat it in collagen, forming scar tissue.

Bypassing the Foreign-Body Response

“Your body is exquisitely good at determining what belongs inside it and what doesn’t,” Ben said. “Take sensors for something like diabetes. They use a little sliver of a needle that goes through the skin. That needle elicits a foreign-body response, so their location must be changed frequently because otherwise the sensor is reading the environment of the scar tissue. That foreign-body response has really hampered the industry going back 50 years.”

To get around the foreign-body response, Profusa makes its tiny sensors out of hydrogel, a soft, pliable substance that is similar to what’s used in contact lenses. These sensors don’t contain electronics of any kind. There are chemicals embedded inside the sensors that emit fluorescent light in the presence of certain chemicals. An external sensor then reads the light to create a specific measurement.

“The device that does the reading is no different than wearing an Apple watch, no different than wearing a pulse oximeter,” Ben said. “It’s so light you can’t feel it. If you want to have readings occur, put the reader on. If you don’t want to have readings occur, take the reader off. Nothing happens. No data is coming out of your body otherwise.”

Successful Clinical Trials

Profusa’s Lumee® Oxygen Platform has been the subject of clinical trials in Europe, where it has shown to be effective in measuring tissue oxygen levels in patients undergoing tissue revascularization, a procedure to restore blood flow to the heart or another organ after the arteries have become clogged. The study found that the Profusa sensor could accurately measure tissue oxygen, which is key to wound healing. The continuous information provided by Profusa sensors might help researchers improve treatment options.

Profusa now is developing injectable sensors that can monitor glucose levels. It’s also working on a sensor that detects early signs of influenza.

In the United States, the Lumee Oxygen Platform is approved as an investigational device only.

“For folks who are suffering from chronic diseases, this creates data their physicians care about, and can actually do something about,” Ben told me. “You can do so without having to fuss around with a lot of hardware in your body. And the cost is no longer a barrier to adoption.”

As with all things health-related, privacy is a big concern. By ensuring its in-body sensors emit no real data, Profusa puts the user in charge of when and how data is captured. “As a matter of fact, you’re the first person to see the data,” Ben said. “If you have a blood test, your doctor, nurses, the lab technicians—they all see the data before you do.”

Huge Potential Impact

Oxygen, glucose, chemicals such as sodium and calcium—all could be detected with a Profusa sensor. That could help change lives for millions of people who suffer from diseases that show up in blood chemistry.

Hwang even envisions a future when a smart refrigerator orders groceries based on its owner’s biochemical profile and glycemic levels. “I think there are a lot of just downstream effects of technology like this that enable real-time opinion, real-time coaching, real time advice, real-time warnings, real-time alarms that you could choose to ignore or heed,” he said.

The impact could be substantial. Healthcare costs in the United States now account for 18 percent of the country’s gross domestic product, with illnesses like diabetes major contributors. Technology that reduces expenditures by even one or two percentage points could lead to enormous savings. “What you could do for US education, or for infrastructure, is mind-boggling,” Hwang said.

Sometimes it really does seem like we are living in the future. Profusa’s technology has gone beyond science fiction to become science fact.