Using injectable biosensors for a real-time readout of health status.

CEO: Ben Hwang
Based: South San Francisco
Founded: 2009

The scoop: Profusa is working to capture biochemical data—“the data that physicians use and care about,” says CEO Ben Hwang—through the use of injectable biosensors, so that people and their healthcare teams can monitor their health and make decisions in real time.

As Hwang puts it, Profusa’s goal is to take the user experience of currently available wearables, such as the Apple Watch or Fitbit, and use it to collect biochemical data, such as tissue oxygen levels or blood glucose levels.

What makes Profusa fierce: What the company is trying to do isn’t new, Hwang says, but a big hurdle for people working on implantable sensors is overcoming the body’s reaction to foreign objects.

“The human body so good at determining what belongs inside the body and what doesn’t belong inside the body,” he says. “If you get a little splinter, the body first elicits an immunological response—the body tries to chew up that element that you’ve put inside. If the body can’t chew it up, it wraps collagen and scar tissue around that element so that it cannot hurt you.”

An enveloped sensor can still take measurements, but it does so from inside the scar tissue, which can yield inaccurate results. One solution is to drug the body to minimize scarring, but Profusa’s approach is to use tiny sensors that can remain in the body for months or even years, with “little to no manual intervention.”

Its biosensor is a 5-mm-long, flexible hydrogel implant—described as similar to a contact lens—that is injected just under the skin. It forms a porous scaffold that causes capillaries to grow into it from the surrounding tissue.

RELATED: Profusa's injectable oxygen biosensor earns CE mark

In addition to the biosensor, Profusa’s Lumee system includes the sensor injector, a hand-held optical reader and instrument console, and a tablet with custom software. It is CE-marked to measure dissolved oxygen in tissues as part of a treatment for peripheral artery disease.

PAD is characterized by narrowed blood vessels that limit blood flow to the limbs, and tissue oxygen levels serve as a proxy measurement for perfusion, or the passage of blood through tissue. The optical reader, held against the skin above the implant, sends light to the biosensor, which emits fluorescent light to signal the concentration of oxygen molecules in the tissue.

The company is working alongside North Carolina State University's ASSIST Center to develop a wearable wireless oxygen monitor. The goal is to create a bandage-like reader to improve upon the “bulky cabled optical reader” currently used in the Lumee system.

Beyond oxygen, Profusa is working on sensors for a “robust pipeline of analytes.” First up is a glucose sensor, currently in human trials in Europe, with a planned regulatory submission toward the end of 2019. It also has a lactate sensor in preclinical studies that’s slated to enter human studies this year.

With the durability and relatively low cost of its sensor—“no more than a pair of tennis shoes,” Hwang says—Profusa hopes to close the “usability gap” for technology that provides continuous, real-time monitoring. He brought up continuous glucose monitors, which are at the forefront of diabetes technology but tend only to be prescribed to the sickest patients. And even then, those sensors must be replaced frequently, upping the cost of treatment.

“For the first time, … having a medical technology that gives you medical-grade, high-value information but be able to do so in a way that anybody can have access to it and anybody can benefit from it, could become reality,” he says.

So how does Profusa pick which diseases it wants to be in, or which data to collect with its sensors?

“We start all of our work … in a clinical, highly regulated setting and then allow the concentric circles to be drawn from an application perspective to get into the home, as opposed to going into the home first and then trying to get the data and trying to find clinical validation afterwards,” Hwang says.

The company starts by looking at “defined disease verticals,” which include PAD, chronic obstructive pulmonary disorder and diabetes management.

“For us, it’s very important to not take it from a consumer perspective first; we’ve got to take it from a clinical, physician first and validate our technology through these verticals,” Hwang says. Otherwise, nobody would trust the data that comes out of its technology, he adds.

And although Profusa is currently looking at individual analytes, the company hopes that once it’s proven it can “create profound change” in areas like COPD and diabetes, it will be able to combine the measurement of, say, oxygen, glucose and lactate in a way that “empowers” patients to make their own health decisions.

In addition to the technology gap and the usability gap, Profusa has also closed the funding gap, Hwang says. Founded in 2009, amid the global financial crisis, the company had trouble securing investments to get off the ground.

RELATED: Profusa awarded $7.5M DARPA grant to work on implantable biosensors

“Our approach has been, how do we go out and get funding and support for the company without having to tap into the private investor model so we can get to work without waiting for the economy to turn around? And what served us well was getting into the government funding sources,” Hwang says. These include the National Institutes of Health and the Department of Defense.

Don’t get him wrong though—Profusa has been backed by both private investors as well as public sources. It raised $45 million in series C financing in August, which followed a $13.2 million series B back in 2015.