From Lab-on-a-Chip to Lab-in-the-Body: The Role of Nanotechnology in the Miniaturization of Medical Diagnostic Tools

Fictional inventor Wayne Szalinsky built a shrink ray while wearing a Caltech hoodie in the film Honey, I Shrunk the Kids. And a shrunken sub and its five-person crew cleared a blood clot deep inside someone's brain in Fantastic Voyage. Now Axel Scherer, Caltech's Bernard Neches Professor of Electrical Engineering, Applied Physics and Physics, is miniaturizing medical equipment without benefit of a shrink ray. He'll tell us how to make a sensor small enough to be injected into an artery at 8 p.m. on Wednesday, November 6, in Caltech's Beckman Auditorium. Admission is free.

Q: What do you do?

A: There's a fantastic scene in Star Trek: The Next Generation where a silicon-based life form calls Captain Picard "you ugly bag of mostly water," which is a really bad insult. But it's true—we are bags of skin containing mostly water, and if we know what's in the water, we can tell whether we're going to be sick. Most health care today is after the fact, which is very inefficient. Your body reacts to some problem—you run a fever or feel dizzy, or whatever—and if it doesn't go away, you go to the emergency room, and someone tries to figure out what's happened. 

So, our goal is to build tiny chemical laboratories that will function inside the body and allow you to know there's a problem before you get symptoms, and you can seek treatment before the damage is done. For example, we work with Eric Topol, a cardiologist at the Scripps Research Institute, who has developed a test that will give you two or three days' warning that you're going to suffer a heart attack. 

Building something small enough to inject is the easy part. In order to sample the water in your bag, we have to evade your natural defenses. The human body assumes that anything it can't recognize must be bad, so it seals that thing off to protect you. That's how we deal with splinters, for example. And the blood stream has all sorts of cells whose entire function is to isolate and destroy foreign objects, so anything we want to introduce into the body we have to somehow camouflage or else build it small enough that it can't be recognized by the immune system.  

Q: Why are you doing this? 

A: The world needs cheap, readily available health care. Traditionally, every new medical technology increases the cost of care, so the PCR thermal cycling apparatus that Eric would use for molecular diagnostics in a hospital setting and my DVD player are both rather complicated, but I can get a DVD player for $49.95, and medical instruments are $49,000. We need to figure out how to make them inexpensively the same way we do for consumer electronics. This is something I think can be done as a cottage industry in a university environment. A few people working together can build a device, and if it works for a single person, or maybe a couple of hundred, then you just feed it into the manufacturing system. I see the implantable devices we want to build as a step along a continuum of more and more capable point-of-care instruments that will ultimately move the point of care out of the hospital to wherever the patient is. 

Q: How did you get into this line of work? 

A: I came to Caltech from Bell Labs in 1993, and since then, my lab has miniaturized things like communications systems, optical spectroscopic systems, and microfluidic systems. And then one day I asked myself, "What do I really want to do with my miniaturization capabilities?" Also, this academic year Caltech has started a new option in medical engineering. The idea is to harness our engineering capabilities by starting with a medical problem, or set of problems, and working backward to design fundamentally new solutions rather than trying to adapt things that were designed for other purposes. The Institute is saying, "This is something society needs, and we're going to educate the people who will be doing this for the next 30 or 40 years." It's a fantastic opportunity to be relevant in health care without opening a medical school. 

Named for the late Caltech professor Earnest C. Watson, who founded the series in 1922, the Watson Lectures present Caltech and JPL researchers describing their work to the public. Many past Watson Lectures are available online at Caltech's iTunes U site.