Research: Little labs for quick reactions


Bau demonstrates a microfluidic minilab.

Photo by Daniel R. Burke

What if you could carry a complex scientific experiment right in the palm of your hands?

A recent $1.26 million grant from the Defense Advanced Research Projects Administration to Penn researchers can help make such portable laboratories a reality.

Professor of Mechanical Engineering and Applied Mechanics Haim H. Bau is leading Penn’s investigation of microfluidic systems.

Resembling circuit boards, these minute devices contain a network of conduits so tiny that they measure from about the thickness of a human hair to a millimeter. The goal is to push liquids from one part of the device to the other so that they undergo chemical or biological reactions—all without the aid of humans.

While Bau and his colleagues are focused on the design aspect of the research, he said the potential applications are manifold. For example, by placing a drop of blood into the device, physicians could potentially make the sample undergo a series of reactions, get results in a matter of minutes and consequently make fast decisions. “A practitioner can decide right away what course of action she or he should take in order to deal with whatever situation one encounters,” said Bau.

The military could also possibly make use of such a device. Meant to be portable and easily manufactured out of silicon, ceramics and/or plastics, the technology could act as a biodetector—a device that could warn the user when harmful biological agents are present. “I’m speculating but the military perhaps would be interested in each soldier or person in each platoon carrying a biodetector in their pocket,” said Bau.

But while these potential applications sound exciting, Bau stressed that the work being conducted now is still at its preliminary stages. “We [have] just a small piece of this very large pie,” he said.

Although he predicted uses in medicine, he cautioned, “We may be generating the necessary tools for this to happen, but we know very little about blood.” And he doesn’t want to mislead people into thinking that his work will solve the bioterrorism dilemma.

For now, he and Howard H. Hu, associate professor of mechanical engineering, are working on the mathematical modeling of microfluidic devices. To test their models, they are depending on Irwin M. Chaiken, research professor of medicine and rheumatology, to conduct experiments involving biological interactions.

And there are other areas which need further research. Bau is searching for an effective means to mix reagents. “Everything that happens here is at very slow flow,” he said. “One has to think of innovative ways to facilitate mixing.” Bau wants to shy away from mechanical means, such as valves, because of their tendency to break and fail. Using electrical and magnetic forces are current possibilities.

Sounds complicated? Not so, said Bau. He hopes to make microfluidic systems user-friendly. “The idea is that the layman should be able to use it,” he said. “Just as to use this PC you don’t need a computer scientist and you don’t need to have any specialized training. After 15 to 20 minutes of fooling around, you can start doing something.”

Originally published on November 29, 2001