New Computer Developed That Operates on Water Droplets

The computer is nearly a decade in the making, incubated from an idea that struck Manu Prakash, an assistant professor of bioengineering at Stanford University, when he was a graduate student.

The work combines his expertise in manipulating droplet fluid dynamics with a fundamental element of computer science - an operating clock.

"In this work, we finally demonstrate a synchronous, universal droplet logic and control," Prakash said.

The droplet computer can theoretically perform any operation that a conventional electronic computer can crunch, although at significantly slower rates.

"We already have digital computers to process information. Our goal is not to compete with electronic computers or to operate word processors on this," Prakash said.

"Our goal is to build a completely new class of computers that can precisely control and manipulate physical matter.

"Imagine if when you run a set of computations that not only information is processed but physical matter is algorithmically manipulated as well. We have just made this possible at the mesoscale," Prakash said.

Prakash wondered if he could use little droplets as bits of information and utilise the precise movement of those drops to process both information and physical materials simultaneously.

Prakash decided to build a rotating magnetic field that could act as clock to synchronise all the droplets.

Prakash and his team built arrays of tiny iron bars on glass slides that look something like a Pac-Man maze. They laid a blank glass slide on top and sandwiched a layer of oil in between.

Then they carefully injected into the mix individual water droplets that had been infused with tiny magnetic nanoparticles.

Next, they turned on the magnetic field. Every time the field flips, the polarity of the bars reverses, drawing the magnetised droplets in a new, predetermined direction.

A camera records the interactions between individual droplets, allowing observation of computation as it occurs in real time.

The presence or absence of a droplet represents the 1s and 0s of binary code, and the clock ensures that all the droplets move in perfect synchrony, and thus the system can run virtually forever without any errors.

Prakash said the most immediate application might involve turning the computer into a high-throughput chemistry and biology laboratory.

Instead of running reactions in bulk test tubes, each droplet can carry some chemicals and become its own test tube, and the droplet computer offers unprecedented control over these interactions.