Indian scientist develops world’s first water-based computer

In a ground-breaking feat, world's first synchronous computer that operates on water droplets has been developed by an Indian-American researcher from Stanford University. Manu Prakash, assistant professor of bioengineering, and his students have built a unique computer that operates using the unique physics of moving water droplets.
The work combines Prakash's 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," said Prakash.

Because of its universal nature, the droplet computer can theoretically perform any operation that a conventional electronic computer can crunch, although at significantly slower rates. The ability to precisely control droplets using fluidic computation could have a number of applications in high-end biology and chemistry and scalable digital manufacturing.

Computer clocks are responsible for everything – smartphones, airplanes and internet. Developing a clock for a fluid-based computer required some creative thinking. Prakash realised that a rotating magnetic field that could act as clock to synchronise all the droplets might do the trick. The team built arrays of tiny iron bars on glass slides. They then 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 nano-particles. Next, they turned on the magnetic field. Every rotation of the field counted as one clock cycle and every drop marched exactly one step forward with each cycle. A camera recorded the interactions between individual droplets, allowing observation of computation as it occurs in real time.

According to Prakash, 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.

Prakash and his colleagues, however, have a more ambitious application in mind. Their goal is to build a completely new class of computers that can precisely control and manipulate physical matter.

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

The results were published in the journal Nature Physics.