Researchers, including one of Indian-origin, have developed a new way of making surfaces that can actively control how fluids or particles move across them.

The discovery may enable new varieties of biomedical, microfluidic devices or solar panels that can clean themselves, according to a report by MIT News.

“Most surfaces are passive,” said Kripa Varanasi, senior author of a paper describing the system in Applied Physics Letters. “They rely on gravity, or other forces, to move fluids or particles.”

The system uses a microtextured surface with bumps and ridges and a fluid that can be manipulated. When droplets of water or tiny particles touch the surface they are coated.

The system makes use of a microtextured surface, with bumps or ridges just a few micrometers across, that is then impregnated with a fluid that can be manipulated—for example, an oil infused with tiny magnetic particles, or ferrofluid, which can be pushed and pulled by applying a magnetic field to the surface. When droplets of water or tiny particles are placed on the surface, a thin coating of the fluid covers them, forming a magnetic cloak.

The thin magnetized cloak can then actually pull the droplet or particle along as the layer itself is drawn magnetically across the surface. Tiny ferromagnetic particles, approximately 10 nanometers in diameter, in the ferrofluid could allow precision control when it’s needed—such as in a microfluidic device used to test biological or chemical samples by mixing them with a variety of reagents. Unlike the fixed channels of conventional microfluidics, such surfaces could have “virtual” channels that could be reconfigured at will.

“This allows us to attain high velocities with small applied forces,” said Karim Khalil, the lead author.

The study, co-authored by Numan Abu-Dheir of the King Fahd University of Petroleum and Minerals (KFUPM) in Saudi Arabia, is published in the journal Applied Physics Letters.