Cornell Researchers Build Programmable Chip Powered by Ultrasound Microbubbles

Researchers at Cornell University have engineered a 3-millimeter chip platform that generates and directs microscopic gas bubbles on demand, creating a programmable method for steering fluid flow in microscale systems. As reported by TechXplore (https://techxplore.com/news/2026-10-tiny-chip-ultrasound-powered-microbubbles.html), the system bypasses conventional microfluidic designs that depend on catching pre-existing bubbles, which are often unpredictable and difficult to trap consistently.

In a study published in Science Advances, co-corresponding authors Itai Cohen and Zhiyuan Zhang detailed how the device produces hydrogen gas bubbles on an electrode array and powers them using acoustic energy. Fabricated at the Cornell NanoScale Science and Technology Facility, the test setup features nine electrodes arranged in a square. Each six-micron-wide electrode generates a hydrogen bubble ranging from 10 to 100 microns by breaking down water molecules through electrolysis, with the duration of the electrical voltage dictating bubble diameter.

Once formed, the bubbles are excited by ultrasound. Because a bubble's physical size sets its natural resonant frequency, matching the acoustic frequency—such as 40 kilohertz—causes the bubble to oscillate vigorously against the surrounding liquid. This oscillation transfers mechanical energy into the fluid, generating localized currents.

The platform allows researchers to reprogram fluid paths in real time by altering bubble size, count, and arrangement. Paired bubbles of identical volume oscillate symmetrically, whereas pairing different sizes unbalances the acoustic force and pushes fluid in a specific direction. Testing showed that rows of three bubbles create directional lines, five bubbles in an L-shape steer flow around curves, and elevated voltage creates rapid bubble clusters that can be propelled directionally.

The system also addresses device failure through built-in regeneration: if a bubble malfunctions or deviates from target resonance, the electrode simply inflates it until it detaches and floats away, clearing the surface to generate a replacement. The team, which includes electrical engineering professor Alyosha Molnar and postdoctoral researcher Jinsong Zhang, plans to explore integrating these bubble-generating circuits directly into microscopic robotic architectures and targeted medical delivery platforms.