Researchers at Northwestern University and Shirley Ryan AbilityLab have built a soft electronic device that wraps around lab-grown human neural organoids and records electrical signals from 91 percent of their surface, a breakthrough that overcomes a major limitation in studying brain-like tissues.
The flexible mesh contains up to 240 individually addressable microelectrodes, each measuring 10 microns in diameter, roughly the size of a single cell. The porous structure allows oxygen and nutrients to flow through while maintaining stable electrical contact, enabling scientists to observe synchronized neural activity across entire organoid networks for the first time.
Neural organoids are three-dimensional structures grown from human stem cells that develop interconnected neural circuits and produce coordinated electrical rhythms. They have become central to research on brain development, neurological disease and drug testing. But existing recording tools are flat and rigid, limiting researchers to sampling signals from only a handful of locations and missing large-scale communication patterns between neurons.
“Human stem cell-derived organoids have become a major focus of biomedical research because they enable patient-specific studies of how tissues respond to drugs and emerging therapies,” said John A. Rogers, who led the device development. “A key missing component is hardware technology that can interrogate, stimulate and manipulate these tiny analogs to organs in the human body.”
The new system transforms from a flat elastic lattice into a three-dimensional framework through controlled mechanical buckling, similar to how a pop-up book folds into shape. This allows the electronics to conform to the spherical organoid without damaging it. John Rogers, who led the device development, said the design must support tissue metabolism without constraining it.
When the Northwestern team tested systems with only eight or 32 electrodes, recordings captured limited, localized signals. With the full 240 channel array, researchers observed synchronized oscillatory waves spanning the entire organoid. Because each electrode’s position is mapped in three dimensions, the system generates detailed activity maps showing how signals spark in one region and ripple across the network.
The platform detected clear changes in neural activity during drug tests. Exposure to 4-aminopyridine, a medication used to improve walking in people with multiple sclerosis, increased neural signaling. Botulinum toxin disrupted coordinated firing patterns. These responses demonstrate that the system can identify meaningful alterations in living neural networks.
“Human neural organoids are living 3D tissues that contain active neural circuits communicating through electrical signals,” said Dr. Colin Franz, who led the organoid development at Shirley Ryan AbilityLab. “By creating soft, shape-matched electronics that conform to the organoid’s geometry, we can now record from and stimulate hundreds of locations across its surface at once. This allows us to study neural activity at the level of whole networks rather than isolated signals.”
The researchers also showed that altering the mesh design can control how organoids grow, producing non-spherical geometries including cubes and hexagons. That capability could enable modular assembly of different tissue types for multi-organ research platforms.
The study, published February 18 in Nature Biomedical Engineering, was conducted by Rogers and Franz with collaborators Yihui Zhang of Tsinghua University in China and John Finan of the University of Illinois Chicago.