Engineers create the world’s tiniest EEG electrode cap

Organoids in a Petri dish

Johns Hopkins University scientists have developed small EEG caps for brain organoids. The group took its cues from human patients' full-size EEG helmets, which are used to measure brain activity. When attaching a flat surface to a spherical organoid, only a small number of cells make full contact, forcing the Hopkins researchers to use flat electrode arrays that were initially intended to record from cell monolayers.


The most recent innovation is a tiny wrap-around EEG headgear for organoids that has polymer-coated electrodes built into leaflets of self-folding polymer. Better data and more insights from brain organoids should result from the gadget.

Organoids have been around for more than 10 years and have a huge potential to shed fresh light on human disease and lead to the development of novel treatments. As long as they are created using human cells, they also provide significant advantages in lowering the number of experimental animals employed in research facilities while producing more data that is specific to humans.

Since the development of organoids more than ten years ago, scientists have altered stem cells to produce miniature kidneys, lungs, livers, and brains. The intricate, small models are utilized to research the development of the organs. Organoids that have been genetically altered, virally injected, or exposed to chemicals are studied alongside organoids that have not undergone these changes.

Because organoids, especially tiny brains, may be employed in investigations that would otherwise need testing on humans or animals, they are becoming more and more significant in medical research.

However, because of their small size and three-dimensional nature, the microscopic structures are sometimes difficult to interact with and evaluate using standard cell culture tools. The majority of cell culture occurs in two dimensions with flat cell monolayers, which can behave very differently from organoids and have very different practical needs for conducting research.


Brain organoids, also sometimes called “mini-brains”, are particularly exciting, as they can offer insights into the human brain. This provides an important tool to understand the development and workings of the human brain, said David Gracias, a researcher involved in the study. Creating micro-instrumentation for mini-organs is a challenge, but this invention is fundamental to new research.

The Hopkins team behind this latest technology wanted to obtain more meaningful and accurate measurements from their brain organoids, and the poorly specific design of flat EEG equipment served as their motivation. A flat surface will only contact a small number of cells on the organoid surface. We want to get information from as many cells as possible in the brain, so we know the state of the cells, how they communicate and their spatiotemporal electrical patterns, said Gracias.

The result is a wrap-around EEG cap for individual brain organoids that allows 3D recording of many neurons within the organoid. If you record from a flat plane, you only get recordings from the bottom of a 3D organoid sphere. However, the organoid is not just a homogeneous sphere, said Qi Huang, another researcher involved in the study. There are neuron cells that communicate with each other that's why we need a spatial-temporal mapping of it.


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About the Author: John Carter

John Carter has been a content and 'ghostwriter' for many popular online publications over the years. John is now our chief editor at NewsGrab.
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