KAIST

Professor Bongsoo Kim 

The newly developed nano-probe needle’s thickness estimates only at 0.1 micrometers with an increased 1,000-fold sensitivity and spatial resolution of 1mm.

Professor Bongsoo Kim and his research team from the Department of Chemistry, KASIT, including the first author, Dr. Mijeong Kang, succeeded in measuring nerve signals of a mouse using the world’s thinnest nano-probe needle made of single-crystal gold nanowires.

The newly developed nano-probe needle possesses the thickness of 100 nanometers (nm), which shows 1,000 times more sensitivity than the conventional nerve probe needles, as well as accurately measures nerve signals with an extremely fine resolution of less than 1mm. Unlike the existing probe needles that cause neural tissues to be damaged during insertion, the new nano-probe needle minimizes the damage and thus can detect large nerve signals. 

The brain neural probe, which collects and analyzes electrical nerve signals generated in the brain, is the most essential element in brain research. A neural probe should minimize tissue damages, but needs to possess a good electrical sensitivity. 

The researchers first applied heat on the gold, which is the necessary material for a probe, until it turned to a vapor phase. Then, the gold evaporation slug was transported to a colder board and left to form single-crystal gold nano structures by condensation. Because the new gold nanowire, produced by using this principle, is a flawless single crystal structure, it shows strong and flexible properties.

Professor Kim and his team applied the nano-probe needle into the brain of a mouse that has been administered a drug to induce epilepsy. They were able to find the exact area in the brain that triggers epilepsy. Furthermore, the researchers also detected neural signal changes in the brain of the mouse when it encountered the intrusion of a stranger mouse. 

Professor Bongsoo Kim commented the meaning of his research:

“The new nano-probe needle is able to detect signals from a single nerve cell with high sensitivity while preserving the nerve cells intact. The probe needle will be useful for creating a precise three-dimensional brain map, as well as providing electrical treatment for brain diseases such as dementia and Parkinson's disease.”

This research results were published online in the August 12, 2014 edition of ACS Nano.