A research team at the Department of Electrical and Electronic Information Engineering and the Electronics-Inspired Interdisciplinary Research Institute at Toyohashi University of Technology in Japan has developed 5μm diameter needle-electrodes on 1 mm × 1 mm block modules (Scienmag, 2016).

The neuron networks in the human brain are extremely complex. Microfabricated silicon needle-electrode devices are expected to be able to record and analyse the electrical activities of the microscale neuronal circuits in the brain. The individual microneedles are fabricated on block modules, which are small enough to use in the narrow spaces present in brain tissue, as demonstrated by a high quality recording using mouse cerebrum cortices. The block module improves the design variability in the packaging, offering numerous in vivo recording applications.

The first author, Assistant Professor Hirohito Sawahata, co-author, researcher Shota Yamagiwa, explained “We demonstrated the high design variability in the packaging of our electrode device, and in vivo neuronal recordings were performed by simply placing the device on a mouse’s brain. We were very surprised that high quality signals of a single unit were stably recorded over a long period using the 5-μm-diameter needle.”

The leader of the research team, Associate Professor Takeshi Kawano, said “Our silicon needle technology offers low invasive neuronal recordings and provides novel methodologies for electrophysiology; therefore, it has the potential to enhance experimental neuroscience. We expect the development of applications to solve the mysteries of the brain and the development of brain-machine interfaces.”

The research was supported by Grants-in-Aid for Scientific Research for Young Scientist, the PRESTO Program from JST, and Strategic Advancement of Multi-Purpose Ultra-Human Robot and Artificial Intelligence Technologies program from NEDO. Rika Numano was also supported by a Grant-in-Aid for Scientific Research, the Asahi Glass Foundation, and the Takeda Science Foundation.

Toyohashi University of Technology, founded in 1976 as a National University of Japan, is a leading research institute in the fields of mechanical engineering, advanced electronics, information sciences, life sciences and architecture.