Professor Takeshi Kawano and his research group have advanced their work on “5-µm-diameter silicon microneedle electrodes” and developed a minimally invasive neural electrode device by introducing a flexible substrate (Fig. 1). This approach further reduces damage to brain tissue and enables stable neural recordings from the mouse brain for over 1 year. The group also confirmed that neuronal death is significantly reduced compared with conventional electrodes. In addition, corroborating with Professor Masahiro Ohsawa at Teikyo University, they successfully developed “parylene microneedle electrode”, in which the needle portion is made flexible, demonstrating even more minimally invasive and recovery of neural signal quality during electrode implantation (Fig. 2).
These technologies preserve native tissue and neuronal networks and provide a promising platform for future neural interface applications.

 

Bibliographic Information
[1] Hinata Sasaki, Koji Yamashita, Sayaki Shimizu, Kensei Sakamoto, Rika Numano, Kowa Koida, Takeshi Kawano, “A flexible‐substrate 5‐µm‐diameter needle electrode: minimizing neuronal death and enabling year‐long neural recording”, Advanced Materials Interfaces, Volume 12, Issue 11, 2400974, June 9, 2025.
DOI: https://doi.org/10.1002/admi.202400974
[2] Hinata Sasaki, Sayaki Shimizu, Rexy Alvian Nerchan, Koji Yamashita, Naohiro Takahashi, Rina Chinone, Yurika Kurashige, Rika Numano, Kowa Koida, Masahiro Ohsawa, Takeshi Kawano, “A self-insertable 5-µm-diameter flexible microneedle for minimally invasive and stable in vivo neural recording”, Sensing and Bio-Sensing Research, Volume 50, 100915, December, 2025.
DOI: https://doi.org/10.1016/j.sbsr.2025.100915

 

 
Fig. 1 A 5-µm-diameter silicon microneedle electrode device. The microneedle electrode integrated on a flexible substrate minimize damage to brain tissue and enable long-term neural recording exceeding one year.

 

Fig. 2 A fully parylene microneedle electrode device. By removing the silicon core inside the microneedle, a flexible parylene microneedle electrode device was developed. Compared with the silicon-based microneedle electrode (Fig. 1), this parylene device enables further reduced invasiveness and more stable in vivo neural recording.