A flexible neural implant with ultrathin substrate for low-invasive brain-computer interface applications

Zhejun Guo; Fang Wang; Longchun Wang; Kejun Tu; Chunpeng Jiang; Ye Xi; Wen Hong; Qingda Xu; Xiaolin Wang; Bin Yang; Bomin Sun; Zude Lin; Jingquan Liu

doi:10.1038/s41378-022-00464-1

A flexible neural implant with ultrathin substrate for low-invasive brain-computer interface applications

Microsyst Nanoeng. 2022 Dec 25:8:133. doi: 10.1038/s41378-022-00464-1. eCollection 2022.

Authors

Zhejun Guo^{1

2}, Fang Wang³, Longchun Wang^{1

2}, Kejun Tu^{1

2}, Chunpeng Jiang^{1

2}, Ye Xi^{1

2}, Wen Hong^{1

2}, Qingda Xu^{1

2}, Xiaolin Wang¹, Bin Yang¹, Bomin Sun³, Zude Lin¹, Jingquan Liu¹

Affiliations

¹ National Key Laboratory of Science and Technology on Micro/Nano Fabrication, Shanghai Jiao Tong University, 200240 Shanghai, China.
² Department of Micro/Nano Electronics, Shanghai Jiao Tong University, 200240 Shanghai, China.
³ Department of Neurosurgery, Center for Functional Neurosurgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 200025 Shanghai, China.

Abstract

Implantable brain-computer interface (BCI) devices are an effective tool to decipher fundamental brain mechanisms and treat neural diseases. However, traditional neural implants with rigid or bulky cross-sections cause trauma and decrease the quality of the neuronal signal. Here, we propose a MEMS-fabricated flexible interface device for BCI applications. The microdevice with a thin film substrate can be readily reduced to submicron scale for low-invasive implantation. An elaborate silicon shuttle with an improved structure is designed to reliably implant the flexible device into brain tissue. The flexible substrate is temporarily bonded to the silicon shuttle by polyethylene glycol. On the flexible substrate, eight electrodes with different diameters are distributed evenly for local field potential and neural spike recording, both of which are modified by Pt-black to enhance the charge storage capacity and reduce the impedance. The mechanical and electrochemical characteristics of this interface were investigated in vitro. In vivo, the small cross-section of the device promises reduced trauma, and the neuronal signals can still be recorded one month after implantation, demonstrating the promise of this kind of flexible BCI device as a low-invasive tool for brain-computer communication.

Keywords: Nanobiotechnology; Sensors.