Ultraflexible PEDOT:PSS/IrOx-Modified Electrodes: Applications in Behavioral Modulation and Neural Signal Recording in Mice

Xueying Wang; Wanqi Jiang; Huiran Yang; Yifei Ye; Zhitao Zhou; Liuyang Sun; Yanyan Nie; Tiger H Tao; Xiaoling Wei

doi:10.3390/mi15040447

Ultraflexible PEDOT:PSS/IrO_x-Modified Electrodes: Applications in Behavioral Modulation and Neural Signal Recording in Mice

Micromachines (Basel). 2024 Mar 27;15(4):447. doi: 10.3390/mi15040447.

Authors

Xueying Wang^{1

2}, Wanqi Jiang^{1

2}, Huiran Yang¹, Yifei Ye^{1

3}, Zhitao Zhou^{1

2}, Liuyang Sun^{1

2

3}, Yanyan Nie⁴, Tiger H Tao^{1

2

3

5

6

7

8

9

10}, Xiaoling Wei^{1

2}

Affiliations

¹ State Key Laboratory of Transducer Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China.
² School of Graduate Study, University of Chinese Academy of Sciences, Beijing 100049, China.
³ 2020 X-Lab, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China.
⁴ Shanghai Laboratory Animal Research Center, Shanghai 201203, China.
⁵ School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China.
⁶ Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China.
⁷ Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China.
⁸ Neuroxess Co., Ltd. (Jiangxi), Nanchang 330029, China.
⁹ Guangdong Institute of Intelligence Science and Technology, Hengqin, Zhuhai 519031, China.
¹⁰ Tianqiao and Chrissy Chen Institute for Translational Research, Shanghai 200040, China.

Abstract

Recent advancements in neural probe technology have become pivotal in both neuroscience research and the clinical management of neurological disorders. State-of-the-art developments have led to the advent of multichannel, high-density bidirectional neural interfaces that are adept at both recording and modulating neuronal activity within the central nervous system. Despite this progress, extant bidirectional probes designed for simultaneous recording and stimulation are beset with limitations, including elicitation of inflammatory responses and insufficient charge injection capacity. In this paper, we delineate the design and application of an innovative ultraflexible bidirectional neural probe engineered from polyimide. This probe is distinguished by its ability to facilitate high-resolution recordings and precise stimulation control in deep brain regions. Electrodes enhanced with a PEDOT:PSS/IrO_x composite exhibit a substantial increase in charge storage capacity, escalating from 0.14 ± 0.01 mC/cm² to an impressive 24.75 ± 0.18 mC/cm². This augmentation significantly bolsters the electrodes' charge transfer efficacy. In tandem, we observed a notable reduction in electrode impedance, from 3.47 ± 1.77 MΩ to a mere 41.88 ± 4.04 kΩ, while the phase angle exhibited a positive shift from -72.61 ± 1.84° to -34.17 ± 0.42°. To substantiate the electrodes' functional prowess, we conducted in vivo experiments, where the probes were surgically implanted into the bilateral motor cortex of mice. These experiments involved the synchronous recording and meticulous analysis of neural signal fluctuations during stimulation and an assessment of the probes' proficiency in modulating directional turning behaviors in the subjects. The empirical evidence corroborates that targeted stimulation within the bilateral motor cortex of mice can modulate the intensity of neural signals in the stimulated locale, enabling the directional control of the mice's turning behavior to the contralateral side of the stimulation site.

Keywords: PEDOT:PSS/IrOx modification; behavior modulation; bilateral BCI; intracortical; ultraflexible probe.

Abstract

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