Imaging the stability of chronic electrical microstimulation using electrodes coated with PEDOT/CNT and iridium oxide

Xin Sally Zheng; Qianru Yang; Alberto Vazquez; Xinyan Tracy Cui

doi:10.1016/j.isci.2022.104539

Imaging the stability of chronic electrical microstimulation using electrodes coated with PEDOT/CNT and iridium oxide

iScience. 2022 Jun 6;25(7):104539. doi: 10.1016/j.isci.2022.104539. eCollection 2022 Jul 15.

Authors

Xin Sally Zheng¹, Qianru Yang^{1

2}, Alberto Vazquez^{1

2

3

4}, Xinyan Tracy Cui^{1

2

4}

Affiliations

¹ Department of Bioengineering, University of Pittsburgh, 5057 Biomedical Science Tower 3, 3501 Fifth Avenue, Pittsburgh, PA 15260, USA.
² Center for Neural Basis of Cognition, 115 Mellon Institute, 4400 Fifth Avenue, Pittsburgh, PA 15213, USA.
³ Department of Radiology, University of Pittsburgh, 200 Lothrop St, Pittsburgh, PA 15213, USA.
⁴ McGowan Institute for Regenerative Medicine, 3025 East Carson Street, Pittsburgh, PA 15219, USA.

Abstract

Chronic microstimulation is faced with challenges that require an additional understanding of stability and safety. We implanted silicon arrays coated with poly(3,4-ethylenedioxythiophene) (PEDOT)/Carbon Nanotubes (CNT), or PCand IrOx into the cortex of GCaMP6s mice and electrically stimulated them for up to 12 weeks. We quantified neuronal responses to stimulation using two-photon imaging and mesoscale fluorescence microscopy and characterized electrode performance over time. We observed dynamic changes in stimulation stability over time and a significant advantage in energy efficiency using PC coated electrodes over IrOx coated electrodes. In a subset of mice, we observed abnormal ictal cortical responses or cortical spreading depression using stimulation parameters commonly used in intracortical stimulation applications, suggesting the need to investigate the potential neuronal damage and redefine the stimulation safety limit. This study not only revealed the dynamic changes in stimulation efficiency after implantation but also reiterates the potential for PC as a high-efficiency material in chronic neuromodulation.

Keywords: Bioelectronics; Biomedical materials; Techniques in neuroscience.

Abstract

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