posted on 2019-02-24, 00:00authored byLinlin Lu, Xuefeng Fu, Yijuin Liew, Yongyi Zhang, Siyuan Zhao, Zheng Xu, Jingna Zhao, Da Li, Qingwen Li, Garrett B. Stanley, Xiaojie Duan
Soft
and magnetic resonance imaging (MRI) compatible neural electrodes
enable stable chronic electrophysiological measurements and anatomical
or functional MRI studies of the entire brain without electrode interference
with MRI images. These properties are important for many studies,
ranging from a fundamental neurophysiological study of functional
MRI signals to a chronic neuromodulatory effect investigation of therapeutic
deep brain stimulation. Here we develop soft and MRI compatible neural
electrodes using carbon nanotube (CNT) fibers with a diameter from
20 μm down to 5 μm. The CNT fiber electrodes demonstrate
excellent interfacial electrochemical properties and greatly reduced
MRI artifacts than PtIr electrodes under a 7.0 T MRI scanner. With
a shuttle-assisted implantation strategy, we show that the soft CNT
fiber electrodes can precisely target specific brain regions and record
high-quality single-unit neural signals. Significantly, they are capable
of continuously detecting and isolating single neuronal units from
rats for up to 4–5 months without electrode repositioning,
with greatly reduced brain inflammatory responses as compared to their
stiff metal counterparts. In addition, we show that due to their high
tensile strength, the CNT fiber electrodes can be retracted controllably
postinsertion, which provides an effective and convenient way to do
multidepth recording or potentially selecting cells with particular
response properties. The chronic recording stability and MRI compatibility,
together with their small size, provide the CNT fiber electrodes unique
research capabilities for both basic and applied neuroscience studies.