posted on 2020-07-10, 15:33authored byHuan Wei, Lijuan Li, Jing Jin, Fei Wu, Ping Yu, Furong Ma, Lanqun Mao
Neuronal
communication relies on cooperation between the chemical
and electrical patterns of neurons. Thus, techniques for illustrating
the linkage of the neurochemical events and action potentials with
high temporal and spatial resolution is imperative to gain a comprehensive
understanding of the intricacies of brain function. Herein, we integrate
galvanic redox potentiometry (GRP) and electrophysiological recording
onto a 16-site Au microelectrode array (MEA), one of which is for
indicating the ascorbate concentration while the others for single-unit
activity assessment. The electrochemical probing site was modified
with single-walled carbon nanotubes to promote electron-transfer kinetics
of ascorbate at low overpotential so as to enlarge the driving force
for the spontaneous ascorbate/O2 cell reaction. The resulting
GRP-based MEA outputs open-circuit potential that is in a linear relationship
with the logarithmic ascorbate concentration and exhibits high selectivity
against a set of coexisting electroactive species. Furthermore, no
reciprocal interference between the two recording systems is observed
during concurrent GRP sensing of ascorbate and single-unit recording
in a rat brain. In vivo feasibility of the GRP-based
MEA is demonstrated by synchronous real-time measurement of ascorbate
release and electrical activity from multiple neuronal populations
during spreading depression. Our GRP-based MEA sensor creates new
opportunities to realize high-throughput screening or mapping of neurochemical
patterns in a larger dimension and correlate them to neuron functions
across a spatial scale.