Galvanic Redox Potentiometry Based Microelectrode Array for Synchronous Ascorbate and Single-Unit Recordings in Rat Brain

Abstract

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.

Tailoring Oxygen-Containing Groups on Graphene for Ratiometric Electrochemical Measurements of Ascorbic Acid in Living Subacute Parkinson’s Disease Mouse Brains

“…Nevertheless, it is still a great challenge to exclude the complex interferents existing in the central nervous system (CNS), especially electrochemical active species . Pioneered by Mao’s group, single-walled carbon nanotubes (SWCNTs) with excellent electrochemical properties were fabricated onto CFE to facilitate AA oxidation, thus implementing real-time monitoring of AA levels in vivo with high sensitivity and selectivity. − However, the traditional electrochemical sensors with single-electric signal outputs suffered from interference from the environment and operating personnel. , Ratiometric electrochemical sensors with dual-electric signal outputs are promising due to their good self-calibration and the ability to overcome the environmental and personal factors and thus enhance the reproducibility greatly. , This is beneficial to the in vivo analysis regarding its distinctly different environment to in vitro detecting solution.…”

Electrochemical aptamer-based biosensors for <italic>in vivo</italic> analysis

“…例如, Mao 等 [25] 利用该方法在大 鼠大脑皮层, 实现了全脑缺血/再灌注过程中脑内抗 坏血酸(AA)的活体原位测定. 此外, 基于 GRP 原理 的电化学传感器可与电生理记录高度兼容 [26,27] , 从 而实现化学信号和电信号的同步记录. 通过合理设 计和调节碳纤维两端的电化学反应, 该类传感可用 于未来多种神经化学物质的活体在线监测.…”

Ag2S/Ag Nanoparticle Microelectrodes for In Vivo Potentiometric Measurement of Hydrogen Sulfide Dynamics in the Rat Brain

“…Electrochemistry using tissue-implantable microelectrodes is one of powerful techniques used to continuously monitor neurochemicals with high time resolution and high spatiotemporal resolution at the level of living animals, which is beneficial for tracking fast response, such as electrical and photostimulation. − To achieve the selectivity in the complexed biological atmosphere, some excellent strategies were developed for amperometric methods using special electrochemical techniques, selective transducers (i.e., enzyme, aptamer), or the modulation of the ion and electron transfer. − However, these strategies are not fit for monitoring hydrogen sulfide because they have no enzymes or aptamers to selectively recognize hydrogen sulfide and the electrochemical oxidation process of hydrogen sulfide is sluggish, which makes other electroactive species to interfere with the detection easily. Potentiometric method is another category to continuously monitor neurochemicals selectively using ion-selective membranes or galvanic redox potentiometric sensors. , Recently, Mao group demonstrate that potentiometric method is less affected by the macromolecular structure when implanting the microelectrodes into the brain and is also well compatible with electrophysiological recording because there are no current flow and voltage applied, which is a great advance in comparison with the amperometric method. − Although the sulfide-ion-selective electrode has been developed and applied in detection of sulfide in the environments, , the use of minimized and implantable solid-contact and ion-selective microelectrodes toward the detection of hydrogen sulfide is seldom studied and has not been applied in the in vivo tissue detection.…”