Insertable Fast-Response Amperometric NO/CO Dual Microsensor: Study of Neurovascular Coupling During Acutely Induced Seizures of Rat Brain Cortex

Abstract

This paper reports the fabrication of an insertable amperometric dual microsensor and its application for the simultaneous and fast sensing of NO and CO during acutely induced seizures of living rat brain cortex. NO and CO are important signaling mediators, controlling cerebrovascular tone. The dual NO/CO sensor is prepared based on a dual microelectrode having Au-deposited Pt microdisk (WE1, 76 μm diameter) and Pt black-deposited Pt disk (WE2, 50 μm diameter). The different deposited metals for WE1 and WE2 allow the selective anodic detection of CO at WE1 (+0.2 V vs Ag/AgCl) and that of NO at WE2 (+0.75 V vs Ag/AgCl) with sufficient sensitivity. Fluorinated xerogel coating on this dual electrode provides exclusive selectivity over common biological interferents, along with fast response time. The miniaturized size (end plane diameter < 300 μm) and tapered needle-like sensor geometry make the sensor become insertable into biological tissues. The sensor is applied to simultaneously monitor dynamic changes of NO and CO levels in a living rat brain under acute seizure condition induced by 4-aminopyridine in cortical tissue near the area of seizure induction. In-tissue measurement shows clearly defined patterns of NO/CO changes, directly correlated with observed LFP signal. Current study verifies the feasibility of a newly developed NO/CO dual sensor for real-time fast monitoring of intimately connected NO and CO dynamics.

Injectable Biomedical Devices for Sensing and Stimulating Internal Body Organs

“…Its capabilities to reach neurons that are 1.5 mm beneath the cerebral cortex and record or stimulate 100 different deep brain sites were ground breaking toward brain science. Other forms of large array probes consisted of microwires39 or metalized microdisks 130. However, long‐term implantation suffered from astroglial response and fibrous encapsulation of the probes, leading to limitations in chronic applications, such as the impedance rise of microelectrodes 113,114,131.…”

Amperometric Microsensors Monitoring Glutamate-Evoked In Situ Responses of Nitric Oxide and Carbon Monoxide from Live Human Neuroblastoma Cells

“…Contrastively, only a few studies have been reported for electrochemical CO sensors aiming at biological applications due to selectivity problems [ 26 , 27 ]. Our group has developed NO/CO dual sensors for simultaneous NO and CO detections, and applied to in vivo and in vitro studies on rat kidneys and rat brains [ 28 , 29 , 30 ].…”

“…In this work, high performance NO/CO dual [ 30 ] and new septuple microsensors were used for monitoring real-time NO and CO changes during glutamate-evoked neuronal activation in vitro. NO and CO were measured in a monolayer of a differentiated SH-SY5Y, which is a widely used dopaminergic neuronal cell type for in vitro model [ 31 ].…”

Electrochemical Impedance Spectroscopy at Well‐Controlled dc Bias for Nanoporous Platinum Microelectrodes in Rat Embryo Brain

“…Anumber of microelectrodes have been introduced for in vitro or in vivo applications [6][7][8][9][10][11][12][13] since electric signals from cultured cells were recorded by means of the microelectrode array 40 years ago. [14,15] Thes urface areas of microelectrodes are typically less than 0.01 mm 2 because as mall electrode area is advantageous for stimulatingt he specific tissue near which it is implanted, and also for recording neural signals with high spatialresolution.…”