Dual Electrochemical Microsensor for Real-Time Simultaneous Monitoring of Nitric Oxide and Potassium Ion Changes in a Rat Brain during Spontaneous Neocortical Epileptic Seizure

Abstract

In this work, we developed a dual amperometric/potentiometric microsensor for sensing nitric oxide (NO) and potassium ion (K(+)). The dual NO/K(+) sensor was prepared based on a dual recessed electrode possessing Pt (diameter, 50 μm) and Ag (diameter, 76.2 μm) microdisks. The Pt disk surface (WE1) was modified with electroplatinization and the following coating with fluorinated xerogel; and the Ag disk surface (WE2) was oxidized to AgCl on which K(+) ion selective membrane was loaded subsequent to the silanization. WE1 and WE2 of a dual microsensor were used for amperometric sensing of NO (106 ± 28 pA μM(-1), n = 10, at +0.85 V applied vs Ag/AgCl) and for potentiometric sensing of K(+) (51.6 ± 1.9 mV pK(-1), n = 10), respectively, with high sensitivity. In addition, the sensor showed good selectivity over common biological interferents, sufficiently fast response time and relevant stability (within 6 h in vivo experiment). The sensor had a small dimension (end plane diameter, 428 ± 97 μm, n = 20) and needle-like sharp geometry which allowed the sensor to be inserted in biological tissues. Taking advantage of this insertability, the sensor was applied for the simultaneous monitoring of NO and K(+) changes in a living rat brain cortex at a depth of 1.19 ± 0.039 mm and near the spontaneous epileptic seizure focus. The seizures were induced with 4-aminopyridine injection onto the rat brain cortex. NO and K(+) levels were dynamically changed in clear correlation with the electrophysiological recording of seizures. This indicates that the dual NO/K(+) sensor's measurements well reflect membrane potential changes of neurons and associated cellular components of neurovascular coupling. The newly developed NO/K(+) dual microsensor showed the feasibility of real-time fast monitoring of dynamic changes of closely linked NO and K(+) in vivo.

Iron Phthalocyanine Decorated Nitrogen-Doped Graphene Biosensing Platform for Real-Time Detection of Nitric Oxide Released from Living Cells

“…However, the N-G/FePc nanocomposites witnessed a redshift for the absorption band of phthalocyanine at 693 nm along with a decrease in absorption intensity. The large bathochromic shift of 34 nm in ground-state absorption is associated with conformational changes such as molecular flattening in the phthalocyanine upon π−π interaction with electrostatically charged surfaces of N-G. 15 The XRD patterns were employed to study the structure of N-G, FePc, and N-G/FePc. As shown in Figure 1D, the XRD pattern of the pristine N-G powder exhibits a characteristic strong diffraction peaks at 2θ = 23.68°(002) and a weak diffraction peak at 2θ = 43°(100).…”

An Electrochemophysiological Microarray for Real‐Time Monitoring and Quantification of Multiple Ions in the Brain of a Freely Moving Rat

“…other three ions determined by separate solution method, [10] were À3.0, À3.7, À4.2, À9.4, respectively (Figure S10, Supporting Information), lower than À2.0 required for biological determination. The results indicated no cross-talk between each ISME, hence allowing simultaneously sensing of K + , Na + , Ca 2+ , and pH using the developed 5-ISMEA.…”

The Important Role of Perituberal Tissue in Epileptic Patients with Tuberous Sclerosis Complex by the Transcriptome Analysis

“…Comparing with CT, 125 upregulated DEGs are found in PT and mainly enriched in the Biological Processes of cellular potassium ion transport and pattern specification process, which are involved in the structure development of neurons and cerebral cortex regionalization [ 18 , 19 ], as well as the occurrence of epilepsy [ 20 ]. Moreover, the 95 downregulated DEGs in PT are mainly enriched in the Biological Processes of positive regulation of receptor-mediated endocytosis and positive regulation of inflammatory response to antigenic stimulus, and also the Cellular Components of collagen-containing extracellular matrix and focal adhesion, which may indicate the decreased perisynaptic extracellular matrix and reduction of cellular hypersensitivity in PT [ 21 , 22 ], and is also consistent with the result that the expression of inflammation-related microRNAs was increased in CT comparing with PT [ 23 ].…”