title: 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.
authors.affiliation: Department of Chemistry and Nano Science, Ewha Womans University , Seoul, 03760, Republic of Korea.
authors.forename: Jungmi
authors.initials: J
authors.lastname: Moon
authors.affiliation: Department of Chemistry and Nano Science, Ewha Womans University , Seoul, 03760, Republic of Korea.
authors.forename: Yejin
authors.initials: Y
authors.lastname: Ha
authors.affiliation: Department of Chemistry and Nano Science, Ewha Womans University , Seoul, 03760, Republic of Korea.
authors.forename: Misun
authors.initials: M
authors.lastname: Kim
authors.affiliation: Center for Neuroscience Imaging Research (CNIR), Institute for Basic Science (IBS) , Suwon, 16419, Republic of Korea.
authors.forename: Jeongeun
authors.initials: J
authors.lastname: Sim
authors.affiliation: Department of Chemistry and Nano Science, Ewha Womans University , Seoul, 03760, Republic of Korea.
authors.forename: Youngmi
authors.initials: Y
authors.lastname: Lee
authors.affiliation: Center for Neuroscience Imaging Research (CNIR), Institute for Basic Science (IBS) , Suwon, 16419, Republic of Korea.
authors.forename: Minah
authors.initials: M
authors.lastname: Suh
mesh_terms: D000818:Animals; D015374:Biosensing Techniques / Q000295:instrumentation; D055664:Electrochemical Techniques / Q000295:instrumentation*; D004566:Electrodes; D004827:Epilepsy / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D004867:Equipment Design; D008297:Male; D019579:Neocortex / Q000378:metabolism / Q000473:pathology* / Q000503:physiopathology; D009569:Nitric Oxide / Q000032:analysis / Q000378:metabolism*; D011188:Potassium / Q000032:analysis / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012640:Seizures / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology
chemical_list: D009569:Nitric Oxide; D011188:Potassium