In Vitro Monitoring of Nitric Oxide Release in the Mouse Colon Using a Boron-Doped Diamond Microelectrode Modified with Platinum Nanoparticles and Nafion

Abstract

This research reports on the preparation of a boron-doped diamond microelectrode modified with platinum nanoparticles and Nafion and its application for detecting nitric oxide (NO) in vitro in the mouse colon. Platinum nanoparticle deposition was performed potentiodynamically using a 2.0 mmol L −1 potassium hexachloroplatinate solution and cycling from −0.2 to 1.3 V vs Ag/AgCl at 0.01 V s −1 for 10 cycles. The Nafion overlayer was applied by immersion in a solution containing 2.5% (w/v) colloidal Nafion and drying overnight at 55 °C in a humid environment. The optimal microelectrode preparation conditions were chosen based on the electrode response for NO oxidation as well as rejection of nitrite (NO 2 − ) oxidation, the main interferent in the electrochemical detection of NO in biological media. Detection figures of merit include a sensitivity of 16.7 ± 2.7 mA M −1 cm −2 (n = 3 electrodes), a detection limit of 0.5 μmol L −1 (S/N = 3), and an electrode response reproducibility of 2.5% (RSD). Electrical stimulation and continuous amperometry were used to measure NO release from myenteric ganglia in wild-type male and female mice in response to an increasing number of electrical stimuli to study nitrergic signaling in the colon. We also present preliminary data regarding the use of optogenetics to selectively stimulate nitrergic myenteric neurons using blue light stimulation with a goal of understanding how inhibitory neuromuscular signaling is involved in the myenteric plexus circuitry that controls intestinal motility.

Ex Vivo Electrochemical Monitoring of Cholinergic Signaling in the Mouse Colon Using an Enzyme-Based Biosensor

“…This tactic was previously used to enhance the sensitivity and stability of ATP biosensors 52 and to platinize boron-doped diamond microelectrodes. 38 These electrodeposition conditions produce a dispersed coverage of Pt nanoparticles across the substrate with a range of diameters. This is characteristic of a progressive nucleation and growth process in which new nuclei continuously form while existing Pt nanoparticles grow out of those nucleation sites.…”

“…To increase the electrochemically active area of the electrode and improve adhesion of the multienzyme film, ,− the Pt microelectrodes were potential cycled in a solution containing 2 mmol L –1 K 2 PtCl 6 in 0.5 mol L –1 H 2 SO 4 from −0.2 to 1.2 V at 10 mV s –1 for 10 cycles with an initial potential of 1.0 V scanning cathodically to reduce Pt­(IV) and initiate nanoparticle nucleation. This tactic was previously used to enhance the sensitivity and stability of ATP biosensors and to platinize boron-doped diamond microelectrodes . These electrodeposition conditions produce a dispersed coverage of Pt nanoparticles across the substrate with a range of diameters.…”

“…In this paper, we report on the use of an electrochemical biosensor and continuous amperometry (CA) to study the real-time release of ACh from myenteric ganglia in the mouse colon. We have previously developed a modified boron-doped diamond microelectrode to electrochemically monitor nitric oxide release from the mouse colon . For this work, we prepared enzyme-based ACh/Ch biosensors based on the literature to measure cholinergic signaling from the mouse colon in male and female wild type mice.…”

“…We have previously developed a modified boron-doped diamond microelectrode to electrochemically monitor nitric oxide release from the mouse colon. 38 For this work, we prepared enzyme-based ACh/Ch biosensors based on the literature 24 to measure cholinergic signaling from the mouse colon in male and female wild type mice. This work is foundational for the planned use of the biosensor to study cholinergic signaling in mouse models of AD.…”

Research and Application Progress of Boron-doped Diamond Films

“…For example, Henderson Skye et al [20] investigated the preparation of nanoparticles and Nafionmodified boron-doped gold BDD microelectrodes and their application in the in vitro detection of nitric oxide ( NO ) in mouse colon; Boonkaew Suchanat et al [21] proposed boron/nitrogen co-doped diamond-graphene nanowall-structured ( DGNW ) integrated with screen-printed graphene electrode ( SPGE ) for the detection of serotonin ( 5-HT ) as a model system and applied the method to synthetic urine samples, the results showed that the DGNW modified electrode has good anti-pollution properties and biocompatibility; while Dushna Olha et al [22] firstly combined a working boron-doped diamond electrode ( BDDE ) with a novel screen-printed sensor to form a planar electro chemical cell consisting of a working boron-doped diamond electrode ( BDDE ) and a novel screen-printed sensor was first used for voltammetric determination of the alkaloid atropine (ATR).…”