A Novel Ruthenium-based Molecular Sensor to Detect Endothelial Nitric Oxide

Achini K. Vidanapathirana, Benjamin J. Pullen, Run Zhang, My Ngan Duong, Jarrad M. Goyne, Xiaozhou Zhang, Claudine S. Bonder, Andrew D. Abell, Christina A. Bursill, Stephen J. Nicholls, Peter J. Psaltis

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Abstract

Nitric oxide (NO) is a key regulator of endothelial cell and vascular function. The direct measurement of NO is challenging due to its short half-life, and as such surrogate measurements are typically used to approximate its relative concentrations. Here we demonstrate that ruthenium-based [Ru(bpy) 2 (dabpy)] 2+ is a potent sensor for NO in its irreversible, NO-bound active form, [Ru(bpy) 2 (T-bpy)] 2+ . Using spectrophotometry we established the sensor’s ability to detect and measure soluble NO in a concentration-dependent manner in cell-free media. Endothelial cells cultured with acetylcholine or hydrogen peroxide to induce endogenous NO production showed modest increases of 7.3 ± 7.1% and 36.3 ± 25.0% respectively in fluorescence signal from baseline state, while addition of exogenous NO increased their fluorescence by 5.2-fold. The changes in fluorescence signal were proportionate and comparable against conventional NO assays. Rabbit blood samples immediately exposed to [Ru(bpy) 2 (dabpy)] 2+ displayed 8-fold higher mean fluorescence, relative to blood without sensor. Approximately 14% of the observed signal was NO/NO adduct-specific. Optimal readings were obtained when sensor was added to freshly collected blood, remaining stable during subsequent freeze-thaw cycles. Clinical studies are now required to test the utility of [Ru(bpy) 2 (dabpy)] 2+ as a sensor to detect changes in NO from human blood samples in cardiovascular health and disease.

Original languageEnglish
Article number1720
Number of pages16
JournalScientific Reports
Volume9
Issue number1
DOIs
Publication statusPublished - 1 Dec 2019

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