Sensitive Electrochemical NO Sensors: Towards Measurement of Nitric Oxide on Primary Epithelial Cell Models

Nitric oxide is an important physiologic metabolite implicated in both health and disease states. Accurate determination of NO in tissues and cells is of paramount importance. The major challenges with NO measurement are its short half-life and often low nanomolar concentrations in tissues. Electrochemical tools provide a mean to accurately measure this analyte in confined environments using miniaturized probes. In the past, our lab explored electrodeposited alternate layers of ruthenium oxide nanoparticles and a conductive sulfur-containing polymer on carbon microelectrode fibers for catalytic determination of NO.

In this work, we explore the performance of combined reference/working electrodes modified with ruthenium oxide in the detection of nitric oxide with the goal to measure nitric oxide at the level of single or collective cultured cells. This is a preliminary work towards preparing a device capable to measure nitric oxide levels in a cystic fibrosis cell line model. It has been found that exhaled NO levels remains unchanged or reduced in cystic fibrosis patients unlike other inflammatory lung diseases like asthma where it increases. However it is not clear whether the lower NO levels in cystic fibrosis correlate with lowered production of this metabolite in the bronchial epithelium. It was shown that levels of nitrite and nitrate, the primary stable end products of NO metabolism increases in the breath condensate of patients with cystic fibrosis. We will present preliminary results of our ruthenium oxide modified combined electrodes and how they can be applied to the study of cystic fibrosis at the cellular level.