A-082 Measuring Peroxynitrite as an Early Biomarker for Cystic Fibrosis Using Organoselenide-Modified Glassy Carbon Electrode
Authors: Ibrahim M , Kalil H , Bayachou M 
Published: September 2023

Abstract

Background
Cystic fibrosis (CF) is a genetic disease that affects the respiratory, digestive, and reproductive systems. One of the issues associated with CF is oxidative stress, which is an imbalance between the production of reactive oxygen species (ROS) and the ability of the body to neutralize them. Peroxynitrite, a member of ROS, is a very noxious molecule formed from the reaction of nitric oxide (NO) and superoxide and can damage cellular components such as proteins, lipids, and DNA. Studies have shown that peroxynitrite levels are elevated in people with CF and that this increased oxidative stress can contribute to the development of lung damage, airway obstruction, and other symptoms associated with the disease. Therefore, understanding the role of peroxynitrite in the pathogenesis of CF is important for developing new therapeutic strategies to reduce oxidative stress and improve the quality of life for people with this disease.

Methods
In this study, we have quantified peroxynitrite levels, which could serve as an early biomarker for CF. A modified glassy carbon electrode (GCE) with a series of organoselenide compounds was adopted using the electro-grafting method to measure peroxynitrite levels in situ. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) were used to examine the structure and surface chemistry of organoselenide. Quartz Crystal Microbalance (QCM) analysis was used to determine the thickness of the electrodeposited selenium on the GCE surface.

Results
Our organoslenide GCE allowed for the application of low positive potential, which enhances the separation of peroxynitrite from other analytes sensitive to higher potentials. Cyclic voltammetry and amperometry showed sensitivity at 110 nA/mol, and the detection limit was recorded at 10 micromolar. This electrochemical technique of our modified electrodes can be miniaturized to detect peroxynitrite at the cell line. The sensitive probe, which was constructed, can be utilized to target the ratiometric changes in several lung slices, from healthy to lung inflammation and cystic fibrosis, via peroxynitrite fluctuation. In addition, ratiometric alterations and the prevalence of cystic fibrosis have a strong linear association, resulting in good potential in predicting the progression of cystic fibrosis in the early stage and improving effective treatment.

Conclusion
The study aimed to quantify peroxynitrite levels in cystic fibrosis (CF) patients as a potential early biomarker for the disease. We have used a modified glassy carbon electrode with organoselenide compounds and adopted an electro-grafting method to measure peroxynitrite levels. The modified electrodes showed sensitivity and a limit of detection of 10 micromolar, which can be miniaturized to detect peroxynitrite in the cell line. The results suggest that peroxynitrite’s sensors could serve as an early biomarker for CF by understanding its role in the pathogenesis, which can improve the quality of life for people with this disease.