The Selectivity and Stability of Epithelial Sodium Channel (ENaC) Aptamer as an Electrochemical Aptasensor

Epithelial sodium channel (ENaC) proteins are proportional to sodium intake and clinically associated with hypertension. The selectivity of aptamer-based electrochemical biosensor for ENaC detection has been developed in this study, and the stability of the cerium oxide modified electrode was reported. The concentration of ENaC was measured using differential pulse voltammetry of [Fe(CN)6]4−/3- redox system. The aptasensor based on the bioconjugate of ENaC aptamer with gold nanoparticle (AuNP) using streptavidin-biotin linker, and immobilized on the screen-printed electrode-CeO2. The ENaC aptamer selectivity was tested for other proteins that might be present in the urine sample, and the stability of the modified SPCE was studied throughout storage of SPCE-CeO2-aptamer. The limit of detection of ENaC protein with this aptasensor was obtained of 0.110 ng mL-1, in the linear range of concentrations 0.05–3.0 ng mL-1. The percentage of selectivity of the aptamer to ENaC compared to creatinine and potassium channel proteins was 79.08%. The cerium oxide modified SPCE/aptamer bioconjugate is stable up to one year of storage. The developed aptasensor is simple and can be miniaturized to determine the ENaC concentration in urine for the realization of a point-of-care device for the early detection of hypertension.