Electrochemically based targeted metabolomics for uric acid, xanthine, and hypoxanthine in plasma samples for early diagnosis of acute renal failure after cardiopulmonary bypass using rGO-GCE

Abstract

Cardiopulmonary bypass (CPB) may cause a systemic inflammatory reaction in patients during cardiac surgery due to the interaction of blood with heart-lung machine circuits. This inflammation may lead to organ failure. One of the most severe complications of cardiac surgery is the development of acute renal failure (ARF). Early diagnosis of ARF using fast, accurate, and sensitive methods may prevent ARF development. Therefore, we developed and validated an electroanalytical method for simultaneous analysis of three biomarker candidates, uric acid (UA), hypoxanthine (HXA), and xanthine (XA), from plasma samples. Their quantification was performed using reduced graphene oxide modified glassy carbon electrode (rGO-GCE) synthesized through rapid one-step electropolymerization. The characterization studies of rGO-GCE with cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and scanning electron microscope (SEM) analyses showed a successful surface modification of GCE with rGO. The electrochemical oxidations of the biomarkers were examined using square wave voltammetry (SWV) with the rGO sensor in 0.1 M phosphate-borate (PB) buffer (pH 7). Various operational parameters, including pH and type of supporting electrolyte, instrumental parameters, electro polymerization cycles, and GO concentration, were optimized. Under optimum conditions, good linear responses were obtained for three metabolites (R2 > 0.99). The LOQ of the method was 0.12 μM for UA, 0.13 μM for XA, and 0.43 μM for HXA. The developed method was successfully applied to patient plasma samples of ARF (n = 9) and control (n = 17) collected at five-time points of CPB. The UA, HXA, and XA levels were significantly altered in ARF patients. The results showed the applicability of the developed method for early diagnosis of ARF developed after CPB.