Amperometric Detector of Uric Acid in Human Serum Based on Glassy Carbon Electrodes Modified By Gold Nanoparticles and Poly(amidoamine) Dendrimers and Its Application to the Early Diagnosis of Preeclampsia

Abstract

Glassy carbon electrodes (GCE) were modified by cysteamine-capped gold nanoparticles (AuNp@cysteamine) and PAMAM dendrimers generation 4.5 bearing 128-COOH peripheral groups (GCE/AuNp@cysteamine/PAMAM), in order to be tested as electrochemical detector of uric acid (UA) in human serum samples. The results showed that concentrations of UA detected by cyclic voltammetry with GCE/AuNp@cysteamine/PAMAM were comparable (deviation <±10%; limits of detection and quantification were 1.7×10-4 and 5.8×10-4 mg/dL, respectively) to those concentrations obtained using the typical uricase-based enzymatic method [1]. Furthermore, results of UA detected by DC-potential amperometry demonstrated that the presence of dendrimers in the GCE/AuNp@cysteamine/PAMAM system minimizes ascorbic acid and serum proteins interferences during UA oxidation, thus improving the electrocatalytic activity of the gold nanoparticles. On the other hand, GCE/AuNp@cysteamine/PAMAM were employed for detecting UA in serum donated by pregnant women having gestational hypertension or preeclampsia (the group of “cases”) and from health pregnant women (the “control” group). The new data confirmed significant differences between the detected UA levels (p<0.001) in the groups of “cases” (6.2±0.5mg/dL) and “control” (4.2±0.9mg/dL), respectively. Therefore, these results demonstrated that the employment of GCE/AuNp@cysteamine/PAMAM - based amperometric detectors as non-enzymatic devices for early diagnosis of preeclampsia constitute a highly reliable route.