A Nanostructured Sensor Based on Gold Nanoparticles and Nafion for Determination of Uric Acid

Abstract

The paper discusses the mechanism of uric acid (UA) electrooxidation occurring on the surface of gold nanoparticles. It has been shown that the electrode process is purely electrochemical, uncomplicated with catalytic stages. The nanoeffects observed as the reduction of overvoltage and increased current of UA oxidation have been described. These nanoeffects are determined by the size of particles and do not depend on the method of particle preparation (citrate and “green” synthesis). The findings of these studies have been used to select a modifier for carbon screen-printed electrode (CSPE). It has been stated that CSPE modified with gold nanoparticles (5 nm) and 2.5% Nafion (Nf) may serve as non-enzymatic sensor for UA determination. The combination of the properties of nanoparticles and Nafion as a molecular sieve at the selected pH 5 phosphate buffer solution has significantly improved the resolution of the sensor compared to unmodified CSPE. A nanostructured sensor has demonstrated good selectivity in determining UA in the presence of ascorbic acid. The detection limit of UA is 0.25 μM. A linear calibration curve has been obtained over a range of 0.5–600 μM. The 2.5%Nf/Au(5nm)/CSPE has been successfully applied to determining UA in blood serum and milk samples. The accuracy and reliability of the obtained results have been confirmed by a good correlation with the enzymatic spectrophotometric analysis (R2 = 0.9938) and the “added−found” technique (recovery close to 100%).

Simultaneous Determination of Four DNA bases at Graphene Oxide/Multi-Walled Carbon Nanotube Nanocomposite-Modified Electrode

“…The LODs were determined as 0.12, 0.11, 0.43, 1.71, and 0.80 µM for UA, G, A, T, and C, respectively. In comparison with the other electrochemical ones reported in the literature, this nanocomposite-modified sensor had a promising performance for detecting all four nucleobases in the presence of UA simultaneously, as it demonstrates a low LOD and a wide linear range for each analyte as shown in Table 2 [5,32,33,[37][38][39][40][41][42]. The performance between classical chromatography methods and our proposed electrochemical method were compared in Table S2.…”

Electrochemical Detection of Dopamine Based on Functionalized Electrodes

“…The biointerface is functionalized with gold nanoparticles, DNA, and a polymer. Gold nanoparticles are known to have many advantages in electrochemistry in that they are highly conductive, allow a faster electron transfer kinetics, increase the electroactive surface of the electrode, and reduce the risks of overvoltage [28,29]. Moreover, depending on the synthesis method, they can be biocompatible and are consequently being used more and more frequently in nanomedicine [30,31].…”

The Effect of the Antioxidant Activity of Plant Extracts on the Properties of Gold Nanoparticles

“…Biocompatibility and low cytotoxicity of AuNPs [14-17] have been proven and, as a result, they can be used for therapeutic purposes in the treatment and diagnosis of various diseases [18][19][20], for drug [21][22][23] and gene [23] delivery. Additionally, AuNPs obtained by green technologies are used as catalysts in the decomposition of 4-nitrophenol [24,25], as electrode modifiers in the determination of chloramphenicol in milk, honey and eye drops [26], carbendazim in soil [27], lead ions in paints and river waters [28], ecotoxicant hydrazine [29], uric acid in milk and blood serum [30].Currently, green methods for AuNPs synthesis are being developed using various bio-objects with high reducing ability: bacteria, viruses, fungi and yeast, plants and algae [31][32][33]. A distinctive feature of the nanoparticle's synthesis with the use of plants (the so-called phytosynthesis) is a higher rate of nanoparticle formation compared to the synthesis rate with the use of microorganisms [34] and the fact that additional reagents are not required [35][36][37][38][39].…”

“…Biocompatibility and low cytotoxicity of AuNPs [14-17] have been proven and, as a result, they can be used for therapeutic purposes in the treatment and diagnosis of various diseases [18][19][20], for drug [21][22][23] and gene [23] delivery. Additionally, AuNPs obtained by green technologies are used as catalysts in the decomposition of 4-nitrophenol [24,25], as electrode modifiers in the determination of chloramphenicol in milk, honey and eye drops [26], carbendazim in soil [27], lead ions in paints and river waters [28], ecotoxicant hydrazine [29], uric acid in milk and blood serum [30].…”