Enhanced Detection of Uric Acid through Fe₃O₄@Au Based Highly Sensitive Electrochemical Biosensor

In this paper, we reported an electrochemical biosensor based on Fe₃O₄@Au nanocomposite for the detection of uric acid (UA). The nanocomposite was prepared by self-assembling technique and the characterisation was carried out using transmission electron microscopy (TEM). A highly sensitive and selective enzyme-free electrochemical based on peroxidemimetic enzyme activity of composite nanoparticles was prepared for the detection uric acid. Cyclic voltammetry (CV) was used to assess the electrocatalytic response of Fe₃O₄@Au towards uric acid, and then the Fe₃O₄@Au exhibited high electrocatalytic response which was attributed to the increased surface area and conductivity of the nanocomposite. The results showed that Fe₃O₄ functionalized with amino groups could be effectively loaded with gold nanoparticles. The optimum detection conditions were as follows: Amount of temperature 60 ℃, Fe₃O₄@Au suspension 1.20 mg/mL, scanning rate was 0.1 V/s, and the electrolyte pH was 5.5. The novel electrochemical detection method showed an extremely high sensitivity towards uric acid under the optimized conditions, with a good linear relationship between the current response and the concentration of uric acid in the range of 0.1~10 mmol/L, and then the equation was y=13.267x+6.044 (R²=0.9952), with the corresponding limit of detection of 0.087 μmol/L. The recoveries ranged from 97.9%~110.2%%, recycling was very well and the accuracy of method was very high. The sensor showed excellent sensitivity for uric acid with good stability and selectivity. Thus, these results implied that the electrochemical sensor provided a popular price and simple method for the reliable analysis of uric acid.