Sensitivity Detection of Uric Acid and Creatinine in Human Urine Based on Nanoporous Gold.

Given the significance of uric acid and creatinine in clinical diagnostic, disease prevention and treatment, a multifunctional electrochemical sensor was proposed for sensitive detection of uric acid and creatinine. The sensitive detection of uric acid was realized based on the unique electrochemical oxidation of nanoporous gold (NPG) towards uric acid, showing good linearity from 10 µM to 750 µM with a satisfactory sensitivity of 222.91 µA mM-1 cm-2 and a limit of detection (LOD) of 0.06 µM. Based on the Jaffé reaction between creatinine and picric acid, the sensitive detection of creatinine was indirectly achieved in a range from 10 to 2000 µM by determining the consumption of picric acid in the Jaffé reaction with a detection sensitivity of 195.05 µA mM-1 cm-2 and a LOD of 10 µM. For human urine detection using the proposed electrochemical sensor, the uric acid detection results were comparable to that of high-performance liquid chromatography (HPLC), with a deviation rate of less than 10.28% and the recoveries of uric acid spiked in urine samples were 89~118%. Compared with HPLC results, the deviation rate of creatinine detection in urine samples was less than 4.17% and the recoveries of creatinine spiked in urine samples ranged from 92.50% to 117.40%. The multifunctional electrochemical sensor exhibited many advantages in practical applications, including short detection time, high stability, simple operation, strong anti-interference ability, cost-effectiveness, and easy fabrication, which provided a promising alternative for urine analysis in clinical diagnosis.

Sensitive electrochemical detection of cholesterol using a portable paper sensor based on the synergistic effect of cholesterol oxidase and nanoporous gold.

As a crucial biomarker for some diseases, the determination of cholesterol in human serum is of great significance for the diagnosis and prevention of these diseases. Hence, a portable cholesterol detection method is necessary for clinical and domestic applications. Here, a portable paper sensor was designed for cholesterol detection by modifying screen-printed electrode (SPE) with nanoporous gold (NPG). To achieve the reliable cholesterol detection, a synergistic strategy was proposed based on the oxidation of cholesterol by cholesterol oxidase (ChOx) and the reduction of oxidation product (H2O2) by NPG. Compared to existing electrochemical sensors, the resulting paper sensor exhibited a wider linear response in a range from 50 µM to 6 mM as well as a higher sensitivity of 32.68 µA mM-1 cm-2 with a lower detection limit of 8.36 µM. Moreover, the portable paper sensor presented strong anti-interference capability and stability in the detection of cholesterol in human serum, and the data detected by the portable paper sensor were consistent with that obtained by an automatic biochemical analyzer. These unique performances confirmed that the proposed paper sensor was a sensitive, reliable, and portable cholesterol detection method, making it a good choice for cholesterol detection.

A Multifunctional Electrochemical Sensor for the Simultaneous Detection of Ascorbic Acid, Dopamine, Uric Acid, and Nitrite.

BACKGROUND: Ascorbic acid (AA), dopamine (DA), uric acid (UA), and nitrite (NO2-) are essential biomarkers for human metabolism and can be used to indicate some chronic diseases and metabolic disorders, including scurvy, Parkinson's disease, hyperuricemia, and kidney disease. OBJECTIVE: A multifunctional electrochemical sensor that can integrate the detection of these species was constructed using nanoporous gold (NPG) as a recognition element to modify glassy carbon electrode (GCE). METHODS: The electrochemical performance of the multifunctional electrochemical sensor was investigated toward AA, DA, UA, and NO2- in citrate buffer solution (CBS, 100 mM, pH 4.0) and human serum using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) methods. RESULTS: In the quaternary mixture detection, the resulting NPG/GCE electrode displayed four independent oxidation peaks with wide peak separations. Further, the NPG/GCE electrode showed good linear responses with the sensitivities of 32, 1103, 71, and 147 µA/mM/cm2 and the detection limits of 1.58, 0.17, 0.37, and 0.36 µM for AA, DA UA, and NO2-, respectively. Additionally, the NPG/GCE electrode exhibited great anti-interference and was successfully applied in human serum samples. CONCLUSIONS: These results indicate that the NPG/GCE electrode can simultaneously and selectively detect AA, DA, UA, and NO2-, which has the potential for application and diagnosis in the screening and diagnosis of chronic diseases and metabolic disorders. HIGHLIGHTS: A multianalyte electrochemical sensor was fabricated for human metabolites detection. The sensor displayed good performance in the simultaneous detection of AA, DA, UA, and NO2- and applied to human serum samples.