Uricase-stimulated etching of silver nanoprisms for highly selective and sensitive colorimetric detection of uric acid in human serum

Abstract

The easy-to-use method for detecting uric acid in human serum is of great importance because of its crucial role in physiological and pathological processes. Herein, a simple and effective strategy was designed for colorimetric sensing of uric acid using the morphological transition of Ag nanoprisms. In the presence of uricase, uric acid was oxidized to produce H2O2. Subsequently, the morphology of Ag nanoprisms changed from triangle to round by etching of H2O2, leading to a more than 120nm blue shift of surface plasmon resonance spectral band. The color change from pale blue to purple related to concentration change of uric acid can be judged by naked eyes. A linear relationship between the blue shift of peak of Ag nanoprisms and uric acid concentration ranged from 1.0 to 40μM. The detection limit of uric acid was 0.7μM. Some potential interferents (e.g., ascorbic acid, glucose, dopamine, hypoxanthine and various amino acids) in human serum showed no interference. Serum samples could be directly added into Ag nanoprism–uricase sensing system, and the assay can be completed within one hour. The proposed sensor was successfully applied for detecting uric acid in human serum with the recoveries over 95%. The obtained results are in agreement with those measured by biochemistry analyzer with the average relative error of 5.1%. The Ag nanoprism–uricase sensor offers advantages of high selectivity and sensitivity, low-cost instruments, and rapid assay without sample pretreatment. Thus, the present uric acid sensor has great potential in applications for biochemical analysis and clinical diagnosis.