Point-of-care testing (POCT) of patients with a high concentration of uric acid by using alginate hydrogel microspheres embedded with CdZnTeS QDs and urate oxidase (Alg@QDs-UOx MSs)

Abstract

High concentration of uric acid is usually related to cardiovascular and cerebrovascular diseases. Developing a simple method for the rapid and efficient detection of uric acid has a great significance in clinical diagnosis. In this work, alginate hydrogel microspheres embedded with CdZnTeS QDs and urate oxidase (Alg@QDs-UOx MSs) were prepared for the first time, and further used for point-of-care testing (POCT) of patients with a high concentration of uric acid. This strategy is mainly based on visual detection of H₂O₂, the product of uric acid after an enzymatic reaction. The proposed sensor (Alg@QDs-UOx MSs) has several advantages. First, it can reduce the interference of the proteins to the fluorescence of QDs. Second, Alg@QDs-UOx MSs help improve the stability of the CdZnTeS QDs as well as the activity of urate oxidase during storage. Third, it is easy to use, has fast response speed, and is of low cost. Therefore, the proposed sensor shows good application prospects. Simply through the built-in camera of a smartphone, we can visualize the urine samples from patients with a high concentration of uric acid within 10 minutes, and the accuracy rates were 100%. In the range of 100.0 μM to 900.0 μM, the I/I₀ values and uric acid concentrations are in a great linear relationship (R² = 0.9973), indicating that this method can be employed for quantitative analysis of uric acid in human urine (<10 mM). The limit of detection (LOD) is 20.3 μM.