Enzyme-free and wide-range portable colorimetric sensing system for uric acid and hydrogen peroxide based on copper nanoparticles

Uric acid (UA) is the final product of purine metabolism. A high concentration of UA in body fluid may lead to kidney stones, gout, and some cardiovascular diseases. Therefore, the non-invasive daily monitoring of UA is of great significance for both hyperuricemia patients and fit people. However, most of the current detection methods for UA are enzyme-dependent which limits the application scenarios and lacks portable instruments for on-site detection, including optics and electrochemistry. In this work, an enzyme-free and wide-range colorimetric sensor for UA and H2O2 detection was developed based on a mercaptosuccinic acid (MSA)-modified Cu nanoparticles (CuNPs). Under the action of UA or H2O2, with the cleavage of MSAs on the CuNPs surface, small Cu particles are further aggregated into larger particles with a lightning violet color. With the employment of the multi-channel handheld automatic photometer (MHAP), the concentration of UA and H2O2 can be determined on-site according to the absorbance measurement by the photodiodes. The linear range of UA was 5 mu M-4.5 mM with the limit of detection (LOD) of 3.7 mu M, while the linear range of H2O2 was 5 mM-500 mM and 5 mu M-5 mM with the LOD of 4.3 mu M. This approach has been applied to the detection of UA in human urine, providing more possibilities for non-invasive home health monitoring, community medical diagnosis, and broader prospects of on-site disease detection.

Automated summary

In this study, an enzyme-free and wide-range colorimetric sensor for uric acid (UA) and hydrogen peroxide (H2O2) detection was developed. By reacting with mercaptosuccinic acid (MSA) modified copper nanoparticles (CuNPs), small Cu particles can be further aggregated into larger particles with a purple-blue color under the action of UA or H2O2. Using a multi-channel handheld automatic photometer (MHAP), the concentration of UA and H2O2 can be determined on-site based on absorbance measurement by photodiodes. This approach has been successfully applied to the detection of UA in human urine, providing possibilities for non-invasive home health monitoring, community medical diagnosis, and on-site disease detection.