Ultrasensitive and selective colorimetric detection of uric acid using peroxidase mimetic activity of biogenic palladium nanoparticles

Uric acid (2,6,8-trihydroxypurine) is a metabolic product of purine, which is one of the important markers of human health. The development of a rapid, facile, highly sensitive, and selective method for uric acid detection is critical for the diagnosis of related diseases and is still a strategic challenge. In this study, we developed a highly sensitive and selective colorimetric assay for the detection of uric acid using biogenic palladium nanoparticles (Pd NPs). The synthesized nanoparticles were shown to acquire peroxidase mimetic activity that oxidized 3,3′,5,5′-tetramethylbenzidine and produced a blue colour in an assay. The developed colorimetric assay is instrument-free detection of uric acid with a limit of detection of 0.05 μM and a 1.11 μM limit of quantification (LOQ). This is the first report determining the LOQ for a colorimetric assay that gives the lowest quantity of analyte that can be evaluated with more precision under the specified conditions of the analysis. The developed assay had a linear response at low uric acid concentrations of 0.05 to 1 μM and a 0.99841 linear regression correlation coefficient. This colorimetric detection provides a rapid, cost-effective, and easy-to-use platform for the clinical diagnosis of uric acid biomarkers.