Objective To establish a novel colorimetric sensor for uric acid in serum via DNA-Ag/Pt bimetallic nanoclusters (DNA-Ag/Pt NCs) with enzyme-like activity.

Methods Firstly, DNA-Ag/Pt NCs with high peroxidase-like activity were synthesized using single-stranded DNA as the template. The DNA-Ag/Pt NCs were characterized by transmission electron microscopy, dynamic light scattering, Zeta potential, X-ray photoelectron spectroscopy, X-ray diffractometer, electron resonance spectroscopy and Fourier transform infrared spectroscopy. Then, DNA-Ag/Pt NCs catalyzed the color reaction between H₂O₂ and 3, 3', 5, 5'-tetramethylbenzidine, in which H 2O2 was generated by the reaction of uricase and UA. The concentration of uric acid was quantitatively determined based on the color changes and the measurement results by UV-vis spectrometer. Furthermore, this method was applied to the detection of uric acid concentration and the standard addition recovery experiments in human serum samples.

Results DNA-Ag/Pt NCs with high peroxidase-like activity were successfully prepared. This method showed a linear detection range for uric acid from 0.3 to 75 μmol/L, with a detection limit of 0.15 μmol/ L. The concentration of uric acid in selected healthy human serum samples were between 203.04 μmol/L and 381.40 μmol/L, while that of samples from patients with hyperuricemia ranged from 420.97 μmol/L to 463.27 μmol/L. The standard addition recovery rate was in the range from 95.0% to 109.8%.

Conclusion The colorimetric assay based on DNA-Ag/Pt NCs for uric acid exhibits high specificity and sensitivity, and successfully achieves the detection of uric acid in serum samples.