Reduced Graphene Oxide-based Covalent Hybrid Film Electrode Self-assembled with Gold Nanoparticles for the Enzyme-Free Amperometric Sensing of Serum Uric Acid.

Purine metabolism in the human body leads to the production of uric acid (UA) at the end. But an abnormal level of UA in the human body creates health problems. The sensing and quantification of UA is essentially required to prevent and diagnose hypertension, arthritis, gout, hyperuricemia or Lesch-Nyhan syndrome, etc. Herein, the development of a sensing platform for the measurement of UA using Au nanoparticle-based hybrid self-assembly is described. The self-assembling of a thiol-terminated silicate network functionalized graphene oxide hybrid on a polycrystalline Au surface yields a three-dimensional assembly. The oxygen functionalities of the self-assembly were partially reduced by an NaBH4 treatment. The free -SH groups of the self-assembly were successfully used for the immobilization of Au nanoparticles by chemisorption. The nanoparticle-based hybrid self-assembly is highly sensitive toward UA, and shows a wide linear response with a detection limit of 40 nM UA (S/N = 7) without interference from co-exiting ascorbic acid. Its practical application was demonstrated using human serum samples.