Bimetallic nanoparticles decorated hollow nanoporous carbon framework as nanozyme biosensor for highly sensitive electrochemical sensing of uric acid.

An ultrasensitive electrochemical biosensor was developed to identify the low levels of uric acid (UA) in human serum. The gold/cobalt (Au/Co) bimetallic nanoparticles (NPs) decorated hollow nanoporous carbon framework (Au/Co@HNCF) was synthesized as a nanozyme by pyrolysis of the Au (III)-etching zeolitic imidazolate framework-67 (ZIF-67). The external Au NPs combined with internal Co NPs on the hollow carbon framework exhibited enhanced activity for UA oxidation, thereby generating superior signals. Accordingly, the Au/Co@HNCF biosensor presented ranking performances with a low detection limit of 0.023 μM (S/N = 3), an ultrahigh sensitivity of 48.4 μA μM-1 cm-2, and an extensive response in the linear region of 0.1-25 μM and the logarithmic region of 25-2500 μM. Owing to the ordered nanoporous framework and carbon interfacial features, the Au/Co@HNCF biosensor displayed adequate selectivity for UA sensing over a series of biomolecules. In addition, the Au/Co@HNCF biosensor was employed to quantify UA in human serum samples. The test results were basically consistent with those of a commercial apparatus, and thus demonstrated that the proposed Au/Co@HNCF biosensor was reliable for UA determination in clinical research.