▎ 摘　　要

Development of hybrid nanozymes with high catalytic efficiency is of critical importance for enzyme mimics in biological catalytic fields. Herein, we reported a polydopamine (PDA) surface modification assisted pyrolysis strategy for preparing CoO nanoparticles/N-doped carbon sheets/reduced graphene oxide composites (CoO/N-CS-rGO). In this strategy, PDA with abundant amines and imines could serve as an ecofriendly N-contained precursor and a connecting agent between GO matrix and CoO. Due to the superior conductivity of N-CS-rGO, synergistic catalysis between CoO nanoparticles (NPs) and N-CS-rGO, and intrinsic oxidase-like characteristic, the CoO/N-CS-rGO was used as an ultrasensitive signal amplification platform for simultaneously analyzing dopamine (DA) and uric acid (UA) in a neutral solution. Significantly, the fabricated electrochemical sensor showed ultrahigh sensitivities of 1378 mu A mM(-1) for DA and 1393 mu A mM(-1) for UA. The linear range of 0.5-110 mu M for DA and 1-125 mu M for UA could be obtained by this sensor. Furthermore, the stability and selectivity of the CoO/N-CS-rGO-based hybrid biosensor were evaluated. The results showed that the biosensor performed good stability and brilliant selectivity against interfering analytes. Also, the CoO/N-CS-rGO/GCE was adopted to monitor two analytes in human serum samples with high accuracy. This work provides an efficient PDA-assisted synthetic strategy to prepare hybrid nanomaterials and shows broad prospects for biosensing, biotechnology, and clinical diagnosis.