▎ 摘　　要

Aiming at substantially improving the electrochemical sensing performance for guanine, we bring out a novel high-efficiency electrocatalyst composed of hierarchical sea urchin-like Prussian blue@palladium core-shell heterostructures supported on nitrogen-doped reduced graphene oxide (PB-U@Pd/N-RGO). The said PB-U@Pd/N-RGO was synthesized by a new and facile wet-chemistry method without using any surfactant and template. More impressively, we demonstrate a new strategy for morphology-controlled synthesis of Prussian blue via simply tuning the ratio of N,N'-dimethyl formamide and H2O in the mixed solvent. In-depth electrochemical characterizations demonstrate the superior electrocatalytic performance of PB-U@Pd/N-RGO toward the oxidation of guanine, which benefits from the synergistic effect of component materials and its unique core-shell heterostructure. Consequently, the constructed PBU@Pd/N-RGO-based electrochemical sensor displays superb comprehensive performance for the guanine assay. To be specifical, the developed sensor exhibits wide detection range (0.01-85.0 mu W), low detection limit (2.6 nM), good reproducibility, long-term stability, high sensitivity and selectivity together with acceptable recovery (97.0-104.0%) for the assay of guanine in biological samples. Such outstanding comprehensive performance is amongst the top of reports for the electrochemical sensing of guanine, promising practical applications in biosensing fields. (C) 2019 Elsevier Ltd. All rights reserved.