▎ 摘　　要

Accurate detection of trace analytes in biological samples is essential for medical diagnostics but usually requires complex and expensive instruments. Nanozymes, a series of nanosized systems with a catalytic activity mimicking that of peroxidase enzymes, offer a useful alternative for the design of sensing devices. In this article, we describe the synthesis of porous 3D nitrogen-doped crumpled graphene nanoparticles (CGNPs) and their use as a platform for the sensitive detection of dopamine (DA) in complex biological media such as blood serum. CGNPs were prepared by doping graphene oxide (GO) using ammonium hydroxide in a hydrothermal treatment. This procedure leads to the crumpling of GO sheets into porous sphere-like nanoparticles, with a diameter of 34 +/- 10 nm. These nanoparticles with high surface area and improved electronic properties proved very active for the oxidation of the peroxidase substrate 3,3 ',5,5 '- tetramethylbenzidine (TMB). Our sensing device relied on the scavenging of hydroxyl radicals by DA, resulting in a turn-off effect for TMB oxidation. The system selectively detected DA with a limit of detection of 1.15 mu M and a linearity range of 1 to 20 mu M. The system also possessed good selectivity for DA in the presence of various interfering species, as well as in human blood serum.