▎ 摘　　要

An electrochemical immunosensor was studied for sensitive detection of Ki-67 protein based on a dual amplification mechanism resulting from Au nanoparticles (AuNP)-polydopamine (PDA) as the sensor platform. By utilizing PDA, biomolecules was immobilized for both the construction of the sensor platform and the signal labeling. The particular platform of AuNP-PDA, as well as synthesizing horseradish peroxidase (HRP)-antibody (Ab2) functionalized AuNP-PDA@graphene was utilized to immensely enhance the sensitivity. The amperometry determination was used to obtain a linear response range of Ki-67 which was from 4 to 800 pg/mL, along with a very low detection limit (1.7 pg/mL).