▎ 摘　　要

The increase of homocysteine (Hcy) is closely related with the development of many diseases. Nevertheless, the effective detection of Hcy remains challenging due to the lack of a simple, specific, and cost-efficient method. Herein, an electrochemical biosensor based on Hcy aptamer/Au nano-particles/graphene sponge (Aptamer/Au NPs/GS) was designed for the detection of homocysteine. The biosensor employed methylene blue (MB) as a redox indicator. Due to the change of aptamer conformation, the adsorbed MB was released from aptamer, resulting in the decrease of electrochemical response. In the range of 1-100 mu M, the concentration of Hcy had a good linear relationship with the relative redox peak current (Delta I) of MB and the lowest detection limit was 1 mu M. The experimental results demonstrated the aptasensor had good selectivity and reproducibility. In real serum sample, the aptasensor showed an acceptable recovery rate indicating its potential applications in the preliminary detection of various diseases associated with Hcy.