In this paper, we report a sensitive electrochemical cytosensor for quantitative determination of human gastric carcinoma (BGC-823) cells using three-dimensional architecture of Au@BSA and lectin-modified nanoprobe. Au@BSA microspheres combining with capture molecules of 3-aminophenylboronic acid (APBA) were used to specifically recognize BGC-823 cells according to the high affinity of APBA for sialic acid (SA) groups on cellular surface. Subsequently, the popcorn-shaped gold nanoprobes (ConA-popcorn-HRP) were fabricated by immobilizing concanavalin A (ConA) and HRP on the surface of popcorn-shaped gold nanoparticles. On the basis of the specific recognition of cell surface mannosyl groups to ConA, the {ConA-popcorn-HRP} nanoprobes were introduced onto the electrode surface, and amplified signals were produced by an enzymatic catalytic response of HRP related to hydrogen peroxide (H2O2)-thionine system. With the dual signal amplification of Au@BSA and {ConA-popcorn-HRP} nanoprobes, the designed cytosensor showed high sensitivity and selectivity, and has been proven to detect BGC-823 cells in a wide linear range from 1.0 x 10(2) to 1.0 x 106 cells mL(-1) with a low detection limit of 40 cells mL(-1). Overall, the proposed strategy offers a new way for sensitive detection of living cancer cells related to abnormal glycosylation and thus may help improve cancer diagnosis and treatment. (C) 2016 The Electrochemical Society.