Standardized detection of mannose-Con A interactions via electrochemical impedance spectroscopy. (a) Averaged current density (I) of ZBW1 decorated on the graphene electrode of different groups. (b) Averaged lectin coverage efficiency (Г) of the graphene electrode decorated with ZBW1 of different groups in the presence of Con A (10 μM). The mean I for group I, II and II are 9.6 · 0.2, 15.4 · 0.5 and 19.8 · 0.6 μA, respectively. The mean Г for group I, II and II are 35.2 · 1.3, 54.3 · 3.5 and 72.9 · 2.4%, respectively. The original DPV and EIS plots of group I, II and III are shown in Additional file 1: Figures S1, S2 and S3, respectively.