Results and discussion
As shown in Scheme 1, the desired anthraquinonyl glycoside (ZBW1) was synthesized by the Cu(I)-catalyzed azide-alkyne 1,3-dipolar cycloaddition (CuAAC) of azido mannoside a[16] with dipropargyl anthraquinone b[5], followed by a de-acetylation, in 66% yield. For the sensor fabrication, the compound was simply spotted to the working electrode (pre-coated with a nano-graphene (nG)) of a screen printed electrode [17]. The presence of graphene may increase the adsorption of AG onto the working electrode [18]. Comparing to the conventional gold-thiol self-assembly, the strong π-interaction between graphene and anthraquinone [5] may provide a more facile and economic means for construction of self-assembled electrochemical biosensors due to the preclusion of using gold as the sensing platform. Upon formation of the sensors, the hydrophilic glycosyl moiety could expose to the environment for lectin recognition