All electrochemical measurements were recorded with a CHI660D electrochemical workstation (Shanghai CHI Instruments Co.,China). The electrochemical system employed the conventionalthree-electrode configuration which consisted of a working elec-trode (an Au disk electrode modified with hairpin capture probeA), a platinum wire as the auxiliary electrode, and an Ag/AgCl(sat.KCl) reference electrode. Cyclic voltammetry (CV) data werecarried out at a scan rate of 100 mV s−1. Square wave voltammetric(SWV) measurements were registered in the potential interval of0.1 to −0.5 V. Electrochemical impedance spectroscopy (EIS) mea-surements were performed in the presence of 5 mM [Fe(CN)6]4−/3−solution (pH 7.4) and were recorded with the frequency changedfrom 0.1 Hz to 10 kHz.