Construction of a self-assembled duplexed aptasensor for the simultaneous detection of haemoglobin and glycated haemoglobin†

Abstract

With the prevalence of diabetes and its secondary complications, the effective monitoring of diabetic biomarkers is necessary. While portable analytical devices for blood glucose have been sophisticatedly developed, those for haemoglobin (Hb) and, especially haemoglobin A1c (HbA_1c), a glycated form of Hb, remain elusive. Here, we developed an aptamer-based duplexed electrochemical sensor for the simultaneous detection of Hb and HbA_1c. Ferrocene (Fc) and a thiol group were introduced to the 5′ and 3′-end of aptamers that bind Hb and HbA_1c, respectively. While the thiol group facilitates the formation of a self-assembled monolayer of the aptamers onto a customized, duplexed screen-printed gold electrode, the presence of Fc provides the electrodes an internal electrochemical signal. Upon analyte binding, the secondary conformation of the aptamers is changed, thus leading to a quenched current signal because of an increased distance between Fc and the electrode surface. Our duplexed electrochemical sensor showed a good linearity for both analytes over a wide concentration range, and has proved effective in simultaneously quantifying Hb and HbA_1c in calibration samples.