An ultrasensitive dual-signal ratio electrochemical aptamer biosensor for the detection of HER2.

Electrochemical ratiometric biosensors have received attention from researchers because of their self-calibration capability, which can improve the accuracy of detection. In the present study, a ratiometric dual signal electrochemical aptamer biosensor based on ZIF-67 @polydopamine (PDA) nanocomposite and Cu/UiO-66 @ 3, 3', 5, 5'-tetramethylbenzidine (TMB) nanocomposite was fabricated for the detection of breast cancer biomarker- human epidermal growth factor receptor 2 (HER2). PDA was chosen as the electroactive material with electrochemical redox activity and ZIF-67 with a high specific surface area, forming the ZIF-67 @PDA+Apt as the nanoprobe for capturing HER2 in this paper. Cu/UiO-66 is a bimetallic compound with high stability, specific surface area, and strong adsorption onto aptamer chains, and the Cu/UiO-66 @TMB+Apt nanocomposite was used as a probe for signal labeling. In the presence of HER2, the capture of HER2 by the ZIF-67 @PDA+Apt probe results in a weakening of the conductivity of the electrode, however, by attenuating the electrochemical signal from the PDA, altering the probe-Cu/UiO-66 @TMB+Apt signaling will result in the enhancement of the TMB electrochemical signal. With a sensitive detection of HER2 biomarkers in as little as 30 min with the detection range of 0.75-40 pg/mL and a limit of detection as low as 44.8 fg/mL. Dual signal ratio biosensors have a low limit of detection, short detection time, which can accurately detect targets in complex biological samples, which has important theoretical importance.