An ultra-sensitive dual-signal ratio electrochemical aptasensor based on functionalized bimetallic MOF nanocomplexes by the in-situ electrochemical synthesis for detect HER2

Ratiometric electrochemical biosensors have attracted the attention of researchers due to their ability to self-calibrate, which can improve accuracy of the detection. We constructed a radiometric electrochemical aptasensor based on functionalized bimetallic Zn–Co-MOF@ferrocene (Fc) and Fe–Co-MOF@methylene blue (MB) composites with high specific surface area, high electrical conductivity and strong adsorption properties to detect human epidermal growth factor receptor 2 (HER2). In this paper, we synthesized bimetallic Zn–Co-MOF@Fc by in situ electrochemical synthesis and bimetallic Fe–Co-MOF, and the MB signal was wrapped in Fe–Co-MOF, making it immune to the interference of the external environment. In addition, bimetallic MOFs can also immobilize aptamer on their surfaces through adsorption. Therefore, we used Zn–Co-MOF@Fc/aptamer as the capture probe for HER2 and Fe–Co-MOF@MB as the signal labeling probe to jointly construct the radiometric electrochemical aptasensor. By calculating the ratio of signal peaks, simple, fast and accurate detection of HER2 is achieved. The linear range of the sensor is 0.75–250 pg/mL, and the detection limit is 0.37 pg/mL. It provides a new idea for the detection of breast cancer tumor biomarkers.