An ultra-sensitive electrochemical aptasensor based on Co-MOF/ZIF-8 nano-thin-film by the in-situ electrochemical synthesis for simultaneous detection of multiple biomarkers of breast cancer

This work developed a new electrochemical aptasensor based on the functional hybrid film for simultaneous single step detection of human epidermal growth factor receptor-2 (HER2) and estrogen receptor (ER) biomarkers. The platform is achieved by in-situ electrochemical synthesis of Zn-MOF (ZIF-8) thin film with the conductivity, the specific surface area, and the easy assembly of 2D Co-MOF nanosheets which can adsorbed the amount of aptamer chains on indium tin oxide (ITO) slices. The aptamers were labeled by adsorption of two organic dyes – neutral red (NB) and methylene blue (MB) through electrostatic action, respectively. In the presence of HER2/ER biomarkers, the aptamers of ER/HER2 will combine with ER/HER2 biomarkers to generate new complexes which will far away from the ITO surface due to the specific coupling between MB/NB-labeled single-stranded deoxyribonucleic acid (ssDNA) aptamer and HER2/ER biomarkers is stronger than the aptamer adhered to the Co-MOF/ZIF-8 film on ITO through intermolecular interaction, electrostatic interaction, and π-π stacking. Therefore, it can sensitive single step detection of HER2-ER biomarkers in only 60 min with the detection range are 0 to 15 pg/mL and detection limits as low as 3.8 fg/mL and 6.8 fg/mL, respectively.