After the immobilization of the mucin1 protein (MUC1) aptamer as the recognition element, the as-developed EC aptasensor exhibited a linear range of 50 to 106 cells mL−1, with low LOD of 20 cells mL−1, which was used successfully to selectively detect MUC1-positive MCF-7 breast cancer cells in complex samples. Here, MUC1 is linked to breast carcinoma.