The simplest sandwich configuration, in which GO‐modified GCE served to immobilize the antibodies of interest (anti‐PSA in this case for the specific biorecognition of membrane PSA) and with a subsequent surface blocking by the use of BSA, was used to detect PC‐3 (prostate cancer) cells down to 260 cells mL−1. Here, PROS1 is linked to prostate carcinoma.