We further demonstrated a sensing strategy employing single-strand DNA probes as FEOS in the nanochannel-systems (3rd stage) (Fig. 5a), for the detection of a broad range of targets including inorganic ions (Hg2+ with 1 pM limit of detection, LoD), small molecules (ATP with 1 pM LoD), proteins (lysozyme with 1 pM LoD), and cancer cells (MCF-7 cells with 400 cells mL−1 LoD) (Fig. 5b, c and Fig. S28). The gene discussed is LYZ; the disease is cancer.