CEACAM5 and neoplasm: As shown in Figure 6A, the fluorescence changes of the C4 biosensor reacting with CEA were significantly larger than those of C4 biosensor reacting with other tumor markers, while it can be seen in Figure 6B that the S1 biosensor showed significant fluorescence changes when reacting with SCCAg, but no significant fluorescence changes were observed when reacting with other tumor markers.