The developed CEA-detecting biosensor showed an ultralowLOD (0.06 fg/mL) and a broad detection range (1 fg/mL to 200 ng/mL).Robby et al. designed a polydopamine-loaded glutathione-responsivepolymer dot (PDA@PD) hydrogel-based electronic-skin sensor with highselectivity toward CD44 receptor for the detection of cancer cells(such as MDA-MB-231, KB and HeLa cancer cell lines)85 (Figure 5b). This evidence concerns the gene CEACAM5 and cancer.