A colorimetric electronic tongue based on bi-functionalized AuNPs for fingerprint detection of cancer markers

Considering the extensive efforts made to fabricate rapid test kits for detection of cancer markers, this study introduces a paper based electronic tongue based on colorimetric methods, providing a naked eye response for cancer antigens 125, 15–3, 19.9 and carcinoembryonic (CEA). The developed sensor consisted of bi-functionalized gold nanoparticles (AuNPs) with different sizes, surface electrical charge, and functional groups, involving various electrostatic, covalent, H-bonding or nucleophilic interactions with the antigens. Due to the different structures of antigens, the NP’s behavior was unique for each analyte. The sensor responses were collected after 3 min because of the aggregation of NPs. According to discrimination analysis, the serum with cancer markers was distinct from normal samples. These antigens were quantified by detection limits less than of 10.0 U/ mL for CA 125, CEA and CA 19.9, and 15.0 U/mL for CA 15-3. Interestingly, the colorimetric sensor was capable of simultaneous determination of four cancer markers with a prediction error rate of less than 6.0 U/mL. Based on the reliable responses obtained in the practical analysis, the proposed method can be used as a valid way for the diagnosis, progression and even monitoring the treatment process of a specific type of cancer.