A Flexible Paper-based Electrochemical Immunosensor Towards Detection of Carbohydrate Antigen 15-3

In this paper, we developed a simple and disposable electrochemical paper-based immunosensor (e-PI) based on manual screen printing method via patterned sticker label film on paper. The proposed electrochemical sensors provide the opportunity for economical single-use analysis of biological samples. The e-PI was constructed with hydrophobic glossy paper layers on a wax paper substrate to define three-electrode system. A carbon ink was used for construction of e-PI which composed of the graphite powder and cellulose acetate. The stability of the e-PI was evaluated using electrochemical methods. Carbohydrate antigen 15-3 (CA15-3) antibodies to the target CA15-3 antigen were immobilized on gold-modified graphite electrodes on the e-PI. Electrochemical properties of e-PI were investigated by cyclic voltammetry, differential pulse voltammetry and electrochemical impedance spectroscopy. The fabricated e-PI offers a vast linear range from 0.5 to 200 U mL−1 with a low limit of detection 0.15 U mL−1. Furthermore, the fabricated e-PI has acceptable stability, accuracy and high sensitivity.