Ultrasensitive Electrochemical Detection of EpCAM Antigen Based on Anti‐EpCAM Conjugated With Highly Flexible Ag@Ti₃C₂T_x Modified Conducting Paper Platform

ABSTRACT In this work, a highly bendable Whatman paper–based immunosensor has been proposed for highly sensitive and real‐time detection of EpCAM antigen. A novel Ag@Ti 3 C 2 T x hybrid material is used with aqueous poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) [PEDOT:PSS] solution to enhance various electrochemical parameters, namely, conductivity, hydrophilicity, stability, and so forth. The conducting paper has been fabricated by simple dip‐coating method followed by doping with dimethyl sulfoxide (DMSO), an organic solvent. The DMSO treatment results in the sharp increase in electrical conductivity of Ag@Ti 3 C 2 T x /CP from 10.9 × 10 −3 to 763.5 × 10 −3 S/cm (around 70 times). Further, the bendability of the fabricated conducting paper is verified by paper folding study at different angles. The developed immunosensor, anti‐EpCAM/Ag@Ti 3 C 2 T x /CP, is found to be highly sensitive (44.12 μA·fg −1 ·mL) to detect EpCAM antigen with ultrabroad linear range (1 fg/mL–10,000 pg/mL). Ultimately, the manufactured immunosensor is used to assess the EpCAM in spiked serum samples, and the results demonstrate a strong correlation with the standard buffer samples.