Electrochemiluminescence immunosensor for cytokeratin fragment antigen 21-1 detection using electrochemically mediated atom transfer radical polymerization

The cytokeratin fragment antigen 21-1 (CYFRA 21-1) protein is a critical tumor biomarker tightly related to non-small cell lung cancer (NSCLC). Herein, we prepared an effective electrochemiluminescence (ECL) immunosensor for CYFRA 21-1 detection using electrochemically mediated atom transfer radical polymerization (eATRP). The CYFRA 21-1 antigen was fixed on the electrode surface by constructing a sandwich type antibody-antigen-antibody immune system. The sensitivity of ECL was improved by using the eATRP reaction. In this method, eATRP was applied to CYFRA 21-1 detection antibody with N-acryloyloxysuccinimide as functional monomer. This is the first time that ECL and eATRP signal amplification technology had been combined. Under the optimized testing conditions, the immunosensor showed a good linear relation in the range from 1 fg mL(−1) to 1 μg mL(−1) at a limit of detection of 0.8 fg mL(−1) (equivalent to ~ 134 molecules in a 10 μL sample). The ECL immunosensing system based on eATRP signal amplification technology provided a new way for rapid diagnosis of lung cancer by detecting CYFRA 21-1. [Figure: see text] SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00604-020-04677-x.