A stable label-free electrochemical immunosensor based on AuNPs/Fe-MOFs/COOH-GO composites for the detection of non-small cell lung cancer marker CYFRA21-1

This study developed a stable, label-free AuNPs/Fe-MOFs/COOH-GO electrochemical immunosensor for the detection of Cytokeratin 19 fragment (CYFRA21-1), a critical biomarker for the early screening and diagnosis of non-small cell lung cancer (NSCLC). The nanocomposites of AuNPs/Fe-MOFs/COOH-GO was synthesized using a combination of hydrothermal synthesis, chemical reduction, and ultrasonic dispersion. AuNPs and COOH-GO components contributed high conductivity and a large specific surface area, which significantly enhanced the sensitivity of the sensor. The three-dimensional mesoporous structure of the Fe-MOFs further improved the stability of the immunosensor. Firstly, our novel nanocomposites was modified by using a glassy carbon electrode (GCE). CYFRA21-1 antibodies were then immobilized on the modified surface via interactions with thiol and carboxyl groups present on the nanomaterial. Bovine serum albumin (BSA) was employed to block non-specific binding sites. The constructed immunosensor exhibited a wide detection range for CYFRA21-1 from 1 pg mL −1 to 100,000 pg mL −1 , with a correlation coefficient (R 2 ) of 0.9989 in differential pulse voltammetry, and the limit of detection was defined as 0.35 pg mL −1 . The sensor also demonstrated high sensitivity, excellent specificity, good reproducibility, and remarkable stability, indicating its potent application potential for the early screening and diagnosis of NSCLC.