Magneto-controlled electrochemical immunosensing platform to assess the senescence-associated GDF-15 marker in colorectal cancer

Abstract

In this study, we report a novel electrochemical immunoplatform using magnetic micro-supports and screen-printed carbon electrodes (SPCEs), overcoming limitations of the methods reported to date, for the rapid and sensitive determination of GDF-15, a molecular marker associated with cellular senescence in aging and cancer development and prognosis. The immunoplatform incorporated a sandwich-type configuration with specific capture and biotinylated-detection antibodies and used a streptavidin–peroxidase (strep–HRP) enzymatic conjugate as label. After magnetic capturing the micro-supports with the sandwich HRP-labeled immunocomplexes onto the surface of a SPCE, the change in cathodic current was quantified in the presence of H₂O₂ and hydroquinone (HQ), showing a direct correlation with the GDF-15 concentration. The proposed bioplatform exhibited attractive performance characteristics, including a good reproducibility (RSD 4.3%), and a wide linear concentration dynamic range from 140 to 10 000 pg mL⁻¹ with a low limit of detection (LOD) of 42 pg mL⁻¹ for GDF-15 standards in buffered solutions. The selectivity of the developed method and the storage stability of the capturing immunoconjugates were noteworthy. Indeed, the immunoconjugates showed a reliable performance for over 28 days when stored in a refrigerator. The immunoplatform was applied to a cohort of 19 plasma samples representing the different stages of colorectal cancer (CRC). The method allowed efficient discrimination between healthy individuals and CRC patients, particularly those in advanced stages, within a rapid 75-minute timeframe. The immunoplatform also presents substantial advantages in terms of cost-effectiveness, assay time reduction, and simplicity compared to other available techniques.