First electrochemical bioplatform to assist in personalized 5-fluorouracil chemotherapy

This work reports a simple biotool for the determination of 5-fluorouracil (5-FU), a drug often used in chemotherapy for the treatment of certain cancers. The methodology involves an indirect competitive immunoassay performed on the surface of magnetic microbeads (MBs) and amperometric transduction at screen-printed carbon electrodes (SPCEs). In brief, free 5-FU competes with 5-FU-BSA covalently immobilized on HOOC-MBs for the limited recognition sites of a 5-FU-selective detection antibody (DAb) labeled with a secondary antibody conjugated to the peroxidase enzyme (HRP-antimIgG). Amperometric transduction was made using the H2O2/hydroquinone (HQ) system. The method provides analytical characteristics in terms of sensitivity (LOD of 1.0 ng mL-1) and selectivity suitable with clinical usefulness and is competitive with other reported electrochemical non-biosensing detection strategies in terms of simplicity and assay time. Most interestingly, the method exhibits high accuracy in the analysis of a pharmaceutical formulation and of serum samples even from a patient with colorectal cancer (CRC) undergoing treatment with 5-FU thus showing potential for chemotherapy monitoring and personalized chemotherapy.