Electrochemical immunoplatform to help managing pancreatic cancer

Abstract

Pancreatic ductal adenocarcinoma (PDAC) is the solid tumor with the worst prognosis, representing today the third cause of cancer-related deaths in developed countries and expected to be the second in 2030. Today, CA19-9 remains the only clinically used marker for management of PDAC (FDA-approved as a disease moni- toring marker). This work reports a disposable amperometric immunoplatform for the determination of CA19-9. The immunoplatform skilfully combines the advantages of magnetic microsupports (MBs) for implementation of the immunoassay and amperometric transduction on screen-printed carbon electrodes (SPCEs). The method involves the preparation of sándwich immunocomplexes enzymatically labeled with the enzyme horseradish peroxidase (HRP) on the MBs and uses a detection antibody conjugated to HRP. Once the HRP- labeled sandwich immunocomplexes-bearing MBs were trapped on the SPCE surface, the variation of the catho- dic current was measured in the presence of H2O2 and hydroquinone (HQ), which was directly proportional to the concentration of CA19-9. Under the optimized experimental conditions, the immunoplatform allowed the amperometric determination of CA19-9 standards over the 5.0 to 500 U mL−1 concentration range, with a limit of detection (LOD) value of 1.5 U mL−1 in 1 h. The method exhibits good reproducibility and selectivity and the magnetic immunoconjugates shows a good storage stability. The immunoplatform was applied to the deter- mination of CA19-9 in serum samples of a medium-sized cohort (22 individuals) of healthy subjects and patients diagnosed with PDAC. The obtained results demonstrated the immunoplatform ability to discriminateboth types of individuals within 1 h after sample dilution. The developed immunoplatform represents an improvement in terms of cost, applicability and accessibility compared to the ELISA-based techniques currently used in the clinic.