Electrochemical immunosensing of Growth arrest‐specific 6 in human plasma and tumor cell secretomes

Abstract

Growth arrest-specific 6 (GAS6) protein plays a key role in processes related toproliferation,inflammation,angiogenesis,andatheroscleroticplaqueformation.In addition, it has been reported that plasma levels of GAS6 are related to cancerprognosis and other relevant pathologies, such as heart failure or sepsis. Wereport here the first electrochemical immunoplatform for the determination ofGAS6, which has demonstrated to be competitive with other available method-ologies in terms of cost, simplicity, and decentralized application. The developedimmunoplatform involves a sandwich immunoassay using magnetic microparti-cles (MBs) and uses amperometric detection at disposable screen-printed carbonelectrodes (SPCEs). The MBs were modified with an antibody specific to GAS6for its selective capture, which is further recognized by a biotinylated secondaryantibody subsequently labeled with a streptavidin-horseradish peroxidase(Strep-HRP) conjugate. The electrochemical detection was carried out using thehydroquinone (HQ)/H2O2system. The developed bioplatform exhibits a greatselectivity and low limit of detection (27 pg/mL) that allowed the determinationof the GAS6 circulating level in plasma samples from patients suffering heartfailure (HF) and diagnosed with pancreatic ductal adenocarcinoma (PDAC),as well as the determination of the target protein in raw secretomes of humancolorectal cancer cell lines.