Monitoring autoimmune diseases by bioelectrochemical detection of autoantibodies. Application to the determination of anti-myelin basic protein autoantibodies in serum of multiple sclerosis patients.

Abstract

This work reports an amperometric bioplatform for the determination of anti-myelin basic protein autoantibodies (anti-MBP), a relevant biomarker for multiple sclerosis (MS) autoimmune disease. The developed configuration involves the use of carboxylated magnetic microparticles (cMBs) where the protein for specific capture of the target autoantibodies was covalently attached. The immobilized anti-MBP were further conjugated with a secondary antibody labelled with horseradish peroxidase (HRP-anti-hIgG) and amperometric transduction was performed by adding hydrogen peroxide and using hydroquinone (HQ) as redox mediator. The cathodic current resulting from the reduction of the corresponding quinone was directly proportional to the logarithmic concentration of the target autoantibodies. The analytical performance of the developed method for the determination of anti-MBP is competitive in terms of sensitivity and range of linearity with that claimed for the only biosensor reported so far in the literature, as well as with commercially available ELISA kits showing a remarkably shorter assay time. The bioplatform was applied to the analysis of serum samples of healthy individuals and patients diagnosed with MS providing results in agreement with the ELISA methodology.