Demyelination detection in CSF based on electrochemical monitoring of myelin basic protein in comparison between Apta vs. Immuno sensing strategies

Abstract

Multiple sclerosis (MS) is a recurrent inflammatory, demyelinating disease of the white matter in central nervous system (CNS). The number of MS patients is increasing, but the diagnostic process is still quite difficult, costly and requires combination of several methods. Myelin basic protein (MBP) makes up to 30 % of the myelin in CNS. It is known that MBP is released into the cerebrospinal fluid (CSF) as MS bioindicator. Herein, myelin specific DNA aptamer earlier developed for possible therapeutic purposes and anti-MBP antibody were applied as bioreceptors for MBP recognition on the same nanomodified sensor surfaces and their performances were compared. Biosensors were developed by using graphene oxide (GO) nanoparticles integrated onto pencil graphite electrodes (PGE) and bioreceptor molecules immobilized to create a bioactive layer for MBP binding. The measurements were run with electrochemical impedance spectroscopy (EIS). Selectivity of the biosensors was evaluated using human serum albumin (HSA). After optimization of binding parameters, biosensors were validated in artificial CSF. It was shown that LJM-5708 based aptasensor had LOD 0.65 ng/mL that was comparable to immunosensor LOD (0.36 ng/mL) in artificial CSF and showed its applicability in the clinical concentration range between 1 and 128 ng/mL.