Graphene as basis of biological sensors for determining markers of neurodegenerative dementia

Abstract

Objective. To develop technique immobilizing antibodies graphene surface of proteins that play a significant role in pathogenesis Alzheimer's disease.Materials and methods. Graphene films were obtained sublimation surface of SiC substrates. Presence graphene monolayer was confirmed spectroscopy spectra. Graphene surface quality was evaluated cyclic voltammetry. Functionalization by amino groups was carried out method based on sorption pyrene derivatives from a solution and phenylnitrogroups electrochemical method. Graphene was kept in solutions monoclonal antibodies to human beta-amyloid peptide 1–42. Preparations were also kept in solution secondary antibodies labeled with FITZ. Results were evaluated fluorescence microscopy. Additionally, samples were kept in solution antibody with peroxidase label, which was detected chemiluminescence.Results. For attachment specific antibodies surface of graphene, quality its surface is great importance. Optimal working concentration of antibodies of human beta-amyloid 1–42 in solution for subsequent manufacture biological sensors is 15 micrograms per 1 ml. Covalent crosslinking antibodies with glutaraldehyde with amino groups on graphene gives a slight gain in the level fluorescence compared with noncovalent sorption on graphene with nitro groups. Functionalization phenylnitrogroups is optimal for further work related to the identification specific antigens.Conclusions. The technique of immobilization on the graphene surface of specific antibodies to beta-amyloid in concentrations detected by fluorescence microscopy and chemiluminescence is investigated. Amount antibodies sufficient to create a biosensor is immobilized on graphene. It was found that functionalization of phenylnitrogroups allows creating optimal conditions for the attachment of antibodies to the graphene surface, as well as washing resulting antibody-antigenic complexes for further reuse of graphene biosensors.