title: A highly sensitive electrochemical immunosensor for hepatitis B virus surface antigen detection based on Hemin/G-quadruplex horseradish peroxidase-mimicking DNAzyme-signal amplification.
abstract: Here we prepared an electrochemical immunosensor employing Au sheet as working electrode, Fe3O4magnetic nanoparticles (MNPs) as supporting matrix and hemin/G-quadruplex DNAzyme as signal amplifier for determination of hepatitis B virus surface antigen (HBsAg). First, the primary antibody of HBs (Ab1) was immobilized on the surface of the carboxyl-modified MNPs. Then, the assembly of antibody and alkylthiol/G-quadruplex DNA/hemin on gold nanoparticles was used as bio-bar-coded nanoparticle probe. Protein target was sandwiched between the primary antibody of HBs (Ab1) immobilized on the MNPs and hemin bio-bar-coded AuNPs probe labeled antibody (Ab2). Hemin/G-quadruplex structure as HRP mimicking-DNAzyme significantly improved the catalytic reduction of H2O2by oxidation of methylene blue (MB). Square wave voltammetry signals of MB provided quantitative measurements of HBsAg with a linear concentration range of 0.3-1000 pgmL-1and detection limit of 0.19 pgmL-1. Due to efficient catalytic activity of HRP mimicking-DNAzyme, the proposed immunosensor exhibited high sensitivity and it holds great promise for clinical application and provides a new platform for immunosensor development and fast disease diagnosis.
authors.affiliation: Department of Chemistry, University of Kurdistan, 66177-15175 Sanandaj, Iran.
authors.forename: Negar
authors.initials: N
authors.lastname: Alizadeh
authors.affiliation: Department of Chemistry, University of Kurdistan, 66177-15175 Sanandaj, Iran; Research Center for Nanotechnology, University of Kurdistan, 66177-15175 Sanandaj, Iran. Electronic address: rhallaj@uok.ac.ir.
authors.forename: Rahman
authors.initials: R
authors.lastname: Hallaj
authors.affiliation: Department of Chemistry, University of Kurdistan, 66177-15175 Sanandaj, Iran; Research Center for Nanotechnology, University of Kurdistan, 66177-15175 Sanandaj, Iran. Electronic address: absalimi@uok.ac.ir.
authors.forename: Abdollah
authors.initials: A
authors.lastname: Salimi
mesh_terms: D000914:Antibodies, Viral / Q000737:chemistry; D015374:Biosensing Techniques / Q000379:methods*; D055664:Electrochemical Techniques; D054856:G-Quadruplexes; D006509:Hepatitis B / Q000175:diagnosis* / Q000821:virology; D006514:Hepatitis B Surface Antigens / Q000737:chemistry / Q000302:isolation & purification*; D006515:Hepatitis B virus / Q000302:isolation & purification* / Q000472:pathogenicity; D006801:Humans; D053768:Metal Nanoparticles / Q000737:chemistry
chemical_list: D000914:Antibodies, Viral; D006514:Hepatitis B Surface Antigens
keywords: DNAzyme; Electrochemical immunosensor; Fe(3)O(4) nanoparticle; Hemin/G-quadruplex; Hepatitis B virus surface antigen