title: Magnetic nanoparticle-based immunosensor for electrochemical detection of hepatitis B surface antigen.
abstract: An electrochemical immunosensor was developed for the detection of hepatitis B surface antigen (HBsAg). The biotinylated hepatitis B surface antibody was immobilized on streptavidin magnetic nanoparticles and used for targeting the HBsAg. By the addition of horseradish peroxidase conjugated with secondary antibody (HRP-HBsAb), a sandwich-type immunoassay format was formed. Aminophenol as substrate for conjugated HRP was enzymatically changed into 3-aminophenoxazone (3-APZ). This electroactive enzymatic production (3-APZ) was transferred into an electrochemical cell and monitored by cyclic voltammetry. Under optimal conditions, the cathodic current response of 3-APZ, which was proportional to the HBsAg concentration, was measured by a glassy carbon electrode. The immunosensor response was linear toward HBsAg in the concentration range from 0.001 to 0.015 ng/ml with a detection limit of 0.9 pg/ml at a signal/noise ratio of 3.
authors.affiliation: Laboratory of Microanalysis, Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran.
authors.forename: Sara
authors.initials: S
authors.lastname: Nourani
authors.forename: Hedayatollah
authors.initials: H
authors.lastname: Ghourchian
authors.forename: Seyed Mehdi
authors.initials: SM
authors.lastname: Boutorabi
mesh_terms: D015374:Biosensing Techniques; D055664:Electrochemical Techniques; D006514:Hepatitis B Surface Antigens / Q000032:analysis* / Q000276:immunology*; D058185:Magnetite Nanoparticles / Q000737:chemistry*
chemical_list: D006514:Hepatitis B Surface Antigens; D058185:Magnetite Nanoparticles
keywords: Aminophenol; Aminophenoxazone; Electrochemical immunosensor; Hepatitis B surface antigen; Magnetic nanoparticles