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Gold Nanoparticle‐Based Redox Signal Enhancement for Sensitive Detection of Human Chorionic Gonadotropin Hormone
Author(s) -
Idegami Koutarou,
Chikae Miyuki,
Kerman Kagan,
Nagatani Naoki,
Yuhi Teruko,
Endo Tatsuro,
Tamiya Eiichi
Publication year - 2008
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/elan.200704011
Subject(s) - differential pulse voltammetry , detection limit , biosensor , colloidal gold , human chorionic gonadotropin , nanoparticle , materials science , chemistry , cyclic voltammetry , nanotechnology , chromatography , electrochemistry , hormone , electrode , biochemistry
A sensitive immunosensor for the detection of pregnancy marker, human chorionic gonadotropin hormone (hCG), was developed using the direct electrical detection of Au nanoparticles. We utilized disposable screen‐printed carbon strips (SPCSs) for the development of our immunosensor, which provided cost‐effective tests with the required antigen sample volume as small as 2 μL. After the recognition reaction between the surface‐immobilized primary antibody and hCG, the captured antigen was sandwiched with a secondary antibody that was labeled with Au nanoparticles. Au nanoparticles were exposed to a preoxidation process at 1.2 V for 40 s, which was subsequently followed with a reduction scan on the same surface using differential pulse voltammetry (DPV). We could observe Au nanoparticle‐labeled antigen‐antibody complexes immobilized on the surface of SPCS using scanning electron microscopy (SEM). Additionally, the number of Au nanoparticles on the immunosensor was determined using SEM images, and showed a linear relationship with the current intensity obtained from the DPV measurements with a detection limit of 36 pg/mL hCG (612 fM, 3.6×10 −4 IU/mL). Our immunosensor system, a combination of the screen‐printing technology with Au nanoparticles provides a promising biosensor for various applications in life sciences.