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An Amperometric Immunosensor Based on Layer‐by‐Layer Assembly of L ‐Cysteine and Nanosized Prussian Blue on Gold Electrode for Determination of Human Chorionic Gonadotrophin
Author(s) -
Wang Jinfen,
Yuan Ruo,
Chai Yaqin,
Yin Bing,
Xu Yang,
Guan Shu
Publication year - 2009
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.200804468
Subject(s) - prussian blue , amperometry , bilayer , cyclic voltammetry , colloidal gold , ferrocyanide , chemistry , detection limit , layer by layer , analytical chemistry (journal) , electrode , nuclear chemistry , materials science , electrochemistry , layer (electronics) , nanoparticle , chromatography , nanotechnology , membrane , biochemistry
A novel amperometric immunosensor based on L ‐cysteine/nanosized Prussian blue bilayer films ({NPB/ L ‐cys} 2 ) and gold nanoparticles (nano‐Au) was fabricated for determination of human chorionic gonadotrophin (HCG). First, L ‐cys and NPB was self‐assembled by layer‐by‐layer (LBL) technology to form {NPB/ L ‐cys} 2 bilayer films on the gold electrode. Subsequently, nano‐Au layer was immobilized on the {NPB/ L ‐cys} 2 bilayer films by electrodepositing gold chloride tetrahydrate and then anti‐HCG was assembly on the nano‐Au layer. Finally hemoglobin (Hb) was employed to block sites against nonspecific binding. With the electrocatalytic ability of Hb and NPB for the reduction of H 2 O 2 , the current signal of the antigen‐antibody reaction was amplified and the enhanced sensitivity was achieved. In this study, the assembly process and performance of the immunosensor were characterized by cyclic voltammetry (CV) and the morphology was researched by scanning electron microscopy (SEM). The immunosensor performed a high sensitivity and a wide linear response to HCG in two ranges from 0.5 to 10 mIU/mL and from 10 to 200 mIU/mL with a relatively low detection limit of 0.2 mIU/mL at 3 times the background noise, as well as good stability and long‐term life.