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

Abstract

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.

Electrochemical Sensors

“…Wang et al fabricated an amperometric human chorionic gonadotrophin (HCG) immunosensor using L-cysteine/nanosized Prussian blue bilayer films and gold nanoparticles (182). Current generated due to antigen-antibody binding was amplified electrocatalytically using hemoblobin and the nanosized Prussian blue bilayer films to enhance sensitivity.…”

Electrochemical nanoarchitectonics and layer-by-layer assembly: From basics to future

“…CEA detection could be improved by immobilizing anti-CEA on LbL films containing gold-decorated NTs [184]. Another tumor marker, human chorionic gonadotropin, has also recently been the subject of detection using an amperometric LbL immunosensor [185]. DNA and nucleotide-based biosensors.…”

Sensitive immunosensor for benzo[a]pyrene detection based on dual amplification strategy of PAMAM dendrimer and amino-modified methylene blue/SiO2 core–shell nanoparticles

“…Then, the modified electrode was incubated in 1 mg/mL HRP solution, instead of BSA, for 4 h at 4 • C to block possible remaining active sites of the PAMAM dendrimer and avoid the nonspecific binding. In this case, except for blocking the remaining active sites, a better electron transfer efficiency of HRP than BSA can improve the conductivity of the platform and increase the current response due to the catalytic properties of enzymes (Li et al, 2007;Wang et al, 2009). After each step, the electrode was washed with PBS (0.01 M) and dried in nitrogen flow.…”