TY - JOUR
T1 - Magnetic nanocomposite of anti-human IgG/COOH-multiwalled carbon nanotubes/Fe3O4 as a platform for electrochemical immunoassay
AU - Zarei, Hajar
AU - Ghourchian, Hedayatollah
AU - Eskandari, Khadijeh
AU - Zeinali, Majid
N1 - Funding Information:
Financial support provided by the Research Council of the University of Tehran and Pishtazteb Diagnostics (Tehran, Iran) is gratefully appreciated.
PY - 2012/2/15
Y1 - 2012/2/15
N2 - An electrochemical immunosensing method was developed based on a magnetic nanocomposite. The multiwalled carbon nanotubes (MWCNTs) were treated with nitric acid to produce carboxyl groups at the open ends. Then, Fe 3O4 nanoparticles were deposited on COOH-MWCNTs by chemical coprecipitation of Fe2+ and Fe3+ salts in an alkaline solution. Goat anti-human IgG (anti-hIgG) was covalently attached to magnetic nanocomposite through amide bond formation between the carboxylic groups of MWCNTs and the amine groups of anti-hIgG. The prepared bio-nanocomposite was used for electrochemical sensing of human tetanus IgG (hIgG) as a model antigen. The anti-hIgG magnetic nanocomposite was fixed on the surface of a gold plate electrode using a permanent magnet. The hIgG was detected using horseradish peroxidase (HRP)-conjugated anti-hIgG in a sandwich model. Electrochemical detection of hIgG was carried out in the presence of H2O2 and KI as substrates of HRP. Using this method, hIgG was detected in a concentration range from 30 to 1000 ng ml-1 with a correlation coefficient of 0.998 and a detection limit of 25 ng ml-1 (signal/noise = 3). The designed immunosensor was stable for 1 month.
AB - An electrochemical immunosensing method was developed based on a magnetic nanocomposite. The multiwalled carbon nanotubes (MWCNTs) were treated with nitric acid to produce carboxyl groups at the open ends. Then, Fe 3O4 nanoparticles were deposited on COOH-MWCNTs by chemical coprecipitation of Fe2+ and Fe3+ salts in an alkaline solution. Goat anti-human IgG (anti-hIgG) was covalently attached to magnetic nanocomposite through amide bond formation between the carboxylic groups of MWCNTs and the amine groups of anti-hIgG. The prepared bio-nanocomposite was used for electrochemical sensing of human tetanus IgG (hIgG) as a model antigen. The anti-hIgG magnetic nanocomposite was fixed on the surface of a gold plate electrode using a permanent magnet. The hIgG was detected using horseradish peroxidase (HRP)-conjugated anti-hIgG in a sandwich model. Electrochemical detection of hIgG was carried out in the presence of H2O2 and KI as substrates of HRP. Using this method, hIgG was detected in a concentration range from 30 to 1000 ng ml-1 with a correlation coefficient of 0.998 and a detection limit of 25 ng ml-1 (signal/noise = 3). The designed immunosensor was stable for 1 month.
KW - Biosensor
KW - Electrochemical immunoassay
KW - Magnetic nanocomposite
KW - Multiwalled carbon nanotubes
KW - Sandwich model
UR - http://www.scopus.com/inward/record.url?scp=84859705187&partnerID=8YFLogxK
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U2 - 10.1016/j.ab.2011.12.031
DO - 10.1016/j.ab.2011.12.031
M3 - Article
C2 - 22245258
AN - SCOPUS:84859705187
VL - 421
SP - 446
EP - 453
JO - Analytical Biochemistry
JF - Analytical Biochemistry
SN - 0003-2697
IS - 2
ER -