Amplification of antigen-antibody interactions based on biotin labeled protein-streptavidin network complex using impedance spectroscopy.
Antibody was covalently immobilized by amine coupling method to gold surfaces modified with a self-assembled monolayer of thioctic acid. The electrochemical measurements of cyclic voltammetry and impedance spectroscopy showed that the hexacyanoferrate redox reactions on the gold surface were blocked due to the procedures of self-assembly of thioctic acid and antibody immobilization. The binding of a specific antigen to antibody recognition layer could be detected by measurements of the impedance change. A new amplification strategy was introduced for improving the sensitivity of impedance measurements using biotin labeled protein-streptavidin network complex. This amplification strategy is based on the construction of a molecular complex between streptavidin and biotin labeled protein. This complex can be formed in a cross-linking network of molecules so that the amplification of response signal will be realized due to the big molecular size of complex. The results show that this amplification strategy causes dramatic improvement of the detection sensitivity of hIgG and has good correlation for detection of hIgG in the range of 2-10 microg/ml.
Pei
R
R
Laboratory of Electroanalytical Chemistry and National Analytical Research Center of Electrochemistry and Spectroscopy Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun Jilin, 130022, People's Republic of China.
Cheng
Z
Z
Wang
E
E
Yang
X
X
D000588:Amines / Q000737:chemistry; D000906:Antibodies / Q000032:analysis / Q000276:immunology; D000937:Antigen-Antibody Reactions / Q000276:immunology; D001426:Bacterial Proteins / Q000032:analysis*; D015374:Biosensing Techniques; D001710:Biotin / Q000031:analogs & derivatives* / Q000032:analysis*; D017097:Electric Impedance; D004563:Electrochemistry; D004566:Electrodes; D006801:Humans; D007103:Immobilization; D007118:Immunoassay / Q000379:methods*; D007074:Immunoglobulin G / Q000032:analysis* / Q000276:immunology; D008063:Thioctic Acid / Q000737:chemistry
D000588:Amines; D000906:Antibodies; D001426:Bacterial Proteins; D007074:Immunoglobulin G; C066114:biotin-streptavidin complex; D001710:Biotin; D008063:Thioctic Acid