Application of impedance spectroscopy for monitoring colloid Au-enhanced antibody immobilization and antibody-antigen reactions.
We used colloidal Au to enhance the amount of antibody immobilized on a gold electrode and ultimately monitored the interaction of antigen-antibody by impedance measurement. Self-assembly of 6 nm (diameter) colloidal Au onto the self-assembled monolayers (SAMs) of 4-aminothiophenol modified gold electrode resulted in an easier attachment of antibody. The redox reactions of [Fe(CN)6](4-)/[Fe(CN)6](3-) on the gold surface were blocked due to the procedures of self-assembly of 4-aminothiophenol and antibody immobilization, which were investigated by cyclic voltammetry and impedance spectroscopy. The interaction of antigen with grafted antibody recognition layers was carried out by soaking the modified electrode into a phosphate buffer at pH 7.4 with various concentrations of antigen at 37 degrees C for 30 min. The antibody recognition layers and their interactions with various concentrations of antigen could be detected by measurements of the impedance change. The results show that this method has good correlation for detection of Hepatitis B virus surface antigen in the range of 0.5-200 microg/l and a detection limit of about 50 ng/l.
Wang
Meijia
M
College of Chemistry, Jilin University, Changchun 130021, PR China.
Wang
Lianying
L
Wang
Gang
G
Ji
Xiaohui
X
Bai
Yubai
Y
Li
Tiejin
T
Gong
Shaoyun
S
Li
Jinghong
J
D000327:Adsorption; D000818:Animals; D000906:Antibodies / Q000032:analysis / Q000276:immunology; D000911:Antibodies, Monoclonal / Q000032:analysis / Q000276:immunology; D000936:Antigen-Antibody Complex / Q000032:analysis* / Q000276:immunology; D000937:Antigen-Antibody Reactions / Q000276:immunology*; D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D020099:Coated Materials, Biocompatible / Q000138:chemical synthesis; D017097:Electric Impedance; D004563:Electrochemistry / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D019544:Equipment Failure Analysis; D017979:Gold Colloid; D006510:Hepatitis B Antibodies / Q000032:analysis / Q000276:immunology; D007118:Immunoassay / Q000295:instrumentation* / Q000379:methods; D051379:Mice; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013057:Spectrum Analysis / Q000295:instrumentation / Q000379:methods*
D000906:Antibodies; D000911:Antibodies, Monoclonal; D000936:Antigen-Antibody Complex; D020099:Coated Materials, Biocompatible; D017979:Gold Colloid; D006510:Hepatitis B Antibodies