Development of an immunoassay based on impedance measurements utilizing an antibody-nanosilver probe, silver enhancement, and electro-microchip

作者：Yeh Chia Hsien; Chen Wei Ting; Lin Hong Ping; Chang Tsung Chain; Lin Yu Cheng^*

来源：Sensors and Actuators B: Chemical , 2009, 139(2): 387-393.

DOI：10.1016/j.snb.2009.03.029

• Immunoassay
• Electro-microchip
• Silver nanoparticles
• Silver enhancement

This study reports a new, simple and sensitive immunoassay that uses the impedance variation caused by silver nanoparticles (AgNPs) coated with an antibody. In this method, an electro-microchip is used to detect the immuno-reaction signal of antibody-antigen recognition, AgNPs as a label of antibody and a catalyst for silver precipitation, and the silver enhancement reaction is used to magnify the detection signal. Our model format is based on the sandwich immunoassay (three-layer format). The AgNPs were introduced into the electro-microchip by the specific binding of the antibodies and then coupled with silver enhancement Solution to reduce silver ions to silver metal. The silver precipitation Constructs a "bridge" between two electrodes of the electro-microchip allowing the electrons to pass. There was a significant difference in impedance between the experimental sample and the negative control after 10min of reaction time. The proposed method requires less time and fewer steps than enzyme-linked immunosorbent assay (ELISA). It also has a high detection sensitivity (10 mu g/mL of 1st antibody (IgG) immobilized on slides and 0.1 ng/mL of antigen (protein A)). Therefore, a new immunoassay is constructed using an electro-microchip. antibody-AgNPs conjugates, and a silver enhancement reaction.

• 出版日期2009-6-4