TY - JOUR
T1 - Development of an immunoassay based on impedance measurements utilizing an antibody-nanosilver probe, silver enhancement, and electro-microchip
AU - Yeh, Chia Hsien
AU - Chen, Wei Ting
AU - Lin, Hong Ping
AU - Chang, Tsung Chain
AU - Lin, Yu Cheng
N1 - Funding Information:
The authors would like to thank the Center for Micro/Nano Technology Research, National Cheng Kung University, Tainan, Taiwan, R.O.C., for access to their equipment and for their technical support. Funding from the Ministry of Education and the National Science Council of Taiwan, R.O.C., under contract no. NSC 95-2221-E-006-006-MY3 and 97-2221-E-006-222-MY3 are gratefully acknowledged.
PY - 2009/6/4
Y1 - 2009/6/4
N2 - 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 10 min 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 μg/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.
AB - 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 10 min 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 μg/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.
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U2 - 10.1016/j.snb.2009.03.029
DO - 10.1016/j.snb.2009.03.029
M3 - Article
AN - SCOPUS:67349239806
VL - 139
SP - 387
EP - 393
JO - Sensors and Actuators, B: Chemical
JF - Sensors and Actuators, B: Chemical
SN - 0925-4005
IS - 2
ER -