An electrochemical impedance spectroscopy method of detection for aptamer-based array electrodes is reported in which the binding of aptamers immobilized on gold electrodes leads to impedance changes associated with target protein binding events. Human IgE was used as a model target protein and incubated with the aptamer-based array consisting of single-stranded DNA containing a hairpin loop. To increase the binding efficiency for proteins, a hybrid modified layer containing aptamers and cysteamine was fabricated on the photolithographic gold surface through molecular self-assembly. Atomic force microscopy analysis demonstrated that human IgE could be specifically captured by the aptamer and stand well above the self-assembled monolayer (SAM) surface. Compared to immunosensing methods using anti-human IgE antibody as the recognition element, impedance spectroscopy detection could provide higher sensitivity and better selectivity for aptamer-modified electrodes. The results of this method show good correlation for human IgE in the range of 2.5-100 nM. A detection limit of 0.1 nM (5 fmol in a 50-microL sample) was obtained, and an average of the relative standard deviation was <10%. The method herein describes the first label-free detection for arrayed electrodes utilizing electrochemical impedance spectroscopy.
%0 Journal Article
%1 citeulike:780934
%A Xu, D.
%A Xu, D.
%A Yu, X.
%A Liu, Z.
%A He, W.
%A Ma, Z.
%C Department of Biochemistry, Beijing Institute of Radiation Medicine, Beijing 100850, China. xudk@nic.bmi.ac.cn
%D 2005
%J Anal Chem
%K aptamer surface electrochemistry
%N 16
%P 5107--5113
%R 10.1021/ac050192m
%T Label-free electrochemical detection for aptamer-based array electrodes.
%U http://dx.doi.org/10.1021/ac050192m
%V 77
%X An electrochemical impedance spectroscopy method of detection for aptamer-based array electrodes is reported in which the binding of aptamers immobilized on gold electrodes leads to impedance changes associated with target protein binding events. Human IgE was used as a model target protein and incubated with the aptamer-based array consisting of single-stranded DNA containing a hairpin loop. To increase the binding efficiency for proteins, a hybrid modified layer containing aptamers and cysteamine was fabricated on the photolithographic gold surface through molecular self-assembly. Atomic force microscopy analysis demonstrated that human IgE could be specifically captured by the aptamer and stand well above the self-assembled monolayer (SAM) surface. Compared to immunosensing methods using anti-human IgE antibody as the recognition element, impedance spectroscopy detection could provide higher sensitivity and better selectivity for aptamer-modified electrodes. The results of this method show good correlation for human IgE in the range of 2.5-100 nM. A detection limit of 0.1 nM (5 fmol in a 50-microL sample) was obtained, and an average of the relative standard deviation was <10%. The method herein describes the first label-free detection for arrayed electrodes utilizing electrochemical impedance spectroscopy.
@article{citeulike:780934,
abstract = {An electrochemical impedance spectroscopy method of detection for aptamer-based array electrodes is reported in which the binding of aptamers immobilized on gold electrodes leads to impedance changes associated with target protein binding events. Human IgE was used as a model target protein and incubated with the aptamer-based array consisting of single-stranded DNA containing a hairpin loop. To increase the binding efficiency for proteins, a hybrid modified layer containing aptamers and cysteamine was fabricated on the photolithographic gold surface through molecular self-assembly. Atomic force microscopy analysis demonstrated that human IgE could be specifically captured by the aptamer and stand well above the self-assembled monolayer (SAM) surface. Compared to immunosensing methods using anti-human IgE antibody as the recognition element, impedance spectroscopy detection could provide higher sensitivity and better selectivity for aptamer-modified electrodes. The results of this method show good correlation for human IgE in the range of 2.5-100 nM. A detection limit of 0.1 nM (5 fmol in a 50-microL sample) was obtained, and an average of the relative standard deviation was <10%. The method herein describes the first label-free detection for arrayed electrodes utilizing electrochemical impedance spectroscopy.},
added-at = {2006-07-31T20:01:51.000+0200},
address = {Department of Biochemistry, Beijing Institute of Radiation Medicine, Beijing 100850, China. xudk@nic.bmi.ac.cn},
author = {Xu, D. and Xu, D. and Yu, X. and Liu, Z. and He, W. and Ma, Z.},
biburl = {https://www.bibsonomy.org/bibtex/26df571f37298fc4a07f93c555995235e/biblio24},
citeulike-article-id = {780934},
comment = {xudk@nic.bmi.ac.cn},
doi = {10.1021/ac050192m},
interhash = {cde352182645fcf5ab3bda4425d94623},
intrahash = {6df571f37298fc4a07f93c555995235e},
issn = {0003-2700},
journal = {Anal Chem},
keywords = {aptamer surface electrochemistry},
month = {August},
number = 16,
pages = {5107--5113},
priority = {2},
timestamp = {2006-07-31T20:01:51.000+0200},
title = {Label-free electrochemical detection for aptamer-based array electrodes.},
url = {http://dx.doi.org/10.1021/ac050192m},
volume = 77,
year = 2005
}