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Washing-free heterogeneous immunosensor using proximity-dependent electron mediation between an enzyme label and an electrode

Authors
 Gorachand Dutta  ;  Sinyoung Kim  ;  Seonhwa Park  ;  Haesik Yang 
Citation
 ANALYTICAL CHEMISTRY, Vol.86(9) : 4589-4595, 2014 
Journal Title
 ANALYTICAL CHEMISTRY 
ISSN
 0003-2700 
Issue Date
2014
Abstract
Washing processes, essential in most heterogeneous labeled assays, have been a big hurdle in simplifying the detection procedure and reducing assay time. Nevertheless, less attention has been paid to washing-free heterogeneous labeled assays. We report a purely washing-free immunosensor that allows fast, sensitive, and single-step detection of prostate-specific antigen in serum with low interference. Proximity-dependent electron mediation of ferrocenemethanol (Fc) between an indium-tin oxide (ITO) electrode and a glucose-oxidase (GOx) label allows us to discriminate between a bound and an unbound label: a bound label offers faster electron mediation than an unbound one. The electrooxidation of Fc at a low applied potential (0.13 V vs Ag/AgCl) and a low electrocatalytic ITO electrode and the oxidation of l-ascorbic acid by l-ascorbate oxidase minimize the effect of the interfering species. With a high concentration of glucose (200 mM), the signal and background levels are hardly dependent on the glucose-concentration variation in the sample. The washing-free immunosensor can detect a concentration of ca. 1 pg/mL for mouse IgG in phosphate-buffered saline and a concentration of ca. 10 pg/mL for prostate-specific antigen spiked in female serum after an incubation period of 10 min. The concentrations measured with actual clinical serum samples are in good agreement with the concentrations measured with a commercial instrument, which renders the washing-free heterogeneous immunosensor appealing for practical use.
Full Text
http://pubs.acs.org/doi/abs/10.1021/ac5006487
DOI
10.1021/ac5006487
Appears in Collections:
1. College of Medicine (의과대학) > Dept. of Laboratory Medicine (진단검사의학교실) > 1. Journal Papers
Yonsei Authors
Kim, Sin Young(김신영) ORCID logo https://orcid.org/0000-0002-2609-8945
URI
https://ir.ymlib.yonsei.ac.kr/handle/22282913/139103
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