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Electrochemical magnetoimmunosensor for the ultrasensitive determination of interleukin-6 in saliva and urine using poly-HRP streptavidin conjugates as labels for signal amplification

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Ojeda, I and Moreno Guzmán, María and González Cortés, Araceli and Yáñez Sedeño, Paloma and Pingarrón Carrazón, José Manuel (2014) Electrochemical magnetoimmunosensor for the ultrasensitive determination of interleukin-6 in saliva and urine using poly-HRP streptavidin conjugates as labels for signal amplification. Analytical and Bioanalytical Chemistry, 406 . pp. 6363-6371. ISSN 1618-2642 (Print) 1618-2650 (Web)

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Official URL: https://link.springer.com/article/10.1007/s00216-014-8055-6



Abstract

A novel magnetoimmunosensor design for interleukin-6 (IL-6) which involved the covalent immobilization of anti-IL-6 antibodies onto carboxyl-functionalized magnetic microparticles and a sandwich-type immunoassay with signal amplification using poly-HRP-streptavidin conjugates is reported. All the variables concerning the preparation and the electroanalytical performance of the immunosensor were optimized. The use of poly-HRP-strept conjugates as enzymatic labels instead of conventional HRP-strept allowed enhanced signal-to-blank current ratios to be obtained. A linear calibration plot between the measured steady-state current and the log of IL-6 concentration was achieved in the 1.75 to 500 pg/mL range, which was not feasible when using HRP-strep as label. A limit of detection of 0.39 pg/mL IL-6 was obtained. The antiIL-6-MB conjugates exhibited an excellent storage stability providing amperometric responses with no significant loss during at least 36 days. The magnetoimmunosensor showed also an excellent selectivity against potentially interfering substances. The immunosensor was used to determine IL-6 in urine samples spiked at three different concentration levels with clinical relevance. Moreover, IL-6 was measured in three different saliva samples corresponding to a periodontitis patient, a smoker volunteer, and a non-smoker volunteer. The obtained results were statistically in agreement with those provided by a commercial ELISA kit.


Item Type:Article
Uncontrolled Keywords:Interleukin-6, Electrochemical magnetoimmunosensor, Signal amplification, Poly-HRP-streptavidin, Urine, Saliva
Subjects:Sciences > Chemistry > Analytic chemistry
ID Code:44805
Deposited On:25 Sep 2017 11:50
Last Modified:05 Aug 2019 08:57

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