Automated-immunosensor with centrifugal fluid valves for salivary cortisol measurement

Point-of-care measurement of the stress hormone cortisol will greatly facilitate the timely diagnosis and management of stress-related disorders. We describe an automated salivary cortisol immunosensor, incorporating centrifugal fluid valves and a disposable disc-chip that allows for truncated repor...

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Main Authors: Masaki Yamaguchi, Hiroki Katagata, Yuki Tezuka, Daisuke Niwa, Vivek Shetty
Format: Article
Language:English
Published: Elsevier 2014-08-01
Series:Sensing and Bio-Sensing Research
Online Access:http://www.sciencedirect.com/science/article/pii/S2214180414000099
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author Masaki Yamaguchi
Hiroki Katagata
Yuki Tezuka
Daisuke Niwa
Vivek Shetty
author_facet Masaki Yamaguchi
Hiroki Katagata
Yuki Tezuka
Daisuke Niwa
Vivek Shetty
author_sort Masaki Yamaguchi
collection DOAJ
description Point-of-care measurement of the stress hormone cortisol will greatly facilitate the timely diagnosis and management of stress-related disorders. We describe an automated salivary cortisol immunosensor, incorporating centrifugal fluid valves and a disposable disc-chip that allows for truncated reporting of cortisol levels (<15 min). The performance characteristics of the immunosensor are optimized through select blocking agents to prevent the non-specific adsorption of proteins; immunoglobulin G (IgG) polymer for the pad and milk protein for the reservoirs and the flow channels. Incorporated centrifugal fluid valves allow for rapid and repeat washings to remove impurities from the saliva samples. An optical reader and laptop computer automate the immunoassay processes and provide easily accessible digital readouts of salivary cortisol measurements. Linear regression analysis of the calibration curve for the cortisol immunosensor showed 0.92 of coefficient of multiple determination, R2, and 38.7% of coefficient of variation, CV, for a range of salivary cortisol concentrations between 0.4 and 11.3 ng/mL. The receiver operating characteristic (ROC) curve analysis of human saliva samples indicate potential utility for discriminating stress disorders and underscore potential application of the biosensor in stress disorders. The performance of our salivary cortisol immunosensor approaches laboratory based tests and allows noninvasive, quantitative, and automated analysis of human salivary cortisol levels with reporting times compatible with point-of-care applications. Keywords: Immunosensor, Centrifugal fluid valve, Automation, Cortisol, Saliva
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spelling doaj.art-3c298afad3a340db9e82682b4f9c75cc2022-12-22T00:03:40ZengElsevierSensing and Bio-Sensing Research2214-18042014-08-0111520Automated-immunosensor with centrifugal fluid valves for salivary cortisol measurementMasaki Yamaguchi0Hiroki Katagata1Yuki Tezuka2Daisuke Niwa3Vivek Shetty4Biomedical Engineering & Robotics Laboratory, Graduate School of Engineering, Iwate University, 4-3-5 Ueda, Morioka 020-8551, Japan; Corresponding author. Tel./fax: +81 19 621 6349.Biomedical Engineering & Robotics Laboratory, Graduate School of Engineering, Iwate University, 4-3-5 Ueda, Morioka 020-8551, JapanBiomedical Engineering & Robotics Laboratory, Graduate School of Engineering, Iwate University, 4-3-5 Ueda, Morioka 020-8551, JapanNano Bionics R&D Center, Research and Development Headquarters, Rohm Co., Ltd., 21 Saiin Mizosaki-cho, Ukyo-ku, Kyoto 615-8585, JapanSection of Oral and Maxillofacial Surgery, UCLA School of Dentistry, University of California, 10833 Le Conte Avenue, Los Angeles, CA 90095-1668, USAPoint-of-care measurement of the stress hormone cortisol will greatly facilitate the timely diagnosis and management of stress-related disorders. We describe an automated salivary cortisol immunosensor, incorporating centrifugal fluid valves and a disposable disc-chip that allows for truncated reporting of cortisol levels (<15 min). The performance characteristics of the immunosensor are optimized through select blocking agents to prevent the non-specific adsorption of proteins; immunoglobulin G (IgG) polymer for the pad and milk protein for the reservoirs and the flow channels. Incorporated centrifugal fluid valves allow for rapid and repeat washings to remove impurities from the saliva samples. An optical reader and laptop computer automate the immunoassay processes and provide easily accessible digital readouts of salivary cortisol measurements. Linear regression analysis of the calibration curve for the cortisol immunosensor showed 0.92 of coefficient of multiple determination, R2, and 38.7% of coefficient of variation, CV, for a range of salivary cortisol concentrations between 0.4 and 11.3 ng/mL. The receiver operating characteristic (ROC) curve analysis of human saliva samples indicate potential utility for discriminating stress disorders and underscore potential application of the biosensor in stress disorders. The performance of our salivary cortisol immunosensor approaches laboratory based tests and allows noninvasive, quantitative, and automated analysis of human salivary cortisol levels with reporting times compatible with point-of-care applications. Keywords: Immunosensor, Centrifugal fluid valve, Automation, Cortisol, Salivahttp://www.sciencedirect.com/science/article/pii/S2214180414000099
spellingShingle Masaki Yamaguchi
Hiroki Katagata
Yuki Tezuka
Daisuke Niwa
Vivek Shetty
Automated-immunosensor with centrifugal fluid valves for salivary cortisol measurement
Sensing and Bio-Sensing Research
title Automated-immunosensor with centrifugal fluid valves for salivary cortisol measurement
title_full Automated-immunosensor with centrifugal fluid valves for salivary cortisol measurement
title_fullStr Automated-immunosensor with centrifugal fluid valves for salivary cortisol measurement
title_full_unstemmed Automated-immunosensor with centrifugal fluid valves for salivary cortisol measurement
title_short Automated-immunosensor with centrifugal fluid valves for salivary cortisol measurement
title_sort automated immunosensor with centrifugal fluid valves for salivary cortisol measurement
url http://www.sciencedirect.com/science/article/pii/S2214180414000099
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