The collection of saliva is far preferable to collection of blood from the point of view of the person being sampled. However, in recent years microfluidic technologies for measuring analytes in blood have advanced rapidly, while the use of saliva as an analyte has lagged, both in terms of the number of analytes measured and the environments in which such measurements are made. In part, this is because saliva is more variable than plasma, has analytes in lower concentrations, and contains viscous and adhesive mucins. If it were practical to use saliva for many analytes commonly measured in blood, and to make those measurements on several analytes at once, inexpensively, and in a way not requiring technical training, enormous improvements in the quality, frequency and scope of biomedical testing for research, therapy, and health maintenance would be possible, particularly for ambulatory outpatients. This project will develop an integrated microfluidic system for rapidly, inexpensively, and simultaneously measuring multiple analytes in saliva, and in a simple disposable polymeric laminate format. A microfluidic device to allow rapid extraction of analytes from the mucins in saliva will be developed. Two new but demonstrated immunoassay technologies will be coupled to a microfluidic system that allows dry storage of all reagents at ambient conditions and measures multiple analytes in parallel. These assays can measure low levels of hormones, drugs, metabolites, and even proteins that indicate the presence of disease, as well as compounds specific to the oral cavity such as pathogens and markers for oral cancer. The immunoassays will initially be validated on hormones for which commercial immunoassays are available. Ongoing work on development of parallel diffusion immunoassays will be extended to saliva testing through coupling with the mucin-extraction system. To measure analytes present at concentrations below the limit of detection of the diffusion immunoassay, chemically amplified surface plasmon resonance imaging will be used. Dissolution of dry reagent will be employed to decorate the gold surface with multiple capture molecules. Finally, a versatile combined system will be designed and tested that will allow monitoring of samples by the two methods simultaneously. ? ?

National Institute of Health (NIH)
National Institute of Dental & Craniofacial Research (NIDCR)
Research Project--Cooperative Agreements (U01)
Project #
Application #
Study Section
Special Emphasis Panel (ZDE1-GH (68))
Program Officer
Shum, Lillian
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University of Washington
Biomedical Engineering
Schools of Engineering
United States
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Fu, Elain; Nelson, Kjell E; Ramsey, Stephen A et al. (2009) Modeling of a competitive microfluidic heterogeneous immunoassay: sensitivity of the assay response to varying system parameters. Anal Chem 81:3407-13
Lai, James J; Nelson, Kjell E; Nash, Michael A et al. (2009) Dynamic bioprocessing and microfluidic transport control with smart magnetic nanoparticles in laminar-flow devices. Lab Chip 9:1997-2002
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Foley, Jennifer O; Mashadi-Hossein, Afshin; Fu, Elain et al. (2008) Experimental and model investigation of the time-dependent 2-dimensional distribution of binding in a herringbone microchannel. Lab Chip 8:557-64
Helton, Kristen L; Nelson, Kjell E; Fu, Elain et al. (2008) Conditioning saliva for use in a microfluidic biosensor. Lab Chip 8:1847-51
Hasenbank, Melissa S; Edwards, Thayne; Fu, Elain et al. (2008) Demonstration of multi-analyte patterning using piezoelectric inkjet printing of multiple layers. Anal Chim Acta 611:80-8
Foley, Jennifer O; Fu, Elain; Gamble, Lara J et al. (2008) Microcontact printed antibodies on gold surfaces: function, uniformity, and silicone contamination. Langmuir 24:3628-35
Fu, Elain; Ramsey, Stephen A; Chen, Jingyi et al. (2007) Resonance wavelength-dependent signal of absorptive particles in surface plasmon resonance-based detection. Sens Actuators B Chem 123:606-613
Fu, Elain; Ramsey, Stephen A; Yager, Paul (2007) Dependence of the signal amplification potential of colloidal gold nanoparticles on resonance wavelength in surface plasmon resonance-based detection. Anal Chim Acta 599:118-23
Helton, Kristen L; Yager, Paul (2007) Interfacial instabilities affect microfluidic extraction of small molecules from non-Newtonian fluids. Lab Chip 7:1581-8

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