The long-term objective of our research is to develop new molecular componentry for the rapidly developing fields of micro- and nano-scale diagnostic devices. While the device innovations and formats for bio-assays and sensors continue to expand, particularly in distributed diagnostic and home healthcare technologies, the reagents for assays and molecular separations remain surprisingly unchanged. Current methods for purification and concentration of diagnostic targets, for example, are based on traditional chromatography technologies that utilize relatively large changes in solution conditions to control separation steps. This research program has developed alternative new approaches to molecular switching and molecular separations that utilize """"""""smart"""""""" or stimuli-responsive conjugates and nanoparticles. Smart polymers serve as both antennae and actuators, to sense signals and respond to them, leading to control of biorecognition or separation events. Their characteristic sharp responses in coil size and physical properties to small changes in pH, temperature, and/or electromagnetic irradiation over narrow ranges or at specific wavelengths permits rapid and precise control of molecular binding and adhesion events via """"""""molecular switching"""""""" activities. This project will create new """"""""smart"""""""" technologies specifically for distributed diagnostic devices that utilize microfluidic lab-cards. These utilities include upstream processing (purification and concentration) of diagnostic targets, and the sequential control of enzyme activities from a multi-plexed mixture of different enzyme/substrate species. The molecular engineering underlying these aims combines sophisticated polymer design and synthesis with protein engineering, and then matches the smart reagent design to advanced fluidics capabilities pioneered at the University of Washington.

Public Health Relevance

There is a critical need for diagnostic technologies that be used in settings outside the hospital laboratory. This project is designed to develop nanomaterial-based technologies that enable small, and even hand-held, devices that accurately diagnose disease from drops of blood, saliva, and/or urine. These point-of-care diagnostic platforms utilize microfluidic lab-cards that can perform multiple assays from a single sample. The successful development of these new reagent technologies and their integration into innovative microfluidic devices could have wide-ranging impact in cancer or infectious disease diagnosis and monitoring.

National Institute of Health (NIH)
National Institute of Biomedical Imaging and Bioengineering (NIBIB)
Research Project (R01)
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Biomaterials and Biointerfaces Study Section (BMBI)
Program Officer
Korte, Brenda
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University of Washington
Biomedical Engineering
Schools of Engineering
United States
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Hoffman, John M; Stayton, Patrick S; Hoffman, Allan S et al. (2015) Stimuli-responsive reagent system for enabling microfluidic immunoassays with biomarker purification and enrichment. Bioconjug Chem 26:29-38
Jose, Rod R; Elia, Roberto; Tien, Lee W et al. (2014) Electroresponsive aqueous silk protein as ""smart"" mechanical damping fluid. ACS Appl Mater Interfaces 6:6212-6
Omura, Tomoyuki; Ebara, Mitsuhiro; Lai, James J et al. (2014) Design of smart nanogels that respond to physiologically relevant pH values and temperatures. J Nanosci Nanotechnol 14:2557-62
Ebara, Mitsuhiro; Hoffman, John M; Hoffman, Allan S et al. (2013) A photoinduced nanoparticle separation in microchannels via pH-sensitive surface traps. Langmuir 29:5388-93
Nash, Michael A; Waitumbi, John N; Hoffman, Allan S et al. (2012) Multiplexed enrichment and detection of malarial biomarkers using a stimuli-responsive iron oxide and gold nanoparticle reagent system. ACS Nano 6:6776-85
Fridley, Gina E; Le, Huy Q; Fu, Elain et al. (2012) Controlled release of dry reagents in porous media for tunable temporal and spatial distribution upon rehydration. Lab Chip 12:4321-7
Kinahan, Michelle E; Filippidi, Emmanouela; Koster, Sarah et al. (2011) Tunable silk: using microfluidics to fabricate silk fibers with controllable properties. Biomacromolecules 12:1504-11
Landesberg, Regina; Woo, Victoria; Cremers, Serge et al. (2011) Potential pathophysiological mechanisms in osteonecrosis of the jaw. Ann N Y Acad Sci 1218:62-79
Kirk, James T; Fridley, Gina E; Chamberlain, Jeffrey W et al. (2011) Multiplexed inkjet functionalization of silicon photonic biosensors. Lab Chip 11:1372-7
Nash, Michael A; Yager, Paul; Hoffman, Allan S et al. (2010) Mixed stimuli-responsive magnetic and gold nanoparticle system for rapid purification, enrichment, and detection of biomarkers. Bioconjug Chem 21:2197-204

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