Barry R. Lutz
Research Assistant Professor
Biomaterials and Regenerative Medicine
Technology for Expanding Access to Heathcare
EducationPhD (Chemical Engineering), University of Washington, 2003
- Biosensor chemical transport & kinetics
- Sound-based microfluidic systems
- Point-of-care diagnostics
Contact InformationDepartment of Bioengineering
University of Washington
William H. Foege Building, Room N530N
From disease diagnosis to fundamental biology, measurements are highly-dependent on fluid flow, chemical transport, and reaction kinetics. These "physical" effects are often overlooked in biological systems – by clearly recognizing simple physical phenomena, we can exploit them to create improved or entirely new biological measurements.
Biosensor chemical transport & kinetics. The central event in most bioassays is binding of the target molecule to a detection surface, and the "speed limit" is controlled by the rate of analyte delivery (diffusion and convection) and the inherent binding kinetics. In most conventional assays, the binding rate is exceedingly slow due to diffusion limitations, and the "no-slip" condition means that mixing is worst where it is most needed. We are developing new methods that generate strong surface mixing to reduce assay times from many hours to minutes, which is a critical requirement for point-of-care diagnostics.
Sound-driven microfluidics. The small scale of microfluidic devices is inherently suited probing biological systems, from molecular assays requiring small samples to cellular assays. Nearly all microfluidic devices rely on simple laminar flow created by steady pumping, but oscillating the fluid back and forth leads to interesting and complex behaviors that provide new functions in microfluidics. 1) An unusual class of flows, known as acoustic streaming, is created when oscillating fluid interacts with any boundary that causes the fluid to turn. At the large scale, streaming is created by low frequencies; for example, ocean wave action (sub-Hertz) around bridge pilings creates eddies that scour earth at the base. Simple frequency scaling tells us that the same eddies can be created in microfluidic devices by oscillation frequencies in the audible range. The unique fluid forces and tunable fluid motion provide a fundamentally new approach to controlling fluids, including new possibilities for chemical mixing and manipulation of single cells. 2) With or without acoustic streaming, networks of microfluidic channels driven by oscillating flow behave like electrical circuits, with direct analogies to resistors, inductors, capacitors, and diodes. They exhibit frequency dependent behaviors, such as band filtering and resonance, and can be used to create pumps. Using simple electrical models, we are designing “AC fluidic circuits” to automate point of care diagnostic tests.
Point-of-Care Diagnostics. The ability to accurately detect disease-specific biomarkers from patient samples can improve diagnosis and treatment. The need for simple and rapid diagnostics is especially important in the developing world, where laboratory facilities are often completely inaccessible, and transient patient/provider interactions often allow only one opportunity for diagnosis and treatment. Microfluidic systems are capable of multi-step automation and can increase the speed of assays; however, conventional microscale flows have limited ability to reproduce required assay functions, and they often rely on expensive controllers (e.g., pumps). We are using shaped pieces of paper to program fluidic processes in simple and easy to use devices. The work focuses on understanding the physical principles that govern flow and transport in wicking materials and exploiting that understanding to design high performance tests in paper.Selected Publications
- Lafleur, Stevens, McKenzie, Ramachandran, Spicar-Mihalic, Singhal, Arjyal, Osborn, Kauffman, Yager, Lutz. “Progress toward multiplexed sample-to-result detection in low resource settings using microfluidic immunoassay cards,” Lab on a Chip, DOI: 10.1039/C2LC20751F (2012).
- Lutz, Trinh, Ball, Fu, Yager. “Two-dimensional paper networks: programmable fluidic disconnects for multi-step processes in shaped paper,” Lab on a Chip, DOI: 10.1039/C1LC20758j (2011).
- Osborn, J., Lutz, B., Fu, E., Kauffman, P., Stevens, D., Yager, P. “Microfluidics without pumps: reinventing the T-sensor and H-filter in paper networks,” Lab on a Chip, DOI: 10.1039/c004821f (2010). Cover image.
- Fu, E., Kauffman, P., Lutz, B., and Yager, P. “Chemical signal amplification in two-dimensional paper networks,” Sensors & Actuators B, 149, 325–328 (2010).
- McKenzie, K.G., Lafleur, L.K., Lutz, B.R. and Yager, P., “Rapid protein depletion from complex samples using a bead-based microfluidic device for the point of care,” Lab on a Chip, DOI: 10.1039/b913806d (2009).
- Lutz, B., Dentinger, C. Sun, L., Nguyen, L., Zhang, J., Chmura, AJ, Allen, A., Chan, S., Knudsen, B. “Spectral analysis of multiplex Raman probe signatures,” ACS Nano, 2, 2306–2314 (2008).
- Lutz, B., Dentinger, C. Sun, L., Nguyen, L., Zhang, J., Chmura, AJ, Allen, A., Chan, S., Knudsen, B. “Raman nanoparticle probes for antibody-based protein detection in tissues,” Journal of Histochemistry and Cytochemistry, 56, 371-379 (2008).
- Sun, L.; Sung, K.-B.; Dentinger, C.; Lutz, B.R.; Nguyen, L.; Zhang, J.; Qin, H.; Yamakawa, M.; Cao, M.; Lu, Y.; Chmura, A.J.; Zhu, J.; Su, X.; Berlin, A.; Chan, C.; Knudsen, B. “Composite organic-inorganic nanoparticles as Raman labels for tissue analysis,” Nano Letters, 7, 351-356 (2007).
- Lutz, B.R.; Chen, J.; & Schwartz, D.T. “Hydrodynamic tweezers: non-contact trapping of single cells using steady streaming microeddies,” Analytical Chemistry, 78, 5429-5435 (2006).
- Lutz, B.R.; Chen, J.; & Schwartz, D.T. “Characterizing homogeneous chemistry using well-mixed microeddies,” Analytical Chemistry, 78, 1606-1620 (2006).
- Lutz, B.R.; Chen, J.; & Schwartz, D.T. “Microscopic steady streaming eddies created around short cylinders in a channel: flow visualization & Stokes layer scaling,” Physics of Fluids, 17, 023601 (2005).
- Lutz, B.R.; Chen, J.; & Schwartz, D.T. “Microfluidics without microfabrication,” Proceedings of the National Academy of Sciences USA, 100, 4395-4398 (2003).