Events Calendar

BME 533 - Seminar in Biomedical Engineering

Speaker: Paul Yager, Chair of the Department of Bioengineering, University of Washington

Talk Title: Microfluidics 2.0: 2-Dimensional Paper Networks for POC Diagnostics in the Developed and Developing Worlds

Abstract: Diagnosis of disease in the developing world is, today, not as well supported by technology as it is in the developed world. A team consisting of the University of Washington, Epoch Biosciences, PATH, and Micronics, Inc., has just completed a 5-year project for developing a point-of-care system for diagnosing infectious diseases at the point-of-care in the developing world. The DxBox, as the prototype was called, was based on a permanent battery-powered reader, and polymer-based disposable microfluidic cards that contain all reagents (dry and wet). Commercial versions of this instrument will bring new capabilities for multiplexed analysis by both immunoassays and nucleic acid amplification to locations that could never support such analysis before.

The problem is that to date all flexible microfluidic systems, including the DxBox disposables, have required supporting technology at least to move fluid through the channels, including syringe pumps, or pressure sources and valves, heaters and voltage sources. This equipment has proven to be irreducibly expensive. In contrast, paper-based lateral flow immunoassays (or immunochromatographic test strips) are used in the home in the developed world (e.g., pregnancy test strips) and in the developing world for point of-care detection of infectious disease. These strips can be inexpensive, because they use only capillarity to move fluids; they require no supporting pumps or pressure sources or readers, and they are well suited to storage of reagents in dry form. However, they often measure only one analyte per strip, and are limited to high-concentration analytes because they can only perform a limited sequence of reactions, and usually provide only qualitative results.

Based on immunoassays for the DxBox on nitrocellulose devices and the work of others who have demonstrated some abilities of paper networks, it is now clear that one can combine the sophistication of the microfluidic circuit with the pump-free simplicity of capillary pumping. Under NIH support, we have been focusing on development of sophisticated but disposable 2-dimensional porous (or paper) networks (2DPNs) that allow programmed sequential delivery of an arbitrarily large set of reagents to specific sites on the devices. This offers the promise of the sophistication of microfluidic systems with no supporting instrument at all, except for a cell phone camera. By limiting the devices as much as possible to single layer of porous material (plus an injection-molded housing), cost can be extremely low. As a first challenge, we are targeting a high-value application—the development of multiplexed immunoassays that are made more sensitive than conventional lateral flow devices by performing chemical and biochemical amplification.

The first challenge was to develop design tools for 2DPNs, coupled with methods for monitoring flow in the opaque 2DPN matrix. We have also demonstrated the several conventional microfluidic devices can be implemented in 2DPNs with excellent performance, but at ~104 times less cost. We have shown that 2DPNs allow automated instrument-free sequential delivery of reagents in a format ideally suited to inexpensive disposables, and have extended this to amplification chemistries, achieving much higher sensitivity without the need for a specialized reader.



Host: Department of Biomedical Engineering, USC

More Info: http://faculty.washington.edu/yagerp/

Location: Ethel Percy Andrus Gerontology Center (GER) - Auditorium

Audiences: BME graduate students, Faculty, contact department if interested (213-740-7237)

Contact: Mischalgrace Diasanta

Event Link: http://faculty.washington.edu/yagerp/