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Paul Yager Talks Paper-Based Diagnostics at TEDx Rainier

Carly Holstein
22 December 2014
Last month, Dr. Paul Yager, Professor of Bioengineering at the University of Washington and one of the pioneers of Microfluidics 2.0, took the stage at TEDx Rainier to discuss his lab's work on and his vision for the future of paper-based diagnostics. Dr. Yager talks about the many use cases for paper-based testing, ranging from at-home testing in the developed world ("Can I send my kid to school?" or "What's that itch down there?") to critical disease diagnosis and outbreak control in the developing world and beyond (Ebola). Dr. Yager's talk was just published to YouTube--I highly encourage you to check it out to learn more about this field and the passion that motivates one if its leading researchers.

Flu Finder Wins 2nd Place in UW Business Plan Competition

Carly Holstein
23 May 2014

Based on their thesis research in the Yager Lab, PhD candidates Carly Holstein and Gina Fridley teamed up with MBA candidates Alyssa Hochman, Jonny Holz, and Joel Loveday to develop a business plan for the Flu Finder diagnostic test. Flu Finder is a paper-based assay that aims to improve upon current flu diagnostics by providing a test that is accurate, inexpensive, and can be administered by anyone, anywhere, with results in less than 20 minutes. Flu Finder is envisioned to start as an improved test for use in the doctor's office, but aims to eventually be sold over the counter for use by the patient at home. The team competed in the University of Washington Business Plan Competition and placed 2nd out of 92 teams from across the state. Flu Finder also took home the Best Innovation prize. For the full story from the UW Department of Bioengineering, click here.

The Flu Finder team poses with their second place prize in the UW Business Plan Competition. From left to right: Carly Holstein (PhD candidate, Bioengineering), Alyssa Hochman (MBA candidate), Joel Loveday (MBA candidate), Gina Fridley (PhD candidate, Bioengineering), and Jonny Holz (MBA candidate).

Powerful Work: Microfluidic Paper Fuel Cells

Greg Thiessen
1 May 2014

Senior Research Fellow, Juan Pablo Esquivel, and his colleagues in Barcelona, Spain were recently published in Energy & Environmental Science for their work on microfluidic paper fuel cells [1]. This work details the development of a fuel cell consisting of methanol and KOH. By harnessing the capillary flow of porous membranes, the need for external pumps to supply reactants is eliminated. The electrolyte (KOH) and fuel (methanol) are stored within a lateral flow device such that the addition of water generates power. The ability to use the sample, such as blood, to generate power is incredibly beneficial and exciting. I’m not the only one to get excited about it either. The work was highlighted in the March edition of Science Magazine in the Editor’s Choice section [2], as well as in Chemistry World. This design can be used to power the detection of analyte, replacing the need for button-cell batteries. This truly is powerful work.

Schematic of a paper-based microfluidic fuel cell design. Figure courtesy of J.P. Esquivel.
  1. Esquivel, J.P., et al., Microfluidic fuel cells on paper: meeting the power needs of next generation lateral flow devices. Energy & Environmental Science, 2014.
  2. Fahrenkamp-Uppenbrink, J., Paper Power. Science, 2014. 343(6176): p. 1179.

Dr. Paul Yager Named a Leader in Health Care by Seattle Business Magazine

Carly Holstein
12 March 2014

Seattle Business Magazine recently honored our own Dr. Paul Yager as part of the magazine's 2014 Leaders in Health Care Awards. Dr. Yager was recognized for his "Achievement in Medical Devices," citing his work in paper-based diagnostics and the use of smartphones for analysis. The magazine writes, "That ability to cheaply bring the lab anywhere can benefit health care in the developing world and for soldiers in the field." Congratulations, Dr. Yager!

For more on the awards, check out this wonderful highlight video (Dr. Yager makes an appearance at 0:45):

Seattle Business magazine's 2014 Leaders in Health Care Awards Highlights from Tiger Oak Media on Vimeo.

Random Laser Emission From a Paper-Based Device

Rahil Jain
23 February 2014

Paper is such a versatile material that it never ceases to amaze. It was not until recently that its potential in developing low-cost microfluidic diagnostic technologies started being utilized [1]. In yet another intriguing demonstration of the use of paper, a group at Istituto Nanoscienze, CNR in Italy realized lasing with paper as the substrate [2]. Paper, with its complex network of randomly distributed fibers, may seem like an odd choice with which to realize a laser, which traditionally required a gain medium of controlled purity, periodicity, size, concentration, and shape. However, the incipient technique of random lasing [3], which employs scattering processes of light for optical gain and doesn’t rely on external feedback to achieve above unity gain, can be implemented on a low-ordered substrate, such as paper. When imbibed with a fluorescent lasing dye like Rhodamine B (RhB), paper provides a randomly distributed network of scatterers (fibers) in an optical gain medium (dye) required for random lasing. The emission spectrum of a paper-based random laser was found to be dependent on laser-dye characteristics, microfluidic channel dimensions, and the shape, pore-size, local refractive index, and functionalization of the substrate (Fig 1). With a tunable spectral response and susceptibility to a variety of channel properties, random lasers may find application as an optical transducer or sensor in biosensing and diagnostics. The disadvantage of random lasing is loss of coherence in light output and the requirement of optical pumping. The understanding of physics behind this observation is still in its incipient stage and further work in lasing in paper is warranted.

Figure 1: Methods and results of paper-based laser. (a) The microfluidic circuit is realized lithographically on a single layer chromatography paper and is filled by capillary driven laser dye (RhB). Inset shows true colors of channel wetting. (b) shows variation in emission peak intensity as a function of optical pumping energy for channels of different widths compared to native non-patterned paper.  (c-d) demonstrates variation in emission characteristics with functionalization of surface with high refractive index TiO2 and channel shape respectively. (e) shows emission spectra for 100μm wide channel and in the inset the emission spectra of pure RhB in ethylene glycol. Pictures adapted without permission from [2]. 


[1] Martinez, Andres W., et al. "Diagnostics for the developing world: microfluidic paper-based analytical devices." Analytical Chemistry 82.1 (2009): 3-10.

[2]Viola, Ilenia, et al. "Random laser emission from a paper-based deviceJournal of Materials Chemistry C 1.48 (2013): 8128-8133.

[3]Gottardo, Stefano, et al. "Resonance-driven random lasing." Nature Photonics 2.7 (2008): 429-432.

Author: Rahil Jain is a graduate student in the Electrical Engineering department at UW, Seattle. His work in the Lutz Lab focusses on developing microfluidic technologies for application in low-cost diagnostics. 

Paper-Based Microfluidics Goes Digital

Karen Keniston
5 February 2014

Due to the passive nature of traditional paper-based microfluidic devices, high precision control of certain parts of multi-step assays can be difficult to acheive.  Researchers R. Fobel et al. at the University of Toronto recently published an article in Advanced Materials reporting the invention of a digital paper-based microfluidic device with high precision control of multistep processes on paper.

Digital microfluidics (DMF) is a technology in which nano-to-microliter sized drops are manipulated on an array of electrodes using electric fields. The electrostatic forces can move, split, merge, and dispense drops to and from reservoirs within a device without the use of active pumps or moving parts. Paper-based DMF devices are fabricated by inkjet printing silver electrodes and reservoirs onto smooth paper surfaces. To test the ability of the novel device to perform a multistep process, the group used one of the chips to perform a serial dilution and create a calibration curve for the chemiliuminescence assay of horseradish peroxidase (HRP) mixed with luminol and hydrogen peroxide. Overall, very interesting applications may come from combining these methods with the traditional paper-based diagnostic assay, especially in steps which would be difficult to perform with solely capillary-driven flow. 

Demonstration of digital microfluidics on a paper-based device. Fobel, R., Kirby, A. E., Ng, A. H. C., Farnood, R. R. and Wheeler, A. R. (2014), Paper Microfluidics Goes Digital. Adv. Mater.. doi: 10.1002/adma.201305168 © 2014 Advanced Materials.



"Little Devices" Spur Global Health Innovation

Gina Fridley
4 February 2014

Our friends in the Little Devices group at MIT were featured in a great NYT piece on January 29th that showcased the amazing medical innovations that are created by hacking together toys and other commonly available parts. From a toy machine gun that can be rigged to buzz when an IV bag is empty (see video below), to an asthma nebulizer constructed from a bike pump, tubing, adapters and filters, these clever hacks are allowing health workers in developing countries to design their own solutions to problems that researchers here in the US can’t predict. Keep it up Little Devices—we can’t wait to see what you guys come up with next!