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Paper-based liver function test

Gina Fridley
24 April 2012

Researchers in the Whitesides group at Harvard and at Diagnostics For All have recently published an article in Analytical Chemistry about their paper-based test for liver function. We heard a bit about these little devices last fall at the MF2.0 workshop, and then again in the winter when Carly blogged about the NYTimes article featuring them, but now we’re getting all of the exciting details.

These multiplexed tests detect three markers of liver function: total serum protein, and the enzymes alkaline phosphatase (ALP) and aspartate aminotransferase (AST). Just 15 µl of whole blood is applied to the top of the device, and it wicks through a plasma separation membrane to remove red blood cells before reaching the test zones on the bottom side. After the assay has developed, the color change of the test zones can be evaluated qualitatively by eye, or quantitatively using a cell phone or desktop scanner. 

A diagram of the top and bottom sides of the liver fuction test before and after the assay is run (upon the addition of a drop of blood).

This was quite a thorough paper--they evaluated several different plasma separation membranes, generated calibration and limit-of-detection curved, confirmed that the test zones were not cross-reactive, and validated their results using real whole blood.  You’ll have to read the paper for all of the results, but I’d definitely recommend it! 

The article citation is: Vella S, Beattie P, Cademartiri R, et al.  Measuring markers of liver function using a micropatterned paper device designed for blood from a fingerstick. Anal. Chem., 2012, 84(6), pp 2883-2891.

Biosensing Applications on Paper

Farhan Ahmad
18 April 2012

Translation of well-established molecular assays (e.g., immunoassays, DNA amplification assays) on paper is highly needed for low-cost and point-of-care diagnostics. However, it is not an easy task as commercial paper products are being treated with unknown chemicals (e.g., surfactants or polymers to improve wettability) by the manufacturers, which could inhibit amplification reactions, effect biomolecular coupling reactions, and enhance nonspecific interactions. Monsur Ali and colleagues from the Li’s lab at McMaster University have published papers in Biomacromolecules (2008)and Chemical Communications (2009) addressing the above problems by activating the paper with colloidal microgel particles. This bioactive paper was successfully applied as a platform to perform molecular assays based on antibody-antigen coupling, aptamer, and nucleic acid amplification. Further simplification in the assay protocols is needed, which would increase the application of bioactive papers in biosensing at POC settings.

     

DNA amplification on bioactive paper. Su et al. “Microgel-based inks for paper-supported biosensing applications”, Biomacromolecules, 2008 and Ali et al. “Detection of DNA using bioactive paper strips”, Chemical Communications, 2009.

Paper Fluidic Batteries

Carly Holstein
28 March 2012

Another big step has been taken in paper microfluidics: self-powering batteries! Nicole Thom and colleagues from the Phillips lab at Penn State University have recently published a communication in Lab on a Chip that describes paper-based batteries that turn on when a sample is loaded on the paper device. They then put these paper fluidic batteries in action, using them to power an LED and conduct an on-paper, self-powered fluorescence assay for β-D-galactosidase. Now that is microfluidics 2.0!

Demonstration of the self-powered paper fluidic fluorescence assay. Thom et al. “’Fluidic batteries’ as low-cost sources of power in paper-based microfluidic devices,” Lab on a Chip, 2012, Advance Article. © Royal Society of Chemistry 2012.

Announcing the 2012 Paper-based Microfluidics Workshop

Shefali Oza
11 March 2012

We are pleased to announce this year’s paper-based microfluidics workshop, which will take place from 30 November – 1 December 2012 in Boston, MA.  Following the success of our 2011 Workshop on Capillary-based Microfluidics for Bioanalysis in Seattle, Dr. Catherine Klapperich’s group at Boston University has volunteered to host this year’s workshop. 

The workshop will include lectures and posters on Friday, November 30 and hands-on demos on Saturday, December 1.  More details will be made available in the near future.  Space will be limited, so be sure to stay tuned and sign up for a spot once the registration opens!

In the meantime, please take a look at last year’s agenda and content (including links to presentation slides) for more information on the current state of paper-based microfluidics. 

We hope to see you at the 2012 workshop in Boston later this year!

Novel Paper-based Chemiluminescence ELISA

Samantha Byrnes
27 February 2012

This article summarizes the Wang et al. article titled "Paper-based chemiluminescence ELISA: Lab-on-paper based on chitosan modified paper device and wax-screen printing".  This article was published in Biosensors and Bioelectronics (2012), vol 31: pg 212-218.  

In this article Wang et al. describe a simple patterning method for a paper-based chemiluminescence ELISA assay (“paper immunoplate”).  The group uses wax-screen printing to isolate individual assay zones on cellulose.  They then modified the cellulose surface with chitosan followed by activation with glutaradhyde to covalently immobilize three different capture antibodies to detect tumor markers.  The assay zones on the paper immunoassay target α-fetoprotein (AFP), cancer antigen 125 (CA125), and carcinoembryonic antigen (CEA).  To detect the chemiluminescence signal (from a luminol-p-iodophenol and hydrogen peroxide reaction), the group created a novel device holder to accurately move between and image various zones on their paper immunoplate.  This novel device uses a photomultiplier for signal detection. 

Schematic of a chemiluminescence assay on paper immunoplates (adapted from Wang et al., Figure 2)

The overall reaction takes place in less than 10 minutes and uses less than 100 µL of fluid.  The linear detection range for all three tumor markers falls within their respective clinical diagnosis values.  The results from the paper immunoplates were within 10% of the values obtained from the traditional plastic plate ELISA assay while taking a fraction of the time.  Thus, this appears to be a novel approach to paper-based diagnostics using chemiluminescence.  

Click here to access the Wang et al. article.  

UW Features on the Yager Lab

Carly Holstein
18 January 2012

Dr. Paul Yager shows off a prototype 2DPN device. Photo by Clare McLean, from UW Today article cited below.

Recently, the Yager laboratory has received much attention from media outlets at the University of Washington, bringing accessible stories about who we are and what we do.

In one article published in student-run newspaper The Daily, undergraduates Tinny Liang and Jared Houghtaling are put in the spotlight. The article describes their work on a paper-based assay for malaria, giving a nice humanistic touch to the research we do in the Yager lab and our motivation for doing it.

Additionally, our current work in the Yager laboratory was recently featured in a high-profile story in UW Today. The article describes recent developments of our work on paper-based diagnostics and how we are using our 2DPN (two-dimensional paper network) platform to enhance the performance and capabilities of these diagnostic devices.

Check out these articles if you’re interested in the Yager lab and the work we do on paper-based diagnostics!

Diagnosing Malaria” by Devon Geary. Published October 11, 2011, The Daily of the University of Washington.

Pushing the envelope on paper-based diagnostics” by Bobbi Nodell. Published November 16, 2011, UW Today.

NY Times Feature on Paper Diagnostics

Carly Holstein
24 December 2011

Recently, the New York Times ran this great feature on paper diagnostics out of the Whitesides laboratory at Harvard University. The article highlights a diagnostic test for liver failure that is both extremely cheap and, at about the size of a postage stamp, is extremely portable. These advantages make the test ideally suited for use in the developing world, where patients on both HIV and tuberculosis drugs are at risk for liver damage and in need of affordable diagnostics. The article also features a short video showing the paper device in action. Check it out!

Far From Any Lab, Paper Bits Find Illness” by Donald G. McNeil Jr. Published September 26, 2011, The New York Times.

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