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Naked Eye Detection of a Lung Cancer Biomarker in a Paper Device

Bhushan Toley
15 April 2013

In making progress towards low cost, almost ‘throw-away’ kind of devices for medical diagnostics, Yildiz and coworkers have come up with a simple and efficient method for the detection of mir21, a micro-RNA sequence associated with lung cancer. An important advantage of this method is that it is non-enzymatic and uses a charged conjugated polyelectrolyte (CPE) as a luminescent reporter. The reporter is impregnated in a robust poly-(vinyledene fluoride) (PVDF) paper. The sensing strategy is based on the color of the triplex species formed between the reporter, mir21, and a peptide nucleic acid (PNA) sequence complementary to mir21. The assay generates an orange color in the presence of mir21 and a purple color in its absence. This platform can detect the presence of mir21 at clinically relevant (nanomolar) levels as well as distinguish mir21 from a single base pair mismatch micro-RNA sequence. The detection can be performed without the use of expensive and complex instruments. The authors have published these results in Analytical Chemistry and their publication may be accessed here: http://pubs.acs.org/doi/abs/10.1021/ac3034008.

Novel detection method described by Yildiz et al. in Analytical Chemistry, 2013, 85 (2), 820-824. © 2012 American Chemical Society.

New Yager Lab Publication: FMIA for Typhoid

Carly Holstein
3 April 2013

In the most recent issue of Diagnostics, released this week, the Yager Lab and collaborators have published their work on a flow-through membrane immunoassay (FMIA) for Tyhphoid. This highly collaborative project features authors from University of Washington Dept. of Bioengineering, PATH, the Oxford University Clinical Research Unit of the Patan Academy of Health Sciences in Nepal, and the Oxford University Clinical Research Unit of the Hospital for Tropical Diseases in Vietnam. The FMIA, which utilizes a porous nitrocellulose membrane, provides similar detection capability to ELISA, but is much faster and simpler to operate than ELISA.

Check it out!

Ramachandran et al., "A Rapid, Multiplexed, High-Throughput Flow-Through Membrane Immunoassay: A Convenient Alternative to ELISA," Diagnostics 2013, 3 (2), 244-260.

Illustration and example data for the FMIA for typhoid detection. From Diagnostics 2013, 3(2), 244-260. © 2013 by the authors.

Automated paper-based device for sequential multistep ELISA

Koji Abe
21 March 2013

In their recent paper published in Lab on a Chip, Amara Apilux and colleagues demonstrate automated paper-based devices for one-step quantitative sandwich ELISA-based analysis.  Two different designs of the patterned nitrocellulose membrane illustrate a potential for creating delayed fluid flow and allowing a multistep process (e.g. preconcentration and washing) with a single-step application of the sample solution. The authors achieved a limit of detection for hCG (8.1 mIU/mL) that is lower than measurable levels of conventional pregnancy test kits (20-100 mIU/mL), resulting from optimization of the pattern design using inkjet printing. This technology has the potential to simplify the efforts of complicated and time-consuming multistep biochemical analyses in the future.

Apilux et al., “Development of automated paper-based devices for sequential multistep sandwich enzyme-linked immunosorbent assays using inkjet printing”, Lab Chip, 2013, 13, 126.

Apply Now: Gordon Research Conference on Microfluidics

Carly Holstein
18 March 2013

We are excited to help spread the word that applications to this year's Gordon Research Conference on the Physics & Chemistry of Microfluidics are currently being accepted! This GRC is a must-attend for anyone in the Microfluidics 2.0 field, as the focus of the conference is on "Challenges, Adcances, and New Technologies for Diagnostics." The co-chairs of the conference, Drs. James Landers and Paul Yager, have selected a wonderful line-up of speakers for talks in the following session areas:

  • Fluidic control
  • Paper microfluidics
  • Microfluidic acoustics
  • Centrifugally-driven microfluidics
  • Diagnostics
  • Commericalization of microfluidic technology
  • Next-generation sequencing

This GRC will be held June 9-14, 2013 at the Renaissance Tuscany Il Ciocco Resort in Lucca (Barga), Italy. Applications are due by May 12, 2013, but applications are reviewed on a first-come, first-served basis, so early applications are encouraged!

Also, if you are a graduate student or post-doc, please also consider attending the corresponding Gordon Research Seminar, taking place directly prior to the GRC (June 8-9, 2013). The theme of this GRS is also very fitting for the MF20 community: "From Bench-to-Beside: From Diagnosis through Treatment." Applications are due by May 11, 2013, but again, early applications are encouraged! Please note that graduate students and post-docs can (and should) also apply to the GRC.

In case this exciting scientific program is not enticing enough, perhaps the beautiful venue can do the talking:

Patio of the Renaissance Tuscany Il Ciocco Resort, where the GRC/GRS will be held. Photo courtesy of the Gordon Research Conferences © 2013.

Hope to see you there!

Weaving Our Way Towards Low-Cost Disease Diagnostics

Bhushan Toley
18 March 2013

While most ongoing development under the realm of Microfluidics 2.0 has been by using different forms of paper for wicking fluids, Dhananjay Dendukuri, CEO and co-founder, Achira Labs (Bangalore, India), decided to utilize silk instead of paper to develop low-cost powerless microfluidic devices. In a land adorned by women clad in 6-yard woven sheets of silk – the famous Indian Sari – silk yarn fabrication is a well-established industry. Dhananjay applied the weaving principles of the warp and the weft to design the proprietary “Fab-Chip” platform. Silk yarns with different properties were selected, pretreated with chemical agents, and handloom-woven into a fabric chip. Wetting and non-wetting yarns were weaved in a desired pattern to define flow channels on the chip. What’s more, the yarn twist frequency and coverage area could be modified to modify the rate of fluid wicking through these chips. This technology was described in their Lab on a Chip publication in July 2011. The technology makes use of the existing silk manufacturing infrastructure to develop products for point-of-care diagnostics – a strategy that will enable low-cost manufacturing as well as create local employment opportunities. Microfluidics 2.0 continues to present paradigm-shifting opportunities…

Images of the silk-based "Fab-Chip" diagnostic platform from Achira Labs. http://www.achiralabs.com/technology.html, accessed 18 March 2013. © Copyrights 2011, Achira.

Thermal Contrast Improves Lateral Flow Signal

Carly Holstein
7 January 2013

In their recent communication in Angewandte Chemie International Edition, Zhenpeng Qin and colleagues show that thermal contrast significantly improves the sensitivity of traditional lateral flow immunoassays. Instead of using visual, colorimetric readout, as is normally done for lateral flow tests that employ gold nanoparticle labels, this group utilized the thermal contrast of the gold nanoparticles for signal generation. Specifically, the investigators excited the test and control line regions with a 532-nm laser and recorded the resulting temperature change of the gold nanoparticles at these lines using an infrared camera. Using this technique, the authors demonstrate a 32-fold improvement in a commercial lateral flow immunoassay for cryptococcal antigen. Perhaps most exciting, the authors also discuss the possibility of a low-cost, portable version of the infrared contrast system, which could be applied to point-of-care diagnostic testing. It will be interesting to see where this work goes!

Illustration of the Bischof group's lateral flow test set-up, which utilizes a thermal contrast readout comprised by a laser for excitement and an infrared camera for the collection of thermal emission. Qin et al., "Significantly Improved Analytical Sensitivity of Lateral Flow Immunoassays by Using Thermal Contrast," Angew. Chem. Int. Ed. 51: 4358-4361 (2012). © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fun Times at MF2.0 in Boston!

Gina Fridley
11 December 2012

Last week some of us had the pleasure of visiting Boston for the 2012 Workshop on Capillary-based Microfluidics for Bioanalysis, hosted by Dr. Cathie Klapperich’s group at Boston University. As those of you who were there or watched the live stream [1] know, there was an incredible line-up of some of the best ideas that paper microfluidics has to offer. This community is using these paper technologies to address a huge range of problems, from identification of counterfeit drugs [2] to inexpensive solar power [3]. Inexpensive and easy-to-use devices are improving our ability to detect antibiotic resistance [4] and monitor water quality [5], while on-paper electrochemical detection [6] and nucleic acid amplification [7] increase the sensitivity achievable in these paperfluidic devices. We heard about the challenges and successes involved when testing new devices in the field [8] and got to experience do-it-yourself fabrication of little devices [9] and tests for TB drug adherence [10].

I didn’t get to see most of the demos on Day 2, because I was busy with the demos from our lab. I heard from other participants that the hand-on experiences were fantastic, and I know that we all had a great time sharing our lab’s work with the group.  One our demos demonstrated a method for visualizing flow through paper networks of arbitrary geometry [11], and the other featured some of my thesis work rehydrating dry reagents from storage depots patterned on assay membranes [12]. 

Thank you Cathie for carrying on the torch… and we’re hoping one of you MF2.0 fans out there will continue the tradition!

[1]      Videos of the talks are still available on the Klapperich lab website

[2]      Dr. Marya Lieberman

[3]      Dr. Karen Gleason

[4]      Dr. Ratmir Derda

[5]      Dr. John Brennan

[6]      Dr. Richard Crooks

[7]      Our own Dr. Barry Lutz!

[8]      Dr. Bernhard Weigl and Diagnostics for all

[9]      Jose Gomez-Marquez

[10]  Adher.io TB with Dr. Jackie Linnes

[11]  Visualizing flow in paper networks and Kauffman, P.; Fu, E.; Lutz, B.; Yager, P., Visualization and measurement of flow in two-dimensional paper networks. Lab on a Chip 2010, 10 (19), 2614-2617.

[12]  Fridley, G.; Le, H.; Fu, E.; Yager, P., Controlled release of dry reagents in porous media for tunable temporal and spatial distribution upon rehydration. Lab on a Chip 2012, 12(21),4321-4327.

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