June 2012 – Lab on a Chip Blog

Archive for June, 2012

HOT article: microfluidic polyplex preparation on a chip

28 Jun 2012

Researchers at Philipps-Universität Marburg, Germany, have developed a new technique for the production of polyplexes that produces more regular sized complexes compared to the standard pipetting methods. Polyplexes are the complexes that form by electrostatic interactions of oppositely charged macromolecules – in this case poly(ethylene imine) (PEI) and plasmid DNA, which are used in gene therapy applications.

The group, led by Thomas Kissel, developed a method that produces the complexes using microfluidics on a chip. Over the course of the study, they investigated the factors that could affect the complex size, and discovered that the most important factor was the ratio of PEI to DNA, whilst other factors were not as important. Using the chip method, regular sized complexes (140 nm and 160 nm) were produced, compared to the more irregular pipetting method. The team also showed that different (targeted) PEI-based vectors could be used for the formation of complexes with pDNA and siRNA.

Read the details of the study here:

Optimized preparation of pDNA/poly(ethylene imine) polyplexes using a microfluidic system
Heiko Debus, Moritz Beck-Broichsitter and Thomas Kissel
DOI: 10.1039/C2LC40176B

This HOT article is free to access for the next four weeks following a simple registration for individual users.

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Have you seen the best of LOC?

22 Jun 2012

The Editors at Lab on a Chip have been busy picking out the top 10% from all our high quality papers to bring you a collection of recent articles that we think will be of exceptional significance for the miniaturisation community.

Papers in this category will have received excellent reports during peer review, and demonstrate a breakthrough in device technology, methodology or demonstrate important new results for chemistry, physics, biology or bioengineering enabled by miniaturisation.

Here are the papers that have caught our eye so far:

Frontier
Microengineered physiological biomimicry: Organs-on-Chips
Dongeun Huh, Yu-suke Torisawa, Geraldine A. Hamilton, Hyun Jung Kim and Donald E. Ingber
DOI: 10.1039/C2LC40089H

Focus
Education: a microfluidic platform for university-level analytical chemistry laboratories
Jesse Greener, Ethan Tumarkin, Michael Debono, Andrew P. Dicks and Eugenia Kumacheva
DOI: 10.1039/C2LC20951A

Tutorial Review
Brain slice on a chip: opportunities and challenges of applying microfluidic technology to intact tissues
Yu Huang, Justin C. Williams and Stephen M. Johnson
DOI: 10.1039/C2LC21142D

Critical Review
Engineers are from PDMS-land, Biologists are from Polystyrenia
Erwin Berthier, Edmond W. K. Young and David Beebe
DOI: 10.1039/C2LC20982A

Communications
“Fluidic batteries” as low-cost sources of power in paper-based microfluidic devices
Nicole K. Thom, Kimy Yeung, Marley B. Pillion and Scott T. Phillips
DOI: 10.1039/C2LC40126F

Sorting cells by size, shape and deformability
Jason P. Beech, Stefan H. Holm, Karl Adolfsson and Jonas O. Tegenfeldt
DOI: 10.1039/C2LC21083E

Papers
High throughput automated chromatin immunoprecipitation as a platform for drug screening and antibody validation
Angela R. Wu, Tiara L.A. Kawahara, Nicole A. Rapicavoli, Jan van Riggelen, Emelyn H. Shroff, Liwen Xu, Dean W. Felsher, Howard Y. Chang and Stephen R. Quake
DOI: 10.1039/C2LC21290K

A microfluidic device for whole-animal drug screening using electrophysiological measures in the nematode C. elegans
Shawn R. Lockery, S. Elizabeth Hulme, William M. Roberts, Kristin J. Robinson, Anna Laromaine, Theodore H. Lindsay, George M. Whitesides and Janis C. Weeks
DOI: 10.1039/C2LC00001F

Ion diode logics for pH control
Erik O. Gabrielsson, Klas Tybrandt and Magnus Berggren
DOI: 10.1039/C2LC40093F

Human gut-on-a-chip inhabited by microbial flora that experiences intestinal peristalsis-like motions and flow
Hyun Jung Kim, Dongeun Huh, Geraldine Hamilton and Donald E. Ingber
DOI: 10.1039/C2LC40074J

A multifunctional pipette
Alar Ainla, Gavin D. M. Jeffries, Ralf Brune, Owe Orwar and Aldo Jesorka
DOI: 10.1039/C2LC20906C

Visualization of microscale particle focusing in diluted and whole blood using particle trajectory analysis
Eugene J. Lim, Thomas J. Ober, Jon F. Edd, Gareth H. McKinley and Mehmet Toner
DOI: 10.1039/C2LC21100A

DNA electrophoresis in a nanofence array
Sung-Gyu Park, Daniel W. Olson and Kevin D. Dorfman
DOI: 10.1039/C2LC00016D

Bipolar electrochemistry for cargo-lifting in fluid channels
Gabriel Loget and Alexander Kuhn
DOI: 10.1039/C2LC21301J

Rapid screening of antibiotic toxicity in an automated microdroplet system
Krzysztof Churski, Tomasz S. Kaminski, Slawomir Jakiela, Wojciech Kamysz, Wioletta Baranska-Rybak, Douglas B. Weibel and Piotr Garstecki
DOI: 10.1039/C2LC21284F

Dual-electrode microfluidic cell for characterizing electrocatalysts
Ioana Dumitrescu, David F. Yancey and Richard M. Crooks
DOI: 10.1039/C2LC21181E

Rapid, sensitive, and multiplexed on-chip optical sensors for micro-gas chromatography
Karthik Reddy, Yunbo Guo, Jing Liu, Wonsuk Lee, Maung Kyaw Khaing Oo and Xudong Fan
DOI: 10.1039/C2LC20922E

A silicone-based stretchable micropost array membrane for monitoring live-cell subcellular cytoskeletal response
Jennifer M. Mann, Raymond H. W. Lam, Shinuo Weng, Yubing Sun and Jianping Fu
DOI: 10.1039/C2LC20896B

Batch fabrication of disposable screen printed SERS arrays
Lu-Lu Qu, Da-Wei Li, Jin-Qun Xue, Wen-Lei Zhai, John S. Fossey and Yi-Tao Long
DOI: 10.1039/C2LC20926H

Bubbles no more: in-plane trapping and removal of bubbles in microfluidic devices
Conrad Lochovsky, Sanjesh Yasotharan and Axel Günther
DOI: 10.1039/C1LC20817A

A digital microfluidic method for multiplexed cell-based apoptosis assays
Dario Bogojevic, M. Dean Chamberlain, Irena Barbulovic-Nad and Aaron R. Wheeler
DOI: 10.1039/C2LC20893H

Technical Innovation
Three-dimensional microfiber devices that mimic physiological environments to probe cell mechanics and signaling
Warren C. Ruder, Erica D. Pratt, Sasha Bakhru, Metin Sitti, Stefan Zappe, Chao-Min Cheng, James F. Antaki and Philip R. LeDuc
DOI: 10.1039/C2LC21117C

We will be adding to this collection throughout the year so keep checking back for more outstanding articles!

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New YouTube videos

22 Jun 2012

View the new videos on the Lab on a Chip YouTube site using the links below:

High-yield cell ordering and deterministic cell-in-droplet encapsulation using Dean flow in a curved microchannel

Limits of miniaturization: Assessing ITP performance in sub-micron and nanochannels

In vitro angiogenesis assay for the study of cell-encapsulation therapy

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New YouTube videos

21 Jun 2012

View the new videos on the Lab on a Chip YouTube site using the links below:

A ternary model for double-emulsion formation in a capillary microfluidic device

A microfluidic “baby machine” for cell synchronization

Automated analysis of single stem cells in microfluidic traps

Live cell imaging analysis of the epigenetic regulation of the human endothelial cell migration at single-cell resolution

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Lab on a Chip publishes its 150th issue

21 Jun 2012

This week we’re celebrating our 150th issue at Lab on a Chip. Albert van den Berg, Deputy Chair of our Editorial Board, writes about the journal’s history and its exciting future, in his editorial.

The issue’s front cover features artwork from Kamlesh Patel and colleagues, whose critical review discusses the recent advances in digital microfluidics, focusing on applications for chemistry, biology and medicine. Topics discussed include the use of droplets for chemical synthesis, enzyme assays and the analysis of blood.

Digital microfluidics: a versatile tool for applications in chemistry, biology and medicine
Mais J. Jebrail, Michael S. Bartsch and Kamlesh D. Patel
DOI: 10.1039/C2LC40318H

A communication from Yanyi Huang and co-workers demonstrating an integrated microfluidic immunoassay chip for high-throughput sandwich immunoassay tests is featured on the inside front cover.

The authors state the device can perform ELISA measurements in one hour with just 1 μL of sample for four repeats.

High-throughput immunoassay through in-channel microfluidic patterning
Chunhong Zheng, Jingwen Wang, Yuhong Pang, Jianbin Wang, Wenbin Li, Zigang Ge and Yanyi Huang
DOI: 10.1039/C2LC40145B

The back cover features artwork from Tony Jun Huang and colleagues, whose paper on acoustic-based tunable patterning demonstrates a technique that can arrange microparticles or cells into arrays using pairs of slanted-finger interdigital transducers.

Tunable patterning of microparticles and cells using standing surface acoustic waves
Xiaoyun Ding, Jinjie Shi, Sz-Chin Steven Lin, Shahrzad Yazdi, Brian Kiraly and Tony Jun Huang
DOI: 10.1039/C2LC21021E

Also in this issue is the latest Research highlight from Ali Khademhosseini, and Acoustofluidics 14: Applications of acoustic streaming in microfluidic devices from Martin Wiklund and co-authors.

Read the rest of the issue here.

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A microfluidic ‘baby-machine’ and nanochannels to allow efficient fluorescent analysis of proteins

18 Jun 2012

Scott Manalis and coworkers at MIT have developed a microfluidic version of the “baby-machine”, a device used to synchronize eukaryotic cells at a specific point in the cell cycle for study of cellular and molecular processes.

The original method which was developed in the 1960s chemically bound cells to a membrane. As they divide one cell remains attached to the membrane and the ‘newborn’ cell is eluted, producing a synchronised population of cells in the G1 phase of the cell cycle. However, the method of chemically attaching cells to the membrane is not suitable for all cell types. Manalis et al have modified this procedure to attach cells by applying pressure differences to capture cells on their microfluidic device, thereby avoiding the use of chemicals that can make cells non-viable.

Read more…
A microfluidic “baby machine” for cell synchronization
Josephine Shaw, Kristofor Payer, Sungmin Son, William H. Grover and Scott R. Manalis
DOI: 10.1039/C2LC40277G

Xing-Hua Xia and colleagues at Nanjing University have recently improved on the fluorescent analysis of proteins by utilising the confines of a nanochannel in a microfluidic device. The nanochannel allows the efficient concentration of proteins and separates labelled proteins from unreacted fluorescent labels due to size. This removes the need for purification to remove the unreacted dye on an external chromatographic instrument and allows protein concentration, labelling, and purification in continuous manner in one device.

Read more…
Rapid protein concentration, efficient fluorescence labeling and purification on a micro/nanofluidics chip
Chen Wang, Jun Ouyang, De-Kai Ye, Jing-Juan Xu, Hong-Yuan Chen and Xing-Hua Xia
DOI: 10.1039/C2LC20977B

These latest two HOT articles are free to access for 4 weeks following a simple registration for individual users

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Paper and plastic HIV test

15 Jun 2012

If untreated, the mortality rate of HIV‐infected infants may reach 35% by one year of age, and 53% by two years of age If untreated, the mortality rate of HIV‐infected infants may reach 35% by one year of age, and 53% by two years of age. Sourced from www.shutterstock.com

A DNA test to detect HIV in infants in resource-poor countries is a step closer, thanks to a technique to amplify DNA samples developed by US scientists.

Currently, there are no suitable methods to test for HIV in infants in resource-poor areas. The rapid anti-HIV antibody tests for adults can’t be used for early diagnosis in infants. This is because maternal anti-HIV antibodies persist in infant blood for 18 months after birth, even in HIV-negative infants, resulting in false positives.

Efforts to improve infant HIV tests include analysing DNA extracted from dried blood spot samples using the polymerase chain reaction to amplify the DNA, but this requires expensive equipment and trained technicians. It can also take four weeks to get a results, so for the many patients who aren’t able to return to the clinic, an instant result is more practical.

Now, Brittany Rohrman and Rebecca Richards-Kortum at Rice University, Houston, have made a paper and plastic-based device that can amplify 10 strands of HIV DNA to detectable levels in just 15 minutes using dried blood samples.

See the full article in Chemistry World

Or read the Lab on a Chip paper:
A paper and plastic device for performing recombinase polymerase amplification of HIV DNA
Brittany Rohrman and Rebecca Richards-Kortum
Lab Chip, 2012, DOI: 10.1039/C2LC40423K

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Superelastic microsprings & electrical fingerprinting to detect circulating tumor cells in Issue 13

12 Jun 2012

Work from Yongfeng Mei, Fudan University, and colleagues on developing superelastic microsprings features on the front cover of Issue 13. The rolled Ti nanomembranes stretch predictably and proportionally due to the drag force in flowing water, and so are potentially useful as sensors in micro-/nano-electromechanical systems.

Superelastic metal microsprings as fluidic sensors and actuators
Weiming Li, Gaoshan Huang, Jiao Wang, Ying Yu, Xiaojing Wu, Xugao Cui and Yongfeng Mei
Lab Chip, 2012, 12, 2322-2328
DOI: 10.1039/C2LC40151G

The back cover is courtesy of Samir M. Iqbal and coworkers, who have developed a solid micropore device to detect tumour cells. By pushing cells through the single micropore one at a time cells can be differentiated based on size, elasticity, viscosity and stiffness.

Electrical fingerprinting, 3D profiling and detection of tumor cells with solid-state micropores
Waseem Asghar, Yuan Wan, Azhar Ilyas, Robert Bachoo, Young-tae Kim and Samir M. Iqbal
Lab Chip, 2012, 12, 2345-2352
DOI: 10.1039/C2LC21012F

Also in this issue we have another of our acoustofluidics series which looks at perturbation methods for analysing acoustic streaming and the latest Research highlights article from Ali Khademhosseini.

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Abstract deadline for Optofluidics 2012 approaching

11 Jun 2012

The 2^nd International Conference on Optofluidics will be held later this year in Dushu Lake Hotel, Suzhou, China between September 13-14, and the submission deadline for abstracts is fast approaching.

The conference will cover the fundamentals of optofluidics, through to fabrication and applications of optofluidic micro- and nano-devices.

Important dates for your diary:

Abstract deadline July 1 2012

Early-bird registration deadline August 31 2012

Lab on a Chip will be publishing a themed issue on optofluidics to coincide with the conference, from papers presented at last year’s conference.

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Lab on a Chip Blog

Archive for June, 2012

HOT article: microfluidic polyplex preparation on a chip

Have you seen the best of LOC?

New YouTube videos

New YouTube videos

Lab on a Chip publishes its 150th issue

A microfluidic ‘baby-machine’ and nanochannels to allow efficient fluorescent analysis of proteins

Paper and plastic HIV test

Superelastic microsprings & electrical fingerprinting to detect circulating tumor cells in Issue 13

Abstract deadline for Optofluidics 2012 approaching

Top ten most accessed articles in April

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