Author Archive

Microdevices in cell biology: not one, but three HOT articles!

microfluidic x-ray cellsBritta Weinhausen and Sarah Köster study hydrated eukaryotic cells device using X-rays in a new microfluidic device in their Technical Innovation, free to access for 4 weeks*.

The team at Georg-August-Universität Göttinghen, Germany, overcome some of the limitations of previous work to create a new type of device suitable for studying hydrated cells, with the possibility of applying it to living cells.

They use UV-curable glue (NOA 81) allowing sophisticated channel structures to be defined, two thin Kapton foils, with advantageous properties for X-ray studies, and a Si3N4 membrane window, upon which cells can be grown and fixed before the device is closed with a second membrane. Despite the small difference in electron density between the cellular material and water, they successfully produce X-ray dark-field images:

Microfluidic devices for X-ray studies on hydrated cells
Britta Weinhausen and Sarah Köster
DOI: 10.1039/C2LC41014A

 

cytometryAs mentioned in the LOC issue 2 blog, Luke Lee et al. at the University of California, Berkeley and Stanford University, featured on the front cover with their work on sorting stem cells using a cell cytometer based on the electrophysiological response to stimulus. As a HOT article that was featured on the cover, this article has been free to access* for 6 weeks from mid-December so get your skates on to read it in full in the next week:

Label-free electrophysiological cytometry for stem cell-derived cardiomyocyte clusters
Frank B. Myers, Christopher K. Zarins, Oscar J. Abilez and Luke P. Lee
DOI: 10.1039/C2LC40905D

 

electroporationIn this Technical Innovation, Rashid Bashir led a team of researchers from the USA, Sweden and Singapore in using silicon nanowires for rapid lysis of single cells by ultra-localized electroporation to release cell components for analysis. They integrate label-free magnetic manipulation to correctly position cells with the use of field effect transistors to apply an electric field for cell lysis.

Their method eliminates the use of microfluidic trapping techniques, transparent substrates for optical tweezing and high voltages, amongst other requirements for previous devices.

This work is featured on the inside front cover of Issue 3, so it’s currently free to access for 6 weeks*. Do have a read of the article here:

Ultra-localized single cell electroporation using silicon nanowires
Nima Jokilaakso, Eric Salm, Aaron Chen, Larry Millet, Carlos Duarte Guevara, Brian Dorvel, Bobby Reddy, Amelie Eriksson Karlstrom, Yu Chen, Hongmiao Ji, Yu Chen, Ratnasingham Sooryakumar and Rashid Bashir
DOI: 10.1039/C2LC40837F

*Free access to individuals is provided through an RSC Publishing personal account. Registration is quick, free and simple

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HOT article: A hydrodynamic study on streamer formation in biofilms

Researchers led by Aloke Kumar at the Oak Ridge National Laboratory, USA, and Thomas Thundat at the University of Alberta, Canada, used a porous microfluidic device to study biofilm streamer development in porous media.

The microfluidic method allowed close observation and measurement of streamers developing between microposts embedded in a microchannel. The formation of streamers in the device forming a web connecting different microposts was strongly influenced by the hydrodynamics.

Higher flow rates resulted in thicker structures and higher numbers of streamers as they grew much faster. At very high flow rate, their formation was only transient as they were destabilized after forming. The fluid flow seems to be the cause of both the formation and destabilization of the streamers. Interestingly, streamers formed parallel to the flow direction in regions of high flow rate and transverse to it in regions of low flow rate. In contrast with a previous report, they observe streamers distributed throughout the height of the device, attributed to secondary flow in the corners of the device. Carrying out numerical simulations, Kumar and Thundat et al. showed that secondary flows in the z-direction do not have a large role to play.

Development of streamers is complex and a great deal of detail remains to be elucidated, however, this Lab on a Chip article indicates that streamer formation might lead to mature microbial structures under the right conditions.

This HOT article is free to access* on our site for the next four weeks, so why not download the paper here:

A web of streamers: biofilm formation in a porous microfluidic device
Amin Valiei ,  Aloke Kumar ,  Partha P. Mukherjee ,  Yang Liu and Thomas Thundat
DOI: 10.1039/C2LC40815E

*Free access to individuals is provided through an RSC Publishing personal account. Registration is quick, free and simple

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