Archive for the ‘Cover articles’ Category

Saving Stripes: using gratings to prevent destructive air-water interfaces

Researchers at National Taiwan University design grating structures to prevent air-water interfaces from destroying lipid bilayers, enabling robust bioassays of synthetic membranes.

Supported lipid bilayers (SLBs) are useful as platforms to simulate cell membranes for evaluating transport of toxins and viral particles1 and screening new pharmaceutical reagents. Yet a significant challenge is maintaining the integrity of SLBs throughout an experiment. Air-water interfaces, commonly formed during reagent changes and rinses, peel apart SLBs and delaminate them from the substrate. Strategies to preserve SLB integrity involve coating SLBs with polymers to increase their rigidity or adding proteins and sugars to form protective layers with a high bending modulus above the membrane. These methods modify the chemical structure and environment of SLBs, preventing analysis of membrane properties and specific assays of membrane-tethered species. Thus, Chung-Ta Han and Ling Chao developed a substrate with patterned gratings to prevent air-water interfaces from directly contacting SLBs when an air bubble is introduced into a microchannel with SLBs.Han2015_Figure2

The grating structures, fabricated by standard photolithography, are perpendicular to fluid flow in the microchannel and act as obstacles to air-water interfaces contacting SLBs directly by a ‘tenting’ mechanism (see figure at right). Holding the obstacle height constant at 2 μm, Han and Chao evaluated obstacle spacing at different flow rates influenced SLB stability after treatment with an air bubble. 40 μm spacing was found to efficiently preserve SLBs from air-water interfaces at a practical range of flow rates: 60 – 6000 mm/min. The authors also confirmed the integrity of the membranes by comparable diffusivity measurements within the SLBs before and after air-bubble treatment. Finally, the authors demonstrated that air bubbles did not affect receptor-ligand interactions between species embedded in the SLBs and surrounding buffer when SLBs were protected using the microfabricated obstacles.

This platform uses integrated barriers to protect SLBs from air-water interfaces, creating SLBs with native properties to study biomolecule behavior within membranes and perform high throughput analytical assays utilizing synthetic membranes.

Download the full article now – free* access for a limited time only!

Using a patterned grating structure to create lipid bilayer platforms insensitive to air bubbles
Chung-Ta Han and Ling Chao. Lab Chip, 2015, 15, 86 – 93.
DOI: 10.1039/c4lc00928b
[1] I. Kusters, A. M. Van Oijen and A. J. Driessen, ACS Nano, 2014, 8, 3380-3392.

*Access is free until 06.02.15 through a registered RSC Publishing account.

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Lectureship presented to Sangeeta Bhatia

Congratulations to Dr. Sangeeta N. Bhatia, winner of  the 2014 Corning Inc./Lab on a Chip Pioneers of Miniaturisation Lectureship.


The picture shows Lab on a Chip Executive Editor, Harpal Minhas (Left) and Director of Polymer processing in Organic & Biochemical Technologies, Science & Technology at Corning Incorporated, Ed Fewkes (right) presenting Sangeeta (middle) with her award earlier this week at the µTAS 2014 Conference.

The 9th ‘Pioneers of Ministurisation‘ Lectureship, is for extraordinary or outstanding contributions to the understanding or development of miniaturised systems and was presented to Dr Bhatia at the µTAS 2014 Conference in San Antonio, Texas in October 2014. Dr Bhatia received a certificate, $5000 and gave a short lecture at the conference. Further information, including past winners, can be viewed on our homepage.

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LOC Issue 11 online! 3D etching, digital microfluidics, lens-free microscopy

Issue 11’s significant front cover article from Ikuro Suzuki et al. at Tokyo University of Technology, Japan, describes the development of a new 3D etching method. An infrared laser allows tight control over the area of cell adhesion, selecting cell number and cell type, as a small area of the collagen gel substrate can be targeted. The researchers can guide neural network formation using this tool. 3D networks are created upon which neurons survived longer than on 2D substrates.

Control of neural network patterning using collagen gel photothermal etching
Aoi Odawara, Masao Gotoh and Ikuro Suzuki 
DOI: 10.1039/C3LC00036B

Work from Jeoren Lammertyn et al. is featured on the inside front cover. The team from University of Leuven, Belgium, use digital microfluidics to facilitate single-molecule detection for the first time. They are able to print and seal thousands of femtolitre droplets in microwells in each step. Single paramagnetic beads can be loaded into the microwells with high capacity.

Digital microfluidics-enabled single-molecule detection by printing and sealing single magnetic beads in femtoliter droplets
Daan Witters, Karel Knez, Frederik Ceyssens, Robert Puers and Jeroen Lammertyn  
DOI: 10.1039/C3LC50119A

A Frontier article from Aydogan Ozcan et al. at University of California, Los Angeles, USA, discusses progress in computational lens-free microscopy on-chip and how such technology is taking over conventional bulky optical microscopes. This article, which is also featured on the back cover, includes a discussion of the applications this new technology opens up.

Toward giga-pixel nanoscopy on a chip: a computational wide-field look at the nano-scale without the use of lenses
Euan McLeod, Wei Luo, Onur Mudanyali, Alon Greenbaum and Aydogan Ozcan
DOI: 10.1039/ c3lc50222h

For more critical reviews, HOT primary research as recommended by referees and Technical Innovations, take a look at the full issue now

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HOT articles and technical innovations in point-of-care flow cytometry

A team from Caltech and MIT, USA, and LeukoDx, Israel, have combined a microflow cytometer and fluorescent dye to produce a portable suitcase-sized point-of-care test for leukocyte count – one of the most common clinical tests. The test can identify four different types of leukocyte using only a small blood sample.

This article was featured on the bright cover of Issue 7!

Four-part leukocyte differential count based on sheathless microflow cytometer and fluorescent dye assay
Wendian Shi, Luke Guo, Harvey Kasdan and Yu-Chong Tai 
DOI: 10.1039/C3LC41059E


 

A technical innovation from Oliver Hayden and Michael Helou et al. in Germany featured on the outside front cover of Issue 6 also concentrates on flow cytometry for point-of-care testing. This vastly different technique uses magnetophoresis instead of fluorescence to detect specific cancer cells in whole blood. Cell diameters are measured from time of flight information. The device integrates sample preparation for ease of point-of-care applications. The can perform cell enrichment, cell focusing and background elimination in situ.

Time-of-flight magnetic flow cytometry in whole blood with integrated sample preparation
Michael Helou, Mathias Reisbeck, Sandro F. Tedde, Lukas Richter, Ludwig Bär, Jacobus J. Bosch, Roland H. Stauber, Eckhard Quandt and Oliver Hayden  
DOI: 10.1039/C3LC41310A

Remember all of our HOT articles are made free to access for 4 weeks*!

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

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Issue 10 online today! Artificial skin, robust SPR sensing platform and plenty of Technical Innovations

Research led by Jan van Hest and Floris Delft at the Institute for Molecules and Materials, The Netherlands, is highlighted by the front cover artwork. Their research finds a robust way to control the immobilization of azide-containing ligands on a surface for surface plasmon resonance sensing (SPR) using strain-promoted cycloaddition on a cyclooctyne-modified surface. Don’t forget our cover articles are free to access for 6 weeks*!

Site-specific peptide and protein immobilization on surface plasmon resonance chips via strain-promoted cycloaddition Angelique
E. M. Wammes, Marcel J. E. Fischer, Nico J. de Mol, Mark B. van Eldijk, Floris P. J. T. Rutjes, Jan C. M. van Hest and Floris L. van Delft  
DOI: 10.1039/C3LC41338A


 

On the distinctive outside back cover, fascinating collaborative work between the Ohio Center for Microfluidic Innovation at University of Cincinnati and the U.S. Air Force Research Laboratory on a device termed artificial microfluidic skin, which mimics human perspiration with a view to replacing human and animal testing of wearable materials.  

Artificial microfluidic skin for in vitro perspiration simulation and testing
Linlin Hou, Joshua Hagen, Xiao Wang, Ian Papautsky, Rajesh Naik, Nancy Kelley-Loughnane and Jason Heikenfeld  
DOI: 10.1039/C3LC41231H


 

Of course Issue 10 also includes Research Highlights from Ali Khademhosseini. In this issue, he focuses on lab-on-DVD devices for HIV diagnosis, atherosclerosis and muscle repair.

Research highlights
João Ribas, Mark W. Tibbitt, Mehmet R. Dokmeci and Ali Khademhosseini 
DOI: 10.1039/C3LC90032K


 

Issue 10 contains plenty of significant primary research, including three Technical Innovation articles:

Measuring material relaxation and creep recovery in a microfluidic device
Alison E. Koser, Lichao Pan, Nathan C. Keim and Paulo E. Arratia
DOI: 10.1039/C3LC41379A

Optically clear alginate hydrogels for spatially controlled cell entrapment and culture at microfluidic electrode surfaces
Jordan F. Betz, Yi Cheng, Chen-Yu Tsao, Amin Zargar, Hsuan-Chen Wu, Xiaolong Luo, Gregory F. Payne, William E. Bentley and Gary W. Rubloff
DOI: 10.1039/C3LC50079A

Multiplexed ionic current sensing with glass nanopores
Nicholas A. W. Bell, Vivek V. Thacker, Silvia Hernández-Ainsa, Maria E. Fuentes-Perez, Fernando Moreno-Herrero, Tim Liedl and Ulrich F. Keyser
DOI: 10.1039/C3LC50069A

Have a quick browse of the contents pages of Issue 10 here

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

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HOT article: Low cost, miniaturised, thermoplastic SPR biosensor

SPR biosensorAs featured on the bright inside front cover of Issue 5, this HOT article from Teodor Veres and colleagues at the National Research Council and McGill University, Canada, steps towards low cost point-of-care sensors for disease diagnosis.

The team present their all-polymeric nanoplasmonic microfluidic (NMF) transmission surface plasmon resonance (SPR) biosensor. SPR, involving light stimulated electron oscillation, is advantageous for sensing as it means label-free, real-time detection with high throughput and automation. The device is miniaturised with a view to small, point-of-care applications. The approach involves nanostructures called nanogratings for transmission SPR, which gives a more stable response. The signal can be turned by altering their characteristics and they are easily fabricated en mass.

Thermoplastic materials present an advantage over traditional PDMS for such miniaturised SPR devices as they are more mechanically robust, inert, transparent and crucially viable for large scale production and commercial applications.  The novel aspect of this work is that the nanostructured surface and the microchannels are incorporated into one substrate quickly and at low cost. Thermoplastic valves are used in large numbers for the first time for a multiplex detection scheme.

They demonstrate its application in sensing glycoprotein sCD44 at picomolar to nanomolar concentrations. Further work by the group is focused on integrating this device with a CCD spectrometer.

See the design and performance results in the full paper, now available free for 4 weeks*:

All-thermoplastic nanoplasmonic microfluidic device for transmission SPR biosensing
Lidija Malic, Keith Morton, Liviu Clime and Teodor Veres
DOI: 10.1039/C2LC41123G

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LOC Issue 9 online! Micronanofabrication, neurotransmitters, SAW-controlled droplets and pharmaceutical screening

Abraham LeeThe packed Issue 9 begins with an editorial celebrating over three decades since the birth of microfluidics by Lab on a Chip Associate Editor Abraham Lee.

Submit your work to his editorial office today at http://mc.manuscriptcentral.com/lc!

The third decade of microfluidics
Abraham Lee
DOI: 10.1039/C3LC90031B



 

An urgent communication from Lothar Schmid and Thomas Franke at University of Augsburg, Germany, and Harvard University, USA, is featured on the outside front cover, in which a surface acoustic wave is applied to control droplet size in real time:

SAW-controlled drop size for flow focusing
Lothar Schmid and Thomas Franke
DOI: 10.1039/C3LC41233D

The inside front cover illustrates the work of researchers in New Zealand and Beijing led by Wenhui Wang who investigate locomotion metrics and muscular forces of C. elegans in one microfluidic assay:

On-chip analysis of C. elegans muscular forces and locomotion patterns in microstructured environments
Shazlina Johari, Volker Nock, Maan M. Alkaisi and Wenhui Wang
DOI: 10.1039/C3LC41403E


Issue 9 includes one Tutorial Review on using microfluidics to study neurotransmitters from Callie Croushore and Jonathan Sweedler at University of Illinois at Urbana-Champaign, USA, and one Critical Review discussing micronanofabrication techniques:

Microfluidic systems for studying neurotransmitters and neurotransmission
Callie A. Croushore and Jonathan V. Sweedler
DOI: 10.1039/C3LC41334A

Fabrication and multifunction integration of microfluidic chips by femtosecond laser direct writing
Bin-Bin Xu, Yong-Lai Zhang, Hong Xia, Wen-Fei Dong, Hong Ding and Hong-Bo Sun
DOI: 10.1039/C3LC50160D

The high quality research published in Issue 9 includes a HOT article from Paul Kenis et al. again at the University of Illinois at Urbana-Champaign, USA, which describes a new microfluidic platform for the screening of salt forms of pharmaceuticals:

Microfluidic Platform for Evaporation-based Salt Screening of Pharmaceutical Parent compounds
Sachit Goyal, Michael R. Thorson, Cassandra L. Schneider, Geoff G. Z. Zhang, Yuchuan Gong and Paul J. A. Kenis
DOI: 10.1039/C3LC41271G

View all of the articles in Issue 9 here

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LOC Issue 8 now online: Art in Science

The winner of the 2012 Art in Science Award presented at October’s MicroTas meeting was Yi Zhang, from Johns Hopkins University, USA and the striking winning image is featured on the outside front cover of Issue 8!

Read what’s in the issue here

A description of the winning image and advice on what makes a worthy Art in Science submission are discussed in the editorial by Michael Gaitan from NIST, USA, and Harp Minhas, Editor of LOC, who were part of the award selection committee.

The Art in Science of microTAS
Michael Gaitan and Harp Minhas
DOI: 10.1039/C3LC90026F


In keeping with the artistry of the front cover, work from Shoji Takeuchi et al. in Japan is featured on the inside front cover of Issue 8. In this paper, they address the problem of how to exchange the solution within a droplet for a new solution, for example to introduce membrane proteins or to wash-out applied chemicals during ion channel analysis. They use microfluidic channels to carry out solution exchange by droplet contact in under 20 seconds with the membrane still intact. Cover articles are free to access for 6 weeks*!

Droplet-based lipid bilayer system integrated with microfluidic channels for solution exchange
Yutaro Tsuji, Ryuji Kawano, Toshihisa Osaki, Koki Kamiya, Norihisa Miki and Shoji Takeuchi
DOI: 10.1039/C3LC41359D


The back cover features the laboratory of Sergey Shevkoplyas at Tulane University, USA. The communication by this laboratory describes their simple point-of-care test for sickle cell disease using characteristic patterns made by blood samples on paper, which can even differentiate between sickle cell disease and those healthy people with sickle cell traits.

A simple, rapid, low-cost diagnostic test for sickle cell disease
Xiaoxi Yang, Julie Kanter, Nathaniel Z. Piety, Melody S. Benton, Seth M. Vignes and Sergey S. Shevkoplyas
DOI: 10.1039/C3LC41302K


This issue also includes plenty of HOT research and a focus article from Tony Huang on the more unconventional applications of microfluidics:

Unconventional microfluidics: expanding the discipline
Ahmad Ahsan Nawaz, Xiaole Mao, Zackary S. Stratton and Tony Jun Huang
DOI: 10.1039/C3LC90023A

Programmable parylene-C bonding layer fluorescence for storing information on microfluidic chips
Ata Tuna Ciftlik, Diego Gabriel Dupouy and Martin A. M. Gijs
DOI: 10.1039/C3LC41280F

Engineering of functional, perfusable 3D microvascular networks on a chip
Sudong Kim, Hyunjae Lee, Minhwan Chung and Noo Li Jeon
DOI: 10.1039/C3LC41320A

In situ synthesis of silver nanoparticle decorated vertical nanowalls in a microfluidic device for ultrasensitive in-channel SERS sensing
Joseph Parisi, Liang Su and Yu Lei
DOI: 10.1039/C3LC41249K

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Issue 7 online! The latest HOT miniaturisation research and critical reviews on microfabricated organ systems, nucleic acid amplification and microfluidics in IVF

As highlighted on the outside front cover, physicists, engineers and chemists at the University of Illinois , USA, describe a new laser-based label-free resonant optical biosensor with high resolution and high sensitivity. The difference with this sensor is that they use a photonic crystal resonant reflector surface to introduce optical gain to the sensor from an external source via simulated emission. All of our cover articles are free to access for 6 weeks,* so you can read the full work now:

External cavity laser biosensor
Chun Ge, Meng Lu, Sherine George, Timothy A. Flood, Clark Wagner, Jie Zheng, Anusha Pokhriyal, J. Gary Eden, Paul J. Hergenrother and Brian T. Cunningham
DOI: 10.1039/C3LC41330F

On the inside front cover, researchers at California Institute of Technology, USA, and LeukoDx Inc., Israel, present a point-of-care test for leukocyte counting using a microflow cytometer and fluorescent dye. This method eliminated excessive dilution and sheath flow, giving a minimal needed sample volume.

Four-part leukocyte differential count based on sheathless microflow cytometer and fluorescent dye assay
Wendian Shi, Luke Guo, Harvey Kasdan and Yu-Chong Tai
DOI: 10.1039/C3LC41059E

Work from Tino Frank and Savaş Tay at ETH Zurich is featured on the inside back cover. To improve studies of cell signalling in vitro, this article introduces a simple cell culture platform that can produce programmable diffusion-based gradients using microfluidics based on modifying flow over time. Read it here:

Flow-switching allows independently programmable, extremely stable, high-throughput diffusion-based gradients
Tino Frank and Savaş Tay
DOI: 10.1039/C3LC41076E

The outside back cover highlights the work of Sung Gap Im at KAIST, South Korea. This article is about a doubly cross-linked nano-adhesive system (DCNA) and the team demonstrate fabrication of microfluidic devices with flexible and rigid substrates with high strength and stability. The flexible devices could be manipulated without delamination occurring.

A doubly cross-linked nano-adhesive for the reliable sealing of flexible microfluidic devices
Jae Bem You, Kyoung-Ik Min, Bora Lee, Dong-Pyo Kim and Sung Gap Im
DOI: 10.1039/C2LC41266G

 

In addition to the primary microfluidics research and high number of HOT articles in issue 7, there are also three critical reviews:

Microfabricated mammalian organ systems and their integration into models of whole animals and humans
Jong H. Sung, Mandy B. Esch, Jean-Matthieu Prot, Christopher J. Long, Alec Smith, James J. Hickman and Michael L. Shuler
DOI: 10.1039/C3LC41017J

Thinking big by thinking small: application of microfluidic technology to improve ART
J. E. Swain, D. Lai, S. Takayama and G. D. Smith
DOI: 10.1039/C3LC41290C

Nucleic acid amplification using microfluidic systems
Chen-Min Chang, Wen-Hsin Chang, Chih-Hung Wang, Jung-Hao Wang, John D. Mai and Gwo-Bin Lee
DOI: 10.1039/C3LC41097H

View the whole issue here

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

 

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HOT review: Forming the wiring of the nervous system – discovering the mechanisms of axon guidance through new technologies

Today’s HOT article is a review article that was featured on the front cover of our Neuroengineering themed issue.

In this review, Santiago Costantino et al. at the University of Montreal and McGill University, Canada, critically discuss the most recent insights into axon guidance that have been enabled by developments in methods and technologies for engineered cell substrates.

This review includes:

  1. Extracellular cues and growth cones
  2. Historical background
  3. The stripe assay in discovery of guidance cues and signalling mechanisms
  4. Microcontact printing – development from the stripe assay
  5. Insights via microfluidics
  6. Studies using laser-assisted printing and patterning 3D hydrogels

The focus is on the biological insights into how axons recognise and interpret external signals in order to reach their synaptic target that have come out of using these technologies, rather than the development of the technology itself. This cover article is still free to access for another couple of weeks*, read it now by clicking the link below:

Engineered cell culture substrates for axon guidance studies: moving beyond proof of concept
Joannie Roy, Timothy E. Kennedy and Santiago Costantino
DOI: 10.1039/C2LC41002H

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

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