Archive for the ‘Chemistry World Highlights’ Category

Microrobot gets to grips with bubbles

A remotely controlled micro-robot uses air bubbles to grip on to and assemble sub-millimetre sized components.

The microgripper lifts a poly(ethylene glycol) diacrylate hydrogel disc (pink) and stacks it on top of a another hydrogel disc (blue). Source: Royal Society of Chemistry

Gripping and manipulating sub-millimetre objects is a tricky problem in microrobotics. Mechanical grasping is difficult at micro level, and techniques such as micro-machined grippers, although very accurate, need to be tethered to a control system and so are unsuitable for work in confined spaces.

To overcome these problems, Metin Sitti and his team from the Max Planck Institute in Germany have developed an untethered microgripper, which uses surface tension, rather than mechanical means, to grab small parts, such as a hair, a cloth fibre or a piece of muscle tissue. The gripper works in an aqueous environment, can grab both hydrophilic and hydrophobic items and, unlike other systems, does not need to be customised to fit to the item.

Read the full article in Chemistry World.


Programmable assembly of heterogeneous microparts by an untethered mobile capillary microgripper

Joshua Giltinan, Eric Diller and Metin Sitti

Lab Chip, 2016, 16, 4445-4457

DOI: 10.1039/C6LC00981F, Paper

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Microfluidics made easy

Automated design helps researchers find the right chip for the job

Scientists in the US have devised an algorithmic process to speed up the design of microfluidic chips, generating a library containing thousands of different chip designs that researchers can search by functionality.

Microfluidic chips, which are widely used in areas such as disease diagnostics and DNA sequencing, consist of tiny channels etched into a glass or plastic. These microchannels are connected to achieve a specific function, for example mixing fluids. The design process, however, has remained relatively unchanged since their emergence as William Grover from the University of California, who led the new study, explains: ’We design them by hand and we test them – if they work great, but more often than not, they don’t, so then I have to start all over again. That process is so slow and inefficient.’

With a new online database created by Grover and his team, even researchers with no microfluidics experience can find the perfect chip to suit their needs. Grover’s team created a computer program that generates thousands of random microfluidic chip designs and simulates their behaviour. The database collects these simulated designs, and users can query it to find chips suitable for given tasks.

Read the full article in Chemistry World.


Random design of microfluidics

Junchao Wang, Philip Brisk and William H. Grover

Lab Chip, 2016, Advance Article

DOI: 10.1039/C6LC00758A, Paper

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Sepsis’ sticking point in for a shock

Simple microfluidic method helps detect life-threatening condition earlier

A new method for monitoring the onset of sepsis touted by US researchers may assist clinicians in helping more of their patients survive this potentially fatal condition.

Sepsis, often referred to as blood poisoning, can be the result of an innocuous infection or injury. Without treatment, the immune system becomes overwhelmed, leading to organ shutdown. In the UK alone, 30,000 people die as a direct result of the condition. Sepsis needs to be caught early to maximise the chances of a full recovery. However, existing diagnostics rely on antibody labelling, which requires samples to be prepared and tested by specialist laboratory staff. This requires time that a patient might not be able to spare. ‘Existing methods are too cumbersome,’ explains Joel Voldman, heading up the new study at Massachusetts Institute of Technology.

detecting sepsis with electrochemical monitoring

The tiny device can process large amounts of blood and detect activated white blood cells that are an indicator for sepsis. Source: © Royal Society of Chemistry

Voldman’s group devised a microfluidic method that takes advantage of the white blood cells’ electrical properties, which makes it possible to detect sepsis quickly in its earliest stages. Sepsis triggers white blood cells to become activated and circulate in the blood. The number of these activated cells indicates the disease’s progression. Applying an electric field then separates activated and non-activated cells based on subtle differences in their electrical properties.

Read the full article in Chemistry World.


Monitoring sepsis using electrical cell profiling

Javier L. Prieto, Hao-Wei Su, Han Wei Hou, Miguel Pinilla Vera, Bruce D. Levy, Rebecca M. Baron, Jongyoon Han and Joel Voldman

Lab Chip, 2016, Advance Article

DOI: 10.1039/C6LC00940A, Paper

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Serial crystallography enhanced by graphene

Introducing graphene into microfluidic devices can make it easier to study proteins at an atomic level, scientists in the US have shown. Devices that are thinner and interfere less with the measurements allow larger and more intricate protein structures to be resolved using techniques that rely on probing thousands of microcrystals.

Not only does this reduce the device’s thickness, improving the signal-to-noise ratio, the graphene also acts as a barrier to prevent the sample evaporating. John Helliwell, an expert in crystallography at the University of Manchester in the UK, explains that preventing water loss from the crystal is ‘vital…because the sample hydration state needs to be preserved for its molecular integrity’.

Perry’s group are now focusing on shrinking down the dimensions and increasing the complexity of the device, as well as studying the structure of proteins involved in programmed cell death.

To read the full article visit Chemistry World.

Click the link below to read the original research paper published in Lab on a Chip for free*:

Graphene-based microfluidics for serial crystallography
Shuo Sui, Yuxi Wang, Kristopher W. Kolewe, Vukica Srajer, Robert Henning, Jessica D. Schiffman, Christos Dimitrakopoulos and Sarah L. Perry
Lab Chip
, 2016, Advance Article
DOI:
10.1039/C6LC00451B

*Article is free to access until 26/07/2016 through a RSC registered account – click here to register

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Cleaning solution test doesn’t move contact lens wearers to tears

In the US, over 30 million people wear contact lenses and each year around 60,000 contract serious eye infections that put them at risk of going blind. Thorough cleaning is vital to prevent bacterial build-up on the lens but research has also shown that an individual’s tear chemistry affects the effectiveness of cleaning solutions.

Personalised care products can prevent serious eye infections caused by ineffective contact lens cleaning solutions

The team use their device to demonstrate how tears impacts lens selection and care, and say it could be adapted for point-of-care testing in eye clinics.

Please visit Chemistry World to read the full article.

Contact lens-on-a-chip companion diagnostic for personalized medicine
Allan Guan, Yi Wang, Kenneth Scott Phillips and Zhenyu Li
Lab Chip
, 2016, Accepted Manuscript
DOI: 10.1039/C6LC00034G

*Access is free through a registered RSC account until 8th April 2016 – click here to register


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Microscopic pumps made from trapped bacteria

Scientists in China have trapped bacteria in 3D-printed structures and used them to pump materials along customised paths.

Transporting materials in the microscopic world is complex. Conventionally, macroscopic pumps drive motion, but pumps are bulky and not ideal for miniaturisation. Now, Hepeng Zhang and colleagues at Shanghai Jiao Tong University have tackled this problem using native inhabitants of the microscopic world – motile bacteria. Not only are they already present in the media, but their energy conversion efficiency is estimated to be greater than existing man-made micro-motors.

Please visit Chemistry World to read the full article.

Using confined bacteria as building blocks to generate fluid flow
Zhiyong Gao, He Li, Xiao Chen and H. P. Zhang
Lab Chip, 2015, Advance Article
DOI: 10.1039/C5LC01093D

*Access is free through a registered RSC account until 10 December 2015 – click here to register
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Microfluidic device lets the drop beat

Scientists in Switzerland have incorporated pulsing human heart tissue into a microfluidic device to make a miniscule model of a living system that could be used to test new drugs.

The hanging drops are connected through 200μm-wide channels

‘This is one of the most interesting recent developments in the field of microfluidic systems,’ comments Wouter van der Wijngaart, who heads up the research into micro- and nanofluidic systems at the KTH Royal Institute of Technology in Sweden. ‘This type of system has the potential to become the de facto workhorse in the field of 3D microtissue culturing.’

Please visit Chemistry World to read the full article.

Adding the ‘heart’ to hanging drop networks for microphysiological multi-tissue experiments*
Saeed Rismani Yazdi, Amir Shadmani, Sebastian C. Bürgel, Patrick M. Misun, Andreas Hierlemann and Olivier Frey
Lab Chip, 2015, Advance Article
DOI: 10.1039/C5LC01000D

*Access is free through a registered RSC account until 19 November 2015 – click here to register

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Gecko-inspired adhesives for microfluidics

Scientists from Canada report an affordable manufacturing advance in microfluidics with a dry adhesive system that demonstrates strong, self-healing and reversible bonding.

This new adhesive technology will make complex microfluidic patterns much simpler to assemble,’ says Ali Dhinojwala, from the University of Akron, US, who is also interested in mimicking the sticking power of geckos. ‘By incorporating mushroom-shape tips in the fabrication of the device, they demonstrate reversible seals with larger burst pressures than PDMS-based devices.’

Please visit Chemistry World to read the full article.


Gecko gaskets for self-sealing and high-strength reversible bonding of microfluidics
A. Wasay and D. Sameoto
Lab Chip
, 2015, Advance Article
DOI: 10.1039/C5LC00342C

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Femtofluidic droplet manipulation now possible

We’ve had microfluidics. We’ve even had nanofluidics. But now, scientists have gone a step smaller by pushing femtofluidics into the realms of possibility.

Droplet microfluidics enables assays and reactions to be performed in droplets of reagent that are just a few nanolitres or picolitres in volume. The main advantages of this are that reactions can be performed in a massively parallel manner using hardly any reagent, and further miniaturisation to give femtolitre droplets promises to enable even higher-throughput with even lower reagent use.

Please visit ChemistryWorld to read the full article .

Droplet-based microfluidics at the femtolitre scale*
Marie Leman, Faris Abouakil, Andrew D. Griffiths and Patrick Tabeling
Lab Chip
, 2015, Advance Article
DOI: 10.1039/C4LC01122H

*Access is free through a registered RSC account until 13 November 2014 – click here to register

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Oil reserves put under the microscope with new lab-on-a-rock

The microfluidic model is etched into a calcite crystal

Scientists in Canada have developed a new microfluidic model carved from rock, which can replicate the conditions found in underground oil reservoirs in a laboratory with more accuracy than ever before. Using it to study the processes that occur in these reservoirs could lead to greater oil yields.

David Sinton’s group, at the University of Toronto, hope that the model they’ve developed will allow them to properly study the rock structure, and see how it’s affected by oil extraction techniques. The techniques could then be optimised to make them much more efficient.

To read the full article please visit ChemistryWorld.

Chip-off-the-old-rock: the study of reservoir-relevant geological processes with real-rock micromodels*
Wen Song, Thomas W. de Haas, Hossein Fadaei and David Sinto.
Lab Chip
, 2014, Advance Article
DOI: 10.1039/C4LC00608A

*Access is free through a registered RSC account until 13 November 2014 – click here to register

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