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News, anecdotes and pictures from across science and engineering at UCL


A molecule-sized magnetic sensor

By Oli Usher, on 26 January 2015

STM image of iron phtalocyanine. Credit: Ben Warner, Fadi El Hallak and Cyrus Hirjibehedin (LCN)

STM image of iron phtalocyanine. Credit: Ben Warner, Fadi El Hallak and Cyrus Hirjibehedin (LCN)

This image shows a scanning tunnelling microscope (STM) image of a molecule of iron phtalocyanine, separated from an underlying layer of copper by a thin barrier of copper nitride.

The image is part of a new piece of research just published by UCL scientists. The iron phtalocyanine molecule forms part of a tiny magnetic sensor which is sufficiently sensitive that it can detect molecule-sized magnetic fields. This technology could allow far smaller hard disks and new computer memory designs.


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The cleanroom at LCN

By Oli Usher, on 12 January 2015

CleanroomLabs are rarely spotless. They are working spaces, busy with people. They are difficult to clean. They are also often home to some pretty messy scientific research. In fact, labs often look more like a workshop or garage than they do the gleaming white rooms we see on TV.

One glaring exception to this is the cleanroom at the London Centre for Nanotechnology. This lab is home to work that would be damaged even by tiny amounts of dust.

For instance, in the photolithography section (above), scientists use light to etch nanoscale circuits and patterns onto silicon surfaces, a process used to make electronic components. Even a speck of dust could derail this by casting a shadow on the surface and ruining the pattern.

For the same reason, the room is lit only with orange light. The light used to etch the surfaces is closer to the blue end of the visible spectrum, and any stray blue light could ruin the process. The distinctive lighting in the room avoids any inadvertent damage being caused to the experiment.


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Simulating nanocomposites

By Oli Usher, on 15 December 2014

A long chain-like molecule of polyvinyl alcohol interacting with particles of clay. Credit: Advanced Materials/Suter/Coveney/Groen

A long chain-like molecule of polyvinyl alcohol (in red) interacting with the tiny sheets that make up a clay particle. Top left: after 0.15 nanoseconds, top right: after 0.8ns, bottom left: after 2.5ns, bottom right: after 4.75ns. Credit: Advanced Materials/Suter/Coveney/Groen

Supercomputer simulations carried out by UCL chemists have successfully modelled the behaviour of clay-polymer nanocomposite materials. These materials, produced by dispersing tiny particles of clay through polymer (plastic) are widely used in industry.

Clay particles are made of tiny mineral sheets; plastics are made of long chain-like molecules. The way these interact when they are mixed determines the properties of the resulting composite material.

In the simulation, images of which are shown above, the polymer chains do not only surround the clay particles, they actually slide into the gaps between the sheets that make them up.

Read a full report of the science behind these pictures on the UCL Mathematical & Physical Sciences website, or read the coverage of the breakthrough on BBC News.


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Nanodrills in action

By Oli Usher, on 2 December 2014

A team of scientists at UCL and partner institutions has today published a study showing how certain harmful bacteria use tiny ‘nanodrills’ to make holes in our cell membranes.

These rings of toxin molecules assemble themselves on the cell membrane, then slice down, punching a hole and spitting out the piece of membrane they cut away. The rings then hold the hole open, much like an eyelet.

Nanodrills in action

Nanodrills in action. Credit: eLife/Bart Hoogenboom/UCL

This image is a still from a ‘video’ produced by an atomic force microscope (AFM) in Bart Hoogenboom’s lab at UCL. AFMs feel a surface rather than seeing it – a tiny needle is repeatedly moved across the surface and feels the shape and hardness of the sample: lighter colours represent raised surfaces.

In the full video (below), we see the ring-like structures skating over the surface of the membrane, before they start perforating the membrane.


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Peeling an egg

By Oli Usher, on 24 November 2014

Peeling a frog's egg

Peeling a frog’s egg. Credit: Armin Kramer

This sequence of images shows the painstaking act of peeling a frog’s egg. The egg is gripped with tweezers, carefully torn open, and the cell nucleus inside is separated out. The nucleus is the small, pale blob in the centre of the final frame, and it is well under a millimetre across.

This difficult procedure is a key element in new research published by UCL scientists today. In the study, scientists probed the membrane that surrounds the cell nucleus in order to determine the structure of tiny pores that play a key role in cell biology.

A full summary of their research, including a remarkable image of these pores, produced using an atomic force microscope, is available from UCL News.

You can also watch a video of the process below.


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Using phones to prevent pandemics

By Oli Usher, on 18 November 2014

Rachel McKendry (London Centre for Nanotechnology at UCL) leads a consortium that develops mobile phone-based diagnostic kits. She gave this year’s Rosalind Franklin lecture at the Royal Society, which you can view above.

In this lecture, Professor Rachel McKendry presented her research to create a new generation of mobile phone connected diagnostic tests for infectious diseases. The widespread use of mobile phones could dramatically increase access to testing outside of hospital settings, particularly in developing countries. Professor McKendry also presented the research foundations of a global early-warning system for infectious diseases that links the millions of symptoms that are self-reported on the web each day to mobile phone connected tests, in real-time and with geographically-linked information. This research lies at the cutting edge of infectious diseases, nanotechnology, telecommunications, big data and public health.


Cleaning up in the cleanroom

By Oli Usher, on 30 June 2014

Inside LCN's cleanroom. Photo: O. Usher (UCL MAPS)

Inside LCN’s cleanroom. Photo: O. Usher (UCL MAPS)

Many scientific processes need spotlessly clean labs. In the life sciences, samples can be contaminated by bacteria or moulds; in chemistry, samples may become impure. In the London Centre for Nanotechnology, where scientists and engineers develop and study microscopic devices, dust is one of the major enemies – and it must be excluded before the researchers can do their work.

The LCN’s cleanroom is a large, sealed facility in which much of this type of research takes place. Users of the facility have to wear special protective suits to prevent dirt and dust from their clothes from contaminating the lab, while any equipment brought into the room needs to be carefully cleaned.

This spotlessly clean environment means that highly precise work can be carried out. One example is photolithography, where the tiny electronic circuits on chips are etched using ultraviolet light. (The room is lit in orange, which is far away from ultraviolet in the electromagnetic spectrum, to avoid damaging this process.) The clean environment helps ensure that the correct patterns are imprinted on the silicon surfaces.


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