NEW NANOTECH DRIVES HEALING BY “TALKING” TO WOUNDS

A Time To Heal

Researchers from Imperial College London have created a new molecule that can “talk” to the cells in the area near injured tissues to encourage wound healing.

“This intelligent healing is useful during every phase of the healing process, has the potential to increase the body’s chance to recover, and has far-reaching uses on many different types of wounds,” lead researcher Ben Almquist said in a news release.

Setting A TrAP

The Imperial team describes the wound-healing molecules, which it calls traction force-activated payloads (TrAPs), in a study published Monday in the journal Advanced Materials.

The first step to creating TrAPs was folding segments of DNA into aptamers, which are three-dimensional shapes that latch tightly to proteins. The researchers then added a “handle” to one end of the aptamer.

As cells navigated the area near a wound during lab testing, they would pull on this handle, causing the aptamer to open and release proteins that encouraged wound healing. By changing the handle, the researchers found they could control which cells activated the TrAPs.

According to Almquist, “TrAPs provide a flexible method of actively communicating with wounds, as well as key instructions when and where they are needed.”

To The Clinic

It can take a long time for research to move from the laboratory to the clinical trial stage, but the TrAPs team might be able to speed along the path. That’s because aptamers are already used for drug delivery, meaning they’re already considered safe for human use.

TrAPs are also fairly straightforward to create, meaning it wouldn’t be difficult to scale the technology to industrial levels. According to the researchers’ paper, doctors could then deliver the TrAPs via anything from collagen sponges to polyacrylamide gels. So if future testing goes well, the molecules could soon change how we heal a variety of wounds.

READ MORE: New Material Could ‘Drive Wound Healing’ Using the Body’s Inbuilt Healing System [Imperial College London]

More on aptamers: New Nanobots Kill Cancerous Tumors by Cutting off Their Blood Supply

Story Source:

Materials provided by Imperial College London. Original written by Caroline Brogan. Note: Content may be edited for style and length.

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Journal Reference:

1. Anna Stejskalová, Nuria Oliva, Frances J. England, Benjamin D. Almquist. Biologically Inspired, Cell‐Selective Release of Aptamer‐Trapped Growth Factors by Traction Forces. Advanced Materials, 2018 DOI: 10.1002/adma.201806380

Researchers @Imperial College of London uncover secret of nanomaterial that makes harvesting sunlight easier

Gold nanoparticles chemically guided inside the hot-spot of a larger gold bow-tie nanoantenna. Credit: Imperial College London

Using sunlight to drive chemical reactions, such as artificial photosynthesis, could soon become much more efficient thanks to nanomaterials.

 

This is the conclusion of a study published today led by researchers in the Department of Physics at Imperial College London, which could ultimately help improve solar energy technologies and be used for new applications, such as using sunlight to break down harmful chemicals.

Sunlight is used to drive many chemical processes that would not otherwise occur. For example, carbon dioxide and water do not ordinarily react, but in the process of photosynthesis, plants take these two chemicals and, using sunlight, produce oxygen and sugar.

The efficiency of this reaction is very high, meaning much of the energy from sunlight is transferred to the chemical reaction, but so far scientists have been unable to mimic this process in manmade artificial devices.

One reason is that many molecules that can undergo chemical reactions with light do not efficiently absorb the light themselves. They rely on photocatalysts – materials that absorb light efficiently and then pass the energy on to the molecules to drive reactions.

In the new study, researchers have investigated an artificial photocatalyst material using nanoparticles and found out how to make it more efficient.

This could lead to better solar panels, as the energy from the Sun could be more efficiently harvested. The photocatalyst could also be used to destroy liquid or gas pollutants, such as pesticides in water, by harnessing sunlight to drive reactions that break down the chemicals into less harmful forms.

Lead author Dr Emiliano Cortés from the Department of Physics at Imperial, said: “This finding opens new opportunities for increasing the efficiency of using and storing sunlight in various technologies.

“By using these materials we can revolutionize our current capabilities for storing and using sunlight with important implications in energy conversion, as well as new uses such as destroying pollutant molecules or gases and water cleaning, among others.”

The material that the team investigated is made of metal nanoparticles – particles only billionths of a metre in diameter. Their results are published today in the Journal Nature Communications.

The team, which included researchers from the Chemistry Department at University of Duisburg-Essen in Germany led by Professor Sebastian Schlücker and theoreticians from the Rensselaer Polytechnic Institute and Harvard University at the US, showed that light-induced chemical reactions occur in certain regions over the surface of these nanomaterials.

They identified which areas of the nanomaterial would be most suitable for transferring energy to chemical reactions, by tracking the locations of very small gold nanoparticles (used as a markers) on the surface of the silver nanocatalytic material.

Now that they know which regions are responsible for the process of harvesting light and transferring it to chemical reactions, the team hope to be able to engineer the nanomaterial to increase these areas and make it more efficient.

Lead researcher Professor Stefan Maier said: “This is a powerful demonstration of how metallic nanostructures, which we have investigated in my group at Imperial for the last 10 years, continue to surprise us in their abilities to control light on the nanoscale.

“The new finding uncovered by Dr Cortés and his collaborators in Germany and the US opens up new possibilities for this field in the areas photocatalysis and nanochemistry.”

Explore further: Artificial leaf as mini-factory for drugs

More information: Emiliano Cortés et al. Plasmonic hot electron transport drives nano-localized chemistry, Nature Communications (2017). DOI: 10.1038/NCOMMS14880

Journal reference: Nature Communications

Provided by: Imperial College London

Flying drones could soon re-charge whilst airborne with new (old) technology: Inductive Coupling

 

Scientists have demonstrated a highly efficient method for wirelessly transferring power to a drone while it is flying.

The breakthrough could in theory allow flying drones to stay airborne indefinitely – simply hovering over a ground support vehicle to recharge – opening up new potential industrial applications.

The technology uses inductive coupling, a concept initially demonstrated by inventor Nikola Tesla over 100 years ago. Two copper coils are tuned into one another, using electronics, which enables the wireless exchange of power at a certain frequency. Scientists have been experimenting with this technology for decades, but have not yet been able to wirelessly power flying technology.

Now, scientists from Imperial College London have removed the battery from an off-the-shelf mini-drone and demonstrated that they can wirelessly transfer power to it via inductive coupling. They believe their demonstration is the first to show how this wireless charging method can be efficiently done with a flying object like a drone, potentially paving the way for wider use of the technology.

To demonstrate their approach the researchers bought an off-the-shelf quadcopter drone, around 12 centimetres in diameter, and altered its electronics and removed its battery. They made a copper foil ring, which is a receiving antennae that encircles the drone’s casing. On the ground, a transmitter device made out of a circuit board is connected to electronics and a power source, creating a magnetic field.

The drone’s electronics are tuned or calibrated at the frequency of the magnetic field. When it flies into the magnetic field an alternating current (AC) voltage is induced in the receiving antenna and the drone’s electronics convert it efficiently into a direct current (DC) voltage to power it.

The technology is still in its experimental stage. The drone can only currently fly ten centimetres above the magnetic field transmission source. The team estimate they are one year away from a commercially available product. When commercialised they believe their breakthrough could have a range of advantages in the development of commercial drone technology and other devices.

The use of small drones for commercial purposes, in surveillance, for reconnaissance missions, and search and rescue operations are rapidly growing. However, the distance that a drone can travel and the duration it can stay in the air is limited by the availability of power and re-charging requirements. Wireless power transfer technology may solve this, say the team.

Dr Samer Aldhaher, a researcher from the Department of Electrical and Electronic Engineering at Imperial College London, said: “There are a number of scenarios where wirelessly transferring power could improve drone technology. One option could see a ground support vehicle being used as a mobile charging station, where drones could hover over it and recharge, never having to leave the air.”

Wirelessly transferring power could have also applications in other areas such as sensors, healthcare devices and further afield, on interplanetary missions.

Professor Paul Mitcheson, from the Department of Electrical and Electronic Engineering at Imperial College London, explains: “Imagine using a drone to wirelessly transmit power to sensors on things such as bridges to monitor their structural integrity. This would cut out humans having to reach these difficult to access places to re-charge them.

“Another application could include implantable miniature diagnostic medical devices, wirelessly powered from a source external to the body. This could enable new types of medical implants to be safely recharged, and reduce the battery size to make these implants less invasive.

“In the future, we may also be able to use drones to re-charge science equipment on Mars, increasing the lifetime of these billion dollar missions.

“We have already made valuable progress with this technology and now we are looking to take it to the next level.”

The next stage will see team exploring collaborations with potential industrial partners.

Explore further: Drone safety: User-centric control software improves pilot performance and safety

Provided by: Imperial College London

 

Plastic electronics made easy

(Nanowerk News)  Scientists have discovered a way to  better exploit a process that could revolutionise the way that electronic  products are made.

The scientists from Imperial College London say improving the  industrial process, which is called crystallisation, could revolutionise the way  we produce electronic products, leading to advances across a whole range of  fields; including reducing the cost and improving the design of plastic solar  cells.

The process of making many well-known products from plastics  involves controlling the way that microscopic crystals are formed within the  material. By controlling the way that these crystals are grown engineers can  determine the properties they want such as transparency and toughness.  Controlling the growth of these crystals involves engineers adding small amounts  of chemical additives to plastic formulations. This approach is used in making  food boxes and other transparent plastic containers, but up until now it has not  been used in the electronics industry.

The team from Imperial have now demonstrated that these  additives can also be used to improve how an advanced type of flexible circuitry  called plastic electronics is made.

The team found that when the additives were included in the  formulation of plastic electronic circuitry they could be printed more reliably  and over larger areas, which would reduce fabrication costs in the industry.

The team reported their findings this month in the journal  Nature Materials (“Microstructure formation in molecular and polymer  semiconductors assisted by nucleation agents”).

Dr Natalie Stingelin, the leader of the study from  the Department of Materials and Centre of Plastic Electronics at Imperial, says:

“Essentially, we have demonstrated a simple way to gain control  over how crystals grow in electrically conducting ‘plastic’ semiconductors. Not  only will this help industry fabricate plastic electronic devices like solar  cells and sensors more efficiently. I believe it will also help scientists  experimenting in other areas, such as protein crystallisation, an important part  of the drug development process.”

Dr Stingelin and research associate Neil Treat looked at two  additives, sold under the names IrgaclearÒ XT 386 and MilladÒ 3988, which are  commonly used in industry. These chemicals are, for example, some of the  ingredients used to improve the transparency of plastic drinking bottles. The  researchers experimented with adding tiny amounts of these chemicals to the  formulas of several different electrically conducting plastics, which are used  in technologies such as security key cards, solar cells and displays.

The researchers found the additives gave them precise control  over where crystals would form, meaning they could also control which parts of  the printed material would conduct electricity. In addition, the  crystallisations happened faster than normal. Usually plastic electronics are  exposed to high temperatures to speed up the crystallisation process, but this  can degrade the materials. This heat treatment treatment is no longer necessary  if the additives are used.

Another industrially important advantage of using small amounts  of the additives was that the crystallisation process happened more uniformly  throughout the plastics, giving a consistent distribution of crystals.  The team  say this could enable circuits in plastic electronics to be produced quickly and  easily with roll-to-roll printing procedures similar to those used in the  newspaper industry. This has been very challenging to achieve previously.

Dr Treat says: “Our work clearly shows that these additives are  really good at controlling how materials crystallise. We have shown that printed  electronics can be fabricated more reliably using this strategy. But what’s  particularly exciting about all this is that the additives showed fantastic  performance in many different types of conducting plastics. So I’m excited about  the possibilities that this strategy could have in a wide range of materials.”

Dr Stingelin and Dr Treat collaborated with scientists from the  University of California Santa Barbara, and the National Renewable Energy  Laboratory in Golden, US, and the Swiss Federal Institute of Technology on this  study. The team are planning to continue working together to see if subtle  chemical changes to the additives improve their effects – and design new  additives.

They will be working with the new Engineering and Physical  Sciences Research Council (EPSRC)-funded Centre for Innovative Manufacturing in  Large Area Electronics in order to drive the industrial exploitation of their  process. The £5.6 million of funding for this centre, to be led by researchers  from Cambridge University, was announced earlier this year. They are also  exploring collaborations with printing companies with a view to further  developing their circuit printing technique.

Controlling crystals

Here are some of the technologies that could benefit from Drs  Treat and Stingelin’s research:

Improving drugs

Most drugs work by blocking or activating proteins in our  bodies. To develop better drugs, scientists must understand what these proteins  look like. The work carried out by the Imperial team could enable researchers in  the future to develop more accurate models of proteins, by converting them into  a crystalline form.

More efficient solar technology

Solar cells are made from a solid mixture of electrically  conducting crystalline chemicals. Currently these cells only convert about 10%  of the Sun’s energy into electricity. Dr Treat and Stingelin’s additives may  provide a way of improving crystal growth in solar cells, which could improve  the amount of energy they convert.

New flexible electronics

Flexible semiconductor films can be made by methods such as  inkjet printing. Using additives that control how inkjet-printed droplets of  semiconductors crystallise will mean they crystallise in evenly distributed  patterns that conduct electricity efficiently. This means industry can produce  these printed electronics more easily and cheaply.

Source: By Joshua Howgego, Imperial College London

Read more: http://www.nanowerk.com/news2/newsid=31181.php#ixzz2YPLhjKF8

Self-assembling Solar-harvesting Films Reveals New Low-Cost Tool for 3D Circuit Printing

4 March 2013 (created 4 March 2013)

Scientists from Imperial College London, working at the Institut Laue-Langevin, have presented a new way of positioning nanoparticles in plastics, with important applications in the production of coatings and photovoltaic material that harvest energy from the sun.  The study used neutrons to understand the role that light – even ambient light – plays in the stabilisation of these notoriously unstable thin films. As a proof of concept the team have shown how the combination of heat and low intensity visible and UV light could in future be used as a precise, low-cost tool for 3D printing of self-assembling, thin-film circuits on these films.
Thin films made up of long organic molecule chains called polymers and fullerenes (large football-shaped molecules composed entirely of carbon) are used mainly in polymer solar cells where they emit electrons when exposed to visible or ultraviolet sun rays. These so-called photovoltaic materials can generate electrical power by converting solar radiation into direct electrical current.
Polymer solar cells are of significant interest for low-power electronics, such as autonomous wireless sensor networks used to monitor everything from ocean temperature to stress inside a car engine. These fullerene-polymer mixtures are particularly appealing because they are lightweight, inexpensive to make, flexible, customisable on the molecular level, and relatively environmentally-friendly.
However current polymer solar cells only offer about one third of the efficiency of other energy harvesting materials, and are very unstable.
In order to improve science’s understanding of the dynamics of these systems and therefore their operational performance, the team carried out neutron reflectometry experiments at the ILL, the world’s flagship centre for neutron science, on a simple model film made up of pure fullerenes with a flexible polymer. Neutron reflectometry is a non-destructive technique that allows you to ‘shave’ layers off these thin films to look at what happens to the fullerenes and the polymers separately, at atomic scale resolution, throughout their depth.
Whilst previous theories suggested that thin film stabilisation was linked to the formation of an expelled fullerene nanoparticle layer at the substrate interface, neutron reflectometry experiments showed that the carbon “footballs” remain evenly distributed throughout the layer. Instead, the team revealed that the stabilisation of the films was caused by a form of photo-crosslinking of the fullerenes. The process imparts greater structural integrity to films, which means that ultrathin films, (down to 10000 times smaller than a human hair) readily become stable with trace amounts of fullerene.
The implications of this finding are significant, particularly in the potential to create much thinner plastic devices which remain stable, with increased efficiency and lifetime (whilst the smaller amount of material required minimises their environmental impact).

The light sensitivity also suggests a unique and simple tool for imparting patterns and designs onto these notoriously unstable films. To prove the concept the team used a photomask to spatially control the distribution of light and added heat. The combination causes the fullerenes to self-assemble into well-defined connected and disconnected patterns, on demand, simply by heating the film until it starts to soften. This results in spontaneous topography and may form the basis of a low-cost tool for 3D printing of thin film circuits.

Other potential applications could include patterning of sensors or biomedical scaffolds.
In the future, the team is looking to apply its findings to conjugated polymers and fullerene derivatives, more common in commercial films, and industrial thin film coatings.

Source: From A neutron investigation into self-assembling solar-harvesting films reveals new low-cost tool for 3D circuit printing. This work is detailed in the paper “Patterning Polymer–Fullerene Nanocomposite Thin Films with Light” by Him Cheng Wong, Anthony M. Higgins, Andrew R. Wildes, Jack F. Douglas, João T. Cabral.

NRL Designs Multi-Junction Solar Cell to Break Efficiency Barrier

U.S. Naval Research Laboratory scientists in the Electronics Technology and Science Division, in collaboration with the Imperial College London and MicroLink Devices, Inc., Niles, Ill., have proposed a novel triple-junction solar cell with the potential to break the 50 percent conversion efficiency barrier, which is the current goal in multi-junction photovoltaic development.

 

Schematic diagram of a multi-junction (MJ) solar cell formed from materials lattice-matched to InP and achieving the bandgaps for maximum efficiency. (Photo: U.S. Naval Research Laboratory)

“This research has produced a novel, realistically achievable, lattice-matched, multi-junction solar cell design with the potential to break the 50 percent power conversion efficiency mark under concentrated illumination,” said Robert Walters, Ph.D., NRL research physicist. “At present, the world record triple-junction solar cell efficiency is 44 percent under concentration and it is generally accepted that a major technology breakthrough will be required for the efficiency of these cells to increase much further.”

In multi-junction (MJ) solar cells, each junction is ‘tuned’ to different wavelength bands in the solar spectrum to increase efficiency. High bandgap semiconductor material is used to absorb the short wavelength radiation with longer wavelength parts transmitted to subsequent semiconductors. In theory, an infinite-junction cell could obtain a maximum power conversion percentage of nearly 87 percent. The challenge is to develop a semiconductor material system that can attain a wide range of bandgaps and be grown with high crystalline quality.

By exploring novel semiconductor materials and applying band structure engineering, via strain-balanced quantum wells, the NRL research team has produced a design for a MJ solar cell that can achieve direct band gaps from 0.7 to 1.8 electron volts (eV) with materials that are all lattice-matched to an indium phosphide (InP) substrate.

“Having all lattice-matched materials with this wide range of band gaps is the key to breaking the current world record” adds Walters. “It is well known that materials lattice-matched to InP can achieve band gaps of about 1.4 eV and below, but no ternary alloy semiconductors exist with a higher direct band-gap.”

The primary innovation enabling this new path to high efficiency is the identification of InAlAsSb quaternary alloys as a high band gap material layer that can be grown lattice-matched to InP. Drawing from their experience with Sb-based compounds for detector and laser applications, NRL scientists modeled the band structure of InAlAsSb and showed that this material could potentially achieve a direct band-gap as high as 1.8eV. With this result, and using a model that includes both radiative and non-radiative recombination, the NRL scientists created a solar cell design that is a potential route to over 50 percent power conversion efficiency under concentrated solar illumination.

Recently awarded a U.S. Department of Energy (DoE), Advanced Research Projects Agency-Energy (ARPA-E) project, NRL scientists, working with MicroLink and Rochester Institute of Technology, Rochester, N.Y., will execute a three year materials and device development program to realize this new solar cell technology.

Through a highly competitive, peer-reviewed proposal process, ARPA-E seeks out transformational, breakthrough technologies that show fundamental technical promise but are too early for private-sector investment. These projects have the potential to produce game-changing breakthroughs in energy technology, form the foundation for entirely new industries, and to have large commercial impacts.