Highlights Beyond Moore
Science and technology in the Beyond Moore field builds upon and moves beyond what is currently possible at micro and nanometre scales in the electronics domain. This research addresses new electronics, spintronics, photonics, light generation and biological interfaces. Possible application areas include gas sensing, new memory and high frequency components, optical communication, drug screening and personal healthcare tools, diagnostic tools and light sources (OLEDs and LASERs).
Transmitting and receiving single photons
Transmitting and detecting single photons. That is possible with the equipment made by Single Quantum. This young company recently received a Valorisation Grant from NanoNextNL to further develop the technology. Possible applications lie in the areas of quantum cryptography and medical imaging.
‘During my PhD research at Delft University of Technology, I worked on a sensitive detector for single photons,’ says CEO of Single Quantum Sander Dorenbos. ‘Other research groups showed considerable interest for our detector chips. We initially gave these away in the context of scientific collaboration, but that was not sustainable. We therefore started a company in 2012 to build and sell detector systems. There are currently about fifteen systems being used in different research institutions worldwide, and we have fifteen additional orders for the next six months.’
The detector chip consists of a single continuous wire of niobium titanium nitride, with a thickness of only five nanometres. This wire is cooled to minus 270 degrees Celsius. At that temperature, the wire becomes superconducting: electrical current that passes through it does not experience resistance. As soon as a photon falls on the chip, the wire loses its superconducting properties for a period of ten nanoseconds. During this short time interval, an electrical resistance is measured.
A microscopic shot of the detector chip, consisting of 1 single thin wire.
Ahead of the competition
Whereas competing technology can detect one in ten passing photons, the detector made by the Delft company detects at least seven. The system is also substantially better than the existing detectors in other technical specifications, says Dorenbos. ‘There is less noise and the downtime between two measurements is far smaller.’
Development of a source
In recent years, the research group of Val Zwiller in Delft, where the detectors were initially developed, has also developed a single-photon source. ‘The sources are technically a special type of LED made from semiconductor materials. They are capable of controlling the emission of a single photon at a time.’
From science to a broader market
With the Valorisation Grant from NanoNextNL, the company will further develop this light source into a fully-fledged product. ‘Here too we will focus on science first,’ says Dorenbos. ‘We will use the experiences of research groups to improve our product. And the scientific articles that have been realised thanks to our technology can convince new clients about the quality of our products.’
At present, Single Quantum is the only company in the world that can produce both single-photon sources and detectors. ‘We will focus on clients to whom we can sell complete systems, which could for example be used to do quantum cryptography experiments. The jury for the Valorisation Grant has advised us not to be too modest in this regard. The scientific market is not large, but beyond that, we see big possibilities for our technology, especially within future forms of communication that use light instead of electronics. We are the first in the world to seriously try to turn this into a commercial success.’
‘It is unusual that a company with such a fundamental technology starts off with practical applications and clients,’ says Valorisation Grant jury member Willem van den Berg from Value Creation Capital. The technology has several unique selling points as a result of which the jury sees a lot of potential, he says. ‘There are applications for which the products of competitors are simply not sensitive enough. Single Quantum’s technology could be used to detect errors in integrated circuits (ICs). That is of major value to computer chip manufacturers.’ Van den Berg also sees sufficient market potential for the sources. ‘You could use these for quantum cryptography and quantum communication.’
The company is now in an important phase, explains the jury member. ‘Many companies that are set up from within science are very content driven. That is good, as this is how this company has gained its first clients, for example. But the trick is to scale up on time. Production and assembly will not be a problem. But how do you establish a commercial basis for something like this? You need a different type of expertise for that. And then it comes down to sales, sales and more sales. It will be interesting to see how Single Quantum develops further.’
Contact lenses as springboard to more
‘Growing numbers of infections due to dirty lenses,’ was a recent headline of Dutch news broadcaster NOS. Ophthalmologists raised the alarm because the incorrect use of contact lenses is leading to a growing number of eye inflammations. The start-up company LipoCoat from Twente has developed a solution for this problem. ‘We can place a coating on the lenses so that they become dirty less quickly. This offers a relatively cheap way of preventing eye problems,’ says CEO Jasper van Weerd.
Contact lenses become dirty while they are being worn. If people wear their lenses too long and fail to clean them often enough or use the wrong cleaning products, then persistent dirt builds up on the lenses. Due to this dirt in the form of proteins and fats, the lenses cause irritation, for example because too much tear fluid evaporates resulting in dry eyes. In addition the lens can become a breeding ground for bacteria, which leads to eye infections.
Jasper van Weerd, CEO LipoCoat (photo: Emiel Muijderman)
The young company LipoCoat recently received a Valorisation Grant from NanoNextNL for the further development of its patented method to deposit very thin layers of a material similar to tear drops on the lenses. This layer ensures that the lenses do not become dirty and people can wear their lenses for longer without getting irritated eyes.
Stable layers similar to cells
‘Our coating is similar to the outside of human cells,’ says entrepreneur Jasper van Weerd. ‘With our patented process we can apply those coatings in such a way that they remain stable.’ These so-called biocompatible layers, materials that do not elicit rejection responses in the human body, already existed, he says. ‘But they were very unstable. If such a layer came into contact with an air bubble it fell apart.’ During his PhD research at the Univeristy of Twente funded by NanoNextNL, Van Weerd investigated the properties of biocompatible coatings and he developed a process to apply stable layers several nanometres thick to a surface.
The process consists of different steps that are not harmful for the material to which the coating is applied, explains Van Weerd. ‘We do not use high temperatures or high pressures but a mild plasma treatment. For example, this treatment does not influence the transparency and refractive index of the material that you coat, which is important for an application on contact lenses.’
Targeting the technology at the contact lens industry
Over the next few years LipoCoat will first focus on coating hard contact lenses. Van Weerd explains this choice: ‘Our coatings can, in principle, be applied to all materials that come into contact with body fluids. Because all of these face the same problem: proteins, fats and bacteria that deposit on these and can give rise to infections. We have carried out market research into this on items such as catheters and tubes for tube feeding. For example, a catheter gets covered in bacteria within 30 minutes, so significant gains could be made. In the end we chose to first of all prove our technology in the contact lens industry. Clients are asking for a solution and lens manufacturers are keen to get their hands on one. And there is a very practical aspect for us: in this market the approval procedures are less long than they are for more medically focused applications that are used in the body.’
Lens manufacturers want safety and lens wearing comfort
The lens wearing comfort of current contact lenses is not satisfactory enough. Lens manufacturers are looking for a product that sets itself apart from the competition. ‘We are starting with hard lenses. In general, people wear these for longer. And hard lenses are more expensive: the price per lens can be up to 300 euros. Our process results in a small increase in the cost price, which is only a fraction of the sale price. Lens manufacturers have indicated that they want to assume more responsibility for the lens wearing comfort. At present that is often still a responsibility of the end user who has to clean his lenses often enough. Manufacturers want to be able to deliver a product with a guaranteed safety and superior lens wearing comfort. With this approach they hope to strongly increase their market share and, for example, to win back earlier lens wearers who have now switched to wearing spectacles.’
The coating must keep the contact lenses clean. However the technology can be used for more than just preventing contamination, says Van Weerd. ‘By changing the composition of the coating its function changes as well. We can manufacture the coating in such a way that it attracts certain cells. That is interesting for hip implants, for example, as with a special coating you can allow these to be covered with the body’s own bone cells faster.’
Manufacturers are in the starting blocks
LipoCoat will be officially founded as a limited company in 2016. The first funding has already been obtained. This includes the Valorisation Grant from NanoNextNL, the first investment from the Dutch Student Investment Fund, and a voucher from NanoLabNL. ‘We have used the NanoLabNL facilities to characterise our layers. Which conditions result in which type of layer? What determines stability in different environments? Which parameters can be altered to satisfy different requirements for different applications? We will use the Valorisation Grant of 93,000 euros to make the transition from a process in the lab to something that we can show clients. We will test this so-called demonstrator on contact lenses: manufacturers are already in the starting blocks.’
New windows on cells
‘We are developing a technology that will open up a completely new window on living cells,’ says Harrie Verhoeven, cell biologist at Wageningen University. ‘This is a complimentary form of microscopy that makes it possible to image previously unexplored properties of cells.’ Together with Serge Lemay and Cecilia Laborde from the University of Twente, he is investigating the possibilities of a new chip that was developed by Frans Widdershoven from semiconductor manufacturer NXP.
Laborde, Lemay, Verhoeven and Widdershoven recently published an article in Nature Nanotechnology disclosing the first, highly promising measurements of a new chip that uses high frequencies to measure small electrical signals in liquids. One of the possibilities the researchers demonstrated was that with this chip you could see how certain aggressive breast cancer tumour cells move, which is an important characteristic for the extent to which they can spread. This provides possibilities for testing the effect of new medicines.
Chip measures small electrical signals from cells
‘At NXP, we had our own biosensor group until the end of 2011. Within this group, we had developed a chip that could measure small electrical signals that originate from cells in liquids. Those signals are a measure for the activity and nature of the cells. Initially, this was mainly a research chip: we wanted to see what we could do with it. To this end, we sought collaboration with university groups via NanoNextNL,’ says Frans Widdershoven of semiconductor manufacturer NXP.
Standard technology as the basis
The chip consists of 256 rows and 256 columns of nanoelectrodes on a standard CMOS (Complementary Metal Oxide Semiconductor) chip. CMOS technology is commonly used in devices such as smartphones, tablets and computers, which derive their calculating power and communication possibilities from these chips. It is a tried and tested technology that uses very little electrical current.
Following cancer cells
Lemay, Laborde and Verhoeven investigated various applications for the chip. For example, the chip appeared to be suitable for detecting the movement of micrometre-sized particles and living cells. You can follow how a particle moves, whether it is growing or whether it is binding to something. For example, during an initial exploratory study, researchers from Wageningen University managed to follow in real time how cancer cells in a growth medium attached to the chip. ‘We examined several different types of tumour cells and we could very clearly distinguish which cells were the most mobile. And that mobility is a measure of how aggressive such a tumour is and how easily it spreads,’ says Verhoeven.
This has consequences for drug research. You can easily add various medicines to a tumour cell and then use the chip to follow what the results are in real-time. ‘Tumour cells differ from normal cells in several aspects. One of the differences lies in their energy metabolism,’ explains Verhoeven. ‘We are increasingly moving towards treatments that specifically target the energy metabolism. I expect that we will be able to make very good use of this chip to visualise the consequences of those treatments on such a tumour cell.’
Growing breast tumours
One of the main advantages of the chip compared to other detection systems is its ability to measure in saline environments. In other measurement systems, the salt, which is found in bodily fluids for example, disrupts the measurements. This means that with this chip, you can study cells in their natural environment. ‘For example, we have studied breast tumour cells in a growth medium,’ says Widdershoven. ‘You are then literally able to see these cells grow.’
The fact that you do not have to pre-treat the cells for this technique is a big advantage, says Verhoeven. ‘For the majority of imaging techniques, you need to add fluorescent substances, or manipulate the cells in another way. This means you cause disruptions in the cell. The question then remains to what extent the behaviour you see actually matches the natural behaviour of such a biological system.’
Cheap and plentiful at the same time
The new technology has many advantages, says Widdershoven. ‘CMOS technology is cheap and you can use it to process large quantities of data. You do not need any lenses or light sources, which means you do not need to purchase an expensive microscope. Furthermore, the technology is easy to scale up.’ That is a most welcome improvement for cell biologists like Verhoeven. ‘At present, we can only examine individual cells if we want to know something about cell membranes. With this chip, you can examine hundreds or thousands simultaneously.’
Seeking the boundaries
Meanwhile, Lemay and Laborde continue exploring the boundaries of the technology. ‘In collaboration with Wageningen University, we are looking at what we can say about cell dynamics based on measurements with the chip, for example,’ says Laborde. ‘We will also investigate how sensitive the sensor is. One of the aspects we want to investigate is what the limits of the measurement technique are. What are the smallest objects we can still see?’ adds Lemay. ‘Electrodes are becoming increasingly smaller. The smaller the electrodes, the closer you can place them next to each other and therefore the smaller the particles you can see,’ says Widdershoven. ‘With this technology, it should be fairly simple to see objects that are smaller than what you could ever render visible using a light microscope,’ adds Verhoeven.
‘And with higher measurement frequencies, we can more easily see through cell walls or in liquids with a high salt concentration. At present, the highest frequency is still limited by the time that a row of transistors on the chip needs to be able to switch simultaneously. However, that speed is increasing in newer CMOS generations. Ultimately, this speed could well end up in the gigahertz range. That would open up new possibilities to extensively study inside and outside of living cells and small particles such as viruses,’ says Lemay.
Seeing a cell communicate
‘These are exciting times for biology,’ says Verhoeven. ‘We have had to invest some time in discovering exactly how we should interpret the electrical signals so that these can be translated into cell behaviour. Now that we have mastered that, I can see many possible applications for this technology. I think it should be possible to use this technique to follow how the ion channels in a nerve cell open and close in real time. You would then be able to see how such a cell communicates with its environment. That would really be spectacular.’
Rapid switch for light particles
Guaranteed safe Internet banking because the laws of physics make it impossible to be hacked unawares. That should be possible with a quantum Internet: a network of quantum computers linked to each other. But before we get that far we must be able to manipulate the individual light particles that transfer the encrypted information between different computers. NanoNextNL researchers have made an ultrarapid light switch that can control the properties of light particles at very short timescales.
If somebody sends a payment instruction while Internet banking this is encrypted behind the scenes. Before the receiving bank can process the transaction it must first of all know which key can be used to decipher the information. These keys are therefore highly attractive prey for people with bad intentions.
Future quantum computers will be capable of transmitting uncrackable keys via a quantum network. Quantum cryptography makes use of light particles, which have specific quantum mechanical properties. As soon as you look at these light particles you change the properties. The intended receiver then knows immediately that somebody else has looked at the light particles during their transmission.
As these light particles are so sensitive for each potential manipulation, it must be possible to rapidly and remotely switch on and off the light sources that transmit the particles. NanoNextNL researchers at Eindhoven University of Technology have now succeeded in doing that. The speed is crucial in this, says project leader Andrea Fiore. ‘Compare it with the shutter time of a camera that needs to be very short to photograph something moving really fast. The speed that we control the transmission of the light particles with allows us to realise a very efficient exchange of particles. And that is important for the future quantum Internet.’
By aiming a laser at the right-hand section, the light source at the left can be switched on and off (image: Yan Liang – L2Molecule.com)
Laser pulse as switch
The researchers used miniscule light sources that spontaneously emit individual light particles as a consequence of atomic processes. Around these they etched a special structure that conducts the light. By using a brief laser pulse at a relatively large distance from the light source to disrupt the refractive index of the surrounding structure, it becomes easier or more difficult to produce light particles. Using this approach the spontaneous emission of light by the light source can be switched on and off at will, and then on a timescale of 200 billionths of a second.
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