Researchers at Eindhoven University of Technology (TU/e) present a new method that should enable controlled drug delivery into the bloodstream using DNA computers. In the journal Nature Communications the team, led by biomedical engineer Maarten Merkx, describes how it has developed the first DNA computer capable of detecting several antibodies in the blood and performing subsequent calculations based on this input. This is an important step towards the development of smart, ‘intelligent’ drugs that may allow better control of the medication for rheumatism and Crohn’s disease, for example, with fewer side-effects and at lower cost.
An analogy for the method presented by the TU/e researchers is a security system that opens the door depending on the person standing in front of it. If the camera recognizes the person, the door unlocks, but if the person is unknown, the door remains locked. “Research into diagnostic tests tends to focus on the ‘recognition’, but what is special about this system is that it can think and that it can be connected to actuation such as drug delivery,” says professor of Biomedical Chemistry Maarten Merkx.
To be able to perform such an action, ‘intelligence’ is needed, a role that is performed in this system by a DNA computer. DNA is best known as a carrier of genetic information, but DNA molecules are also highly suitable for performing molecular calculations. The sequence within a DNA molecule determines with which other DNA molecules it can react, which allows a researcher to program desired reaction circuits.
To date biomedical applications of DNA computers have been limited because the input of DNA computers typically consists of other DNA and RNA molecules. To determine whether someone has a particular disease, it is essential to measure the concentration of specific antibodies – agents that our immune system produces when we are ill. Merkx and his colleagues are the first to have succeeded in linking the presence of antibodies to a DNA computer.
Their method translates the presence of each antibody into a unique piece of DNA whereby the DNA computer can decide on the basis of the presence of one or more antibodies whether drug delivery, for example, is necessary. “The presence of a particular DNA molecule sets in motion a series of reactions whereby we can get the DNA computer to run various programs,” explains PhD student and primary author Wouter Engelen. “Our results show that we can use the DNA computer to control the activity of enzymes, but we think it should also be possible to control the activity of a therapeutic antibody.”
In treating chronic diseases like rheumatism or Crohn’s disease, such therapeutic antibodies are used as medication. One of the potential applications of this system is to measure the quantity of therapeutic antibodies in the blood and decide whether it is necessary to administer any extra medication. Merkx: “By directly linking the measurement of antibodies to the treatment of the disease, we may be able to prevent side-effects and reduce costs in the future.”
Its motto is Mens agitat molem (The mind brings matter into motion). The university was the second of its kind in the Netherlands, only Delft University of Technology existed previously. Until mid-1980 it was known as the Technische Hogeschool Eindhoven (abbr. THE). In 2011 QS World University Rankings placed Eindhoven at 146th internationally, but 61st globally for Engineering & IT. Furthermore, in 2011 Academic Ranking of World Universities (ARWU) rankings, TU/e was placed at the 52-75 bucket internationally in Engineering/Technology and Computer Science (ENG) category and at 34th place internationally in the Computer Science subject field.
Eindhoven University research articles from Innovation Toronto
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From vehicles to architectural lighting
VTT Technical Research Centre of Finland develops novel LED light sources based on large, flexible and transparent substrates in collaboration with the Finnish companies Flexbright and Lighting Design Collective. An easy-to-customise LED foil suitable for mass production enables the introduction of the large area lighting and display technologies to applications such as vehicles, greenhouses, shopping centres and architectural lighting.
The three-year European project Delphi4LED develops design and simulation tools for LED structures to better meet the needs of the rapidly evolving lighting industry and end users.
Heat management is a key factor dictating the performance and reliability of LED lighting solutions. The operation of LED components is also affected by their electrical and optical characteristics. Combining all of these properties is difficult using the existing design tools.
In Delphi4LED project new simulation models are being developed to consider the above factors in a simplified form. This saves on computing capacity, enabling a more comprehensive design than is currently possible.
Elaborated measurements are performed to produce a standardised electronic datasheet of the LEDs, which is then fed into a modelling software. This makes the design process more efficient and reduces the number of design errors, enabling the faster introduction of the products on the market, with higher quality and at a lower cost than before.
A Finnish consortium coordinated by VTT Technical Research Centre of Finland is applying the results of the Delphi4LED project to the development of LED luminaires based on transparent large-area foil. These kinds of novel structures enable the implementation of thin, flexible light source for lighting and display applications. For example, a multi-coloured video screen can be integrated between planar or curved glass surfaces.
The electronic data connections within and between microchips are increasingly becoming a bottleneck in the exponential growth of data traffic worldwide. Optical connections are the obvious successors but optical data transmission requires an adequate nanoscale light source, and this has been lacking. Scientists at Eindhoven University of Technology (TU/e) now have created a light source that has the right characteristics: a nano-LED that is 1000 times more efficient than its predecessors, and is capable of handling gigabits per second data speeds. They have published their findings in the online journal Nature Communications.
Nano- or microwatts
With electrical cables reaching their limits, optical connections like fiberglass are increasingly becoming the standard for data traffic. Over longer distances almost all data transmission is optical. Within computer systems and microchips, too, the growth of data traffic is exponential, but that traffic is still electronic, and this is increasingly becoming a bottleneck. Since these connections (‘interconnects’) account for the majority of the energy consumed by chips, many scientists around the world are working on enabling optical (photonic) interconnects. Crucial to this is the light source that converts the data into light signals which must be small enough to fit into the microscopic structures of microchips. At the same time, the output capacity and efficiency have to be good. Especially the efficiency is a challenge, as small light sources, powered by nano- or microwatts, have always performed very inefficiently to date.
Less light is lost
Researchers at TU Eindhoven have now developed a light-emitting diode (LED) of some hundred nanometers with an integrated light channel (waveguide) to transport the light signal. This integrated nano-LED is a 1000 times more efficient than the best variants developed elsewhere. The Eindhoven-based researchers have especially made progress in the quality of the integrated coupling of the light source and the waveguide whereby much less light is lost and therefore far more light enters the waveguide. The efficiency of the new nano-LED currently lies between 0.01 and 1 percent, but the researchers expect to be well above that figure soon thanks to a new production method.
Another key characteristic of the new nano-LED is that it is integrated into a silicon substrate on a membrane of indium phosphide. Silicon is the basic material for microchips but is not suitable for light sources whereas indium phosphide is. Furthermore, tests reveal that the new element converts electrical signals rapidly into optical signals and can handle data speeds of several gigabits per second.
The researchers in Eindhoven believe that their nano-LED is a viable solution that will take the brake off the growth of data traffic on chips. However, they are cautious about the prospects. The development is not yet at the stage where it can be exploited by the industry and the production technology that is needed still has to get off the ground.
Use your computer without the need to start it up: a new type of magnetic memory makes it possible.
This ‘MRAM’ is faster, more efficient and robust than other kinds of data storage. However, switching bits still requires too much electrical power to make large-scale application practicable. Researchers at Eindhoven University of Technology (TU/e) have discovered a smart way of solving this problem by using a ‘bending current’. They publish their findings today in the journal Nature Communications.
MRAM (Magnetic Random Access Memory) stores data by making smart use of the ‘spin’ of electrons, a kind of internal compass of the particles. Since magnetism is used instead of an electrical charge, the memory is permanent, even when there is a power failure, and so the computer no longer has to be started up. These magnetic memories also use much less power, which means that mobile phones, for example, can run longer on a battery.
In a MRAM bits are projected by the direction of the spin of the electrons in a piece of magnetic material: for example, upwards for a ‘1’ and downwards for a ‘0’. The storage of data occurs by flipping the spin of the electrons over to the correct side. Normal practice is to send an electrical current which contains electrons with the required spin direction through the bit. The large quantity of electrical current needed to do this hindered a definitive breakthrough for MRAM, which appeared on the market for the first time in 2006.
In Nature Communications a group of TU/e physicists, led by professor Henk Swagten, today publishes a revolutionary method to flip the magnetic bits faster and more energy-efficiently. A current pulse is sent under the bit, which bends the electrons at the correct spin upwards, so through the bit. “It’s a bit like a soccer ball that is kicked with a curve when the right effect is applied,” says Arno van den Brink, TU/e PhD student and the first author of the article.
The new memory is really fast but it needs something extra to make the flipping reliable. Earlier attempts to do this required a magnetic field but that made the method expensive and inefficient. The researchers have solved this problem by applying a special anti-ferromagnetic material on top of the bits. This enables the requisite magnetic field to be frozen, as it were, energy-efficient and low cost.
“This could be the decisive nudge in the right direction for superfast MRAM in the near future, ” according to Van den Brink.