Cantilevers are miniature diving boards that measure 200 micrometers long and 40 micrometers wide, about half the width of a human hair. Two cantilevers are placed in a sensor and liquid is passed through them. When the molecule or microbe that is being looked for binds to its surface, the board bends and its electrical resistance is altered. Detection is achieved by measuring the change in resistance.
The device can be designed to search for specific things, for example, if the organism to be detected was E. coli, the cantilever could be coated in antibodies specific to E. coli cells. Many different molecules or organisms can also be recognized simultaneously. “The sensor can be expanded to contain several cantilevers, each coated with a specific detector molecule” says Professor Anja Boisen.
Lid devices also have a flexible board or ‘lid’ but it is placed on top of a tiny box that contains marker molecules, which produce colour visible to the naked eye. An organism, for example, binds to the lid, which then opens and releases the colour, indicating the presence of the organism. This can also be achieved by coating the board with ‘food’ for bacteria instead of binding molecules, so deflection occurs when the coating is removed. It can therefore be used to measure bacterial activity. The device is contained in a 1cm plastic box so, like the cantilever, it is portable.
Cantilevers and lid devices may soon be available to consumers. “We use processes where the cantilevers are fabricated by etching a thin silicon wafer three-dimensionally” says Professor Anja Boisen. “The procedure is suitable for mass production and it might be possible to make sensors so cheaply that they can be disposable.”
The applications for this new technology are abundant. The sensors can detect DNA, so may be used to test for human genetic diseases. They are also extremely sensitive and can measure deflections of just 1 nanometre, so are able to detect the presence of very small molecules. Conversely, whole bacteria and even parts of bacteria can be identified, making the sensors ideal for testing the quality of water and food samples.
“The lid device could be included in food packaging since it requires no external energy and is cheap to make. When a food is infected, the control unit in the plastic wrapping becomes coloured. Thus a simple colour indicator can show the quality of the food.”
Oestrogen regulates pathological changes of bones via bone lining cells
28.07.2017 | Veterinärmedizinische Universität Wien
Programming cells with computer-like logic
27.07.2017 | Wyss Institute for Biologically Inspired Engineering at Harvard
Spectrally narrow x-ray pulses may be “sharpened” by purely mechanical means. This sounds surprisingly, but a team of theoretical and experimental physicists developed and realized such a method. It is based on fast motions, precisely synchronized with the pulses, of a target interacting with the x-ray light. Thereby, photons are redistributed within the x-ray pulse to the desired spectral region.
A team of theoretical physicists from the MPI for Nuclear Physics (MPIK) in Heidelberg has developed a novel method to intensify the spectrally broad x-ray...
Physicists working with researcher Oriol Romero-Isart devised a new simple scheme to theoretically generate arbitrarily short and focused electromagnetic fields. This new tool could be used for precise sensing and in microscopy.
Microwaves, heat radiation, light and X-radiation are examples for electromagnetic waves. Many applications require to focus the electromagnetic fields to...
Strong light-matter coupling in these semiconducting tubes may hold the key to electrically pumped lasers
Light-matter quasi-particles can be generated electrically in semiconducting carbon nanotubes. Material scientists and physicists from Heidelberg University...
Fraunhofer IPA has developed a proximity sensor made from silicone and carbon nanotubes (CNT) which detects objects and determines their position. The materials and printing process used mean that the sensor is extremely flexible, economical and can be used for large surfaces. Industry and research partners can use and further develop this innovation straight away.
At first glance, the proximity sensor appears to be nothing special: a thin, elastic layer of silicone onto which black square surfaces are printed, but these...
3-D shape acquisition using water displacement as the shape sensor for the reconstruction of complex objects
A global team of computer scientists and engineers have developed an innovative technique that more completely reconstructs challenging 3D objects. An ancient...
26.07.2017 | Event News
21.07.2017 | Event News
19.07.2017 | Event News
28.07.2017 | Health and Medicine
28.07.2017 | Power and Electrical Engineering
28.07.2017 | Life Sciences