Electronic noses are used to sniff out exhaust fumes and assist with quality control of foods. Less well known is the fact that equivalent devices, electronic tongues, are capable of recognizing dissolved substances.
In the journal Angewandte Chemie, French researchers have now presented a new and particularly simple approach to making an electronic tongue that can differentiate between proteins.
Biosensors use specific ligands, such as antibodies, that selectively bind the molecules being detected. If the goal is to differentiate between different substances, a suitable ligand must be developed for each substance – a complex undertaking. In contrast, electronic noses and tongues use an array of different “receptors” that bind to the desired compounds with differing strengths.
The receptors are sensitive toward multiple target molecules. The combined response of all receptors gives a specific pattern for each of the compounds detected. Because none of the receptors needs to be highly specific, they can be developed much more quickly and easily.
A consortium headed by Yanxia Hou, David Bonnaffé, and Thierry Livache is seeking to further reduce the difficulty involved in designing and producing electronic tongues. Their receptors are made from mixtures of a few molecular building blocks with different physicochemical properties. Individual droplets containing different concentration ratios of the building blocks are deposited directly onto the gold surface of a detector.
Through a self-assembly process, these form the receptors in the form of tiny spots of molecular monolayers with varying compositions. Surface plasmon resonance imaging was used for detection: the electron oscillations (plasmons) measure change when molecules are adsorbed by the receptors on the detector.
To test out their new idea, the researchers took inspiration from the heparan sulfates, which are found on the surfaces of cells and recognize various mediator molecules like growth factors that play a role in many physiological and pathological processes. Heparan sulfates are polysaccharides with different arrangements of sulfate side groups and different binding specificities.
The researchers synthesized two components similar to heparin sulfate, one with sulfate side groups and one without. They used mixtures with varying ratios of these components to produce an array of new receptors and tested it with different proteins. A plot of the intensity of the responses for each receptor gives a continuous profile or a 3D landscape characteristic of the protein that can be used for its identification in a greatly simplified manner. Profiles for mixtures of proteins could also be used to identify the individual components by computer.
By introducing more building blocks, the diversity of the receptors used in this first version of the tongue is currently being enriched. This will allow differentiation between very similar proteins in the future.About the Author
Yanxia Hou | Angewandte Chemie
A novel socio-ecological approach helps identifying suitable wolf habitats
17.02.2017 | Universität Zürich
New, ultra-flexible probes form reliable, scar-free integration with the brain
16.02.2017 | University of Texas at Austin
In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport
Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...
The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.
The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...
Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...
Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".
Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...
13.02.2017 | Event News
10.02.2017 | Event News
09.02.2017 | Event News
17.02.2017 | Medical Engineering
17.02.2017 | Medical Engineering
17.02.2017 | Health and Medicine