Adding a few graphene layers onto the conventional gold-film SPR biosensor will boost up its sensitivity dramatically. The improved sensitivity comes from the graphene layer’s increased adsorption of biomolecules and the graphene layer’s optical modification to the SPR.
Surface plasmon resonance (SPR) biosensors are optical sensors, which use surface plasmon polariton waves to probe the interactions between biomolecules and the sensor surface. In the conventional SPR biosensor configuration, a thin metallic film is coated on one side of the prism, separating the sensing medium and the prism. The metallic film is typically made from noble metals, such as gold and silver, which support the propagation of surface plasmon polariton at visible light frequencies. But, gold is usually preferred because it has good resistance to oxidation and corrosion in different environments.
However, biomolecules adsorb poorly on gold. This drawback limits the sensitivity of the conventional SPR biosensor.
An attractive way to improve the sensitivity of SPR biosensor is to functionalize the gold film with biomolecular recognition elements (BRE) in order to enhance the adsorption of biomolecules on the gold surface.
Here, we propose to use graphene as the BRE, where a sheet of graphene is coated on the gold surface in the conventional SPR biosensor setup. Graphene-on-Au (111) has been proposed and fabricated recently, which is shown to stably adsorb biomolecules with carbon-based ring structures (e.g. ssDNA).
This special property of graphene enables a greater refractive index change near the graphene | sensing medium interface than that of the conventional SPR biosensor. Moreover, the coating of the gold surface with graphene will also modify the propagation constant of surface plasmon polariton (SPP); thereby change the sensitivity to refractive index change.
Space observation with radar to secure Germany's space infrastructure
23.03.2018 | Fraunhofer-Institut für Hochfrequenzphysik und Radartechnik FHR
Researchers at Fraunhofer monitor re-entry of Chinese space station Tiangong-1
21.03.2018 | Fraunhofer-Institut für Hochfrequenzphysik und Radartechnik FHR
Satellites in near-Earth orbit are at risk due to the steady increase in space debris. But their mission in the areas of telecommunications, navigation or weather forecasts is essential for society. Fraunhofer FHR therefore develops radar-based systems which allow the detection, tracking and cataloging of even the smallest particles of debris. Satellite operators who have access to our data are in a better position to plan evasive maneuvers and prevent destructive collisions. From April, 25-29 2018, Fraunhofer FHR and its partners will exhibit the complementary radar systems TIRA and GESTRA as well as the latest radar techniques for space observation across three stands at the ILA Berlin.
The "traffic situation" in space is very tense: the Earth is currently being orbited not only by countless satellites but also by a large volume of space...
An international team of researchers has discovered a new anti-cancer protein. The protein, called LHPP, prevents the uncontrolled proliferation of cancer cells in the liver. The researchers led by Prof. Michael N. Hall from the Biozentrum, University of Basel, report in “Nature” that LHPP can also serve as a biomarker for the diagnosis and prognosis of liver cancer.
The incidence of liver cancer, also known as hepatocellular carcinoma, is steadily increasing. In the last twenty years, the number of cases has almost doubled...
In just a few weeks from now, the Chinese space station Tiangong-1 will re-enter the Earth's atmosphere where it will to a large extent burn up. It is possible that some debris will reach the Earth's surface. Tiangong-1 is orbiting the Earth uncontrolled at a speed of approx. 29,000 km/h.Currently the prognosis relating to the time of impact currently lies within a window of several days. The scientists at Fraunhofer FHR have already been monitoring Tiangong-1 for a number of weeks with their TIRA system, one of the most powerful space observation radars in the world, with a view to supporting the German Space Situational Awareness Center and the ESA with their re-entry forecasts.
Following the loss of radio contact with Tiangong-1 in 2016 and due to the low orbital height, it is now inevitable that the Chinese space station will...
Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP, provider of research and development services for OLED lighting solutions, announces the founding of the “OLED Licht Forum” and presents latest OLED design and lighting solutions during light+building, from March 18th – 23rd, 2018 in Frankfurt a.M./Germany, at booth no. F91 in Hall 4.0.
They are united in their passion for OLED (organic light emitting diodes) lighting with all of its unique facets and application possibilities. Thus experts in...
A new scenario seeking to explain how Mars' putative oceans came and went over the last 4 billion years implies that the oceans formed several hundred million...
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