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Nano in Cancer Research Photochemical cross-linking of nucleic acid assemblies Nanosensors for determination of ATP in living cells Aktuel naturvidenskab, 6, 2006 December 2006: Front page for: Nanofiber Frequency Doublers, Nanoletters Dec. 2006, vol. 6,12, 2639. September 2006: Carbon nanotube forests: a non-stick workbench for nanomanipulation K.Gjerde, J.Kjelstrup-Hansen, C. H. Clausen, K.B.K.Teo, W.I.Milne, H.-G.Rubahn and P.Boggild, Nanotechnology 17(2006)4917. Interpreting the protein language using proteomics PDF>> Polymer electrolyte membranes for low temperature fuel cells PDF>> The new clean room NanoSYD PDF>> Use of optical nanobiosensors to study metabolism / CelCom Group click here >> Bleaching of organic nanofibers / NANOLASE Group click here >> A photonic crystal fibre used as a micro-sample compartment in a mini Raman spectroscopy system / Biosensor Group click here >> Nanoparticles for local sensing of chemical and cellular properties click here >>
Use of optical nanobiosensors to study metabolism Metabolism in biological cells is not stationary. In most cells studied the amounts of low-molecular-weight metabolites oscillate and waves of metabolites travel through the cytoplasm. The oscillations and waves have many physiological functions in maintaining the living cell in a healthy state, so it is important to be able to measure them and reproduce them with mathematical models. Only few metabolites can be measured on-line in single intact cells. Most measurements of metabolism have been carried out on cells that have been disrupted and the cell content subsequently extracted and analysed. In the CelCom group at the Institute of Biochemistry and Molecular Biology, University of Southern Denmark we have synthesized new nanobiosensors that enable us to measure an almost unlimited number of metabolites in cells. The sensors consist of a polyacrylamide matrix in which we have embedded fluorescent probes specific for various metabolites. The sensing molecules may be simple fluorescent compounds that bind to specific metabolites, or they may encompass complex enzyme assays. The latter allow us to measure more than one compound simultaneously. Poly-acrylamide is a biocompatible material and the presence of sensors seems to have little or no effect on the viability of the cells. We have successfully incorporated sensors into yeast cells and liver cells using a gene gun (see below).
Liver cells with incorporated nanobiosensors. The sensors (45 nm in diamter) are incorporated into the cells using a gene gun. A) shows a phase contrast picture of the cells; b) and c) shows fluorescence from the sensing molecule (b) and a reference dye (a); d) is an overlay of a) and c). Figure prepared by Allan K. Poulsen.
Bleaching of organic nanofibers / NANOLASE Group Recently we have demonstrated that long organic nanofibers from functionalized phenylenes, grown on muscovite mica single crystal surfaces, have structural and optical properties that make them very promising elements for future submicron-sized photonics and optoelectronics. In order to use these properties by generating new photonic and optoelectronic devices such as submicron sized waveguides, sensors, light sources and converters a few stringent conditions have to be fulfilled. For example, the stability of the nanofibers against heat treatment and against optical bleaching has to be measured and improved. Under ambient air conditions and in the limit of strong optical excitation the degradation of luminescence intensity is accompanied by an increasing surface roughness of the aggregates, followed by material depletion. This is shown in the below image (size 3.7 x 3.7 m m 2 , height 65 nm) directly by illuminating the fibers on a combined inverted fluorescence microscope/atomic force microscope. One clearly observes that with increasing illumination time material is removed from the top of the nanofibers.
In further work we have shown that ablation can be stopped bleaching can be considerably slowed down by coating the nanofibers with a few hundred nanometers thick layer of SiOx. Such coated nanofibers could be integrated into new devices. Further reading: C.Maibohm, J.Brewer, H.Sturm, F.Balzer, H.-G.Rubahn, 'Bleaching of organic nanofibers', Journal of Applied Physics, submitted.
A photonic crystal fibre used as a micro-sample compartment in a mini Raman spectroscopy system / Biosensor Group
The BioPhotonics group at SDU, in collaboration with the DTU-based COM center and Crystal Fibre A/S, has early results, that indicates the possibility of using an air-clad photonic crystal fibre, as a micro-sample compartment for chemical or biochemical samples. Specifically, Raman spectroscopy in a fibre setup is about to become reality. Raman Spectroscopy provides a molecular fingerprint, which can be used to detect specific molecules in complex compounds or environments. The unique nanostructure of photonic-crystal fibres can be customized to achieve optimum condition for the spectroscopic processes. Combined with a diode laser and a specially designed mini-spectrograph, where the user is able to rapidly change a disposable fibre micro- sample compartment, the setup is a fully functional Raman spectroscopy system. Applications of such systems are currently being investigated in the BioPhotonics group. For further information please contact Stefan Ovesen Banke.
Nanoparticles for local sensing of chemical and cellular properties/ Biosensor Group
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Fig. 1. Nanoparticles of gold with a size of app. 100 nm. (SEM-picture by J.Holst). 
Fig. 2. Optical characterization demonstrating an optical resonance around the target wavelength of 575 nm (S. Hassing). 
Fig. 3. Modeling of the light intensity enhancement at the surface of the nanoparticle (T. Søndergaard). | SDU-HOME / 03/10/2009 , webmaster: kru@tek.sdu.dk |
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