TY - JOUR A1 - Cywinski, Piotr J. A1 - Nono, Katia Nchimi A1 - Charbonniere, Loic J. A1 - Hammann, Tommy A1 - Löhmannsröben, Hans-Gerd T1 - Photophysical evaluation of a new functional terbium complex in FRET-based time-resolved homogenous fluoroassays JF - Physical chemistry, chemical physics : a journal of European Chemical Societies N2 - A new functional luminescent lanthanide complex (LLC) has been synthesized with terbium as a central lanthanide ion and biotin as a functional moiety. Unlike in typical lanthanide complexes assembled via carboxylic moieties, in the presented complex, four phosphate groups are chelating the central lanthanide ion. This special chemical assembly enhances the complex stability in phosphate buffers conventionally used in biochemistry. The complex synthesis strategy and photophysical properties are described as well as the performance in time-resolved Forster Resonance Energy Transfer (FRET) assays. In those assays, this biotin-LLC transferred energy either to acceptor organic dyes (Cy5 or AF680) labelled on streptavidin or to quantum dots (QD655 or QD705) surfacefunctionalised with streptavidins. The permanent spatial donor-acceptor proximity is assured through strong and stable biotin-streptavidin binding. The energy transfer is evidenced from the quenching observed in donor emission and from a decrease in donor luminescence decay, both associated with simultaneous increase in acceptor intensity and in the decay time. The dye-based assays are realised in TRIS and in PBS, whereas QD-based systems are studied in borate buffer. The delayed emission analysis allows for quantifying the recognition process and for auto-fluorescence-free detection, which is particularly relevant for application in bioanalysis. In accordance with Forster theory, Forsterradii (R0) were found to be around 60 angstrom for organic dyes and around 105 angstrom for QDs. The FRET efficiency (Z) reached 80% and 25% for dye and QD acceptors, respectively. Physical donor-acceptor distances (r) have been determined in the range 45-60 angstrom for organic dye acceptors, while for acceptor QDs between 120 angstrom and 145 angstrom. This newly synthesised biotin-LLC extends the class of highly sensitive analytical tools to be applied in the bioanalytical methods such as time-resolved fluoroimmunoassays (TR-FIA), luminescent imaging and biosensing. Y1 - 2014 U6 - https://doi.org/10.1039/c3cp54883j SN - 1463-9076 SN - 1463-9084 VL - 16 IS - 13 SP - 6060 EP - 6067 PB - Royal Society of Chemistry CY - Cambridge ER - TY - JOUR A1 - Zakrevskyy, Yuriy A1 - Cywinski, Piotr A1 - Cywinska, Magdalena A1 - Paasche, Jens A1 - Lomadze, Nino A1 - Reich, Oliver A1 - Löhmannsröben, Hans-Gerd A1 - Santer, Svetlana T1 - Interaction of photosensitive surfactant with DNA and poly acrylic acid JF - The journal of chemical physics : bridges a gap between journals of physics and journals of chemistr Y1 - 2014 U6 - https://doi.org/10.1063/1.4862679 SN - 0021-9606 SN - 1089-7690 VL - 140 IS - 4 PB - American Institute of Physics CY - Melville ER - TY - JOUR A1 - Cywinski, Piotr J. A1 - Moro, Artur J. A1 - Löhmannsröben, Hans-Gerd T1 - Cyclic GMP recognition using ratiometric QD-fluorophore conjugate nanosensors JF - Biosensors and bioelectronics : the principal international journal devoted to research, design development and application of biosensors and bioelectronics KW - Quantum dots KW - Naphthyridines KW - Cyclic GMP KW - Base pairing KW - Fluorescent nanoconjugate KW - Nanosensor Y1 - 2014 U6 - https://doi.org/10.1016/j.bios.2013.09.002 SN - 0956-5663 SN - 1873-4235 VL - 52 SP - 288 EP - 292 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Schirmack, Janosch A1 - Boehm, Michael A1 - Brauer, Chris A1 - Löhmannsröben, Hans-Gerd A1 - de Vera, Jean-Pierre Paul A1 - Moehlmann, Diedrich A1 - Wagner, Dirk T1 - Laser spectroscopic real time measurements of methanogenic activity under simulated Martian subsurface analog conditions JF - Planetary and space science N2 - On Earth, chemolithoautothrophic and anaerobic microorganisms such as methanogenic archaea are regarded as model organisms for possible subsurface life on Mars. For this reason, the methanogenic strain Methanosarcina soligelidi (formerly called Methanosarcina spec. SMA-21), isolated from permafrost-affected soil in northeast Siberia, has been tested under Martian thermo-physical conditions. In previous studies under simulated Martian conditions, high survival rates of these microorganisms were observed. In our study we present a method to measure methane production as a first attempt to study metabolic activity of methanogenic archaea during simulated conditions approaching conditions of Mars-like environments. To determine methanogenic activity, a measurement technique which is capable to measure the produced methane concentration with high precision and with high temporal resolution is needed. Although there are several methods to detect methane, only a few fulfill all the needed requirements to work within simulated extraterrestrial environments. We have chosen laser spectroscopy, which is a non-destructive technique that measures the methane concentration without sample taking and also can be run continuously. In our simulation, we detected methane production at temperatures down to -5 degrees C, which would be found on Mars either temporarily in the shallow subsurface or continually in the deep subsurface. The pressure of 50 kPa which we used in our experiments, corresponds to the expected pressure in the Martian near subsurface. Our new device proved to be fully functional and the results indicate that the possible existence of methanogenic archaea in Martian subsurface habitats cannot be ruled out. (C) 2013 Published by Elsevier Ltd. KW - Mars KW - Methanogens KW - Methane KW - Sub-zero temperature (Celsius) KW - Wavelength modulation spectroscopy (laser spectroscopy) Y1 - 2014 U6 - https://doi.org/10.1016/j.pss.2013.08.019 SN - 0032-0633 VL - 98 SP - 198 EP - 204 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Riebe, Daniel A1 - Beitz, Toralf A1 - Dosche, Carsten A1 - Löhmannsröben, Hans-Gerd A1 - Raab, Volker A1 - Raab, Corinna A1 - Unverzagt, Matthias T1 - High-resolution spectrometer using combined dispersive and interferometric wavelength separation for raman and laser-induced Breakdown Spectroscopy (LIBS) JF - Applied spectroscopy : an international journal of spectroscopy ; official publication of the Society for Applied Spectroscopy N2 - In this paper the concept of a compact high-resolution spectrometer based on the combination of dispersive and interferometric elements is presented. Dispersive elements are used to spectrally resolve the light in one direction with coarse resolution (Delta lambda < 0.5 nm), while perpendicular to that direction an etalon provides high spectral resolution (Delta lambda < 50 pm). This concept for two-dimensional spectroscopy has been implemented for the wavelength range lambda = 350-650 nm. Appropriate algorithms for reconstructing spectra from the two-dimensional raw data and for wavelength calibration were established in an analysis software. Potential applications for this new spectrometer are Raman and laser-induced breakdown spectroscopy (LIBS). Resolutions down to 28 pm (routinely 54 pm) could be realized for these applications. KW - Raman spectroscopy KW - Laser-induced breakdown spectroscopy KW - LIBS KW - Fabry-Perot etalon KW - High-resolution spectrometer Y1 - 2014 U6 - https://doi.org/10.1366/13-07426 SN - 0003-7028 SN - 1943-3530 VL - 68 IS - 9 SP - 1030 EP - 1038 PB - Society for Applied Spectroscopy CY - Frederick ER - TY - JOUR A1 - Salffner, Katharina A1 - Boehm, Michael A1 - Reich, Oliver A1 - Löhmannsröben, Hans-Gerd T1 - A broadband cavity ring-down spectrometer based on an incoherent near infrared light source JF - Applied physics : B, Lasers and optics Y1 - 2014 U6 - https://doi.org/10.1007/s00340-014-5762-9 SN - 0946-2171 SN - 1432-0649 VL - 116 IS - 4 SP - 785 EP - 792 PB - Springer CY - New York ER - TY - JOUR A1 - Cywinski, Piotr J. A1 - Hammann, Tommy A1 - Huehn, Dominik A1 - Parak, Wolfgang J. A1 - Hildebrandt, Niko A1 - Löhmannsröben, Hans-Gerd T1 - Europium-quantum dot nanobioconjugates as luminescent probes for time-gated biosensing JF - Journal of biomedical optics N2 - Nanobioconjugates have been synthesized using cadmium selenide quantum dots (QDs), europium complexes (EuCs), and biotin. In those conjugates, long-lived photoluminescence (PL) is provided by the europium complexes, which efficiently transfer energy via Forster resonance energy transfer (FRET) to the QDs in close spatial proximity. As a result, the conjugates have a PL emission spectrum characteristic for QDs combined with the long PL decay time characteristic for EuCs. The nanobioconjugates synthesis strategy and photo-physical properties are described as well as their performance in a time-resolved streptavidin-biotin PL assay. In order to prepare the QD-EuC-biotin conjugates, first an amphiphilic polymer has been functionalized with the EuC and biotin. Then, the polymer has been brought onto the surface of the QDs (either QD655 or QD705) to provide functionality and to make the QDs water dispersible. Due to a short distance between EuC and QD, an efficient FRET can be observed. Additionally, the QD-EuC-biotin conjugates' functionality has been demonstrated in a PL assay yielding good signal discrimination, both from autofluorescence and directly excited QDs. These newly designed QD-EuC-biotin conjugates expand the class of highly sensitive tools for bioanalytical optical detection methods for diagnostic and imaging applications. (C) 2014 Society of Photo-Optical Instrumentation Engineers (SPIE) KW - quantum dots KW - europium complex KW - amphiphilic polymer assembly KW - nanobioconjugate KW - biosensor KW - time-resolved fluorescence Y1 - 2014 U6 - https://doi.org/10.1117/1.JBO.19.10.101506 SN - 1083-3668 SN - 1560-2281 VL - 19 IS - 10 PB - SPIE CY - Bellingham ER - TY - GEN A1 - Morgner, Frank A1 - Lecointre, Alexandre A1 - Charbonnière, Loic J. A1 - Löhmannsröben, Hans-Gerd T1 - Detecting free hemoglobin in blood plasma and serum with luminescent terbium complexes N2 - Hemolysis, the rupturing of red blood cells, can result from numerous medical conditions (in vivo) or occur after collecting blood specimen or extracting plasma and serum out of whole blood (in vitro). In clinical laboratory practice, hemolysis can be a serious problem due to its potential to bias detection of various analytes or biomarkers. Here we present the first ‘‘mix-and-measure’’ method to assess the degree of hemolysis in biosamples using luminescence spectroscopy. Luminescent terbium complexes (LTC) were studied in the presence of free hemoglobin (Hb) as indicators for hemolysis in TRIS-buffer, and in fresh human plasma with absorption, excitation and emission measurements. Our findings indicate dynamic as well as resonance energy transfer (FRET) between the LTC and the porphyrin ligand of hemoglobin. This transfer leads to a decrease in luminescence intensity and decay time even at nanomolar hemoglobin concentrations either in buffer or plasma. Luminescent terbium complexes are very sensitive to free hemoglobin in buffer and blood plasma. Due to the instant change in luminescence properties of the LTC in presence of Hb it is possible to access the concentration of hemoglobin via spectroscopic methods without incubation time or further treatment of the sample thus enabling a rapid and sensitive detection of hemolysis in clinical diagnostics. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 288 Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-99485 ER - TY - GEN A1 - Cywiński, Piotr J. A1 - Nono, Katia Nchimi A1 - Charbonnière, Loïc J. A1 - Hammann, Tommy A1 - Löhmannsröben, Hans-Gerd T1 - Photophysical evaluation of a new functional terbium complex in FRET-based time-resolved homogenous fluoroassays N2 - A new functional luminescent lanthanide complex (LLC) has been synthesized with terbium as a central lanthanide ion and biotin as a functional moiety. Unlike in typical lanthanide complexes assembled via carboxylic moieties, in the presented complex, four phosphate groups are chelating the central lanthanide ion. This special chemical assembly enhances the complex stability in phosphate buffers conventionally used in biochemistry. The complex synthesis strategy and photophysical properties are described as well as the performance in time-resolved Förster Resonance Energy Transfer (FRET) assays. In those assays, this biotin-LLC transferred energy either to acceptor organic dyes (Cy5 or AF680) labelled on streptavidin or to quantum dots (QD655 or QD705) surface-functionalised with streptavidins. The permanent spatial donor–acceptor proximity is assured through strong and stable biotin–streptavidin binding. The energy transfer is evidenced from the quenching observed in donor emission and from a decrease in donor luminescence decay, both associated with simultaneous increase in acceptor intensity and in the decay time. The dye-based assays are realised in TRIS and in PBS, whereas QD-based systems are studied in borate buffer. The delayed emission analysis allows for quantifying the recognition process and for auto-fluorescence-free detection, which is particularly relevant for application in bioanalysis. In accordance with Förster theory, Förster-radii (R0) were found to be around 60 Å for organic dyes and around 105 Å for QDs. The FRET efficiency (η) reached 80% and 25% for dye and QD acceptors, respectively. Physical donor–acceptor distances (r) have been determined in the range 45–60 Å for organic dye acceptors, while for acceptor QDs between 120 Å and 145 Å. This newly synthesised biotin-LLC extends the class of highly sensitive analytical tools to be applied in the bioanalytical methods such as time-resolved fluoroimmunoassays (TR-FIA), luminescent imaging and biosensing. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 252 KW - acceptors KW - bioanalysis KW - contrast agents KW - europium KW - fluoroimmunoassay KW - labels KW - lanthanide luminescence KW - quantum dots KW - resonance energy-transfer Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-95390 SP - 6060 EP - 6067 ER -