TY - JOUR A1 - Martynenko, Irina V. A1 - Kusic, Dragana A1 - Weigert, Florian A1 - Stafford, S. A1 - Donnelly, F. C. A1 - Evstigneev, R. A1 - Gromova, Y. A1 - Baranov, A. V. A1 - Rühl, Bastian A1 - Kunte, Hans-Jörg A1 - Gun'ko, Y. K. A1 - Resch-Genger, Ute T1 - Magneto-fluorescent microbeads for bacteria detection constructed from superparamagnetic Fe3O4 nanoparticles and AIS/ZnS quantum dots JF - Analytical chemistry N2 - The efficient and sensitive detection of pathogenic microorganisms in aqueous environments, such as water used in medical applications, drinking water, and cooling water of industrial plants, requires simple and fast methods suitable for multiplexed detection such as flow cytometry (FCM) with optically encoded carrier beads. For this purpose, we combine fluorescent Cd-free Ag−In−S ternary quantum dots (t-QDs) with fluorescence Lifetimes (LTs) of several hundred nanoseconds and superparamagnetic Fe3O4 nanoparticles (SPIONs) with mesoporous CaCO3 microbeads to a magneto-fluorescent bead platform that can be surface-functionalized with bioligands, such as antibodies. This inorganic bead platform enables immuno-magnetic separation, target enrichment, and target quantification with optical readout. The beads can be detected with steady-state and time-resolved fluorescence microscopy and flow cytometry (FCM). Moreover, they are suited for readout by time gated emission. In the following, the preparation of these magneto-fluorescent CaCO3 beads, their spectroscopic and analytic characterization, and their conjugation with bacteria-specific antibodies are presented as well as proof-of-concept measurements with Legionella pneumophila including cell cultivation and plating experiments for bacteria quantification. Additionally, the possibility to discriminate between the long-lived emission of the LT-encoded capture and carrier CaCO3 beads and the short-lived Emission of the dye-stained bacteria with time-resolved fluorescence techniques and single wavelength excitation is demonstrated. KW - Fluorescence KW - method KW - lifetime KW - quantum yield KW - particle KW - magnetic nanoparticle KW - immunoseparation KW - flow cytometry KW - fluorescence microscopy KW - nanoparticle KW - quantum dot KW - AIS QD KW - fluorescence KW - bacteria detection KW - bacteria KW - antibody KW - Legionella KW - screening tes KW - FLIM PY - 2019 DO - https://doi.org/10.1021/acs.analchem.9b01812 SN - 0003-2700 SN - 1520-6882 VL - 91 SP - 12661 EP - 12669 PB - American Chemical Society CY - Washington, DC AN - OPUS4-50117 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hübner, Oskar A1 - Resch-Genger, Ute T1 - Spectral and Lifetime Encoding of Polymer Particles with Cd-free Ternary Semiconductor Nanocrystals for Flow Cytometry with Time Resolved Fluorescence Detection N2 - Multiplexed encoding schemes of nano- and micrometer sized particles with fluorescent dyes or quantum dots (QDs) and their optical detection, are of increasing interest for applications in the life sciences, for example in flow cytometry. Almost all strategies utilizing fluorescence focus on spectrally distinguishable emission bands or colors and different intensity levels as fluorescence codes. The fluorescence parameter lifetime has been, however, barely exploited. In this work the goal is to perform multiplexing with encoding fluorophores with different fluorescence lifetimes (LTs). In comparison to the spectral multiplexing strategies this has the advantage, that the different fluorescence LT codes can be measured with the excitation and emission wavelength, thus reducing instrument costs. Moreover, LTs should not depend on emitter concentration. Unlike organic dyes, the LTs of which are typically < 10 ns, the fluorescence LTs of ternary semiconductor QDs that represent a “green” alternative to conventional Cd-containing QDs are in the range of several hundred ns, independent of oxygen concentration, and can be tuned to a certain extent by chemical composition and surface chemistry. This present a time region that can be barely covered by other emitters that have either much shorter or longer lifetimes. In this project, different encoding strategies will be assessed and the encoded particles will be then used for fluorescence assays for the analysis of several targets in parallel. Therefor the encoded particles will be functionalized with different target-specific bioligands and read out with a specifically designed flow cytometer enabling time-resolved fluorescence detection. With this instrument, the particles will be discriminated by their fluorescence LTs In one detection channel while the analytes will be quantified by fluorescence labels in a second channel in the intensity domain. T2 - Bad Honnef Physics School Exciting nanostructures: Characterizing advanced confined systems CY - Bad Honnef, Germany DA - 21.07.2019 KW - Multiplexing KW - Lifetime KW - Bead KW - Flow cytometry KW - Fluorescence KW - Quantum dot KW - InP KW - AIS KW - Dye KW - Encoding KW - Barcoding KW - Assay KW - Method PY - 2019 AN - OPUS4-49723 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hübner, Oskar A1 - Resch-Genger, Ute A1 - Wegner, Karl David A1 - Hoffmann, Kristin T1 - Lifetime Barcoding of Polystyrene Beads with Fluorescent Nanocrystals for Fluorescent Lifetime Detection in Flow Cytometry N2 - Multiplexed encoding schemes of nano- and micrometer sized polymer particles with fluorescent dyes or quantum dots (QDs) and their optical detection, are of increasing interest for applications in the life sciences, for example in flow cytometry. Almost all strategies utilizing fluorescence focus on spectrally distinguishable emission bands or colors and different intensity levels as fluorescence codes. In this work the goal is to perform multiplexing with encoding fluorophores with different fluorescence lifetimes (LTs). In comparison to the spectral multiplexing strategies this has the advantage, that the different fluorescence LT codes can be measured with the same excitation and emission wavelength, thus reducing instrumental costs. Moreover, LTs should not depend on emitter concentration. Unlike organic dyes, the LTs of which are typically <10ns, the fluorescence LTs of ternary semiconductor QDs which represent a “green” alternative to conventional Cd-containing QDs are in the range of several hundred ns, independent of oxygen concentration, and can be tuned to a certain extent by chemical composition and surface chemistry. This presents a time region that can barely be covered by other emitters that have either much shorter or longer lifetimes. In this project, different encoding strategies will be assessed, and the encoded particles will then be used for fluorescence assays for the analysis of several targets in parallel. Therefore, the encoded particles will be functionalized with different target-specific bioligands and read out with a specifically designed flow cytometer enabling time-resolved fluorescence detection. With this instrument, the particles will be discriminated by their fluorescence LTs in one detection channel while the analytes will be quantified by fluorescence labels in a second channel in the intensity domain. T2 - Tag der Chemie 2019 CY - Berlin, Germany DA - 11.07.2019 KW - Multiplexing KW - Lifetime KW - Bead KW - Flow cytometry KW - Fluorescence KW - Quantum dot KW - InP KW - AIS KW - Dye KW - Encoding KW - Barcoding KW - Assay KW - Method PY - 2019 AN - OPUS4-49722 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hübner, Oskar A1 - Kage, Daniel A1 - Hoffmann, Katrin A1 - Wegner, Karl David A1 - Dhamo, Lorena A1 - Göhde, W. A1 - Resch-Genger, Ute T1 - Luminescence lifetime encoding for flow cytometry with quantum-dot-encoded beads N2 - Spectral encoding of cells or particles and the discrimination of multiple spectral codes are a critical process in flow cytometry (FCM). Typical issues in spectral encoding are, e.g., the spectral overlap of codes, or the increasing complexity of instruments . The exploitation of the photoluminescence lifetime (LT) as an encoding parameter could be used to circumvent both of these issues, as it adds another dimension to the parameter space, or, when used as a stand-alone parameter, requiring only one excitation light source and one detector. While LT encoding was considered already decades ago it is still not implemented as a routine technique in FCM yet, mainly due to the challenge of very few photons being available within the limited transition time of a cell or particle through the laser spot. Recently, we demonstrated LT-FCM based on luminophores with ns LTs in a compact and low-cost flow cytometer. Measurements on polymer microbeads containing luminophores with distinctly different excited state LTs enabled the complete discrimination of three LT codes and five codes in total could be identified. Now, we have extended our approach towards considerably longer LTs by custom-made polymer microbeads loaded with different ratios of InP/ZnS and AgInS2 quantum dots. The use of these materials significantly expands the usable time range for LT encoding to up to several hundred ns. Our studies demonstrate the possibility to further increase the number of viable LT codes for multiplexing in LT-FCM without the need for extensive hardware modifications. T2 - Visions in Cytometry - 29th Annual Conference of the German Society for Cytometry CY - Berlin, Germany DA - 25.07.2019 KW - Multiplexing KW - Lifetime KW - Bead KW - Flow cytometry KW - Fluorescence KW - Quantum dot KW - InP KW - AIS KW - Dye KW - Encoding KW - Barcoding KW - Assay KW - Method PY - 2019 AN - OPUS4-49390 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Huang, J. A1 - Tarábek, J. A1 - Kulkarni, R. A1 - Wang, Cui A1 - Dračínský, M. A1 - Smales, Glen Jacob A1 - Pauw, Brian Richard A1 - Resch-Genger, Ute A1 - Bojdys, M. J. T1 - A π-conjugated, covalent phosphinine framework JF - Chemistry a European Journal N2 - Structural modularity of polymer frameworks is a key advantage of covalent organic polymers, however, only C, N, O, Si and S have found their way into their building blocks so far. Here, we expand the toolbox available to polymer and materials chemists by one additional nonmetal, phosphorus. Starting with a building block that contains a λ⁵‐phosphinine (C₅P) moiety, we evaluate a number of polymerisation protocols, finally obtaining a π‐conjugated, covalent phosphinine‐based framework (CPF‐1) via Suzuki‐Miyaura coupling. CPF‐1 is a weakly porous polymer glass (72.4 m2 g‐1 N2 BET at 77 K) with green fluorescence (λmax 546 nm) and extremely high thermal stability. The polymer catalyzes hydrogen evolution from water under UV and visible light irradiation without the need for additional co‐catalyst at a rate of 33.3 μmol h‐¹ g‐¹. Our results demonstrate for the first time the incorporation of the phosphinine motif into a complex polymer framework. Phosphinine‐based frameworks show promising electronic and optical properties that might spark future interest in their applications in light‐emitting devices and heterogeneous catalysis. KW - Phosphinine KW - Fully aromatic frameworks KW - Suzuki-Miyaura coupling KW - Polymers KW - Fluorescence KW - Small-angle scattering PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-485330 DO - https://doi.org/10.1002/chem.201900281 SP - 2 EP - 10 PB - Wiley VCH-Verlag CY - Weinheim AN - OPUS4-48533 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gharaati, S. A1 - Wang, Cui A1 - Förster, C. A1 - Weigert, Florian A1 - Resch-Genger, Ute A1 - Heinze, K. T1 - Triplet–Triplet Annihilation Upconversion in a MOF with AcceptorFilled Channels JF - Chemistry - A European Journal N2 - In summary, we report a highly modular solid TTA-UC system comprising of a crystalline, thermally stable PCN222(Pd) MOF with CA-coated MOF channels and with a DPA annihilator embedded in a solution-like environment in the MOF channels. This solid material displays blue upconverted delayed emission with a luminescence lifetime of 373 us, a threshold value of 329 mW*cm-2 and a triplet–triplet energy transfer efficiency of 82%. This optical application adds another facet to the versatile chemistry of PCN-222 MOFs. The design concept is also applicable to other TTA-UC pairs and enables tuning of the UCL color, for example, by replacing DPA with other dyes as exemplarily shown for 2,5,8,11-tetra-tert-butyl-perylene, that yields UCL at 450 nm. Current work aims to reduce the oxygen sensitivity and to increase the retention of the trapped annihilators in organic environments, for example, by tuning the chain length of the carboxylic acid and by coating the MOF surface. In addition, the TTA-UC efficiency will be further enhanced by reducing the reabsorption of the UC emission caused by Pd(TCPP) and by optimizing the sensitizer/annihilator interface. KW - Porphyrin KW - Method KW - MOF KW - Fluorescence KW - Dye KW - Sensor KW - Oxygen sensitive KW - Single molecule KW - DPA KW - Lifetime KW - Upconverstion KW - Quantum yield KW - Triplet-triplet annihilation KW - Sensitization KW - Energy transfer KW - NMR PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-500580 DO - https://doi.org/10.1002/chem.201904945 VL - 26 IS - 5 SP - 1003 EP - 1007 PB - Wiley-VCH Verlag CY - Weinheim AN - OPUS4-50058 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -