TY - CONF A1 - Pauli, Jutta A1 - Brehm, Robert A1 - Grabolle, Markus A1 - Behnke, Thomas A1 - Mathejczyk, J. A1 - Hamann, F. A1 - Alves, F. A1 - Hilger, I. A1 - Resch-Genger, Ute ED - Achilefu, S. ED - Raghavachari, R. T1 - Dye-biomolecule conjugates and NIR-fluorescent particles for targeting of disease-related biomarkers N2 - Indispensable for fluorescence imaging are highly specific and sensitive molecular probes that absorb and emit in the near infrared (NIR) spectral region and respond to or target molecular species or processes. Here, we present approaches to targeted fluorescent probes for in vivo imaging in the intensity and lifetime domain exploiting NIR dyes. Screening schemes for the fast identification of suitable fluorophores are derived and design criteria for highly emissive optical probes. In addition, as a signal amplification strategy that enables also the use of hydrophobic NIR fluorophores as fluorescent reporters, first steps towards versatile strategies for the preparation of NIR-fluorescent polymeric particles are presented that can be utilized also for the design of targeted and analyte-responsive probes. KW - Fluorescence KW - Fluorescence lifetime imaging KW - Near-infrared KW - NIR KW - Cyanine dye KW - Cancer KW - In vivo imaging KW - Aggregation KW - Nanoparticle PY - 2011 U6 - https://doi.org/10.1117/12.876828 SN - 1605-7422 N1 - Serientitel: Proceedings of SPIE – Series title: Proceedings of SPIE IS - 7910 SP - 791014-1 EP - 791014-15 AN - OPUS4-24353 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Felbeck, Tom A1 - Behnke, Thomas A1 - Hoffmann, Katrin A1 - Grabolle, Markus A1 - Lezhnina, M.M. A1 - Kynast, U.H. A1 - Resch-Genger, Ute T1 - Nile-red-nanoclay hybrids: Red emissive optical probes for use in aqueous dispersion N2 - Water-dispersible and (bio)functionalizable nanoclays have a considerable potential as inexpensive carriers for organic molecules like drugs and fluorophores. Aiming at simple design strategies for red-emissive optical probes for the life sciences from commercial precursors with minimum synthetic effort, we systematically studied the dye loading behavior and stability of differently functionalized laponites. Here, we present a comprehensive study of the absorption and emission properties of the red emissive hydrophobic and neutral dye Nile Red, a well-known polarity probe, which is almost insoluble and nonemissive in water. Adsorption of this probe onto disk-shaped nanoclays was studied in aqueous dispersion as function of dye concentration, in the absence and presence of the cationic surfactant cetyltrimethylammonium bromide (CTAB) assisting dye loading, and as a function of pH. This laponite loading strategy yields strongly fluorescent nanoclay suspensions with a fluorescence quantum yield of 0.34 at low dye loading concentration. The dye concentration-, CTAB-, and pH-dependent absorption, fluorescence emission, and fluorescence excitation spectra of the Nile-Red6#8211;nanoclay suspensions suggest the formation of several Nile Red species including emissive Nile Red monomers facing a polar environment, nonemissive H-type dimers, and protonated Nile Red molecules that are also nonfluorescent. Formation of all nonemissive Nile Red species could be suppressed by modification of the laponite with CTAB. This underlines the great potential of properly modified and functionalized laponite nanodisks as platform for optical probes with drug delivery capacities, for example, for tumor and therapy imaging. Moreover, comparison of the Nile Red dimer absorption spectra with absorption spectra of previously studied Nile Red aggregates in dendrimer systems and micelles and other literature systems reveals a considerable dependence of the dimer absorption band on microenvironment polarity which has not yet been reported so far for H-type dye aggregates. KW - Nile Red KW - Dye KW - Laponite KW - Nanoclay KW - Photoluminescence KW - Fluorescence KW - Polarity probe KW - Aggregate KW - Dimer PY - 2013 UR - http://pubs.acs.org/doi/pdf/10.1021/la402165q U6 - https://doi.org/10.1021/la402165q SN - 0743-7463 SN - 1520-5827 VL - 29 IS - 36 SP - 11489 EP - 11497 PB - American Chemical Society CY - Washington, DC AN - OPUS4-29017 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hoffmann, Katrin A1 - Behnke, Thomas A1 - Grabolle, Markus A1 - Resch-Genger, Ute T1 - Nanoparticle-encapsulated vis- and NIR-emissive fluorophores with different fluorescence decay kinetics for lifetime multiplexing N2 - Bioanalytical, clinical, and security applications increasingly require simple, efficient, and versatile strategies to measure an ever increasing number of analytes or events in parallel in a broad variety of detection formats as well as in conjunction with chromatographic separation techniques or flow cytometry. An attractive alternative to common optical multiplexing and encoding methods utilizing spectral multiplexing/color encoding and intensity encoding is lifetime multiplexing, which relies on the discrimination between different fluorescent reporters based on their fluorescence decay kinetics. Here, we propose a platform of surface-functionalizable polymeric nanoparticles stained with fluorophores differing in their fluorescence lifetimes as a new multiplexing and encoding approach. Proof-of-concept measurements with different sets of lifetime-encoded polystyrene nanoparticles are presented, obtained via staining of preformed particles with visible (vis)- and near-infrared (NIR)-emissive organic dyes, which display very similar absorption and emission spectra to enable excitation and detection at the same wavelengths, yet sufficiently different fluorescence decay kinetics in suspension, thereby minimizing instrumentation costs. Data analysis was performed with a linear combination approach in the lifetime domain. Our results and first cell experiments with these reporter sets underline the suitability of our multiplexing strategy for the discrimination between and the quantification of different labels. This simple and versatile concept can be extended to all types of fluorophores, thereby expanding the accessible time scale, and can be used, e.g., for the design of labels and targeted probes for fluorescence assays and molecular imaging, cellular imaging studies, and barcoding applications, also in conjunction with spectral and intensity encoding. KW - Fluorescent label KW - Multiplexing KW - Optical KW - encoding KW - Lifetime multiplexing KW - Fluorescence lifetime imaging FLIM KW - Nanoparticles PY - 2014 U6 - https://doi.org/10.1007/s00216-013-7597-3 SN - 1618-2642 SN - 1618-2650 VL - 406 IS - 14 SP - 3315 EP - 3322 PB - Springer CY - Berlin AN - OPUS4-30077 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Resch-Genger, Ute A1 - Behnke, Thomas A1 - Brehm, Robert A1 - Grabolle, Markus A1 - Hennig, Andreas A1 - Hoffmann, Angelika A1 - Hoffmann, Katrin A1 - Linck, Lena A1 - Lochmann, Cornelia A1 - Pauli, Jutta A1 - Spieles, Monika A1 - Würth, Christian T1 - Funktionelle Chromophor-Systeme, innovative Validierungskonzepte und rückführbare Standards für die fluoreszenzbasierte multiparametrische Bioanalytik N2 - Unter dem Motto „Innovation und Qualitätssicherung in der (Bio)Analytik“ werden in der Arbeitsgruppe Fluoreszenzspektroskopie der BAM, Bundesanstalt für Materialforschung und -prüfung, funktionelle Chromophor-Systeme, einfache Signalverstärkungs- und Multiplexingstrategien sowie innovative Validierungs- und rückführbare Standardisierungskonzepte für verschiedene fluorometrische Messgrößen und Methoden entwickelt. Im Mittelpunkt stehen dabei molekulare Fluorophore, Nanokristalle mit größenabhängigen optischen Eigenschaften (sogenannte Quantenpunkte, QDs) und fluoreszierende Partikel variabler Größe sowie Sonden und Sensormoleküle für neutrale und ionische Analyte und für die Charakterisierung von funktionellen Gruppen. Dabei erfolgen auch methodische Entwicklungen für die Fluoreszenzspektroskopie, die Fluoreszenzmikroskopie, die Milcrofluorometrie, die Sensorik und die Mikroarraytechnologie. Ziele sind u. a. das Design und die Untersuchung von multiplexfähigen selektiven und sensitiven Sonden für die Biomarkeranalytik, die Entwicklung von Methoden zur Charakterisierung der signalrelevanten Eigenschaften dieser Chromophor-Systeme und zur Charakterisierung von funktionellen Gruppen an Oberflächen und ihre Validierung sowie die Entwicklung und Bereitstellung von formatadaptierbaren, flexibel ersetzbaren Standards für die fluoreszenzbasierte Multiparameteranalytik. T2 - 5. Senftenberger Innovationsforum Multiparameteranalytik CY - Senftenberg, Deutschland DA - 10.03.2011 KW - Multiparametric KW - Multiplexing KW - Fluorescence KW - Nanoparticles KW - NIR dyes KW - Surface analysis KW - Quantum yield KW - Quantum dot KW - Lifetime PY - 2011 SP - 86 EP - 108 CY - Senftenberg AN - OPUS4-23635 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -