TY - CONF A1 - Radunz, Sebastian T1 - Development of UCL-based reporters for monitoring microbial induced corrosion N2 - Kurzpräsentation zur Vorstellung der Promotionsthematik während der SpringSchool der UpCon2016 in Polen. T2 - Konferenz UpCon2016 CY - Breslau, Poland DA - 23.05.2016 KW - UCNP PY - 2016 AN - OPUS4-36265 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Radunz, Sebastian T1 - Development of UCL-based reporters for monitoring microbial induced corrosion 2 N2 - Recent results concering analyte-responsive chromophores for UCL-based sensor systems T2 - Projekttreffen MIC CY - BAM, Berlin, Germany DA - 06.10.2016 KW - Fluoreszenz KW - UCNP KW - Optical Assay KW - Quantum Yield PY - 2016 AN - OPUS4-37823 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Andresen, Elina A1 - Radunz, Sebastian A1 - Resch-Genger, Ute T1 - Novel PET-Operated Rosamine Sensor Dyes with Substitution Pattern-Tunable pKa Values and Temperature Sensitivity N2 - We present the synthesis and characterization of a family of regioisomerically pure pH-sensitive rosamine fluorophores consisting of xanthene fluorophore cores, which determine the dyes’ photophysical properties such as excitation/emission wavelength, fluorescence quantum yield, and fluorescence lifetime, and differently substituted phenol moieties. The hydroxyl substituent of the phenol moiety introduces a pH sensitivity of the dyes’ fluorescence exploiting a photoinduced electron transfer (PET), that leads to a protonation-induced switching ON of the rosamine emission. Rational tuning of the pKa value of the rosamine fluorescence between 4 to 9 is achieved by altering the substitution pattern and degree of bromination of the phenolic subunits. Additionally, a temperature sensitivity of the fluorescence quantum yield is introduced or suppressed based upon the degree of rigidity of the xanthene scaffold. KW - Fluorescence KW - Optical probe KW - Sensor KW - Dye KW - Rosamine KW - Synthesis KW - Photophysics KW - PH KW - Quantum yield KW - Quality assurancemechanism KW - temperature PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-530562 DO - https://doi.org/10.1039/d1nj02505h VL - 45 IS - 31 SP - 13934 EP - 13940 PB - Royal Society of Chemistry AN - OPUS4-53056 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Neumann, L. A1 - Jakobs, F. A1 - Spelthann, S. A1 - Zaremba, D. A1 - Radunz, Sebastian A1 - Resch-Genger, Ute A1 - Evert, R. A1 - Kielhorn, J. A1 - Kowalsky, W. A1 - Johannes, H.-H. T1 - Integration of β-NaYF4 Upconversion Nanoparticles into Polymers for Polymer Optical Fiber Applications N2 - Producing active polymer optical fibers (POFs) is a key step towards new applications such as fluorescent fiber solar concentrators (FFSCs), sensors, contactless coupling devices, or fiber integrated light sources and lasers. Therefore, integration of fluorescent nanoparticles into the polymer matrix is necessary and becomes accessible via in situ polymerization. For optical applications, the polymer has to fulfill various requirements such as chemical and physical stability, optical transparency in the application-relevant spectral region as well as a good synthetic accessibility. A common material for these is poly(methyl methacrylate) (PMMA). The β-phase NaYF4:Yb3+,Er3+ upconversion nanoparticles (UCNP) were synthesized from the rare earth salts via thermal decomposition method in high-boiling point solvent 1-octadecene and capping agent oleic acid. Current results show hazy samples of the polymer with integrated nanoparticles made from monomer solution of methyl methacrylate. However, further optical tuning such as increasing the transparency of the bulk samples by changing the monomer solution to non-polar n-butyl methacrylate (nButMA) or cyclohexyl methacrylate (CHMA) or further optimization of the UCNP shell could lead to more suitable polymer bulk samples. T2 - PCNSPA 2018 - Photonic Colloidal Nanostructures: Synthesis, Properties, and Applications CY - St. Petersburg, Russia DA - 04.06.2018 KW - Copolymer KW - Active fibers KW - Rare earth nanoparticles KW - Upconversion PY - 2018 SP - 1 EP - 9 AN - OPUS4-45883 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Radunz, Sebastian T1 - Simple approach to pKa tunable BOIDPY-based fluorescent pH sensors N2 - Successfull synthesis of pH-responsive fluorescence ON/OFF sensor dyes with tunable pK values covering the pH range of 5 to 12 Immobilizing of multiple dyes with different pK values into a polymer host matrix provides a pH sensor with a dynamic range. T2 - First European/ 10th German BioSensor Symposium CY - Potsdam, Germany DA - 20.03.2017 KW - Fluorescence KW - Sensing KW - pH PY - 2017 AN - OPUS4-39683 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Neumann, L. A1 - Jakobs, F. A1 - Spelthann, S. A1 - Zaremba, D. A1 - Radunz, Sebastian A1 - Resch-Genger, Ute A1 - Evert, R. A1 - Kowalsky, W. A1 - Johannes, H.-H. T1 - Upconverting POF by Incubation of β-NaYF4:Yb3+, Er3+ Nanoparticles via in situ Polymerization for Production of active Polymer Optical Fibers N2 - In the past, integration of fluorescent dyes into polymers for active polymer optical fibers (POFs) is well studied, however, photobleaching of organic chromophores is still a problem for several optical applications. Inorganic luminescent nanoparticles like lanthanide-based systems can present an alternative due to their high chemical stability. Furthermore they do not show photobleaching and photoblinking. Certainly, integration of nanoparticles into a polymer matrix is challenging because of their high affinity to agglomeration which leads to scattering of the polymer samples. T2 - 27th International Conference on Plastic Optical Fibers CY - Seattle, Washington, USA DA - 04.09.2018 KW - Copolymer KW - Active fibers KW - Rare earth nanoparticles KW - Upconversion PY - 2018 SP - 1 EP - 5 CY - Seattle, Washington, USA AN - OPUS4-45882 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Radunz, Sebastian A1 - Tschiche, Harald Rune A1 - Moldenhauer, Daniel A1 - Resch-Genger, Ute T1 - Broad range ON/OFF pH sensors based on pKa tunable fluorescent BODIPYs N2 - A set of highly fluorescent, pH-responsive boron dipyrromethene dyes covering the pH range of 5-12 is presented for broad range pH measurements in mixed aqueous-organic median and polymer matrices. Readout in the intensity Domain with low cost and miniaturized Instrumentation utilizes reversible protonation induced switching ON of their initially completely quenched flourescence mediated by photoinduced electron Transfer. All dyes, rationally designed to reveal closely matching Absorption and Emission properties, are accessible via facile two-step reactions in Overall yields of up to 20%. By modifying the Substitution pattern of the meso-Aryl substiuent, the pKa values could be fine-tuned from 6 to 11. Integration of these molecules into polymeric films by a simple mixing procedure yielded reversible and longterm stable pH sensors for naked eye detection. KW - Fluorescence KW - Sensor KW - PH KW - Dye KW - BODIPY KW - Synthesis KW - Quantification KW - Film KW - Quantum yield KW - Lifetime KW - PET PY - 2017 DO - https://doi.org/10.1016/j.snb.2017.05.080 SN - 0925-4005 VL - 251 SP - 490 EP - 494 PB - Elsevier AN - OPUS4-41782 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Radunz, Sebastian T1 - Investigation of upconverting nanoparticle growth utilizing in-situ luminescence monitoring in combination with offline small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM) N2 - - UCNPs were succesfully synthesized and characterized - Various stages of UCNP growth were tracked using different analytical methods including real time in-situ & time-resolved luminescence spectroscopy, SAXS and TEM measurements - Additional size determination will be performed using inductively coupled plasma - mass spectrometry (ICP-MS) T2 - BAM-PTB-Nanoworkshop CY - PTB, Berlin, Germany DA - 14.05.2018 KW - Rare earth nanoparticles KW - Upconversion KW - TEM KW - SAXS PY - 2018 AN - OPUS4-45884 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Neumann, L. A1 - Jakobs, F. A1 - Spelthann, S. A1 - Zaremba, D. A1 - Radunz, Sebastian A1 - Resch-Genger, Ute A1 - Evert, R. A1 - Kielhorn, J. A1 - Kowalsky, W. A1 - Johannes, H. H. T1 - Integration of beta-NaYF4 Upconversion Nanoparticles into Polymers for Polymer Optical Fiber Applications N2 - Producing active polymer optical fibers (POFs) is a key step towards new applications such as fluorescent fiber solar concentrators (FFSCs), sensors, contactless coupling devices, or fiber integrated light sources and lasers. Therefore, integration of fluorescent nanoparticles into the polymer matrix is necessary and becomes accessible via in situ polymerization. For optical applications, the polymer has to fulfill various requirements such as chemical and physical stability, optical transparency in the application-relevant spectral region as well as a good synthetic accessibility. A common material for these is poly(methyl methacrylate) (PMMA). The beta-phase NaYF4 : Yb3+, Er3+ upconversion nanoparticles (UCNP) were synthesized from the rare earth salts via thermal decomposition method in high-boiling point solvent 1-octadecene and capping agent oleic acid. Current results show hazy samples of the polymer with integrated nanoparticles made from monomer solution of methyl methacrylate. However, further optical tuning such as increasing the transparency of the bulk samples by changing the monomer solution to non-polar n-butyl methacrylate (nButMA) or cyclohexyl methacrylate (CHMA) or further optimization of the UCNP shell could lead to more suitable polymer bulk samples. KW - Active fibers KW - Rare earth nanoparticles KW - Upconversion KW - Polymer PY - 2018 UR - https://journals.ioffe.ru/articles/46830 DO - https://doi.org/10.1134/S0030400X18110206 SN - 0030-400X VL - 125 IS - 5 SP - 711 EP - 715 PB - Pleiades Publishing CY - New York, NY AN - OPUS4-47167 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Radunz, Sebastian T1 - Upconverting nanoparticle based assays and sensor systems for bacteria/biofilm detection N2 - Results of the short term scientific mission of Sebastian Radunz funded by the european upconversion network. T2 - Short term scientific mission CY - Turku, Finland DA - 09.01.2017 KW - Upconverting nanoparticles KW - Assays PY - 2017 AN - OPUS4-39328 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Radunz, Sebastian A1 - Andresen, Elina A1 - Würth, Christian A1 - Koerdt, Andrea A1 - Rune Tschiche, Harald A1 - Resch-Genger, Ute T1 - Simple self-referenced luminescent pH sensors based on upconversion nanocrystals and pH-sensitive fluorescent BODIPY dyes N2 - We present the design and fabrication of pH responsive ratiometric dual component sensor systems based on multicolor emissive upconversion nanoparticles (UCNP) and pH sensitive BODIPY dyes with tunable pKa values embedded into a polymeric hydrogel matrix. The use of NIR excitable NaYF4:Yb3+,Tm3+ UCNPs enables background free read-out. Furthermore, the spectrally matching optical properties of the UCNPs and the dyes allow the UCNPs to serve as excitation light source for the analyteresponsive BODIPY as well as intrinsic reference. The blue upconversion luminescence (UCL) of NaYF4:Yb3+,Tm3+ UCNPs excited at 980 nm, that overlaps with the absorption of the pH-sensitive fluorophore, provides reabsorption based excitation of the dye, the spectrally distinguishable green fluorescence of which is switched ON upon protonation, preventing photoinduced electron transfer (PET) within the dye moiety, and the pH-inert red UCL act as reference. The intensities ratios of the dye’s fluorescence and the analyte-inert red Tm3+ UCL correlate directly with pH, which was successfully utilized for Monitoring timedependent pH changes of a suspension of quiescent E. coli metabolizing D-glucose. KW - pH sensor KW - UpConversion PY - 2019 DO - https://doi.org/10.1021/acs.analchem.9b01174 SN - 0003-2700 SN - 1520-6882 VL - 91 SP - 7756 EP - 7764 PB - acs publications AN - OPUS4-48490 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Radunz, Sebastian A1 - Wedepohl, S. A1 - Röhr, Mathilde A1 - Calderón, M. A1 - Tschiche, H. R. A1 - Resch-Genger, Ute T1 - pH-Activatable Singlet Oxygen-Generating Boron-dipyrromethenes N2 - Singlet oxygen can severely damage biological tissue, which is exploited in photodynamic therapy (PDT). In PDT, the effective range is limited by the distribution of the photosensitizer (PS) and the illuminated area. However, no distinction is made between healthy and pathological tissue, which can cause undesired damage. This encouraged us to exploit the more acidic pH of cancerous tissue and design pH-controllable singlet oxygen-generating boron-dipyrromethene (BODIPY) dyes. A pH sensitivity of the dyes is achieved by the introduction of an electronically decoupled, photoinduced electron transfer (PET)-capable subunit in meso-position of the BODIPY core. To favor triplet-state formation as required for singlet Oxygen generation, iodine substituents were introduced at the chromophore core. The resulting pH-controlled singlet oxygen-generating dyes with pKa values in the physiological range were subsequently assessed regarding their potential as pH-controlled PS for PDT. Using HeLa cells, we could successfully demonstrate markedly different pH-dependent cytotoxicities upon illumination. KW - Fluorescence KW - Sensor KW - Switch KW - pH KW - Singlet oxygen KW - PDT KW - Cell KW - BODIPY KW - Dye KW - Probe KW - Synthesis PY - 2019 DO - https://doi.org/10.1021/acs.jmedchem.9b01873 VL - 63 IS - 4 SP - 1699 EP - 1708 PB - ACS Publications AN - OPUS4-50554 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Radunz, Sebastian A1 - Kraus, Werner A1 - Bischoff, F. A. A1 - Emmerling, Franziska A1 - Resch-Genger, Ute A1 - Tschiche, Harald T1 - Temperature- and Structure-Dependent Optical Properties and Photophysics of BODIPY Dyes N2 - We report on the temperature- and structural-dependent optical properties and photophysics of a set of boron dipyrromethene (BODIPY) dyes with different substitution patterns of their meso-aryl subunit. Single-crystal Xray diffraction analysis of the compounds enabled a classification of the dyes into a sterically hindered and a unhindered group. The steric hindrance refers to a blocked rotational motion of the aryl subunit around the bond connecting this moiety to the meso-position of the BODIPY core. The energy barriers related to this rotation were simulated by DFT calculations. As follows from the relatively low rotational barrier calculated to about 17 kcal/mol, a free rotation is only possible for sterically unhindered compounds. Rotational barriers of more than 40 kcal/mol determined for the sterically hindered compounds suggest an effective freezing of the rotational motion in These molecules. With the aid of temperature-dependent spectroscopic measurements, we could show that the ability to rotate directly affects the optical properties of our set of BODIPY dyes. This accounts for the strong temperature dependence of the fluorescence of the sterically unhindered compounds which show a drastic decrease in fluorescence quantum yield and a significant shortening in fluorescence lifetime upon heating. The optical properties of the sterically hindered compounds, however, are barely affected by temperature. Our results suggest a nonradiative deactivation of the first excited singlet state of the sterically unhindered compounds caused by a conical intersection of the potential energy surfaces of the Ground and first excited state which is accessible by rotation of the meso-subunit. This is in good agreement with previously reported deactivation mechanisms. In addition, our results suggest the presence of a second nonradiative depopulation pathway of the first excited singlet state which is particularly relevant for the sterically hindered compounds. KW - Fluorescence KW - Sensor KW - Switch KW - pH KW - BODIPY KW - Dye KW - Probe KW - Synthesis KW - Photophysics KW - Mechanism PY - 2020 DO - https://doi.org/10.1021/acs.jpca.9b11859 SN - 1089-5639 VL - 124 IS - 9 SP - 1787 EP - 1797 PB - American Chemical Society AN - OPUS4-50639 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -