TY - JOUR
A1 - Wang, Cui
A1 - Ebel, Kenny
A1 - Heinze, Katja
A1 - Resch-Genger, Ute
A1 - Bald, Ilko
T1 - Quantum Yield of DNA Strand Breaks under Photoexcitation of a Molecular Ruby
N2 - Photodynamic therapy (PDT) used for treating cancer relies on the generation of highly reactive oxygen species, for example, singlet oxygen 1O2, by light-induced excitation of a photosensitizer (PS) in the presence of molecular oxygen, inducing DNA damage in close proximity of the PS. Although many precious metal complexes have been explored as PS for PDT and received clinical approval, only recently, the potential of photoactive complexes of nonnoble metals as PS has been discovered. Using the DNA origami technology that can absolutely quantify DNA strand break cross sections, we assessed the potential of the luminescent transition metal complex [Cr(ddpd)2]3+ (ddpd=N,N’-dimethyl-N,N’-dipyridine-2-ylpyridine-2,6-diamine) to damage DNA in an air-saturated aqueous environment upon UV/Vis illumination. The quantum yield for strand breakage, that is, the ratio of DNA strand breaks to the number of absorbed photons, was determined to 1–4%, indicating efficient transformation of photons into DNA strand breaks by [Cr(ddpd)2]3+.
KW - Fluorescence
KW - Synthesis
KW - Production
KW - Optical spectroscopy
KW - Ligand
KW - Photophysics
KW - Cr(III)
KW - Mechanism
KW - NIR
KW - PDT
KW - Singlet oxygen
KW - DNA
KW - Origami
KW - Quantum yield
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-573631
DO - https://doi.org/10.1002/chem.202203719
SP - 1
EP - 7
AN - OPUS4-57363
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hernández-García, María Amparo
A1 - Rurack, Knut
A1 - Bell, Jérémy
T1 - Rapid fabrication of optical elements for sensing applications using a standard SLA printer
N2 - The demand for compact, high-performance optical components has driven the development of increasingly sophisticated and miniaturized optical elements, often requiring complex and costly fabrication methods. In this study, we propose a cost-effective and accessible methodology for the fabrication of lenses and free-form optics using a commercially available stereolithography (SLA) 3D printer. A systematic characterisation of six transparent photopolymer resins was conducted in terms of their spectroscopic, optical, and morphological properties, i.e., surface and dimensional properties. The evaluation encompassed parameters such as transmittance, autofluorescence, refractive index,
and surface roughness. A straightforward yet resilient printing and post-treatment protocol was formulated, facilitating the fabrication of optical components with over 80% transmittance, minimal intrinsic fluorescence, and surface quality that is compatible with exacting optical applications. The fabricated components demonstrated excellent dimensional fidelity to digital designs and high reproducibility. To demonstrate the versatility of this approach, aspherical, miniaturized, and freeform lenses were designed and integrated into three fluorogenic sensing systems, including oil (strip-based) and chlorine (microfluidic-based) detection platforms, as well as a smartphone-based SARS-CoV-2 biosensor. The integration of customized 3D-printed optics has been demonstrated to enhance signal collection and readout performance, thereby highlighting the potential of this approach to
democratize the rapid prototyping and deployment of miniaturized optical systems. This work
represents a significant advancement in the field of additive manufacturing, particularly in relation to the development of functional photonic devices. Furthermore, it opens new prospects for sensor applications in biosensing, microfluidics, imaging, and integrated optics.
KW - 3D-printing
KW - Free-form
KW - Prototyping
KW - Optical resin
KW - Surface finishing
KW - Fluorescence
KW - Sensor
PY - 2026
DO - https://doi.org/10.37188/lam.2026.024
VL - 7
SP - 1
EP - 19
PB - Light Publishing Group
CY - Changchun
AN - OPUS4-65555
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Homann, Christian
A1 - Peeters, Régis
A1 - Mirmajidi, Hana
A1 - Berg, Jessica
A1 - Fay, Michael
A1 - Rodrigues, Lucas Carvalho Veloso
A1 - Radicchi, Eros
A1 - Jain, Akhil
A1 - Speghini, Adolfo
A1 - Hemmer, Eva
T1 - Rapid microwave-assisted synthesis of morphology-controlled luminescent lanthanide-doped Gd2O2S nanostructures
N2 - Gadolinium oxysulfide (Gd2O2S) is an attractive material of demonstrated suitability for a variety of imaging applications, leveraging its magnetic, scintillating, and luminescent properties, particularly when doped with optically active lanthanide ions (Ln3+). For many of these applications, control over size and morphology at the nanoscale is crucial. This study demonstrates the rapid microwave-assisted Synthesis of colloidal Ln2O2S (Ln = Gd and dopants Yb, Er, Tb) nanostructures in as little as 20 min. Structural characterization using X-ray diffraction analysis (XRD), Raman spectroscopy, as well as Transmission electron microscopy (TEM), including elemental mapping via energy dispersive X-ray spectroscopy (EDS), unveiled the key role of elemental sulphur (S8) in the reaction mixtures for materials growth. By systematically varying the Ln-to-S ratio from 1 : 0.5 to 1 : 15, controlled morphologies ranging from triangular nanoplatelets to berry- and flower-like shapes were achieved. Doping with Er3+/Yb3+ endowed the nano-triangles with upconverting and near-infrared emitting properties. Tb3+-doped Gd2O2S exhibited the characteristic green Tb3+ emission under UV excitation, while also showing X-ray excited optical luminescence (XEOL), rendering the material interesting as a potential nano-scintillator.
KW - Upconversion
KW - Microwave-assisted synthesis
KW - Synthesis
KW - Fluorescence
KW - Nano
KW - Particle
KW - NIR
KW - XRD
KW - X-ray fluoressence
KW - Morphology control
KW - Raman
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-647907
DO - https://doi.org/10.1039/D5TC01646K
SN - 2050-7526
VL - 13
IS - 35
SP - 18492
EP - 18507
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-64790
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Prakash, Swayam
A1 - Bell, Jérémy
A1 - Rurack, Knut
T1 - Rapid Onsite Detection of Fecal Contamination in Water Using a Portable Fluorometric Assay
N2 - Fecal pollution in water poses significant health risks, especially when contaminated sources are used for drinking and food production. Traditional water quality testing methods are expensive, slow, and require skilled personnel, limiting their accessibility. This work addresses these issues by developing a portable fluorometric assay for the detection of the fecal indicator pigment urobilin (UB). The assay uses silane-functionalized glass fiber strips impregnated with zinc chloride, providing a ‘drop-&-detect’ approach with enhanced fluorescence response mediated by the unique complexation properties of ZnCl2 and UB. This approach allows for the detection of UB at sub-nanomolar concentrations in less than 1 min using a 3D-printed setup with miniaturized optical components powered by a smartphone with its camera as a detector. The results validated with a benchtop fluorometer show the effectiveness of this method. The successful application of this userfriendly, rapid, and sensitive assay to real water samples from three rivers and the influx and efflux of a wastewater treatment plant advances field-based water quality monitoring, meets the WHO’s ASSURED criteria, and supports progress toward the global clean water and sanitation goals.
KW - Fecal pigment
KW - Fluorescence
KW - Signal amplification
KW - Surface chemistry
KW - Water quality testing
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655543
DO - https://doi.org/10.1021/acssensors.5c03922
SN - 2379-3694
VL - 11
SP - 1
EP - 9
PB - American Chemical Society
CY - Washington, D.C.
AN - OPUS4-65554
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sun, Yijuan
A1 - Pérez-Padilla, Víctor
A1 - Valderrey, Virginia
A1 - Bell, Jérémy
A1 - Gawlitza, Kornelia
A1 - Rurack, Knut
T1 - Ratiometric detection of perfluoroalkyl carboxylic acids using dual fluorescent nanoparticles and a miniaturised microfluidic platform
N2 - The widespread contamination of soil and water with perfluoroalkyl substances (PFAS) has caused considerable societal and scientific concern. Legislative measures and an increased need for remediation require effective on-site analytical methods for PFAS management. Here we report on the development of a green-fluorescent guanidine-BODIPY indicator monomer incorporated into a molecularly imprinted polymer (MIP) for the selective detection of perfluorooctanoic acid (PFOA). Complexation of PFOA by the indicator, which is mediated by concerted protonation-induced ion pairing-assisted hydrogen bonding, significantly enhances fluorescence in polar organic solvents. The MIP forms as a thin layer on silica nanoparticles doped with tris(bipyridine)ruthenium(II) chloride, which provides an orange emission signal as internal reference, resulting in low measurement uncertainties. Using a liquid-liquid extraction protocol, this assay enables the direct detection of PFOA in environmental water samples and achieves a detection limit of 0.11 µM. Integration into an opto-microfluidic system enables a compact and user-friendly system for detecting PFOA in less than 15 minutes.
KW - PFAS
KW - Molecular imprinting
KW - Microfluidics
KW - Fluorescence
KW - Onsite assay
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-650270
DO - https://doi.org/10.1038/s41467-025-66872-9
SN - 2041-1723
VL - 16
IS - 1
SP - 1
EP - 16
PB - Springer Science and Business Media LLC
AN - OPUS4-65027
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sun, Yijuan
A1 - Gawlitza, Kornelia
A1 - Valderrey, Virginia
A1 - Bhattacharya, Biswajit
A1 - Rurack, Knut
T1 - Ratiometric Molecularly Imprinted Particle Probes for Reliable Fluorescence Signaling of Carboxylate-Containing Molecules
N2 - In addition to sensitivity, selectivity, and portability, chemical sensing systems must generate reliable signals and offer modular configurability to address various small molecule targets, particularly in environmental applications. We present a versatile, modular strategy utilizing ratiometric molecularly imprinted particle probes based on BODIPY indicators and dyes for recognition and internal referencing. Our approach employs polystyrene core particles doped with a red fluorescent BODIPY as an internal standard, providing built-in reference for environmental influences. A molecularly imprinted polymer (MIP) recognition shell, incorporating a green-fluorescent BODIPY indicator monomer with a thiourea binding site for carboxylate containing analytes, is grafted from the core particles in the presence of the analyte as the template. The dual-fluorescent MIP probe detects fexofenadine as the model analyte with a change in green emission signal referenced against a stable red signal, achieving a detection limit of 0.13 μM and a broad dynamic range from 0.16 μM to 1.2 mM, with good discrimination against other antibiotics in acetonitrile. By selecting a versatile dye scaffold and recognition element, this approach can be extended to other carboxylate-containing analytes and/or wavelength combinations, potentially serving as a robust multiplexing platform.
KW - Core-shell particles
KW - Molecular imprinting
KW - Pharmaceutical contaminants
KW - Self-referenced measurements
KW - Fluorescence
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-609385
DO - https://doi.org/10.1021/acsami.4c09990
SP - 1
EP - 13
PB - American Chemical Society (ACS)
AN - OPUS4-60938
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zavoiura, O.
A1 - Resch-Genger, Ute
A1 - Seitz, O.
T1 - Reactive Quantum Dot-Based FRET Systems
N2 - Oligonucleotide-templated reactions (OTRs) between two reactive hybridization probes allow for the detection of a DNA or RNA of interest by exploiting the target molecule as a catalyst of chemical reactions.
The product of such a reaction commonly exhibits distinct fluorescence properties and can be detected by the means of fluorescence spectroscopy. The vast majority of OTR systems utilize organic dyes as fluorescent reporters. However, the use of brighter emitters, such as semiconductor quantum dots (QDs), has potential to improve the sensitivity of detection by providing brighter signals and permitting the use of probes at very low concentrations. Here we report an RNA-templated reaction between two fluorescently labeled peptide nucleic acid (PNA)-based probes, which proceeds on the surface of a QD. The QD-Bound PNA probe bears a cysteine functionality, while the other PNA is functionalized with an organic dye as a thioester. OTR between these probes proceeds through a transfer of the organic dye to the QD and can be conveniently monitored via fluorescence resonance energy transfer (FRET) from the QD to the Cy5. The reaction was performed in a conventional fluorescence microplate reader and permits the detection of RNA in the picomolar range.
KW - Fluorescence
KW - Nano
KW - Particle quantum dot
KW - FRET
KW - Assay
KW - Sensor
KW - RNA-templated reactions
KW - Bioconjugation
KW - Synthesis
KW - Dye
KW - Click chemistry
KW - Peptide nucleic acid
KW - Quantum dots
KW - RNA
KW - Fluorescence spectroscopy
PY - 2020
DO - https://doi.org/10.1007/978-1-0716-0243-0_11
VL - 2105
SP - 187
EP - 198
PB - Springer Sience+Business Media
AN - OPUS4-50553
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Li, Q.
A1 - Shinde, S.
A1 - Grasso, G.
A1 - Caroli, A.
A1 - Abouhany, R.
A1 - Lanzillotta, M.
A1 - Pan, G.
A1 - Wan, Wei
A1 - Rurack, Knut
A1 - Sellergren, B.
T1 - Selective detection of phospholipids using molecularly imprinted fluorescent sensory core-shell particles
N2 - Sphingosine-1-phosphate (S1P) is a bioactive sphingo-lipid with a broad range of activities coupled to its role in G-protein coupled receptor signalling. Monitoring of both intra and extra cellular levels of this lipid is challenging due to its low abundance and lack of robust affinity assays or sensors. We here report on fluorescent sensory core-shell molecularly imprinted polymer (MIP) particles responsive to near physiologically relevant levels of S1P and the S1P receptor modulator fingolimod phosphate (FP) in spiked human serum samples. Imprinting was achieved using the tetrabutylammonium (TBA) salt of FP or phosphatidic acid (DPPA·Na) as templates in combination with a polymerizable nitrobenzoxadiazole (NBD)-urea monomer with the dual role of capturing the phospho-anion and signalling its presence. The monomers were grafted from ca 300 nm RAFT-modified silica core particles using ethyleneglycol dimethacrylate (EGDMA) as crosslinker resulting in 10–20 nm thick shells displaying selective fluorescence response to the targeted lipids S1P and DPPA in aqueous buffered media. Potential use of the sensory particles for monitoring S1P in serum was demonstrated on spiked serum samples, proving a linear range of 18–60 μM and a detection limit of 5.6 μM, a value in the same range as the plasma concentration of the biomarker.
KW - Molecularly imprinted polymers
KW - Phospholipids
KW - Fluorescence
KW - Dye monomers
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509485
DO - https://doi.org/10.1038/s41598-020-66802-3
SN - 2045-2322
VL - 10
IS - 1
SP - 9924
PB - Nature Research
CY - London
AN - OPUS4-50948
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Biesen, L.
A1 - Nirmalananthan-Budau, Nithiya
A1 - Hoffmann, Katrin
A1 - Resch-Genger, Ute
A1 - Müller, T. J. J.
T1 - Solid-State Emissive Aroyl-S,N-Ketene Acetals with Tunable
N2 - N-Benzyl aroyl-S,N-ketene acetals can be readily synthesized by condensation of aroyl chlorides and N-Benzyl 2-methyl benzothiazolium salts in good to excellent yields, yielding a library of 35 chromophores with bright solid-state emission and aggregation-induced emission characteristics.
Varying the substituent from electron-donating to electronwithdrawing enables the tuning of the solid-state emission Color from deep blue to red.
KW - Nano
KW - Nanoparticle
KW - Photoluminescence
KW - Fluorescence
KW - Quantum yield
KW - Photophysics
KW - Lifetime
KW - Sensor
KW - dye
KW - Enhancement
KW - Particle
KW - Polarity
KW - AIE
KW - Aggregation
KW - Aggregation-induced emission
KW - Solid state emission
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509072
DO - https://doi.org/10.1002/anie.201916396
VL - 59
IS - 25
SP - 10037
EP - 10041
PB - Wiley Online Libary
AN - OPUS4-50907
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Auxillos, J.
A1 - Crouigneau, R.
A1 - Li, Y.-F.
A1 - Dai, Y.
A1 - Stigliani, A.
A1 - Tavernaro, Isabella
A1 - Resch-Genger, Ute
A1 - Sandelin, A.
A1 - Marie, R.
A1 - Pedersen, S. F.
T1 - Spatially resolved analysis of microenvironmental gradient impact on cancer cell phenotypes
N2 - Despite the physiological and pathophysiological significance of microenvironmental gradients, e.g., for diseases such as cancer, tools for generating such gradients and analyzing their impact are lacking. Here, we present an integrated microfluidic-based workflow that mimics extracellular pH gradients characteristic of solid tumors while enabling high-resolution live imaging of, e.g., cell motility and chemotaxis, and preserving the capacity to capture the spatial transcriptome. Our microfluidic device generates a pH gradient that can be rapidly controlled to mimic spatiotemporal microenvironmental changes over cancer cells embedded in a 3D matrix. The device can be reopened allowing immunofluorescence analysis of selected phenotypes, as well as the transfer of cells and matrix to a Visium slide for spatially resolved analysis of transcriptional changes across the pH gradient. This workflow is easily adaptable to other gradients and multiple cell types and can therefore prove invaluable for integrated analysis of roles of microenvironmental gradients in biology.
KW - Bioimaging
KW - Fluorescence
KW - Cell
KW - Cancer
KW - Method
KW - Microfluids
KW - Model
KW - Calibration
KW - Sensor
KW - Ph
KW - Probe
KW - Workflow
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-604631
DO - https://doi.org/10.1126/sciadv.adn3448
VL - 19
IS - 18
SP - 1
EP - 17
AN - OPUS4-60463
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Paul, Andrea
ED - Reese, M.
ED - Goldhammer, T.
ED - Schmalsch, C.
ED - Weber, J.
ED - Bannick, C. G.
T1 - Spectroscopic evidence for adsorption of natural organic matter on microplastics
N2 - The interaction of microcroplastics (MP) with dissolved organic matter, especially humic substances, is of great importance in understanding the behavior of microplastics in aquatic ecosystems. Surface modification by humic substances plays an essential role in transport and interaction of MP with abiotic and biotic components. Previous studies on the interaction between MP and humic substances were largely based on a model compound, humic acid (Sigma-Aldrich). In our work, we therefore investigated the interaction of natural organic matter (NOM) sampled from a German surface water with low-density polyethylene particles (LDPE). Highpressure size exclusion chromatography (HPSEC) and UV/vis absorption and fluorescence spectroscopy were used to characterize the incubation solutions after modifications due to the presence of LDPE, and Raman spectroscopy was used to characterize the incubated microplastics. While the studies of the solutions generally showed only very small effects, Raman spectroscopic studies allowed clear evidence of the binding of humic fractions to MP. The comparison of the incubation of NOM and a lignite fulvic acid which also was tested further showed that specific signatures of the humic substances used could be detected by Raman spectroscopy. This provides an elegant opportunity to conduct broader studies on this issue in the future.
KW - Humic matter
KW - Raman
KW - HPSEC
KW - Fluorescence
KW - MCR
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-574519
DO - https://doi.org/10.1002/appl.202200126
SN - 2702-4288
VL - 3
IS - 2
SP - 1
EP - 30
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-57451
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Reichenauer, F.
A1 - Wang, Cui
A1 - Förster, C.
A1 - Boden, P.
A1 - Ugur, N.
A1 - Báez-Cruz, R.
A1 - Kalmbach, J.
A1 - Carrella, L. M.
A1 - Rentschler, E.
A1 - Ramanan, C.
A1 - Niedner-Schatteburg, G.
A1 - Gerhards, M.
A1 - Seitz, M.
A1 - Resch-Genger, Ute
A1 - Heinze, K.
T1 - Strongly Red-Emissive Molecular Ruby [Cr(bpmp)2]3+ Surpasses [Ru(bpy)3]2+
N2 - Gaining chemical control over the thermodynamics and kinetics of photoexcited states is paramount to an efficient and sustainable utilization of photoactive transition metal complexes in a plethora of technologies. In contrast to energies of charge Transfer states described by spatially separated orbitals, the energies of spinflip states cannot straightforwardly be predicted as Pauli Repulsion and the nephelauxetic effect play key roles. Guided by multireference quantum chemical calculations, we report a novel highly luminescent spin-flip emitter with a quantum chemically predicted blue-shifted luminescence. The spin-flip emission band of the chromium complex [Cr(bpmp)2]3+ (bpmp = 2,6-bis(2-pyridylmethyl) pyridine) shifted to higher energy from ca. 780 nm observed for known highly emissive chromium(III) complexes to 709 nm. The photoluminescence quantum yields climb to 20%, and very long excited state lifetimes in the millisecond range are achieved at room temperature in acidic D2O solution. Partial ligand deuteration increases the quantum yield to 25%. The high excited state energy of [Cr(bpmp)2]3+ and its facile reduction to [Cr(bpmp)2]2+ result in a high excited state redox potential. The ligand’s methylene bridge acts as a Brønsted acid quenching the luminescence at high pH. Combined with a pH-insensitive chromium(III) emitter, ratiometric optical pH sensing is achieved with single wavelength excitation. The photophysical and Ground state properties (quantum yield, lifetime, redox potential, and acid/base) of this spin-flip complex incorporating an earth-abundant metal surpass those of the classical precious metal [Ru(α-diimine)3]2+ charge transfer complexes, which are commonly employed in optical sensing and photo(redox) catalysis, underlining the bright future of these molecular ruby analogues.
KW - Fluorescence
KW - Optical probe
KW - Sensor
KW - PH
KW - Quantum yield
KW - Quality assurance
KW - Complex
KW - Cr(III)
KW - Lifetime
KW - Ligand
KW - Theory
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-530548
DO - https://doi.org/10.1021/jacs.1c05971
VL - 143
IS - 30
SP - 11843
EP - 11855
PB - ACS Publications
AN - OPUS4-53054
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nirmalananthan-Budau, Nithiya
A1 - Budau, J. H.
A1 - Moldenhauer, Daniel
A1 - Hermann, G.
A1 - Kraus, Werner
A1 - Hoffmann, Katrin
A1 - Paulus, Beate
A1 - Resch-Genger, Ute
T1 - Substitution pattern controlled aggregation-induced emission in donor-acceptor-donor dyes with one and two propeller-like triphenylamine donors
N2 - We present a comparative study of the spectroscopic properties of the donor–acceptor–donor substituted dyes triphenylamine-allylidenemalononitrile-julolidine (TMJ) and triphenylamine-allylidenemalononitriletriphenylamine (TMT), bearing one and two propeller-like triphenylamine donor moieties, in solvents of varying polarity and viscosity and in the aggregated and solid state. Our results reveal control of the aggregation-induced spectroscopic changes and the packing motifs of the dye molecules in the solid state by the chemical nature and structure of the second nitrogen-containing donor, i.e., a planar and a rigid julolidine or a twisted triphenyl group. Assuming that the TMT and TMJ aggregates show a comparable arrangement of the molecules to the respective crystals, these different molecular interactions in the solid state are responsible for aggregation induced emission (AIE) in the case of TMT and its absence for TMJ. Moreover, a versatile strategy for the fluorescence enhancement of only weakly emissive AIE dyes is shown, turning these dyes into bright nanoscale fluorescent reporters by using them as stains for preformed polymer particles.
KW - Nano
KW - Nanoparticle
KW - Photoluminescence
KW - Fluorescence
KW - Quantum yield
KW - Photophysics
KW - Lifetime
KW - Sensor
KW - Dye
KW - Enhancement
KW - Particle
KW - Polarity
KW - AIE
KW - Aggregation
KW - Aggregation-induced emission
KW - Solid state emission
PY - 2020
DO - https://doi.org/10.1039/d0cp00413h
VL - 22
IS - 25
SP - 14142
EP - 14154
AN - OPUS4-50967
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - López-Puertollano, Daniel
A1 - Tobias, Charlie
A1 - Bell, Jérémy
A1 - Abad-Somovilla, A.
A1 - Abad-Fuentes, A.
A1 - Rurack, Knut
T1 - Superparamagnetic Bead-Based Microfluidic Fluoroimmunoassay Platform for Rapid Ochratoxin A Detection in Flour
N2 - Simplification and reduction of time and costs are the primary goals in the development and use of onsite methods in diagnostics and food safety. To facilitate the transition from laboratory techniques to simple, miniaturized devices, we have developed a modular microfluidic platform. This platform integrates a competitive fluorescence immunoassay on the surface of superparamagnetic beads, serving as a complementary technique to traditional cytometry assays. In the first chip module, a fast competitive reaction (5 min) occurs, after which the particles are retained in the second module. This module consists of a PDMS chip and a permanent magnet, allowing only the fluorescent competitor to reach the detection module. Ochratoxin A (OTA) was chosen as the model analyte for device development, using fluorescein-labeled OTA as a competitor. The system efficiently separates particles, with OTA concentration directly correlated to the amount of fluorescent competitor remaining in solution after the competitive reaction. This innovative setup allows to perform rapid measurements with small sample volumes in a short time (10 min), achieving a limit of detection for OTA of 1.2 μg L–1. The system was successfully applied to the accurate determination of OTA in wheat flour spiked at regulatorily relevant concentrations. Using this device, conventional cytometry immunoassays can be seamlessly transformed into user-friendly, miniaturized analytical methods at reduced cost for applications outside of a laboratory directly at the point of need.
KW - Bead-based assay
KW - Fluorescence
KW - Immunoassay
KW - Microfluidics
KW - mycotoxins
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-638472
DO - https://doi.org/10.1021/acssensors.5c01119
SN - 2379-3694
SP - 1
EP - 10
PB - American Chemical Society
CY - Washington, D.C.
AN - OPUS4-63847
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wasternack, J.
A1 - Schröder, H. V.
A1 - Witte, J. F.
A1 - Ilisson, M.
A1 - Hupatz, H.
A1 - Hille, J. F.
A1 - Gaedke, M.
A1 - Valkonen, A. M.
A1 - Sobottka, S.
A1 - Krappe, A.
A1 - Schubert, M.
A1 - Paulus, B.
A1 - Rissanen, K.
A1 - Sarkar, B.
A1 - Eigler, S.
A1 - Resch-Genger, Ute
A1 - Schalley, C. A.
T1 - Switchable protection and exposure of a sensitive squaraine dye within a redox active rotaxane
N2 - In nature,molecular environments in proteins can sterically protect and stabilize reactive species such as organic radicals through non-covalent interactions.Here, wereport a near-infrared fluorescent rotaxane in which the stabilization of a chemically labile squaraine fluorophore by the coordination of a tetralactam macrocycle can be controlled chemically and electrochemically. The rotaxane can be switched between two co-conformations inwhich thewheel either stabilizes or exposes the fluorophore. Coordination by the wheel affects the squaraine’s stability across four redox states and renders the radical anion significantly more stable—by a factor of 6.7—than without protection by a mechanically bonded wheel. Furthermore, the fluorescence properties can be tuned by the redox reactions in a stepwise manner. Mechanically interlockedmolecules provide an excellent scaffold to stabilize and selectively expose reactive species in a co-conformational switching process controlled by external stimuli.
KW - Fluorescence
KW - Dye
KW - Sensor
KW - Quantum yield
KW - Spectroscopy
KW - Photophysics
KW - Synthesis
KW - Squaraine
KW - Switch
KW - Redox-active
KW - Rotaxane
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-614959
DO - https://doi.org/10.1038/s42004-024-01312-1
VL - 7
SP - 1
EP - 11
AN - OPUS4-61495
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Srivastava, Priyanka
A1 - Fürstenwerth, Paul Christian
A1 - Witte, J. F.
A1 - Resch-Genger, Ute
T1 - Synthesis and spectroscopic characterization of a fluorescent phenanthrene-rhodamine dyad for ratiometric measurements of acid pH values
N2 - We present the rational design, synthesis and spectroscopic characterization of a novel dual excitation, three color emitting, pH-responsive fluorescent probe consisting of two phenanthrene and one rhodamine B units linked by click chemistry. The rhodamine moiety, excitable at λEx = 315 nm and at λEx = 560 nm in its ring-opened form, provides the pH-responsive fluorophore, while the pH-insensitive phenanthrene, excited at λEx = 315 nm, serves as inert internal reference, The presence of two phenanthrene moieties enables a blue monomer and a blueish green excimer emission at 351 nm and 500 nm, respectively. Opening of the rhodamine B spirolactam ring at an acidic pH below 5.0 (pKa = 2.59 ± 0.04) switches on its emission at 580 nm. Simultaneously, the phenanthrene excimer emission decreases caused by a change in orientation of the phenanthrene units, while the monomer emission is barely affected. This sensor design enables ratiometric measurements in the low acidic pH range utilizing the intensity ratios of the rhodamine B and phenanthrene excimer emission at 580 nm and 500 nm. Alternatively, also the intensity ratios of the rhodamine B and the phenanthrene monomer emission could be exploited or the sum of the phenanthrene monomer and excimer fluorescence. To the best of our knowledge, this is the first report of ratiometric sensing utilizing such a versatile type of tricolor emissive dyad probe bearing phenanthrene moieties and showing phenanthrene monomer and excimer emission.
KW - Fluorescence
KW - Optical probe
KW - Sensor
KW - Dye
KW - Rhodamine
KW - Synthesis
KW - Photophysics
KW - PH
KW - Quantum yield
KW - Quality assurance
KW - Mechanism
KW - Chemodosimeter
KW - Phenanthrene
KW - Ratiometric
KW - Dyad
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-530554
DO - https://doi.org/10.1039/d1nj01573g
SN - 1144-0546
VL - 45
IS - 31
SP - 13755
EP - 13762
PB - Royal Society of Chemistry
AN - OPUS4-53055
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bertorelle, F.
A1 - Wegner, Karl David
A1 - Berkulic, M. P.
A1 - Fakhouri, H.
A1 - Comby-Zerbino, C.
A1 - Sagar, A.
A1 - Bernadó, P.
A1 - Resch-Genger, Ute
A1 - Bonacic-Koutecký, V.
A1 - Le Guével, X.
A1 - Antoine, R.
T1 - Tailoring the NIR-II Photoluminescence of Single Thiolated Au25 Nanoclusters by Selective Binding to Proteins
N2 - Atomically precise gold nanoclusters are a fascinating class of nanomaterials that exhibit molecule-like properties and have outstanding photoluminescence (PL). Their ultrasmall size, molecular chemistry, and biocompatibility make them extremely appealing for selective biomolecule labeling in investigations of biological mechanisms at the cellular and anatomical levels. In this work, we report a simple route to incorporate a preformed Au25 nanocluster into a model bovine serum albumin (BSA) protein. A new approach combining small-angle X-ray scattering and molecular modeling provides a clear localization of a single Au25 within the protein to a cysteine residue on the gold nanocluster surface.
Attaching Au25 to BSA strikingly modifies the PL properties with enhancement and a redshift in the second near-infrared (NIR-II) window. This study paves the way to conrol the design of selective sensitive probes in biomolecules through a ligand-based strategy to enable the optical detection of biomolecules in a cellular environment by live imaging.
KW - Fluorescence
KW - Aggregation
KW - Signal enhancement
KW - Cluster
KW - Nano
KW - Metal
KW - NIRII
KW - SWIR
KW - Sensor
KW - Quantum yield
KW - Lifetime
KW - Photophysics
KW - Synthesis
KW - Protein
KW - Imaging
KW - Bioimaging
KW - Ligand
KW - Gold
PY - 2022
DO - https://doi.org/10.1002/chem.202200570
SN - 1521-3765
VL - 28
IS - 39
SP - 1
EP - 8
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-55077
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bandi, V.G.
A1 - Luciano, M.P.
A1 - Saccomano, M.
A1 - Patel, N.L.
A1 - Bischof, Th. S.
A1 - Lingg, J.G.P.
A1 - Tsrunchev, P.T.
A1 - Nix, M.N.
A1 - Ruehle, Bastian
A1 - Sanders, C.
A1 - Riffle, L.
A1 - Robinson, C.M.
A1 - Difilippantonio, S.
A1 - Kalen, J.D.
A1 - Resch-Genger, Ute
A1 - Ivanic, J.
A1 - Bruns, O.T.
A1 - Schnermann, M.
T1 - Targeted multicolor in vivo imaging over 1,000 nm enabled by nonamethine cyanines
N2 - Recent progress has shown that using wavelengths between 1,000 and 2,000 nm, referred to as the shortwave-infrared or near-infrared (NIR)-II range, can enable high-resolution in vivo imaging at depths not possible with conventional optical wavelengths.
However, few bioconjugatable probes of the type that have proven invaluable for multiplexed imaging in the visible and NIR range are available for imaging these wavelengths. Using rational design, we have generated persulfonated indocyanine dyes with absorbance maxima at 872 and 1,072 nm through catechol-ring and aryl-ring fusion, respectively, onto the nonamethine scaffold. Multiplexed two-color and three-color in vivo imaging using monoclonal antibody and dextran conjugates in several tumor models illustrate the benefits of concurrent labeling of the tumor and healthy surrounding tissue and lymphatics.
These efforts are enabled by complementary advances in a custom-built NIR/shortwave-infrared imaging setup and software package for multicolor real-time imaging.
KW - Photoluminescence
KW - Fluorescence
KW - Dye
KW - Cyanine
KW - Antibody
KW - Bioconjugate
KW - Conjugate
KW - Quantum yield
KW - Photophysics
KW - Lifetime
KW - Sensor
KW - NIR
KW - SWIR
KW - Mechanism
KW - Imaging
KW - Application
KW - Contrast agent
KW - Bioimaging
PY - 2021
DO - https://doi.org/10.1038/s41592-022-01394-6
VL - 19
IS - 3
SP - 353
EP - 358
PB - Nature Research
AN - OPUS4-54465
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 -
TY - JOUR
A1 - Ramirez, Alejandra
A1 - Pauli, Jutta
A1 - Crasselt, C.
A1 - Simon, S.
A1 - Schmidt, W.
A1 - Resch-Genger, Ute
T1 - The effect of a polycarboxylate ether on C3A / CaSO4.2H2O passivation monitored by optical spectroscopy
N2 - Polycarboxylate ethers (PCEs) are widely used in construction, but the exact nature of their interaction with cement is still debated. Aiming at a better understanding of the role of tricalcium Aluminate (C3A) in cement hydration, we assessed the potential of optical spectroscopy in combination with a water-soluble fluorescent organic reporter dye (S0586) to monitor the early hydration of C3A in the presence of 26 wt% CaSO4.2H2O (C3A26G-S) with and without PCE. As optical methods, steady-state fluorescence and diffuse reflectance (UV–VisDR) spectroscopy were employed. Phase characterization and particle size distribution were performed with in-situ X-ray diffraction (in-situ XRD) and dynamic light scattering (DLS). Our results show that fluorescence and UV–VisDR spectroscopy can be used to monitor the formation of metastable phases by the disaggregation of the dye S0586 in a cement paste as well as changes in ettringite formation. Addition of PCE slowed down the disaggregation of the dye as reflected by the corresponding changes of the dyes absorption and fluorescence. This prolonged induction period is a well-known side effect of PCEs and agrees with previous reported calorimetric studies and the Inhibition of gypsum dissolution observed by in-situ XRD. This demonstrates that fluorescence and UV–VisDR spectroscopy together with a suitable optical probe can provide deeper insights into the influence of PCE on C3A-gypsum hydration which could be e.g., utilized as screening method for comparing the influences
of different types of PCEs.
KW - Fluorescence
KW - Cement
KW - Nano
KW - Particle
KW - Optical spectroscopy
KW - PCE
KW - XRD
KW - Calorimetry
KW - Monitoring
KW - Diffuse
KW - Reflection
KW - Phase
KW - Dye
KW - Optical probe
KW - Cyanine
KW - Sensor
KW - Method
KW - Analysis
PY - 2020
DO - https://doi.org/10.1016/j.conbuildmat.2020.121856
VL - 270
SP - 121856
PB - Elsevier Ltd.
AN - OPUS4-52118
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -