TY - JOUR
A1 - Kang, Y.
A1 - Nack, L. M.
A1 - Liu, Y.
A1 - Qi, B.
A1 - Huang, Y.
A1 - Liu, Z.
A1 - Chakraborty, I.
A1 - Schulz, F.
A1 - Ahmed, A. A. A.
A1 - Poveda, M. C.
A1 - Hafizi, F.
A1 - Roy, S.
A1 - Mutas, M.
A1 - Holzapfel, M.
A1 - Sanchez-Cano, C.
A1 - Wegner, Karl David
A1 - Feliu, N.
A1 - Parak, W. J.
T1 - Quantitative considerations about the size dependence of cellular entry and excretion of colloidal nanoparticles for different cell types
N2 - Most studies about the interaction of nanoparticles (NPs) with cells have focused on how the physicochemical properties of NPs will influence their uptake by cells. However, much less is known about their potential excretion from cells. However, to control and manipulate the number of NPs in a cell, both cellular uptake and excretion must be studied quantitatively. Monitoring the intracellular and extracellular amount of NPs over time (after residual noninternalized NPs have been removed) enables one to disentangle the influences of cell proliferation and exocytosis, the major pathways for the reduction of NPs per cell. Proliferation depends on the type of cells, while exocytosis depends in addition on properties of the NPs, such as their size. Examples are given herein on the role of these two different processes for different cells and NPs.
KW - Cell proliferation
KW - Exocytosis
KW - Gold nanoparticles
KW - Quantum dots
KW - Fluorescence
KW - Uptake studies
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543476
DO - https://doi.org/10.1007/s40828-021-00159-6
SN - 2199-3793
VL - 8
IS - 1
SP - 1
EP - 8
PB - Springer
CY - Berlin
AN - OPUS4-54347
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chazeau, E.
A1 - Pipier, A.
A1 - Wegner, Karl David
A1 - Ghiringhelli, F.
A1 - Sancey, L.
A1 - Paul, C.
A1 - Goze, C.
T1 - NIR-II aza-BODIPY Platform for the Development of a Fluorescent Antibody Drug Conjugate
N2 - Real-time imaging of antibody-drug conjugates (ADCs) offers valuable insights for assessing tumor targeting specificity, monitoring therapeutic efficacy, and detecting off-target accumulation that may cause adverse effects. To enable precise tracking, we developed a versatile fluorescent platform based on an NIR-II emitting aza-BODIPY dye, which can be site-specifically grafted onto an IgG1 antibody to generate well-defined fluorescent ADCs. As a proof of concept, we synthesized an HER2-targeting trastuzumab immunoconjugate bearing a NIR-II aza-BODIPY fluorophore. The cytotoxic monomethyl auristatin E (MMAE) payload was introduced in the final step, resulting in a trackable and homogeneous ADC suitable for both in vitro and in vivo investigations. The resulting Trastu-azaNIRII-MMAE selectively accumulated in HER2-positive subcutaneous tumors, significantly reducing the tumor growth. Using NIR-II optical imaging, a single injection of the NIR-II-ADC allowed for the detection of the conjugate over a period of more than one month, highlighting its potential for long-term tracking and therapeutic applications.
KW - NIR-II
KW - Fluorescence
KW - Quality assurance
KW - Antibody drug conjugate
KW - In vivo imaging
PY - 2025
DO - https://doi.org/10.1021/acs.jmedchem.4c02777
VL - 68
IS - 7
SP - 7232
EP - 7242
PB - ACS Publications
AN - OPUS4-63025
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 - Valderrey, Virginia
A1 - Gawlitza, Kornelia
A1 - Rurack, Knut
T1 - Thiourea- and Amino-Substituted Benzoxadiazole Dyes with Large Stokes Shifts as Red-Emitting Probe Monomers for Imprinted Polymer Layers Targeting Carboxylate-Containing Antibiotics
N2 - Bifunctional fluorescent molecular oxoanion probes based on the benzoxadiazole (BD) chromophore are described which integrate a thiourea binding motif and a polymerizable 2-aminoethyl methacrylate unit in the 4,7-positions of the BD core. Concerted charge transfer in this electron donor-acceptor-donor architecture endows the dyes with strongly Stokes shifted (up to >250 nm) absorption and fluorescence. Binding of electron-rich carboxylate guests at the thiourea receptor leads to further analyte-induced red-shifts of the emission, shifting the fluorescence maximum of the complexes to ≥700 nm. Association constants for acetate are ranging from 1–5×105 M−1 in acetonitrile. Integration of one of the fluorescent probes through its polymerizable moiety into molecularly imprinted polymers (MIPs) grafted from the surface of submicron silica cores yielded fluorescent MIP-coated particle probes for the selective detection of antibiotics containing aliphatic carboxylate groups such as enoxacin (ENOX) at micromolar concentrations in highly polar solvents like acetonitrile.
KW - Molecular imprinting
KW - Anion recognition
KW - Antibiotics
KW - Benzoxadiazole dyes
KW - Charge transfer
KW - Fluorescence
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-545027
DO - https://doi.org/10.1002/chem.202104525
SN - 1521-3765
SP - 1
EP - 9
PB - Wiley-VCH
AN - OPUS4-54502
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 - Osiopova, Viktoriia
A1 - Tavernaro, Isabella
A1 - Ge, L.
A1 - Kitzmann, W. R.
A1 - Heinze, K.
A1 - Reithofer, M. R.
A1 - Resch-Genger, Ute
T1 - Complete protection of NIR-luminescent molecular rubies from oxygen quenching in air by L-arginine-mediated silica nanoparticles
N2 - The application of emerging luminophores such as near-infrared (NIR) emissive complexes based on earth-abundant chromium as central ion and triplet-triplet annihilation upconversion (TTA-UC) systems in air as optical reporters for bioimaging or photonic materials for energy conversion requires simple and efficient strategies for their complete protection from uminescence quenching by oxygen. Therefore, we explored the influence of sol–gel synthesis routes on the oxygen protection efficiency of the resulting core and core/shell silica nanoparticles (SiO2 NPs), utilizing the molecular ruby-type luminophores CrPF6 ([Cr(ddpd)2](PF6)3; ddpd = N,N'-dimethyl-N,N'-dipyridin-2-ylpyridin-2,6-diamine) and CrBF4 ([Cr(ddpd)2](BF4)3) with their oxygendependent, but polarity-, proticity-, viscosity-, and concentration-independent luminescence as optical probes for oxygen permeability. The sol–gel chemistry routes we assessed include the classical Stöber method and the underexplored Larginine approach, which relies on the controlled hydrolysis of tetraethoxysilane (TEOS) in a biphasic cyclohexane/water system with the catalyst L-arginine. As demonstrated by luminescence measurements of air- and argon-saturated dispersions of CrPF6- and CrBF4-stained SiO2 NPs of different size and particle architecture, utilizing the luminescence decay kinetics of argon-saturated solutions of CrPF6 and CrBF4 in acetonitrile (ACN) as benchmarks, only SiO2 NPs or shells synthesized by the L-arginine approach provided complete oxygen protection of the CrIII complexes under ambient conditions. We ascribe the different oxygen shielding efficiencies of the silica networks explored to differences in density and surface chemistry of the resulting nanomaterials and coatings, leading to different oxygen permeabilities. Our Larginine based silica encapsulation strategy can open the door for the efficient usage of oxygen-sensitive luminophores and TTA-UC systems as optical reporters and spectral shifters in air in the future.
KW - Quality assurance
KW - Fluorescence
KW - Quantification
KW - Advanced materials
KW - Nano
KW - Quantum yield
KW - NIR
KW - Characterization
KW - Electron microscopy
KW - Silica
KW - Synthesis
KW - Oxygen sensing
KW - Surface
KW - Doping
KW - Lifetime
KW - Cr(III) complex
KW - Shielding
KW - Sensing
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-638271
DO - https://doi.org/10.26599/NR.2025.94907241
SN - 1998-0000
VL - 18
IS - 3
SP - 1
EP - 13
PB - SciOpen
AN - OPUS4-63827
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wang, Z.
A1 - Wegner, Karl David
A1 - Stiegler, L. M. S.
A1 - Zhou, X.
A1 - Rezvani, A.
A1 - Odungat, A. S.
A1 - Zubiri, B. A.
A1 - Wu, M.
A1 - Spiecker, E.
A1 - Walter, J.
A1 - Resch-Genger, Ute
A1 - Segets, D.
T1 - Optimizing the Shelling Process of InP/ZnS Quantum Dots Using a Single-Source Shell Precursor: Implications for Lighting and Display Applications
N2 - InP/ZnS core/shell quantum dots (QDs), recognized as highly promising heavy-metal-free emitters, are increasingly being utilized in lighting and display applications. Their synthesis in a tubular flow reactor enables production in a highly efficient, scalable, and reproducible manner, particularly when combined with a single-source shell precursor, such as zinc diethyldithiocarbamate (Zn(S2CNEt2)2). However, the photoluminescence quantum yield (PLQY) of QDs synthesized with this route remains significantly lower compared with those synthesized in batch reactors involving multiple steps for the shell growth. Our study identifies the formation of absorbing, yet nonemissive ZnS nanoparticles during the ZnS shell formation process as a main contributing factor to this discrepancy. By varying the shelling conditions, especially the shelling reaction temperature and InP core concentration, we investigated the formation of pure ZnS nanoparticles and their impact on the optical properties, particularly PLQY, of the resultant InP/ZnS QDs through ultraviolet−visible (UV−vis) absorption, steady-state and time-resolved photoluminescence (PL) spectroscopy, scanning transmission electron microscopy (STEM), and analytical ultracentrifugation (AUC) measurements. Our results suggest that process conditions, such as lower shelling temperatures or reduced InP core concentrations (resulting in a lower external surface area), encourage homogeneous nucleation of ZnS. This reduces the availability of shell precursors necessary for effective passivation of the InP core surfaces, ultimately resulting in lower PLQYs. These findings explain the origin of persistently underperforming PLQY of InP/ZnS QDs synthesized from this synthesis route and suggest further optimization strategies to improve their emission for lighting and display applications.
KW - Nano
KW - Particle
KW - Synthesis
KW - InP
KW - Shell
KW - Fluorescence
KW - Quantum yield
KW - ZnS
KW - Semiconductor
KW - Quantum dot
KW - Flow reactor
KW - Method
KW - AUC
KW - Size
KW - Automation
KW - Sensor
PY - 2024
DO - https://doi.org/10.1021/acsanm.4c05265
SN - 2574-0970
VL - 7
IS - 20
SP - 24262
EP - 24273
PB - ACS Publications
AN - OPUS4-61518
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 - Sun, Yijuan
A1 - Gawlitza, Kornelia
A1 - Valderrey, Virginia
A1 - Bell, Jérémy
A1 - Rurack, Knut
T1 - Polymerizable BODIPY probe crosslinker for the molecularly imprinted polymer-based detection of organic carboxylates via fluorescence
N2 - This contribution reports the development of a polymerizable BODIPY-type fluorescent probe targeting small-molecule carboxylates for incorporation into molecularly imprinted polymers (MIPs). The design of the probe crosslinker includes a urea recognition site p-conjugated to the 3-position of the BODIPY core and two methacrylate moieties. Titration experiments with a carboxylate-expressing antibiotic, levofloxacin (LEVO), showed a blue shift of the absorption band as well as a broadening and decrease in emission, attributed to hydrogen bonding between the probe’s urea group and the carboxylate group of the antibiotic. Using this probe crosslinker, core–shell particles with a silica core and a thin MIP shell were prepared for the detection of LEVO. The MIP exhibited highly selective recognition of LEVO, with an imprinting factor of 18.1 compared to the non-imprinted polymer. Transmission electron microscopy confirmed the core–shell structure and spectroscopic studies revealed that the receptor’s positioning leads to a unique perturbation of the polymethinic character of the BODIPY chromophore, entailing the favourable responses. These features are fully preserved in the MIP, whereas no such response was observed for competitors such as ampicillin. The sensory particles allowed to detect LEVO down to submicromolar concentrations in dioxane. We have developed here for the first time a BODIPY probe for organic carboxylates and incorporated it into polymers using the imprinting technique, paving the way for BODIPY-type fluorescent MIP sensors.
KW - Fluorescence
KW - BODIPY probe
KW - Molecularly Imprinted Polymers
KW - Sensor Materials
KW - Dyes
KW - Water analysis
KW - Advanced materials
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-598629
DO - https://doi.org/10.1039/D3MA00476G
SP - 1
EP - 11
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-59862
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yanbaeva, M.
A1 - Soyka, J.
A1 - Holthoff, J. M.
A1 - Rietsch, P.
A1 - Engelage, E.
A1 - Ruff, A.
A1 - Resch-Genger, Ute
A1 - Weiss, R.
A1 - Eigler, S.
A1 - Huber, S. M.
T1 - Dimethylene-Cyclopropanide Units as Building Blocks for Fluorescence Dyes
N2 - Many organic dyes are fluorescent in solution. In the solid state, however, quenching processes often dominate, hampering material science applications such as light filters, light-emitting devices, or coding tags. We show that the dimethylene-cyclopropanides caffold can be used to form two structurally different types of chromophores, which feature fluorescence quantum yields up to 0.66 in dimethyl sulfoxide and 0.53 in
solids. The increased fluorescence in the solid state for compounds bearing malonate substituents instead of dicyanomethide ones is rationalized by the induced twist between the planes of the cyclopropanide core and a pyridine ligand.
KW - Fluorescence
KW - Dye
KW - Sensor
KW - Quantum yield
KW - Spectroscopy
KW - Photophysics
KW - Synthesis
KW - Solvatochromism
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-614931
DO - https://doi.org/10.1002/chem.202402476
VL - 30
IS - 56
SP - 1
EP - 7
PB - Chemistry - A European Journal
AN - OPUS4-61493
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kromer, C.
A1 - Schwibbert, Karin
A1 - Gadicherla, A. K.
A1 - Thiele, Dorothea
A1 - Nirmalananthan-Budau, Nithiya
A1 - Laux, P.
A1 - Resch-Genger, Ute
A1 - Luch, A.
A1 - Tschiche, H. R.
T1 - Monitoring and imaging pH in biofilms utilizing a fluorescent polymeric nanosensor
N2 - Biofilms are ubiquitous in nature and in the man-made environment. Given their harmful effects on human health, an in-depth understanding of biofilms and the monitoring of their formation and growth are important. Particularly relevant for many metabolic processes and survival strategies of biofilms is their extracellular pH. However, most conventional techniques are not suited for minimally invasive pH measurements of living biofilms. Here, a fluorescent nanosensor is presented for ratiometric measurements of pH in biofilms in the range of pH 4.5–9.5 using confocal laser scanning microscopy. The nanosensor consists of biocompatible polystyrene nanoparticles loaded with pH-inert dye Nile Red and is surface functionalized with a pH-responsive fluorescein dye. Its performance was validated by fluorometrically monitoring the time-dependent changes in pH in E. coli biofilms after glucose inoculation at 37 °C and 4 °C. This revealed a temperature-dependent decrease in pH over a 4-h period caused by the acidifying glucose metabolism of E. coli. These studies demonstrate the applicability of this nanosensor to characterize the chemical microenvironment in biofilms with fluorescence methods.
KW - Dye
KW - Fluorescence
KW - Signal enhancement
KW - Sensor
KW - Quantum yield
KW - Synthesis
KW - Nanoparticle
KW - Nano
KW - Polymer
KW - Ph
KW - Biofilm
KW - MIC
KW - Corrosion
KW - Microorganism
KW - Bacteria
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-550751
DO - https://doi.org/10.1038/s41598-022-13518-1
SN - 2045-2322
VL - 12
IS - 1
SP - 1
EP - 10
PB - Nature Publishing Group
CY - London
AN - OPUS4-55075
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Reiber, T.
A1 - Hübner, Oskar
A1 - Dose, C.
A1 - Yushchenko, D. A.
A1 - Resch-Genger, Ute
T1 - Fluorophore multimerization on a PEG backbone as a concept for signal amplification and lifetime modulation
N2 - Fluorescent labels have strongly contributed to many advancements in bioanalysis, molecular biology, molecular imaging, and medical diagnostics. Despite a large toolbox of molecular and nanoscale fluorophores to choose from, there is still a need for brighter labels, e.g., for flow cytometry and fluorescence microscopy, that are preferably of molecular nature. This requires versatile concepts for fluorophore multimerization, which involves the shielding of dyes from other chromophores and possible quenchers in their neighborhood. In addition, to increase the number of readout parameters for fluorescence microscopy and eventually also flow cytometry, control and tuning of the labels’ fluorescence lifetimes is desired. Searching for bright multi-chromophoric or multimeric labels, we developed PEGylated dyes bearing functional groups for their bioconjugation and explored their spectroscopic properties and photostability in comparison to those of the respective monomeric dyes for two exemplarily chosen fluorophores excitable at 488 nm. Subsequently, these dyes were conjugated with anti-CD4 and anti-CD8 immunoglobulins to obtain fluorescent conjugates suitable for the labeling of cells and beads. Finally, the suitability of these novel labels for fluorescence lifetime imaging and target discrimination based upon lifetime measurements was assessed. Based upon the results of our spectroscopic studies including measurements of fluorescence quantum yields (QY) and fluorescence decay kinetics we could demonstrate the absence of significant dye-dye interactions and self-quenching in these multimeric labels. Moreover, in a first fluorescence lifetime imaging (FLIM) study, we could show the future potential of this multimerization concept for lifetime discrimination and multiplexing.
KW - Imaging
KW - Quantum yield
KW - Quality assurance
KW - Antibody
KW - Conjugate
KW - Cell
KW - FLIM
KW - PEG
KW - Flow cytometry
KW - Lifetime
KW - Energy transfer
KW - Quantitative spectroscopy
KW - Nano
KW - Particle
KW - Fluorescence
KW - Dye
KW - Amplification
KW - Microscopy
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-602197
DO - https://doi.org/10.1038/s41598-024-62548-4
SN - 2045-2322
VL - 14
IS - 1
SP - 1
EP - 11
AN - OPUS4-60219
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Richter, Maria
A1 - Güttler, Arne
A1 - Pauli, Jutta
A1 - Vogel, K.
A1 - Homann, Christian
A1 - Würth, Christian
A1 - Resch-Genger, Ute
T1 - Extending certified spectral fluorescence standards for the calibration and performance validation of fluorescence instruments to the NIR—closing the gap from 750 to 940 nm with two novel NIR dyes
N2 - Fluorescence techniques such as fluorescence spectroscopy, microfluorometry, and fluorescence microscopy, providing spectral, intensity, polarization, and lifetime information, are amongst the most broadly utilized analytical methods in the life and materials sciences. However, the measured fluorescence data contain sample- and instrument-specific contributions, which hamper their comparability across instruments and laboratories. Comparable, instrument-independent fluorescence data require the determination of the fluorescence instrument’s wavelength-dependent spectral responsivity, also termed emission correction curve, for the same instrument settings as those used for the fluorescence measurements as a prerequisite for the subsequent correction of the measured instrument-specific data. Such a spectral correction is essential for the performance comparison of different fluorescent labels and reporters, quantitative fluorescence measurements, the determination of the fluorescence quantum yield, and the spectroscopic measure for the fluorescence efficiency of a fluorophore. Simple-to-use tools for obtaining emission correction curves are chromophore-based reference materials (RMs), referred to as fluorescence standards, with precisely known, preferably certified instrument-independent fluorescence spectra. However, for the increasingly used near-infrared (NIR) wavelength region >700 nm, at present, no spectral fluorescence standards are available. To close this gap, we developed two novel spectral fluorescence standards, BAM F007 and BAM-F009, with broad emission bands from about 580 to 940 nm in ethanolic solution. These liquid fluorescence standards currently under certification, which will be released in 2025, will expand the wavelength range of the already available certified Calibration Kit BAM F001b-F005b from about 300–730 to 940 nm. In this research article, we will detail the criteria utilized for dye and matrix selection and the homogeneity and stability tests accompanying dye certification as well as the calculation of the wavelength-dependent uncertainty budgets of the emission spectra BAM F007 and BAM-F009, determined with the traceably calibrated BAM reference spectrofluorometer. These fluorescence standards can provide the basis for comparable fluorescence measurements in the ultraviolet, visible, and NIR for the fluorescence community.
KW - Quality assurance
KW - Reference material
KW - Fluorescence
KW - Dye
KW - Traceability
KW - Metrology
KW - Calibration
KW - Reference data
KW - Reference product
KW - Digital certificate
KW - NIR
KW - Instrument performance validation
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-626317
DO - https://doi.org/10.1007/s00216-024-05723-w
SN - 1618-2650
SP - 1
EP - 15
PB - Springer
AN - OPUS4-62631
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Frenzel, F.
A1 - Fiedler, S.
A1 - Bardan, A.
A1 - Güttler, Arne
A1 - Würth, Christian
A1 - Resch-Genger, Ute
T1 - Influence of Measurement Geometry and Blank on Absolute Measurements of Photoluminescence Quantum Yields of Scattering Luminescent Films
N2 - For a series of 500 μm-thick polyurethane films containing different concentrations of luminescent and scattering YAG:Ce microparticles, we systematically explored and quantified pitfalls of absolute measurements of photoluminescence quantum yields (Φf) for often employed integrating sphere (IS) geometries, where the sample is placed either on a sample holder at the bottom of the IS surface or mounted in the IS center. Thereby, the influence of detection and illumination geometry and sample position was examined using blanks with various scattering properties for measuring the number of photons absorbed by the sample. Our results reveal that (i) setup configurations where the scattering sample is mounted in the IS center and (ii) transparent blanks can introduce systematic errors in absolute Φf measurements.
For strongly scattering, luminescent samples, this can result in either an under- or overestimation of the absorbed photon flux and hence an under- or overestimation of Φf. The size of these uncertainties depends on the scattering properties of the sample and instrument parameters, such as sample position, IS size, wavelength-dependent reflectivity of the IS surface coating, and port configuration. For accurate and reliable absolute Φf measurements, we recommend (i) a blank with scattering properties closely matching those of the sample to realize similar distributions of the diffusely scattered excitation photons within the IS, and (ii) a sufficiently high sample absorption at the excitation wavelength. For IS setups with center-mounted samples, measurement geometries should be utilized that prevent the loss of excitation photons by reflections from the sample out of the IS.
KW - Quality assurance
KW - Fluorescence
KW - Nano
KW - Particle
KW - Quantum yield
KW - Characterization
KW - Silica
KW - Scattering
KW - Uncertainty
KW - Film
KW - Pphosphor
KW - YAG:Ce
KW - LED
KW - Converter material
KW - Solid material
KW - Polymer
KW - Composite material
KW - Advanced material
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-638304
DO - https://doi.org/10.1021/acs.analchem.4c06726
SN - 1520-6882
SP - 1
EP - 8
PB - ACS Publications
AN - OPUS4-63830
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Resch-Genger, Ute
A1 - Richter, Maria
A1 - Güttler, Arne
A1 - Pauli, Jutta
A1 - Vogel, K.
A1 - Homann, Christian
A1 - Würth, Christian
T1 - Extending Certified Spectral Fluorescence Standards for the Calibration and Performance Validation of Fluorescence Instruments to the NIR – Closing the Gap from 750 nm to 940 nm with Two Novel NIR Dyes
N2 - Fluorescence methods provide spectral, intensity, polarization, and lifetime information, which contain sample- and instrument-specific contributions. Fluorescence data, comparable across instruments and laboratories, require validated calibration procedures and certified fluorescence standards.
KW - Quality assurance
KW - Reference material
KW - Fluorescence
KW - Dye
KW - Traceability
KW - Metrology
KW - Calibration
KW - Reference data
KW - Reference product
KW - Digital certificate
KW - NIR
KW - Instrument performance validation
PY - 2025
SP - 1
EP - 4
PB - Springer Nature
CY - London
AN - OPUS4-62739
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 - CONF
A1 - Biyikal, Mustafa
T1 - Development of a handheld device for the trace detection of explosives
N2 - This presentation introduces a new explosives trace detector (ETD), a handheld device developed by True Detection Systems (TDS). Addressing the limitations of current handheld detectors—such as unreliable measurements and cumbersome operation— the new ETD XT-1 integrates advanced sensor technology, including a Lab-on-a-Chip, to deliver high sensitivity and accuracy. Capable of detecting trace levels of substances like TNT, TATP, and ammonium nitrate, the device offers rapid, user-friendly detection through AI/ML-enhanced algorithms. These algorithms enable precise substance identification by analyzing absorption and desorption rates, significantly reducing false positives. The XT-1 has broad applications in security, hazardous material detection, and environmental monitoring.
T2 - Photonics Days Berlin Brandenburg
CY - Berlin, Germany
DA - 09.10.2024
KW - Explosives
KW - Trace detection
KW - Handheld device
KW - Lab-on-a-chip
KW - Fluorescence
PY - 2024
AN - OPUS4-61433
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 - Billimoria, K.
A1 - Diaz Fernandez, Y. A.
A1 - Andresen, Elina
A1 - Sorzabal-Bellido, I.
A1 - Huelga-Suarez, G.
A1 - Bartczak, D.
A1 - Ortiz de Solórzano, C.
A1 - Resch-Genger, Ute
A1 - Goenaga Infante, H.
T1 - The potential of bioprinting for preparation of nanoparticle-based calibration standards for LA-ICP-ToF-MS quantitative imaging
N2 - This paper discusses the feasibility of a novel strategy based on the combination of bioprinting nano-doping technology and laser ablation-inductively coupled plasma time-of-flight mass spectrometry analysis for the preparation and characterization of gelatin- based multi-element calibration standards suitable for quantitative imaging. To achieve this, lanthanide up-conversion nanoparticles were added to a gelatin matrix to produce the bioprinted calibration standards. The features of this bioprinting approach were com- pared with manual cryosectioning standard preparation, in terms of throughput, between batch repeatability and elemental signal homogeneity at 5 μm spatial resolution. By using bioprinting, the between batch variability for three independent standards of the same concentration of 89 Y (range 0–600 mg/kg) was reduced to 5% compared to up to 27% for cryosectioning. On this basis, the relative standard deviation ( RSD ) obtained between three independent calibration slopes measured within 1 day also reduced from 16% (using cryosectioning ) to 5% (using bioprinting), supporting the use of a single standard preparation replicate for each of the concentrations to achieve good calibration performance using bioprinting. This helped reduce the analysis time by approximately 3-fold. With cryosectioning each standard was prepared and sectioned individually, whereas using bio-printing it was possible to have up to six different standards printed simultaneously, reducing the preparation time from approximately 2 h to under 20 min (by approxi- mately 6-fold). The bio-printed calibration standards were found stable for a period of 2 months when stored at ambient temperature and in the dark.
KW - Environmental analysis
KW - LA-ICP-MS
KW - Lanthanide
KW - Tag
KW - Fluorescence
KW - Nanoparticles
KW - Reference material
KW - Quality assurance
KW - 3D-printing
KW - Synthesis
KW - Production
KW - Multimodal
PY - 2022
DO - https://doi.org/10.1093/mtomcs/mfac088
SN - 1756-591X
VL - 14
IS - 12
SP - 1
EP - 9
PB - Oxford University Press
CY - Oxford
AN - OPUS4-57018
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wegner, Karl David
T1 - Luminescent Quantum dots – the next-generation nano light bulbs
N2 - Fluorescent semiconductor nanocrystals, also known as quantum dots (QDs), enabled many advancements in biotechnology, photovoltaics, photocatalysis, quantum computing and display devices. The high versatility of this nanomaterial is based on their unique size-tunable photoluminescence properties, which can be adjusted from the visible to the near-infrared range. In contrast to other nanomaterials, QDs made the transition from a laboratory curiosity to the utilization in commercial products, like the QLED television screen or in smartphone displays. The best investigated QDs are composed of heavy metals like cadmium or lead, which is not the best choice in terms of toxicity and environmental pollution. A more promising material is Indium Phosphide (InP), which is also currently used by Samsung, Sony and co. in the QLED displays.
In this contribution, I would like to give you a sneak peek behind the curtains of nanomaterial synthesis and show how this material is produced, how to stabilize their structural properties, and assess their toxicity in environmentally relevant conditions. Furthermore, I would like to present a synthesis method to accomplish the last open challenge in display technology of a blue luminescent LED based on QDs by introducing a new element to the InP QDs.
T2 - The Berlin Postdoc Day
CY - Berlin, Germany
DA - 03.11.2022
KW - InP
KW - Quantum dots
KW - Fluorescence
KW - Aging
KW - Doping
KW - Nanomaterial
KW - Cytotoxicity
PY - 2022
AN - OPUS4-56194
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Scholtz, Lena
A1 - Resch-Genger, Ute
T1 - Behind the Paper - Dual color pH probes made from silica and polystyrene nanoparticles and their performance in cell studies
N2 - In this contribution we highlight the importance of comparison for scientific research while developing a new, functional pH sensor system, and the valuable insights this can provide.
KW - Dye
KW - Optical Spectroscopy
KW - pH probe
KW - Silica and Polystyrene Particles
KW - Nano
KW - Surface groups
KW - Safe-by-Design
KW - Cell studies
KW - Sensors
KW - Particle Synthesis
KW - Fluorescence
PY - 2023
UR - https://communities.springernature.com/posts/dual-color-ph-probes-made-from-silica-and-polystyrene-nanoparticles-and-their-performance-in-cell-studies
SP - 1
EP - 2
PB - Springer Nature
CY - London
AN - OPUS4-59150
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wen, Keqing
A1 - Gorbushina, Anna
A1 - Schwibbert, Karin
A1 - Bell, Jérémy
T1 - Microfluidic platform with precisely controlled hydrodynamic parameters and integrated features for generation of microvortices to accurately form and monitor biofilms in flow
N2 - Microorganisms often live in habitats characterized by fluid flow, and their adhesion to surfaces in industrial systems or clinical settings may lead to pipe clogging, microbially influenced corrosion, material deterioration, food spoilage, infections, and human illness. Here, a novel microfluidic platform was developed to investigate biofilm formation under precisely controlled (i) cell concentration, (ii) temperature, and (iii) flow conditions. The developed platform central unit is a single-channel microfluidic flow cell designed to ensure ultrahomogeneous flow and condition in its central area, where features, e.g., with trapping properties, can be incorporated. In comparison to static and macroflow chamber assays for biofilm studies, microfluidic chips allow in situ monitoring of biofilm formation under various flow regimes and have better environment control and smaller sample requirements. Flow simulations and experiments with fluorescent particles were used to simulate bacteria flow in the platform cell for calculating flow velocity and direction at the microscale level. The combination of flow analysis and fluorescent strain injection in the cell showed that microtraps placed at the center of the channel were efficient in capturing bacteria at determined positions and to study how flow conditions, especially microvortices, can affect biofilm formation. The microfluidic platform exhibited improved performances in terms of homogeneity and robustness for in vitro biofilm formation. We anticipate the presented platform to be suitable for broad, versatile, and high-throughput biofilm studies at the microscale level.
KW - Topographical pattern
KW - E. coli
KW - Fluorescence
KW - Bacteria trapping
KW - Particle velocimetry
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-610450
DO - https://doi.org/10.1021/acsbiomaterials.4c00101
SN - 2373-9878
VL - 10
IS - 7
SP - 4626
EP - 4634
PB - ACS Publ.
CY - Washington, DC
AN - OPUS4-61045
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 - Oskoei, Párástu
A1 - Afonso, Rúben
A1 - Bastos, Verónica
A1 - Nogueira, João
A1 - Keller, Lisa-Marie
A1 - Andresen, Elina
A1 - Saleh, Maysoon I.
A1 - Rühle, Bastian
A1 - Resch-Genger, Ute
A1 - Daniel-da-Silva, Ana L.
A1 - Oliveira, Helena
T1 - Upconversion Nanoparticles with Mesoporous Silica Coatings for Doxorubicin Targeted Delivery to Melanoma Cells
N2 - Melanoma is one of the most aggressive skin cancers and requires innovative therapeutic strategies to overcome the limitations of conventional therapies. In this work, upconversion nanoparticles coated with mesoporous silica and functionalized with folic acid (UCNP@mSiO2-FA) were developed as a targeted nanocarrier system for the delivery of doxorubicin (DOX). The UCNPs were synthesized via thermal decomposition, coated with mesoporous silica shells, and functionalized with folic acid (FA) to enable receptor-mediated targeting. DOX was then loaded into the mesoporous silica coating by adsorption, yielding UCNP@mSiO2-FA-DOX. The different UCNPs were characterized for size, composition, colloidal stability, and loading and release of DOX. This comprehensive physicochemical characterization confirmed a high DOX loading efficiency and a slightly increased drug release under acidic conditions, mimicking the tumour microenvironment. In vitro assays using four melanoma cell lines (A375, B16-F10, MNT-1, and SK-MEL-28) revealed an excellent biocompatibility of UCNP@mSiO2-FA and a significantly higher cytotoxicity of UCNP@mSiO2-FA-DOX compared to unloaded UCNPs, in a dose-dependent manner. Cell cycle analysis demonstrated G2/M phase arrest after treatment with UCNP@mSiO2-FA-DOX, confirming its antiproliferative effect. Overall, UCNP@mSiO2-FA-DOX represents a promising nanoplatform for targeted melanoma therapy, combining active tumour targeting and enhanced anticancer efficacy.
KW - Fluorescence
KW - Synthesis
KW - Nano
KW - Particle
KW - Silica
KW - Cell
KW - Uptake
KW - Drug
KW - Characterization
KW - DOX
KW - Imaging
KW - Toxicity
KW - Release
KW - pH
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-653596
DO - https://doi.org/10.3390/molecules31010074
SN - 1420-3049
VL - 31
IS - 1
SP - 1
EP - 18
PB - MDPI AG
AN - OPUS4-65359
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wen, Keqing
A1 - Gorbushina, Anna
A1 - Schwibbert, Karin
A1 - Bell, Jérémy
T1 - A microfluidic platform for monitoring biofilm formation in flow under defined hydrodynamic conditions
N2 - Bacterial adhesion on surfaces of medical, water and food applications may lead to infections, water or food spoilage and human illness. In comparison to traditional static and macro flow chamber assays for biofilm formation studies, microfluidic chips allow in situ monitoring of biofilm formation under various flow regimes, have better environment control and smaller sample requirements.
In this work, a novel microfluidic platform is developed to investigate biofilm adhesion under precisely controlled bacteria concentration, temperature, and flow conditions. This platform central unit is a single-inlet microfluidic flow cell with a 5 mm wide chamber designed and tested to achieve ultra-homogenous flow in the central area of chamber. Within this area, defined microstructures are integrated that will disturb the homogeneity of the flow, thus changing bacterial adhesion pattern.
Here we present the monitoring of bacterial biofilm formation in a microfluidic chip equipped with a microstructure known as micro-trap. This feature is based on a 3D bacteria trap designed by Di Giacomo et al. and successfully used to sequester motile bacteria.
At first, fluorescent particles similar in size to Escherichia coli (E. coli) are used to simulate bacteria flow inside the flow cell and at the micro-trap. The turbulences induced by the trap are analyzed by imaging and particle tracking velocimetry (PTV). Secondly, the model strain E. coli TG1, ideal and well described for biofilm studies, is used to analyze biofilm formation in the micro-trap. Therefore, a stable fluorescent strain E. coli TG1-MRE-Tn7-141 is constructed by using Tn7 transposon mutagenesis according to the method described by Schlechter et al. Sequestering of E. coli cells within the micro-trap was followed using epifluorescence microscopy.
The novel microfluidic platform shows great potential for assessment of bacterial adhesion under various flow regimes. The performance of structural feature with respect to the generation of turbulences that promote or reduce bacterial adhesion can be systematically examined.
The combination of flow analysis and fluorescent strain injection into the microfluidic chip shows that the micro-trap is useful for capturing bacteria at defined positions and to study how flow conditions, especially micro-turbulences, can affect biofilm formation. It represents a powerful and versatile tool for studying the relation between topography and bacteria adhesion.
T2 - International Conference on Miniaturized Systems for Chemistry and Life Sciences
CY - Katowice, Poland
DA - 15.10.2023
KW - Biofilm
KW - E. coli
KW - Microfluidics
KW - Velocimetry
KW - Fluorescence
PY - 2023
AN - OPUS4-59593
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Prakash, Swayam
A1 - Mishra, Ashok Kumar
T1 - Facile Fluorometric Detection of Faecal Pigments: Challenges and Solutions Concerning Water Quality Testing
N2 - AbstractDetection and monitoring of faecal contaminants in water is an important component of water quality testing protocol worldwide. However, a systematic overview of the faecal indicator paradigm, including its fundamentals and challenges in analytical applications, is missing. In particular, with respect to the advantages of using faecal indication pigments (FIP) over faecal indication bacteria (FIB). This discussion is based on two FIPs, Urobilin (UB) and Stercobilin (SB), which can enable rapid and real‐time indication of faecal contaminants in ground/surface water. Novel strategies for enhancing sensitive fluorescence‐based techniques for trace concentration detection have been discussed in detail, with specific reference to understanding their physicochemical properties, photophysics, metal‐ligand complexation, molecular aggregations, thermodynamics, fluorescence response and matrix interferences in aqueous media or environmental samples. The insights provided in this perspective article could inspire procedures by avoiding ambiguities and misinterpretations.
KW - Faecal contamination
KW - Fluorescence
KW - Metal complexes
KW - Water analysis
KW - Optical and chemical sensing
KW - Spectroscopy
PY - 2025
DO - https://doi.org/10.1002/asia.202401750
SN - 1861-471X
SP - 1
EP - 8
PB - Wiley VHC-Verlag
AN - OPUS4-63082
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rurack, Knut
T1 - Advanced Onsite Analysis for Point-of-Need Applications: Innovations for Robust, Reliable, and User-Friendly Detection
N2 - The advancement of portable analytical assays has transformed onsite analysis in several areas, including food safety, environmental monitoring and forensics. The SARS-CoV-2 pandemic has fueled a need for rapid, onsite solutions that enable immediate decision making without the need for and use of laboratory infrastructure. The integration of mobile devices with advanced cameras and significant computing power improves the accessibility and usability of these tests. However, many current methods are limited to the detection of single parameters. The next challenge is to develop robust multiplexed assays that can analyze multiple parameters simultaneously with high sensitivity. In this lecture, innovative approaches developed at BAM will be presented with a focus on supramolecular chemistry, luminescence detection, nanomaterials and miniaturization of devices. Examples will include mesoporous nanomaterials, gated indicator systems, imprinted polymers, microfluidic devices, test strips and smartphone-based analytical tools, focusing on two use cases, i.e., the detection of contaminants in surface waters and immunoanalytical explosives detection.
T2 - International Conference on Emergin Trends in Materials Chemistry
CY - Coimbatore, India
DA - 03.04.2025
KW - Onsite analysis
KW - Rapid tests
KW - Mobile devices
KW - Supramolecular chemistry
KW - Fluorescence
PY - 2025
AN - OPUS4-65434
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 - 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 - Kossatz, Philipp
A1 - Mezhov, Alexander
A1 - Andresen, Elina
A1 - Prinz, Carsten
A1 - Schmidt, Wolfram
A1 - Resch-Genger, Ute
T1 - Assessing the Applicability of Lanthanide-Based Upconverting Nanoparticles for Optically Monitoring Cement Hydration and Tagging Building Materials
N2 - Chemically stable, lanthanide-based photon upconversion micro- and nanoparticles (UCNPs) with their characteristic multicolor emission bands in the ultraviolet (UV), visible (vis), near-infrared (NIR), and short-wave infrared (SWIR) arepromising optical reporters and barcoding tags. To assess the applicability of UCNPs for the monitoring of early stage cement hydration processes and as authentication tags for cementitious materials, we screened the evolution of the luminescence of Selfmade core-only NaYF4:Yb,Er UCNPs and commercial μm-sized Y2O2S:Yb,Er particles during the first stages of cement hydration, which largely determines the future properties of the hardened material. Parameters explored from the UCNP side included particle size, morphology, surface chemistry or coating, luminescence properties, and concentration in different cement mixtures. From the cement side, the influence of the mineral composition of the cement matrix was representatively examined for ordinary Portland cement (OPC) and its constituents tricalcium aluminate (C3A), tricalcium silicate (C3S), and gypsum at different water to cement ratios. Based on reflection and luminescence measurements, enabling online monitoring, which were complemented by XRD and isothermal heat-flow calorimetric measurements to determine whether the incorporation of these particles could impair cement hydration processes, well suited lanthanide particle reporters could be identified as well as application conditions. In addition, thereby the reporter influence on cement hydration kinetics could be minimized while still preserving a high level of information content. The best performance for the luminescence probing of changes during early stage cement hydration processes was observed for 25 nm-sized oleate (OA)-coated UCNPs added in a concentration of 0.1 wt %. Higher UCNP amounts of 1.0 wt % delayed cement hydration processes size- and surface coatingspecifically in the first 24 h. Subsequent luminescence stability screening studies performed over a period of about one year support the applicability of UCNPs as optical authentication tags for construction materials.
KW - Quality assurance
KW - Fluorescence
KW - Nano
KW - Particle
KW - Synthesis
KW - Quantum yield
KW - NIR
KW - Mechanism
KW - Characterization
KW - XRD
KW - Calorimetry
KW - Advanced material
KW - Cement
KW - Monitoring
KW - Surface
KW - Size
KW - Lifetime
KW - Barcode
KW - Lanthanide
KW - Upconversion
KW - Encoding
KW - Method
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-638318
DO - https://doi.org/10.1021/acsomega.5c02236
SN - 2470-1343
VL - 10
IS - 29
SP - 31587
EP - 31599
PB - ACS Publications
CY - Washington, DC
AN - OPUS4-63831
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tavernaro, Isabella
A1 - Rajotte, Isabelle
A1 - Thibeault, Marie-Pier
A1 - Sander, Philipp C.
A1 - Kodra, Oltion
A1 - Lopinski, Gregory
A1 - Radnik, Jörg
A1 - Johnston, Linda J.
A1 - Brinkmann, Andreas
A1 - Resch-Genger, Ute
T1 - Quantifying surface groups on aminated silica nanoparticles of different size, surface chemistry, and porosity with solution NMR, XPS, optical assays, and potentiometric titration
N2 - We assessed the quantification of surface amino functional groups (FGs) for a large set of commercial and custom-made aminated silica nanoparticles (SiO2 NPs) with sizes of 20–100 nm, prepared with different sol–gel routes, different amounts of surface amino FGs, and different porosity with four methods providing different, yet connected measurands in a bilateral study of two laboratories, BAM and NRC, with the overall aim to develop standardizable measurements for surface FG quantification. Special emphasis was dedicated to traceable quantitative magnetic resonance spectroscopy (qNMR) performed with dissolved SiO2 NPs. For the cost efficient and automatable screening of the amount of surface amino FGs done in a first step of this study, the optical fluorescamine assay and a potentiometric titration method were utilized by one partner, i.e., BAM, yielding the amount of primary amino FGs accessible for the reaction with a dye precursor and the total amount of (de)protonatable FGs. These measurements, which give estimates of the minimum and maximum number of surface amino FGs, laid the basis for quantifying the amount of amino silane molecules with chemo-selective qNMR with stepwise fine-tuned workflows, involving centrifugation, drying, weighting, dissolution, measurement, and data evaluation steps jointly performed by BAM and NRC. Data comparability and relative standard deviations (RSDs) obtained by both labs were used as quality measures for method optimization and as prerequisites to identify method-inherent limitations to be later considered for standardized measurement protocols. Additionally, the nitrogen (N) to silicon (Si) ratio in the near-surface region of the SiO2 NPs was determined by both labs using X-ray photoelectron spectroscopy (XPS), a well established surface sensitive analytical method increasingly utilized for microparticles and nano-objects which is currently also in the focus of international standardization activities. Overall, our results underline the importance of multi-method characterization studies for quantifying FGs on NMs involving at least two expert laboratories for effectively identifying sources of uncertainty, validating analytical methods, and deriving NM structure–property relationships.
KW - Advanced Materials
KW - Amino Groups
KW - Calibration
KW - Characterization
KW - Functional groups
KW - Method Comparison
KW - Nano Particle
KW - Validation
KW - XPS
KW - Optical Assay
KW - Quantification
KW - Surface Analysis
KW - Reference Materials
KW - Synthesis
KW - Fluorescence
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-649992
DO - https://doi.org/10.1039/d5na00794a
VL - 7
IS - 21
SP - 6888
EP - 6900
PB - Royal Society of Chemistry
AN - OPUS4-64999
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
ED - Resch-Genger, Ute
ED - Koch, Matthias
ED - Meermann, Björn
ED - Weller, Michael G.
T1 - Topical collection: Analytical methods and applications in the materials and life sciences
N2 - Current trends in materials and life sciences are flanked by the need to push detection limits to single molecules or single cells, enable the characterization of increasingly complex matrices or sophisticated nanostructures, speed up the time of analysis, reduce instrument complexity and costs, and improve the reliability of data. This requires suitable analytical tools such as spectroscopic, separation and imaging techniques, mass spectrometry, and hyphenated techniques as well as sensors and their adaptation to application-specific challenges in the environmental, food, consumer product, health sector, nanotechnology, and bioanalysis. Increasing concerns about health threatening known or emerging pollutants in drinking water, consumer products, and food and about the safety of nanomaterials led to a new awareness of the importance of analytical sciences. Another important driver in this direction is the increasing demand by legislation, particularly in view of the 17 sustainable development goals by the United Nations addressing clean energy, industry, and innovation, sustainable cities, clean water, and responsible consumption and production. In this respect, also the development of analytical methods that enable the characterization of material flows in production processes and support recycling concepts of precious raw materials becomes more and more relevant. In the future, this will provide the basis for greener production in the chemical industry utilizing recycled or sustainable starting materials.
This makes analytical chemistry an essential player in terms of the circular economy helping to increase the sustainability of production processes. In the life sciences sector, products based on proteins, such as therapeutic and diagnostic antibodies, increase in importance. These increasingly biotechnologically produced functional biomolecules pose a high level of complexity of matrix and structural features that can be met only by highly advanced methods for separation, characterization, and detection. In addition, metrological traceability and target definition are still significant challenges for the future, particularly in the life sciences.
However, innovative reference materials as required for the health and food sector and the characterization of advanced materials can only be developed when suitable analytical protocols are available. The so-called reproducibility crisis in sciences underlines the importance of improved measures of quality control for all kinds of measurements and material characterization. This calls for thorough method validation concepts, suitable reference materials, and regular interlaboratory comparisons of measurements as well as better training of scientists in analytical sciences.
The important contribution of analytical sciences to these developments is highlighted by a broad collection of research papers, trend articles, and critical reviews from these different application fields. Special emphasis is dedicated to often-overlooked quality assurance and reference materials.
T2 - 150 years BAM: Science with impact
CY - Berlin, Germany
DA - 01.01.2021
KW - 150th anniversary
KW - ABC
KW - Analysis
KW - Analytical sciences
KW - BAM
KW - Collection
KW - Environment
KW - Fluorescence
KW - Life sciences
KW - Limit of detection
KW - Material sciences
KW - Method
KW - Nanoparticle
KW - Pollutant
KW - Quality assurance
KW - Reference material
KW - Sensor
KW - Special issue
KW - Bundesanstalt für Materialforschung und -prüfung
KW - Jahrestag
PY - 2022
UR - https://link.springer.com/journal/216/topicalCollection/AC_16a2ef9b81853377e321ef84d9c4a431
SN - 1618-2642
SN - 1618-2650
VL - 414
SP - 4267
EP - 4529
PB - Springer
CY - Berlin
AN - OPUS4-55670
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Resch-Genger, Ute
A1 - Meermann, Björn
A1 - Koch, Matthias
A1 - Weller, Michael G.
T1 - Editorial: Analytical methods and applications in materials and life sciences
N2 - Current trends in materials and life sciences are flanked by the need to push detection limits to single molecules or single cells, enable the characterization of increasingly complex matrices or sophisticated nanostructures, speed up the time of analysis, reduce instrument complexity and costs, and improve the reliability of data. This requires suitable analytical tools such as spectroscopic, separation and imaging techniques, mass spectrometry, and hyphenated techniques as well as sensors and their adaptation to application-specific challenges in the environmental, food, consumer product, health sector, nanotechnology, and bioanalysis. Increasing concerns about health threatening known or emerging pollutants in drinking water, consumer products, and food and about the safety of nanomaterials led to a new awareness of the importance of analytical sciences. Another important driver in this direction is the increasing demand by legislation, particularly in view of the 17 sustainable development goals by the United Nations addressing clean energy, industry, and innovation, sustainable cities, clean water, and responsible consumption and production. In this respect, also the development of analytical methods that enable the characterization of material flows in production processes and support recycling concepts of precious raw materials becomes more and more relevant. In the future, this will provide the basis for greener production in the chemical industry utilizing recycled or sustainable starting materials.
This makes analytical chemistry an essential player in terms of the circular economy helping to increase the sustainability of production processes. In the life sciences sector, products based on proteins, such as therapeutic and diagnostic antibodies, increase in importance. These increasingly biotechnologically produced functional biomolecules pose a high level of complexity of matrix and structural features that can be met only by highly advanced methods for separation, characterization, and detection. In addition, metrological traceability and target definition are still significant challenges for the future, particularly in the life sciences.
However, innovative reference materials as required for the health and food sector and the characterization of advanced materials can only be developed when suitable analytical protocols are available. The so-called reproducibility crisis in sciences underlines the importance of improved measures of quality control for all kinds of measurements and material characterization. This calls for thorough method validation concepts, suitable reference materials, and regular interlaboratory comparisons of measurements as well as better training of scientists in analytical sciences.
The important contribution of analytical sciences to these developments is highlighted by a broad collection of research papers, trend articles, and critical reviews from these different application fields. Special emphasis is dedicated to often-overlooked quality assurance and reference materials.
T2 - 150 years BAM: Science with impact
CY - Berlin, Germany
DA - 01.01.2021
KW - Analysis
KW - Life sciences
KW - Analytical sciences
KW - Quality assurance
KW - Reference material
KW - Fluorescence
KW - Nanoparticle
KW - Sensor
KW - Material sciences
KW - Pollutant
KW - Environment
KW - Method
KW - Limit of detection
KW - 150th anniversary
KW - ABC
KW - BAM
KW - Collection
KW - Editorial
KW - Special issue
KW - Bundesanstalt für Materialforschung und -prüfung
KW - Jahrestag
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-550720
DO - https://doi.org/10.1007/s00216-022-04082-8
SN - 1618-2642
SN - 1618-2650
VL - 414
IS - Topical collection: Analytical methods and applications in the materials and life sciences
SP - 4267
EP - 4268
PB - Springer
CY - Berlin
AN - OPUS4-55072
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hernández García, María Amparo
T1 - SAF-based optical biosensor with 3D-printed free-form optics for targeted explosives immuno-detection
N2 - Guaranteeing safety and security of citizens requires a significant effort and innovative tools from national and international agencies and governments, especially when it comes to the field of explosives detection. The need to detect Improvised Explosive Devices (IEDs) and Home-made Explosives (HMEs) at a point of suspicion, has grown rapidly due to the ease with which the precursors can be obtained and the reagents synthesised. The limited availability of immunoanalytical tools for HME detection presents an opportunity for the development of new devices, which enable a rapid detection and recognise the target analyte with high specificity and sensitivity. In this work, we introduce an optical biosensor for highly specific and sensitive HME detection. The immunoassay system is placed in a hydrogel environment permeable to the analyte and transparent to light interrogating the fluorescently labelled antibodies. The readout of the immunoanalytical system is realized with Supercritical Angle Fluorescence (SAF), an advanced microscopy technique. To accomplish this, we made use of recent, commercial high resolution (< 22 µm) Liquid Crystal Display 3D printers to fabricate a parabolic optical element with high refractive index (RI>1.5) and transmission values (>90%) from photo-resin. Aiming at a new generation of sensors, which not only can meet the requirements of trace detection, but can also be used for substance identification, the combination of immunoanalytical recognition with SAF detection offers a modularity and versatility that is principally well suitable for the measurements of target analytes at trace levels.
T2 - 8th International conference in Biosensing Technology
CY - Seville, Spain
DA - 12.05.2024
KW - 3D printing
KW - Biosensor
KW - Fluorescence
KW - Explosives
PY - 2024
AN - OPUS4-60561
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -