Analytische Chemie
Filtern
Dokumenttyp
Sprache
- Englisch (258)
- Deutsch (11)
- Mehrsprachig (1)
Schlagworte
- Fluorescence (111)
- Quantum yield (85)
- Dye (61)
- Lifetime (60)
- Nano (58)
- Sensor (52)
- Photophysics (48)
- Quality assurance (46)
- Nanoparticle (38)
- NIR (37)
- Lanthanide (36)
- Photoluminescence (36)
- Particle (34)
- Nanomaterial (30)
- Surface chemistry (27)
- Mechanism (26)
- Method (25)
- Synthesis (25)
- Upconversion (22)
- Upconversion nanoparticle (21)
- Reference material (20)
- Quantum dot (19)
- Quantum dots (18)
- SWIR (18)
- Nanoparticles (15)
- Integrating sphere spectroscopy (14)
- Luminescence (14)
- Optical spectroscopy (14)
- Multiplexing (13)
- Optical probe (13)
- Quantification (13)
- Brightness (11)
- Imaging (11)
- Assay (10)
- Energy transfer (10)
- pH (10)
- Flow cytometry (9)
- Ligand (9)
- Single particle (9)
- Size (9)
- Aggregation (8)
- Bead (8)
- Cr(III) (8)
- Environment (8)
- Microscopy (8)
- Nanocrystal (8)
- Nanosensor (8)
- Temperature (8)
- Bioimaging (7)
- Coating (7)
- Cr(III) complex (7)
- Life sciences (7)
- Oxygen (7)
- PH (7)
- Polymer particles (7)
- Quantitative spectroscopy (7)
- Reference materials (7)
- Single particle spectroscopy (7)
- Standard (7)
- Uncertainty (7)
- Barcoding (6)
- Calibration (6)
- Electron microscopy (6)
- Encoding (6)
- Polymer (6)
- Polymerization (6)
- Ratiometric (6)
- Reference data (6)
- Semiconductor quantum dot (6)
- Silica (6)
- Surface (6)
- Surface group analysis (6)
- AIE (5)
- AIS (5)
- Absolute fluorometry (5)
- Application (5)
- Cement (5)
- Cleavable probe (5)
- Complex (5)
- Crystal (5)
- Electrochemistry (5)
- Excitation power density (5)
- FRET (5)
- IR (5)
- Medical diagnostics (5)
- Microbeads (5)
- Modeling (5)
- Optical Spectroscopy (5)
- Optical quantification (5)
- Reference product (5)
- Semiconductor (5)
- Signal enhancement (5)
- Spectroscopy (5)
- Stability (5)
- Surface analysis (5)
- Switch (5)
- Traceability (5)
- Aging (4)
- Catch and release assay (4)
- Cell (4)
- Certification (4)
- Enhancement (4)
- FITC (4)
- Flourescence (4)
- Hydration (4)
- Image segmentation (4)
- InP (4)
- Nanocrystals (4)
- Nanomaterials (4)
- Optical assays (4)
- Probe (4)
- Quenching (4)
- Reliability (4)
- Shell (4)
- Standardization (4)
- Theory (4)
- Upconversion nanoparticles (4)
- Upconverting nanoparticles (4)
- XPS (4)
- Advanced Materials (3)
- Aggregation-induced emission (3)
- Analysis (3)
- BODIPY (3)
- CHO functions (3)
- Cell studies (3)
- Extracellular vesicles (EV) (3)
- Fluorescence Spectroscopy (3)
- Fluorescence lifetime (3)
- Fluorescence standard (3)
- Fluoride (3)
- Gold nanocluster (3)
- ICP-OES (3)
- Iron oxide nanoparticles (3)
- Label (3)
- Measurement uncertainty (3)
- Medicine (3)
- Method development (3)
- Monitoring (3)
- Multimodal reporters (3)
- Oxygen sensor (3)
- PDT (3)
- Particle Synthesis (3)
- Performance validation (3)
- Plasmonic enhancement (3)
- Polarity (3)
- Quantitative NMR (3)
- Ratiometric sensors (3)
- Reporter (3)
- Rhodamine (3)
- Safe-by-Design (3)
- Safety (3)
- Semiconductor nanocrystal (3)
- Sensors (3)
- Silica coating (3)
- Solid state emission (3)
- Standards (3)
- Surface functionalization (3)
- Surface group quantification (3)
- pH probe (3)
- pH sensing (3)
- 150th anniversary (2)
- ABC (2)
- AIS QD (2)
- Absolute fluorescence (2)
- Absolute fluorescence quantum yield (2)
- Absolute measurement (2)
- Aggregates (2)
- Aggregation induced emission (2)
- Amorphous silica particles (2)
- Analytical sciences (2)
- Anti-Counterfeiting (2)
- Antibody (2)
- Automated image analysis (2)
- Automatisation (2)
- BAM (2)
- Bacteria (2)
- Bead-based assay (2)
- Biology (2)
- Biosensing (2)
- Bundesanstalt für Materialforschung und -prüfung (2)
- Cancer (2)
- Carbon dot (2)
- Certified reference material (2)
- Characterization (2)
- Charge transfer (2)
- Cleavable probes (2)
- Cleavable reporter (2)
- Collection (2)
- Comparability (2)
- Comparison (2)
- Concrete (2)
- Contrast agent (2)
- Convolutional neural networks (2)
- Core-shell nanoparticles (2)
- Cyanine (2)
- DNA (2)
- Data (2)
- Deactivation pathways (2)
- Decay kinetics (2)
- Dissolution (2)
- Doping (2)
- EMPIR 18HLT01 MetVesII (2)
- Engineered Nanomaterials (2)
- Enhancement strategy (2)
- Excitation (2)
- FCM (2)
- Flow cytometry (FCM) (2)
- Fluorescein (2)
- Fluorescence decay kinetics (2)
- Fluorescence microscopy (2)
- Fluorescence spectroscopy (2)
- Fluorescent particles (2)
- Functional group (2)
- Funtional Groups (2)
- Gold (2)
- In vivo imaging (2)
- Instrument calibration (2)
- Interlaboratory comparison (2)
- Jahrestag (2)
- LA-ICP-MS (2)
- Life science (2)
- Ligand design (2)
- Ligands (2)
- Limit of detection (2)
- Mass spectrometry (2)
- Material sciences (2)
- Metal cluster (2)
- Method comparison (2)
- Method validation (2)
- Microparticle (2)
- Monomer (2)
- Multimodal (2)
- NIR-II (2)
- Nano particle (2)
- Nano- and microsensors (2)
- Nanosafety (2)
- Nanotoxicity (2)
- Neural networks (2)
- Optical assay (2)
- Particle size (2)
- Particle surface analysis (2)
- Particle synthesis (2)
- Photonic crystal (2)
- Pollutant (2)
- Power density (2)
- Production (2)
- Protein (2)
- Quantitative Analysis (2)
- Quantum yields (2)
- SAXS (2)
- Sensing (2)
- Sensor molecules (2)
- Shape (2)
- Silica and Polystyrene Particles (2)
- Silica and polystyrene nanoparticles (2)
- Simulation (2)
- Single molecule (2)
- Solid state (2)
- Special issue (2)
- Surface Group Analysis (2)
- Surface groups (2)
- Sythesis (2)
- TEM (2)
- Tag (2)
- Ternary quantum dots (2)
- Titration (2)
- Toxicity (2)
- Upconversion luminescence (2)
- Upconversion nanocrystal (2)
- Viscosity (2)
- Water synthesis (2)
- Yb(III) complex (2)
- pH sensor (2)
- 18HLT01 MetVes II (1)
- 3D-printing (1)
- A4F (1)
- ASAXS (1)
- Aaerosol particles (1)
- Ab initio calculation (1)
- Abklingzeit (1)
- Absolute quantum yield (1)
- Absorption (1)
- Advanced materials (1)
- Advanced nanomaterials (1)
- Ag2S (1)
- AgInS2 (1)
- Air pollution (1)
- Airborne particles (1)
- Airborne particulate pollutants (1)
- Aluminum (1)
- Analytical chemistry (1)
- Analytical services (1)
- Anions (1)
- Anthracene (1)
- Antibody conjuagtes (1)
- Antibody conjugates (1)
- Antimicrobial resistance (1)
- Apyrase (1)
- Array (1)
- Artificial Intelligence (1)
- Artificial intelligence (1)
- Automated Image Analysis (1)
- Automated assay (1)
- Automated synthesis (1)
- Automation (1)
- Aza-BODIPY (1)
- Bead-based assays (1)
- Benzothiadiazole (1)
- Biocides (1)
- Bioconjugate (1)
- Biofilm (1)
- Boron Neutron Capture Therapy (BNCT) (1)
- Boron compound (1)
- Building material (1)
- C-dot (1)
- C3A (1)
- CEA (1)
- COSMO (1)
- CRP (1)
- Calibrated fluorescence measurements (1)
- Calibration beads (1)
- Calorimetry (1)
- Capillary electrophoresis (1)
- Carboxyl group (1)
- Catalogue of services (1)
- Cathodoluminescence (1)
- CdS shell (1)
- CdSe (1)
- Cement Hydration (1)
- Cement hydration (1)
- Chemical composition (1)
- Chemodosimeter (1)
- Chromium (III) complexes (1)
- Cleavable linker (1)
- Cluster (1)
- Color (1)
- Complexation (1)
- Conductometry (1)
- Conductor-like screening model (1)
- Conjugate (1)
- Conventional dyes (1)
- Converter material (1)
- Core shell structure (1)
- Core-shell (1)
- Core/shell materials (1)
- Core/shell nanoparticle (1)
- Core/shell particle (1)
- Corrosion (1)
- Coumarin (1)
- Cr(III)-Komplex (1)
- Cr-complex (1)
- Cross section (1)
- Curcubituril (1)
- Cycloaddition (1)
- Cyclohexane (1)
- Cytotoxicity (1)
- DFT (1)
- DNA Origami (1)
- DNA origami (1)
- Diameter (1)
- Diffuse (1)
- Disinfection (1)
- Drug delivery (1)
- Dyad (1)
- Dyad molecules (1)
- Dyes (1)
- EC4SafeNano (1)
- EMPIR project (1)
- Editorial (1)
- Electrochemical Titration (1)
- Electrochemical titration (1)
- Electron Microscopy (1)
- Electron transfer (1)
- Embedded sensors (1)
- Emission enhancement (1)
- Energy (1)
- Engineered nanomaterials (1)
- Ensemble measurements (1)
- Environmental analysis (1)
- Epithelial cell (1)
- Er(III) (1)
- European Centre (1)
- Europium (1)
- Ex vivo (1)
- Excitation path (1)
- Exciton (1)
- Extracellualr vesicles (1)
- FLIM (1)
- FTIR (1)
- Fiber optic sensing (1)
- Field sensor (1)
- Film (1)
- Flourescin (1)
- Fluoranthene (1)
- Fluorescence correlation spectroscopy FCS (1)
- Fluorescence imaging (1)
- Fluorescence intensity ratio (1)
- Fluorescence life time (1)
- Fluorescence quantum yield (1)
- Fluorescence standards (1)
- Fluorescent dye (1)
- Fluorescent glasses (1)
- Fluorescent indicator (1)
- Fluorescent label (1)
- Fluorescent probe (1)
- Fluoreszenz (1)
- Fluorophore (1)
- Food (1)
- Fully aromatic frameworks (1)
- Functional group analysis (1)
- Functional group quantification (1)
- Functionalized Nanomaterials (1)
- Functionalized nano- and microparticles (1)
- Functionalized silica and polymeric particles (1)
- Gas analysis (1)
- Gold nanoclusters (1)
- Graphene quantum dots (1)
- Green light excitation (1)
- Green synthesis (1)
- Gypsum (1)
- HAXPES (1)
- HPLC-DAD/FLD (1)
- Heory (1)
- Hexabenzocoronenes (1)
- High-resolution transmission electron microscopy (1)
- Homogeneity (1)
- Host-guest interaction (1)
- IEC (1)
- IR spectroscopy; conductometry (1)
- ISO REMCO (1)
- Image Segmentation (1)
- Imaging system (1)
- Immuno assay (1)
- Immunoassay (1)
- In vivo (1)
- Inflammation (1)
- Infrastructure (1)
- Instrument performance validation (1)
- Integrating sphere spectroscopy, (1)
- Integration sphere spectroscopy (1)
- Interlabority comparison (1)
- Intermixing (1)
- Iron oxide (1)
- Job plot (1)
- K+ doped (1)
- LT-FCM (1)
- Lanthanide Nanocrystals (1)
- Lanthanide-doped nayf-4 (1)
- Lanthanides (1)
- Legionella (1)
- LiYF4 (1)
- Lifetime analysis (1)
- Lifetime encoding (1)
- Lifetime standard (1)
- Lifetime, synthesis (1)
- Lifetime-encoded beads (1)
- Lifetime-encoding (1)
- Ligand exchange (1)
- Ligand quantification (1)
- Ligation Assay (1)
- Light harvesting (1)
- Linearity (1)
- Llifetime (1)
- Lluminescence (1)
- Longst luminescence lifetime (1)
- Luminescence lifetime (1)
- Luminescence lifetime measurments (1)
- MIC (1)
- MLCT (1)
- MS (1)
- Macrocyclus (1)
- Merocyanine (1)
- Metal (1)
- Metal-tag (1)
- Metasurface (1)
- Methanol oxidation (1)
- Microfluidics (1)
- Microorganism (1)
- Microparticles (1)
- Mie resonances (1)
- Modelling (1)
- Multicolored (1)
- NIR emitter (1)
- NIR-I (1)
- NIR-II fluorescence (1)
- NIRII (1)
- NMR (1)
- NSE (1)
- Nanaoparticle (1)
- Nano-safety (1)
- Nanocarrier (1)
- Nanogenotoxicity (1)
- Nanomanufacturing (1)
- Nanomaterial design (1)
- Nanomaterialien (1)
- Nanoparticle characterization (1)
- Nanopartikel (1)
- Nanoplattform (1)
- Nanosafety (Safe-by-design) (1)
- Nanoscale luminescent reporters (1)
- Nanosensors (1)
- Near-infrared light (1)
- Neuartige Materialien (1)
- Neural Networks (1)
- Nicht lineare Prozesse (1)
- Nnanoparticle (1)
- Non lienear processes (1)
- Non-thermally coupled levels (1)
- Optical Assays (1)
- Optical detection (1)
- Optical imaging (1)
- Optical probes (1)
- Optical spectroscopie (1)
- Optical temperature sensing (1)
- Organic–inorganic nanostructures (1)
- Ovarian cancer (1)
- Oxygen sensing (1)
- PCE (1)
- PEG ligands (1)
- PH monitoring in concrete (1)
- PH probe (1)
- PH-sensing (1)
- PSA (1)
- Particle architecture (1)
- Particle modification (1)
- Particle sensors (1)
- Particle, imaging (1)
- Particulate matter (1)
- Passivation shell (1)
- Pd(II) (1)
- Pentaphenes (1)
- Perovskite (1)
- Perovskites (1)
- Ph (1)
- Phase (1)
- Phenanthrene (1)
- Phorsphorescence (1)
- Phosphinine (1)
- Phosphor (1)
- Phosphorescence (1)
- Photocatalytic activity (1)
- Photochemistry (1)
- Photoinduced electron transfer (1)
- Photoluminescence quantum yield (1)
- Photophysic (1)
- Photosensitizer (1)
- Polymer particle (1)
- Polymers (1)
- Porosity (1)
- Power density dependence (1)
- Pphotophysics (1)
- Process monitoring (1)
- Pt(111) (1)
- Pt(II) (1)
- QNMR (1)
- Qantum yield (1)
- Qdots (1)
- Quality assurancemechanism (1)
- Quality assurcance (1)
- Quantenausbeute (1)
- Quantum Yield (1)
- Quantum Yields (1)
- Quantum chemistry (1)
- Quantum do (1)
- Quantum yield standard (1)
- Ratiometric Sensors (1)
- Ratiometric fluorescence (1)
- Ratiometric sensing (1)
- Record luminescence quantum yield (1)
- Redox (1)
- Redox switch (1)
- Reference Material (1)
- Reference methods (1)
- Reference particles (1)
- Referenzmaterial (1)
- Reflection (1)
- Reflection spectroscopy (1)
- Rekord Luminescence Quantum Ausbeute (1)
- Release (1)
- Release kinetics (1)
- Renewable energy (1)
- Rheology (1)
- Risk assessment (1)
- Rosamine (1)
- Rreference material (1)
- Ruthenium(II) complexes (1)
- SPIONS (1)
- SWIR photoluminescence (1)
- Saccharide sensing (1)
- Safer by design (1)
- Scattering (1)
- Self-assembly (1)
- Semiconductur (1)
- Sensitization (1)
- Shortwave infrared (1)
- Silanization (1)
- Silica Nanoparticles (1)
- Silica nanoparticles (1)
- Silica particles (1)
- Silica- and Polystyrene Particles (1)
- Silica- and polystyrene particles (1)
- Silicon nanoparticles (1)
- Single emitter (1)
- Single enhancement (1)
- Single-source-precursor (1)
- Singlet oxygen (1)
- Small angle x-ray scattering (1)
- Small-angle scattering (1)
- Solar cell (1)
- Solid (1)
- Solid-state fluorescence (1)
- Solvent polarity (1)
- Spectroscopy / Instrumentation (1)
- Spectroscopy / Theory (1)
- Stranski–Krastanow growth (1)
- Structure-property relationship (1)
- Superplasticizer (1)
- Supported catalyst (1)
- Supramolecular chemistry (1)
- Surface Chemistry (1)
- Surface Modification (1)
- Surface coating (1)
- Surface functional group quantification (1)
- Surface functional groups (1)
- Surface functions (1)
- Surface ligand (1)
- Surface modification (1)
- Surface modified nano- and microparticles (1)
- Sustainable-by-Design (1)
- Suzuki-Miyaura coupling (1)
- TTA-UC (1)
- Temperature sensing (1)
- Terminal functional groups (1)
- Ternary quantum dot (1)
- Theranostic (1)
- Therapy (1)
- Thermal coupling energy level (1)
- Thermally coupled levels (1)
- Thickness (1)
- Thiols (1)
- Time-gated emission (1)
- Time-resolved (1)
- Time-resolved flow cytometry (1)
- Tissue (1)
- Transient absorbtion spectroscopy (1)
- Transmission electron microscopy (1)
- Triggered (1)
- Triplet-triplet annihilation (1)
- Tumor (1)
- UpConversion (1)
- Upconversation nanocrystal (1)
- VAMAS (1)
- Validation (1)
- Vanadium oxide catalysts (1)
- Water (1)
- X-Ray analysis (1)
- X-ray (1)
- X-ray Photoelectron Spectroscopy (1)
- X-ray spectroscopy (1)
- XRD (1)
- Yb(III) (1)
- Yield stress (1)
- antibody (1)
- bacteria (1)
- bacteria detection (1)
- bioimaging (1)
- calibration (1)
- dye (1)
- flow cytometry (1)
- fluorescence (1)
- fluorescence microscopy (1)
- fluorescence standards (1)
- imaging (1)
- immunoseparation (1)
- lifetime (1)
- magnetic nanoparticle (1)
- method (1)
- nanoparticle (1)
- particle (1)
- ph (1)
- photoluminescence (1)
- photophysics (1)
- quality assurcance (1)
- quantum dot (1)
- quantum yield (1)
- screening tes (1)
- solvent-induced changes (1)
- surface group analysis (1)
- synthesis (1)
- temperature (1)
Organisationseinheit der BAM
- 1.2 Biophotonik (270) (entfernen)
Paper des Monats
- ja (6)
Eingeladener Vortrag
- nein (67)
Scattering luminescent materials dispersed in liquid and solid matrices and luminescent powders are increasingly relevant for fundamental research and industry. Examples are luminescent nano- and microparticles and phosphors of different compositions in various matrices or incorporated into ceramics with applications in energy conversion, solid-state lighting, medical diagnostics, and security barcoding. The key parameter to characterize the performance of these materials is the photoluminescence/fluorescence quantum yield (Φf), i.e., the number of emitted photons per number of absorbed photons. To identify and quantify the sources of uncertainty of absolute measurements of Φf of scattering samples, the first interlaboratory comparison (ILC) of three laboratories from academia and industry was performed by following identical measurement protocols. Thereby, two types ofcommercial stand-alone integrating sphere setups with different illumination and detection geometries were utilized for measuring the Φf of transparent and scattering dye solutions and solid phosphors, namely, YAG:Ce optoceramics of varying surface roughness, used as converter materials for blue light emitting diodes. Special emphasis was dedicated to the influence of the measurement geometry, the optical properties of the blank utilized to determine the number of photons of the incident excitation light absorbed by the sample, and the sample-specific surface roughness. While the Φf values of the liquid samples matched between instruments, Φf measurements of the optoceramics with different blanks revealed substantial differences. The ILC results underline the importance of the measurement geometry, sample position, and blank for reliable Φf data of scattering the YAG:Ce optoceramics, with the blank’s optical properties accounting for uncertainties exceeding 20%.
Heterogeneous sandwich immunoassays are widely used for biomarker detection in bioanalysis and medical diagnostics. The high analyte sensitivity of the current “gold standard” enzyme-linked immunosorbent assay (ELISA) originates from the signal-generating enzymatic amplification step, yielding a high number of optically detectable reporter molecules. For future point-of-care testing (POCT) and point-of-need applications, there is an increasing interest in more simple detection strategies that circumvent time-consuming and temperature-dependent enzymatic reactions. A common concept to aim for detection limits comparable to those of enzymatic amplification reactions is the usage of polymer nanoparticles (NP) stained with a large number of chromophores. We explored different simple NP-based signal amplification strategies for heterogeneous sandwich immunoassays
that rely on an extraction-triggered release step of different types of optically detectable reporters. Therefore, streptavidinfunctionalized polystyrene particles (PSP) are utilized as carriers for (i) the fluorescent dye coumarin 153 (C153) and (ii) hemin (hem) molecules catalyzing the luminol reaction enabling chemiluminescence (CL) detection. Additionally, (iii) NP labeling with hemin-based microperoxidase MP11 was assessed. For each amplification approach, the PSP was first systematically optimized regarding size, loading concentration, and surface chemistry. Then, for an immunoassay for the inflammation marker C- eactive protein (CRP), the analyte sensitivity achievable with optimized PSP
ystems was compared with the established ELISA concept for photometric and CL detection. Careful optimization led to a limit of detection (LOD) of 0.1 ng/mL for MP11-labeled PSP and CL detection, performing similarly well to a photometric ELISA (0.13 ng/mL), which demonstrates the huge potential of our novel assay concept.
SWIR luminescent nanomaterials – key chemical parameters for bright probes for in vivo bioimaging
(2024)
A current challenge for studying physio-pathological phenomena and diseaserelated processes in living organisms with non-invasive optical bioimaging is the development of bright optical reporters that enable deep tissue penetration, a high detection sensitivity, and a high spatial and temporal resolution. The focus of this project are nanomaterials, which absorb and emit in the shortwave infrared (SWIR) between ~900–2500 nm where scattering, absorption, and autofluorescence of the tissue are strongly reduced compared to the visible and NIR.
The frequency-domain (FD) method provides an alternative to the commonly used time-domain (TD) approach in characterizing the luminescence kinetics of luminophores, with its own strengths, e.g., the capability to decouple multiple lifetime components with higher reliability and accuracy. While extensively explored for characterizing luminophores with down-shifted emission, this method has not been investigated for studying nonlinear luminescent materials such as lanthanide-doped upconversion nanoparticles (UCNPs), featuring more complicated kinetics. In this work, employing a simplified rate-equation model representing a standard two-photon energy-transfer upconversion process, we thoroughly analyzed the response of the luminescence of UCNPs in the FD method. We found that the FD method can potentially obtain from a single experiment the effective decay rates of three critical energy states of the sensitizer/activator ions involved in the upconversion process. The validity of the FD method is demonstrated by experimental data, agreeing reasonably well with the results obtained by TD methods.
Four donor-acceptor boron difluoride complexes based on the carbazole electron donor and the [1,3,5,2]oxadiazaborinino[3,4-a][1,8]naphthyridine acceptor were designed, synthesized, and systematically spectroscopically investigated in solutions, in the solid states, and dye-doped polymer films. The dyes exhibit an intense blue to red solid-state emission with photoluminescence quantum yields of up to 56% in pure dye samples and 86% in poly(methyl methacrylate) films. All boron complexes show aggregation-induced emission and reversible mechanofluorochromism. The optical properties of these dyes and their solid state luminescence can be tuned by substitution pattern, i.e., the substituents at the naphthyridine unit. Exchange of CH3- for CF3-groups does not only increase the intramolecular charge transfer character, but also provides a crystallization-induced emission enhancement.
Antibacterial photodynamic therapy (a‐PDT) has emerged as a promising non‐invasive therapeutic modality that utilizes the combination of a photosensitive agent, molecular oxygen, and excitation light to generate reactive oxygen species (ROS), demonstrating remarkable activity against multidrug‐resistant bacterial infections. However, the effective use of conventional photosensitizers is significantly limited by a number of their shortcomings, namely, poor water solubility and low selectivity. Herein, we present a novel biocompatible water‐soluble nanocomposite based on hydrophobic tetraphenylporphyrin (TPP) molecules and hydrophilic ternary AgInS2/ZnS quantum dots incorporated into a chitosan matrix as an improved photosensitizer for a‐PDT. We demonstrated that TPP molecules could be successfully transferred into chitosan solution while remaining primarily in the form of monomers, which are capable of singlet oxygen generation. We performed a detailed analysis of the Förster resonance energy transfer (FRET) between quantum dots and TPP molecules within the nanocomposite and proposed the mechanism of the singlet oxygen efficiency enhancement via FRET.
The development of new fluorescent organic probes effective in the NIR-II region is currently a fast-growing field and represents a challenge in the domain of medical imaging. In this study, we have designed and synthesized an innovative series of aza-boron dipyrromethenes emitting in the NIR-II region. We have investigated the effect of different water-solubilizing groups not only on the photophysical properties of the compounds but also on their in vitro and in vivo performance after bioconjugation to the antibody trastuzumab. Remarkably, we discovered that the most lipophilic compound unexpectedly displayed the most favorable in vivo properties after bioconjugation. This underlines the profound influence that the fluorophore functionalization approach can have on the efficiency of the resulting imaging agent.
Surface functionalized silica nanoparticles (SiO2-NP) gained great interest in the life and material sciences, as they can be used e.g. as drug carriers, fluorescent sensors, and multimodal labels in bioanalytical assays and imaging applications. They are highly stable, are easily produced and modified on a large scale at low cost and can be labeled or stained with a multitude of sensor dyes. These dye modified particle conjugates have several advantages as compared to conventional molecular probes like enhanced brightness, ease of designing ratiometric systems by combining analyte-sensitive and inert reference dyes, and increased photostability. Moreover, stained nanoparticles can enable the use of hydrophobic dyes in aqueous environments.
Here we present our work on multicolored sensors for the measurement of pH, oxygen and saccharides utilizing amorphous SiO2 NPs.
In recent years, chromium (III) complexes have received a lot of attention as novel near-infrared (NIR) emitters triggered by the report on the first molecular ruby Cr(ddpd)2(BF4)3 with a high photoluminescence quantum yield of 13.7% of its near infrared (NIR) emission band and a long luminescence lifetime of 1.122 ms at room temperature.[1] However, in an oxygen-containing environment, the photoluminescence quantum yields and luminescence lifetimes of these chromium(III) complexes show only very small values. This hampers their application as NIR luminescence labels. This application, that cannot be tackled by conventional deoxygenating approaches, requires suitable strategies to protect the luminescence of the chromium(III) complexes from oxygen quenching. An elegant approach to reduce the undesired luminescence quenching by triplet oxygen explored by us presents the incorporation of these chromium(III) complexes into different types of amorphous, non-porous silica nanoparticles, that can be simply surface functionalized, e.g., with targeting ligands and/or other sensor molecules. In this work, as first proof-of-concept experiments, a set of chromium (III) complexes constituting of different ligands and counter anions, were embedded into the core of silica nanoparticles. Subsequently, the optical properties of the resulting luminescent silica nanoparticles were spectroscopically assessed by steady state and time-resolved luminescence spectroscopy. First results of time-resolved luminescence measurements confirm our design concept of nanoscale NIR emissive Cr(III) complex-based reporters