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Search for "fluorescence" in Full Text gives 433 result(s) in Beilstein Journal of Nanotechnology. Showing first 200.
Boosting of photocatalytic hydrogen evolution via chlorine doping of polymeric carbon nitride
Beilstein J. Nanotechnol. 2021, 12, 473–484, doi:10.3762/bjnano.12.38
- ) radiation in a Prevac (Poland) system equipped with a Scienta SES 2002 (Sweden) electron energy analyzer operating with a constant transmission energy (Ep = 50 eV). The analysis chamber was evacuated to a pressure below 5 × 10−9 mbar. The PL spectra were measured using a fluorescence spectrophotometer
Doxorubicin-loaded gold nanorods: a multifunctional chemo-photothermal nanoplatform for cancer management
Beilstein J. Nanotechnol. 2021, 12, 295–303, doi:10.3762/bjnano.12.24
- properties such as significant absorption or scattering in the visible and near-infrared (NIR) regions, tunable aspect ratio, biocompatibility, fluorescence properties, and the ease of biofunctionalization, which makes them ideal in biomedical applications [13]. Gold-based nanomaterials (i.e., nanospheres
- fluorescence measurements (Biotek synergy H4 multi-mode plate reader) following the method reported in [23]. In vitro cytotoxicity assays The in vitro cytotoxicity of PSS-GNRs was measured using 3T3 and HepG2 cells. Cells were seeded in 96-well plates (4 × 103 cells per well) in 100 μL DMEM supplemented with
- DOX release at different pH values. Fluorescence intensity was measured from 0 to 30 h. (b) Heating curves of water, PSS GNRs and PSS-GNRs-DOX (10 µg Au/mL) under NIR (808 nm) laser irradiation. (a) Relative viabilities of HepG2 and 3T3 cells after being incubated with different concentrations of PSS
Differences in surface chemistry of iron oxide nanoparticles result in different routes of internalization
Beilstein J. Nanotechnol. 2021, 12, 270–281, doi:10.3762/bjnano.12.22
- ; Introduction Magnetic iron oxide nanoparticles (MNPs) as chemically inert material have been increasingly employed as contrast agents in magnetic resonance imaging (MRI), positron emission tomography (PET), and near-infrared fluorescence (NIRF) imaging [1]. The superparamagnetic properties of MNPs make them
The nanomorphology of cell surfaces of adhered osteoblasts
Beilstein J. Nanotechnol. 2021, 12, 242–256, doi:10.3762/bjnano.12.20
- fluorescence lifetime map of a membrane label is transferred into a gap distance map [48]. The cell is adhered to a transparent metal layer and gap distances of 67 ± 7 nm have been determined for fibroblast-like cells (A549). Interestingly, the gap varies by more than 40 nm along the adhesion interface and by
Fusion of purple membranes triggered by immobilization on carbon nanomembranes
Beilstein J. Nanotechnol. 2021, 12, 93–101, doi:10.3762/bjnano.12.8
- the final linker is shown in Figure 2a. The functionalization was tested with the His-tagged fluorescent protein mTurqoise. Confirmation of successful functionalization was provided by fluorescence imaging as seen in Figure 2b. The images show that the complex bonds formed with His-labeled proteins
- CNM and a c-His PM. The c-His PM consists of BR (purple) with a lipid bilayer between the BR molecules. The chemical structure shows the linker used to build a complex between NTA CNM and c-His PM. (b) Fluorescence microscopy of NTA-functionalized NBPT CNMs incubated with a fluorescent protein
- fluorescence signal in I. indicates that the functionalization was successful. (c) XPS spectra of the NBPT SAM (green), NBPT CNM (blue), and NBPT CNM after the NTA functionalization (red). (d) IRRAS spectrum of NBPT CNM after the first functionalization step. (e) UV–vis absorption spectrum of a c-His PM
Effect of different silica coatings on the toxicity of upconversion nanoparticles on RAW 264.7 macrophage cells
Beilstein J. Nanotechnol. 2021, 12, 35–48, doi:10.3762/bjnano.12.3
- scattering setup, Prof. Dr. E. Rühl (Freie Universität Berlin) for providing access to the fluorescence spectrometer, and Dr. S. Berendts from the research group of Prof. Dr. M. Lerch (Technische Universität Berlin) for the XRD measurements. This work is primarily based on the doctoral dissertation of its
Bio-imaging with the helium-ion microscope: A review
Beilstein J. Nanotechnol. 2021, 12, 1–23, doi:10.3762/bjnano.12.1
- holds promise to detect fluorescent biomarkers with better resolution than that achievable even with the most advanced super-resolution optical microscopy techniques, for instance, stimulated emission depletion microscopy [51]. In particular, it may allow for correlating fluorescence microscopy with HIM
- that coating, as required for SEM, introduces artefacts such as a granular structure on the cell surfaces and a partial closing of pores, thus highlighting one of the benefits of HIM. Bazou et al. also studied tumour cell-induced platelet aggregation by fluorescence microscopy and HIM. In this study
PEG/PEI-functionalized single-walled carbon nanotubes as delivery carriers for doxorubicin: synthesis, characterization, and in vitro evaluation
Beilstein J. Nanotechnol. 2020, 11, 1728–1741, doi:10.3762/bjnano.11.155
- antitumor activity. Furthermore, fluorescence detection and flow cytometry (FCM) analysis results indicated that the internalization into cells of CNTs-PEG-PEI was significantly enhanced, thus inducing tumor cell death through apoptosis more efficiently. The above series of benefits of CNTs-PEG-PEI may be
- wells, and the cells were trypsinized with trypsin–EDTA and washed with cold PBS for three times to remove the nanocarriers outside the cells. The cells were then collected and resuspended in 200 μL of PBS by centrifugation. The mean fluorescence intensity (MFI) was determined using FCM (BD Biosciences
- , SanJose), with 488 nm wavelength excitation and 590 nm wavelength emission, and untreated cells were used as blank. Fluorescence observation of the cellular internalization was also conducted. In brief, cells were seeded into 24-well plates, after complete attachment, fresh serum-free medium containing
Cardiomyocyte uptake mechanism of a hydroxyapatite nanoparticle mediated gene delivery system
Beilstein J. Nanotechnol. 2020, 11, 1685–1692, doi:10.3762/bjnano.11.150
- vector in HL-1 cells, we used plasmid-enhanced green fluorescent protein (pEGFP) as a model plasmid and evaluated the transfection efficiency via fluorescence microscopy. First, we used HAp (1 µg/mL) mixed with 0.075, 0.30, and 0.75 µg pEGFP, based on our previous results with endothelial cells
- . Fluorescence microscopy images showed that the highest transfection efficiency was observed with 0.75 µg of pEGFP (Figure 3). No gene expression was obtained by adding only pEGFP in HL-1 cells (data not shown). The results shown in Figure 3b demonstrated that the transfection efficiency of pEGFP increased in a
- commonly used as an indicator of the macropinocytic pathway [25], enabling the quantification of macropinocytosis. The quantification of TMR–dextran was performed by measuring the fluorescence intensity per cell, using fluorescence microscopy images, in accordance with a previous report. As shown in Figure
The influence of an interfacial hBN layer on the fluorescence of an organic molecule
Beilstein J. Nanotechnol. 2020, 11, 1663–1684, doi:10.3762/bjnano.11.149
- organic molecule 3,4,9,10-perylene tetracarboxylic dianhydride (PTCDA) from the supporting Cu(111) surface by Raman and fluorescence (FL) spectroscopy. The Raman fingerprint-type spectrum of PTCDA served as a monitor for the presence of molecules on the surface. Several broad and weak FL lines between
- the optical excitation can occur. The different FL lines can be ascribed to different environments of the adsorption sites, namely molecules adsorbed at surface defects, in large ordered domains, and located in the second layer. Keywords: decoupling; fluorescence; hexagonal boron nitride; 3,4,9,10
- separated from those of the molecule leading to a reduced overlap. The overlap of molecular and metallic wave functions has, in particular, an impact on excited molecular states. For fluorescent molecules, this is observed as a strongly reduced quantum yield of the fluorescence (FL) due to non-radiant decay
Electrokinetic characterization of synthetic protein nanoparticles
Beilstein J. Nanotechnol. 2020, 11, 1556–1567, doi:10.3762/bjnano.11.138
- low-conductivity EK media used in the subsequent experiments. To test the potential of using EK microfluidics as a high-throughput SPNP purification technique, our particles had to be fluorescently labeled to be visualized with a fluorescence microscope. To accomplish this, we incorporated
- assay using BSA standard for the standard curve. Particle fluorescence was confirmed using a Leica DMi8 inverted microscope (Wetzlar, Germany), which was paired with a Leica DFC7000 T camera and the software LASX provided by the manufacturer. Microdevice fabrication Microchannels with oval insulating
- as-synthesized SPNPs, using SPNPs made from BSA as an example. All SPNPs studied showed indistinguishable morphologies when viewed with SEM. (c) Image of SPNPs loaded with BSA-Alexa 488 to make them visible for characterization via electrokinetic microscale experiments. The fluorescence was confirmed
Self-assembly and spectroscopic fingerprints of photoactive pyrenyl tectons on hBN/Cu(111)
Beilstein J. Nanotechnol. 2020, 11, 1470–1483, doi:10.3762/bjnano.11.130
- characterizing a family of pyridin-4-ylethynyl-functionalized pyrene derivatives in different environments. UV–vis measurements in toluene solutions revealed absorption at wavelengths consistent with density functional theory (DFT) calculations, while emission experiments showed a high fluorescence quantum yield
- ][48][49][50][51][52][53][54]. With prominent fluorescence properties, pyrene is often considered the "fruitfly of photochemists", and several materials have been prepared for applications in optoelectronic devices and organic electronics [47]. On metal surfaces under ultrahigh vacuum (UHV
- , studies comparing orbital-resolved STM/STS data to optical gaps are scarce [86]. In addition to this effect, the adsorption and supramolecular organization on hBN could sensitively affect the optical transitions [14][16][21]. For example, the fluorescence peak energy of perylene derivatives was reduced
Antimicrobial metal-based nanoparticles: a review on their synthesis, types and antimicrobial action
Beilstein J. Nanotechnol. 2020, 11, 1450–1469, doi:10.3762/bjnano.11.129
- constituent can be determined after 24 h of incubation [149]. The cytofluorometry method is an advanced and important technique that allows for the accurate identification of a cell population with fluorescence tagging by using a flow cytometer and a photodetector [150]. In comparison to other techniques
Transient coating of γ-Fe2O3 nanoparticles with glutamate for its delivery to and removal from brain nerve terminals
Beilstein J. Nanotechnol. 2020, 11, 1381–1393, doi:10.3762/bjnano.11.122
- ratio (F), index of the membrane potential, was calculated as F = Ft/F0, where F0 and Ft were the fluorescence intensities of rhodamine 6G in the absence and presence of nerve terminals, respectively. F0 was calculated through extrapolation of the exponential decay function to t = 0. The fluorescence
- measurements were carried out using the potential-sensitive fluorescent dye rhodamine 6G, which binds to negatively charged membranes. The addition of synaptosomes to the dye-containing medium was accompanied by a partial decrease in fluorescence signal due to rhodamine 6G binding to the synaptosomal plasma
- membrane. First, the membrane potential index at the steady-state level was reached after a period of 3 min. As shown in Figure 4, the application of γ-Fe2O3 nanoparticles at a concentration of 1 µg/mL did not change the fluorescence signal of the dye. An increase in the nanoparticle concentration up to 50
Ultrasensitive detection of cadmium ions using a microcantilever-based piezoresistive sensor for groundwater
Beilstein J. Nanotechnol. 2020, 11, 1242–1253, doi:10.3762/bjnano.11.108
- been already identified. Sensors based on luminescence or fluorescence sensors have been used by many researchers to selectively detect HMIs [17][18][19][20][21][22]. However, this method also requires laboratory equipment for analysis and detection. Also, most of the reported fluorescent probes reply
- only on absorption and fluorescence change and need dynamic acquisition [23]. A magnetic field powered pressure sensor proposed by Khan et al. [24] is capable of measuring pressure in the range of kilopascals but the suitability for the very low pressure caused by HMIs needs to be examined. A reduced
- nanoparticles require the laboratory equipment such as fluorescence spectroscopy, which ultimately leads to a non-portable platform. Hence, our primary focus is the selective detection of the Cd(II) using the fabricated portable experimental platform. We used the following experimental procedure. A stock
Thermophoretic tweezers for single nanoparticle manipulation
Beilstein J. Nanotechnol. 2020, 11, 1126–1133, doi:10.3762/bjnano.11.97
- multiple heating spots by time-sharing (switching frequency 100 kHz) of the beam. Behind the AODs, the laser beam is directed by mirrors and an afocal system towards a custom-built fluorescence microscope. Finally, it is focused with a long working distance IR objective (Mitutoyo M Plan Apo NIR, 50×, NA
- 1b,c). Temperature measurements are performed using the temperature-dependent fluorescence of sulforhodamine B (Radiant dyes Chemie), which is calibrated in an independent measurement (accuracy ±2 K). Since the sapphire glass with a high thermal conductivity helps cooling the thin sample film, the
- implemented using a custom-built fluorescence microscope. By using an LED-optimized filter cube (Dapi/FITC/Cy3/Cy5 Quad LED HC Filter Set, AHF analysentechnik AG), Köhler illumination is utilized for fluorescence imaging using an LED as its light source. Light is collected from the sample plane by a 63
Applications of superparamagnetic iron oxide nanoparticles in drug and therapeutic delivery, and biotechnological advancements
Beilstein J. Nanotechnol. 2020, 11, 1092–1109, doi:10.3762/bjnano.11.94
- on the environment. Many nanoparticles showed great potential and proved their utility in biology and medicine. There are multiple types of nanoparticles routinely used in biology and related sciences for sensing, targeting or imaging, including quantum dots for fluorescence applications and electron
- been extensively examined regarding biocompatibility, targeted or intended cytotoxicity (ferroptosis), local hyperthermia treatments, photothermal or photodynamic therapy, and MRI. Also, there are increasingly more studies reporting on combinations with in vivo fluorescence imaging, sensing and
- for MRI and fluorescence imaging with good cytocompatibility. Park et al. [161] synthesized SPIONs coated with folate containing 64Cu for positronic emission tomography and MRI. Cai et al. [162] obtained 12 nm SPIONs coated with a near-infrared fluorescent dye for dual in vivo imagistics (MRI and
A few-layer graphene/chlorin e6 hybrid nanomaterial and its application in photodynamic therapy against Candida albicans
Beilstein J. Nanotechnol. 2020, 11, 1054–1061, doi:10.3762/bjnano.11.90
- 3.5 mm at 1000 nm excitation [7]. Figure 3b shows the singlet oxygen production tests of FLG-Ce6 and pristine Ce6. The singlet oxygen production is indirectly observed through the fluorescence intensity of the singlet oxygen sensor green reagent (SOSG), which is a singlet oxygen reporter. Thus, FLG
- -Ce6 and pristine Ce6 samples were exposed to SOSG and photoactivated during 5, 10, and 15 min of visible light irradiation at 632 nm at an incident power of 150 mW. When analyzed using fluorescence spectroscopy, it was observed that ROS production is up to 5-fold higher in FLG-Ce6 than in pristine Ce6
- ROS that accumulate in its surroundings. Conclusion The FLG-Ce6 hybrid nanomaterial presented in this work was shown to enhance the capacity for the generation of ROS species compared with Ce6 alone, as corroborated by measuring the fluorescence intensity produced by the reporter SOSG. This hybrid
Key for crossing the BBB with nanoparticles: the rational design
Beilstein J. Nanotechnol. 2020, 11, 866–883, doi:10.3762/bjnano.11.72
- -6 was an accurate probe for the nanoparticle detection. It was therefore possible to conclude that the fluorescence detected in the abluminal compartment during the transcytosis assay was due to the probe inside the nanoparticles, and not due to free coumarin-6. Hence, it seems that CBSA-conjugated
- fluorescence imaging [68]. Nanoparticles could be observed in the glioma bed and infiltrating margin, showing that nanoparticles functionalized with angiopep-2 could exhibit dual-targeting abilities. Firstly, angiopep-2 allowed the nanoparticles to cross the BBB through RMT by recognition of LRP1 on the BBB
- ]. Using in vivo fluorescence molecular tomography revealed that the SLNs could be observed in the brain after intravenous and intratracheal administration, showing their ability to cross the BBB. Furthermore, a superior retention of the nanoparticles in the brain was noticed after intratracheal
Hexagonal boron nitride: a review of the emerging material platform for single-photon sources and the spin–photon interface
Beilstein J. Nanotechnol. 2020, 11, 740–769, doi:10.3762/bjnano.11.61
- ⟩. Making use of the above discussion, the second order correlation function for the fluorescence light of a 2-level system can be written as: Using the quantum regression theorem [70], we get: where with the evolution of written as for some operator As the expectation value gives the population of the
- function for the fluorescence light of a 2-level system is at τ = 0, g(2)(τ) = 0. Therefore, a non-resonantly driven 2-level system behaves as an SPS, emitting light in the SP state. The anti-bunching decay time τ0 for zero excitation power (i.e., k12 = 0) is τ0(P → 0) = 1/k12. Since k12 is the decay time
- of the excited state, τ0(P → 0) is the fluorescence lifetime of the 2-level emitter. A 3-level system comprises an intermediate meta-stable state together with the ground and the excited states. Figure 1c shows the representation of a 3-level system. The state |3⟩ is a metastable state, i.e
Silver-decorated gel-shell nanobeads: physicochemical characterization and evaluation of antibacterial properties
Beilstein J. Nanotechnol. 2020, 11, 620–630, doi:10.3762/bjnano.11.49
- . The analyses were conducted using the LIVE/DEAD BacLight bacterial viability kit and the samples were imaged with confocal fluorescence microscopy [50]. The test uses the properties of fluorescent dyes, namely, green SYTO 9 and red propidium iodide. The SYTO 9 stain labels the bacteria with intact
- membranes and those with damaged membranes. In contrast, propidium iodide penetrates only the bacteria with damaged membranes, thereby reducing the fluorescence of SYTO 9 when both dyes are present. The living cells appear green while the dead cells are red in the images of the biofilms. One can see that
- nanobeads, which likely stabilizes these structures. The hybrid particles reveal considerable antibacterial properties. This has been evaluated based on the determination of MIC and MBIC values and an estimation of bacterial viability through fluorescence staining. Experimental Chemicals All chemicals were
Soybean-derived blue photoluminescent carbon dots
Beilstein J. Nanotechnol. 2020, 11, 606–619, doi:10.3762/bjnano.11.48
- varies with pH and temperature [18]. Wang et al. [18] studied the fluorescence of the CDs made from glucose with glutathione in a temperature range of 15 to 90 °C and observed the change of the color from dark blue to light blue and the quenching of the fluorescence at high temperatures. They attributed
- at various wavelengths. The Raman scattering of the annealed CDs has a relatively low yield. The Raman peaks can be only observed when the gain or slit bandwidth of the instrument is increased to compensate for the low fluorescence signal. In contrast to the annealed-CDs, the LA-CDs-10%, which are
- % under 393 nm excitation. Temporal evolution of the quantum yields for the HTC-CDs under 360 nm excitation and the LA-CDs-x% under 390 nm excitation. The fluorescence intensity was calculated by integrating over the wavelength range of 340–700 nm for the HTC-CDs and 370–760 nm for the LA-CDs-x
Examination of the relationship between viscoelastic properties and the invasion of ovarian cancer cells by atomic force microscopy
Beilstein J. Nanotechnol. 2020, 11, 568–582, doi:10.3762/bjnano.11.45
- understanding the molecular mechanism regulating the relationship between the viscoelastic and tumorigenic properties in ovarian cancer cells, the microfilament density of F-actin cytoskeleton was examined by fluorescence imaging of these cells after treatment with 0.25 μM Ech for 0, 3 and 6 h (Figure 7). The
- stained with ActinGreen (KeyGEN BioTECH). A laser scanning confocal microscope (SP8, Leica) was used to image the cytoskeletal organization by F-actin. The fluorescence imaging was captured at 488 nm excitation wavelength. Moreover, the images were processed with the software Image J. Statistical analysis
Identification of physicochemical properties that modulate nanoparticle aggregation in blood
Beilstein J. Nanotechnol. 2020, 11, 550–567, doi:10.3762/bjnano.11.44
- absence of agonists for up to 40 min of incubation. PRP without NPs was used as the control. The data are expressed as the mean of three independent experiments. Flow cytometry fluorescence-activated cell sorting (FACS) Flow cytometry fluorescence-activated cell sorting (FACS) was used to evaluate
- reactions were stopped by the addition of PBS to a final volume of 1 mL. The mean fluorescence intensity (MFI) was read on a Beckman Coulter Cytomics FC500 flow cytometer. The experiments were repeated by adding 5 µL of ADP (10 µM). The data are expressed as the mean of three independent experiments
Luminescent gold nanoclusters for bioimaging applications
Beilstein J. Nanotechnol. 2020, 11, 533–546, doi:10.3762/bjnano.11.42
- bioimaging in preclinical, clinical evaluation and patient treatment has encouraged extensive investigation to develop new imaging methods [3][4]. Among several imaging techniques, fluorescence microscopy has evolved as a widely used non-invasive method to visualize real-time biological processes with high
- spatial resolution [5][6]. The image quality of biological structures under fluorescence microscopy also depends on the performance of the fluorophores. Furthermore, bioimaging of cells and tissues faces additional challenges due to background autofluorescence generated from the intrinsic emission of
- ]. Luminescence can also be achieved via intramolecular energy transfer between an organic ligand and lanthanide metal ions through chelation [11]. Large Stokes shift, high quantum yield and long fluorescence lifetime make lanthanide complexes excellent candidates in imaging applications [12][13]. The lanthanide
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