scholarly journals Hybrid inorganic-organic fluorescent silica nanoparticles—influence of dye binding modes on dye leaching

2021 ◽  
Author(s):  
Nadja Klippel ◽  
Gregor Jung ◽  
Guido Kickelbick
Keyword(s):  
Silica Nanoparticles ◽  
Rhodamine B ◽  
Fluorescent Dyes ◽  
Matrix Material ◽  
Fluorescein Isothiocyanate ◽  
Silica Matrix ◽  
Physical Interaction ◽  
Binding Modes ◽  
Xanthene Dyes ◽  
Rhodamine B Isothiocyanate

AbstractSilica nanoparticles with embedded fluorescent dyes represent an important class of markers for example in biological imaging. We systematically studied the various incorporation mechanisms of fluorescent xanthene dyes in 30–40 nm silica nanoparticles. An important parameter was the interaction of the dye with the matrix material, either by weak electrostatic or strong covalent interactions, which also has implications on the stability of fluorescence and brightness of the dyes. Factors that can influence leaching of dyes such as the position of the dyes in particles and the intensity of the particle-dye interaction were investigated by using the solvatochromic effect of xanthene dyes and by stationary fluorescence anisotropy measurements. We compared uranine and rhodamine B, which were physically embedded, with modified fluorescein isothiocyanate and rhodamine B isothiocyanate, which were covalently bound to the silica matrix within a usual Stöber synthesis. Systematic leaching studies of time spans up to 4 days revealed that covalent bonding of dyes like fluorescein isothiocyanate or rhodamine B isothiocyanate is necessary for fluorescence stability, since dyes bound by physical interaction tend to leach out of porous silica networks. Coverage of silica particles with hydrophobic protection layers of alkyltrialkoxysilanes or hydrophilic polyethylene glycol (PEG) groups resulted in a better retention of physisorbed dyes and provides the possibility to adapt the particles to the polarity of the medium. Best results were archived with PEG groups, but even small trimethylsilyl (TMS) groups already reduce leaching.

scholarly journals Silver Nanoparticles Functionalized by Fluorescein Isothiocyanate or Rhodamine B Isothiocyanate: Fluorescent and Plasmonic Materials

2021 ◽  
Vol 11 (6) ◽  
pp. 2472
Author(s):  
Ilaria Fratoddi ◽  
Chiara Battocchio ◽  
Giovanna Iucci ◽  
Daniele Catone ◽  
Antonella Cartoni ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Rhodamine B ◽  
Photoelectron Spectroscopy ◽  
Transient Absorption ◽  
Fluorescein Isothiocyanate ◽  
Dye Molecules ◽  
Chemical Surface ◽  
Vis Spectroscopy ◽  
Rhodamine B Isothiocyanate ◽  
Fluorescent Molecules

This paper presents the synthesis of silver nanoparticles (AgNPs) functionalized with fluorescent molecules, in particular with xanthene-based dyes, i.e., fluorescein isothiocyanate (FITC, λmax = 485 nm) and rhodamine B isothiocyanate (RITC, λmax = 555 nm). An in-depth characterization of the particle–dye systems, i.e., AgNPs–RITC and AgNPs–FITC, is presented to evaluate their chemical structure and optical properties due to the interaction between their plasmonic and absorption properties. UV–Vis spectroscopy and the dynamic light scattering (DLS) measurements confirmed the nanosize of the AgNPs–RITC and AgNPs–FITC. Synchrotron radiation X-ray photoelectron spectroscopy (SR-XPS) was used to study the chemical surface functionalization by structural characterization, confirming/examining the isothiocyanate–metal interaction. For AgNPs–RITC, in which the plasmonic and fluorescence peak are not superimposed, the transient dynamics of the dye fluorescence were also studied. Transient absorption measurements showed that by exciting the AgNPs–RITC sample at a wavelength corresponding to the AgNP plasmon resonance, it was possible to preferentially excite the RITC dye molecules attached to the surface of the NPs with respect to the free dye molecules in the solution. These results demonstrate how, by combining plasmonics and fluorescence, these AgNPs can be used as promising systems in biosensing and imaging applications.

scholarly journals Ultrabright Fluorescent Silica Nanoparticles for Dual pH and Temperature Measurements

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1524
Author(s):  
Saquib Ahmed M. A. Peerzade ◽  
Nadezhda Makarova ◽  
Igor Sokolov
Keyword(s):  
Silica Nanoparticles ◽  
Fluorescent Dyes ◽  
Silica Matrix ◽  
Temperature Measurements ◽  
Dye Molecules ◽  
Absolute Deviation ◽  
Biologically Relevant ◽  
Close Proximity ◽  
Ratiometric Sensors ◽  
Relevant Range

The mesoporous nature of silica nanoparticles provides a novel platform for the development of ultrabright fluorescent particles, which have organic molecular fluorescent dyes physically encapsulated inside the silica pores. The close proximity of the dye molecules, which is possible without fluorescence quenching, gives an advantage of building sensors using FRET coupling between the encapsulated dye molecules. Here we present the use of this approach to demonstrate the assembly of ultrabright fluorescent ratiometric sensors capable of simultaneous acidity (pH) and temperature measurements. FRET pairs of the temperature-responsive, pH-sensitive and reference dyes are physically encapsulated inside the silica matrix of ~50 nm particles. We demonstrate that the particles can be used to measure both the temperature in the biologically relevant range (20 to 50 °C) and pH within 4 to 7 range with the error (mean absolute deviation) of 0.54 °C and 0.09, respectively. Stability of the sensor is demonstrated. The sensitivity of the sensor ranges within 0.2–3% °C−1 for the measurements of temperature and 2–6% pH−1 for acidity.

DETERMINATION OF A SUITABLE CONDITION OF GRAFT COPOLYMERIZATION OF VINYLTRIETHOXYSILANE ONTO NR TO FORM NANOMATRIX STRUCTURE

2018 ◽  
Vol 91 (4) ◽  
pp. 767-775 ◽  
Author(s):  
Yuanbing Zhou ◽  
Yoshimasa Yamamoto ◽  
Seiichi Kawahara
Keyword(s):  
Silica Nanoparticles ◽  
Graft Copolymerization ◽  
Monomer Concentration ◽  
Minor Component ◽  
Suitable Condition ◽  
Average Diameter ◽  
Silica Matrix ◽  
Rubber Particles ◽  
Hydrolysis And Condensation ◽  
Nanomatrix Structure

ABSTRACT Graft copolymerization of vinyltriethoxysilane (VTES) onto NR particles in the latex stage is a unique reaction, since it occurs together with hydrolysis and condensation of the triethoxysilane group of VTES to form a colloidal silica linking to the rubber particles. These reactions may contribute to the formation of a silica nanomatrix structure that consists of a dispersoid of rubber particles as the major component and a silica matrix as the minor component. Here, the graft copolymerization of VTES followed by hydrolysis and condensation is investigated to determine a suitable condition to prepare NR with a silica nanomatrix structure. The mechanical properties of the resulting graft copolymer are discussed in relation to the morphology, silica content, and gel content of the rubber. Based on morphological observations, NR particles with an average diameter of approximately 1 μm are well dispersed in a nanomatrix consisting of silica nanoparticles. The thickness of the silica nanomatrix increases as the monomer concentration increases, and a long incubation time generates large silica nanoparticles. The tensile strength and viscoelastic properties are significantly improved by forming the silica nanomatrix structure, with its continuous structure that prevents the NR particles from merging.

Efficient artificial light-harvesting systems based on aggregation-induced emission constructed in supramolecular gels

Soft Matter ◽  
2021 ◽  
Author(s):  
Xinxian Ma ◽  
bo qiao ◽  
Jinlong Yue ◽  
JingJing Yu ◽  
yutao geng ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Rhodamine B ◽  
Fluorescent Dyes ◽  
Light Harvesting ◽  
Artificial Light ◽  
Efficient Energy Transfer ◽  
Aggregation Induced Emission ◽  
Efficient Energy ◽  
Harvesting Systems ◽  
Acyl Hydrazone

Based on a new designed acyl hydrazone gelator (G2), we developed an efficient energy transfer supramolecular organogel in glycol with two different hydrophobic fluorescent dyes rhodamine B (RhB) and acridine...

scholarly journals Synthesis of Silica Nanoparticles with Physical Encapsulation of Near-Infrared Fluorescent Dyes and Their Tannic Acid Coating

ACS Omega ◽  
2021 ◽  
Author(s):  
Yoshio Nakahara ◽  
Yukiho Nakajima ◽  
Soichiro Okada ◽  
Jun Miyazaki ◽  
Setsuko Yajima
Keyword(s):  
Silica Nanoparticles ◽  
Tannic Acid ◽  
Near Infrared ◽  
Fluorescent Dyes ◽  
Acid Coating

scholarly journals OLIGOMERIC SILSESQUIOXANES COMBINING AZO- AND FLUORESCENT DYES IN ORGANIC SHELL

2019 ◽  
Vol 85 (4) ◽  
pp. 71-80
Author(s):  
Mariana Gumenna ◽  
Nina Klimenko ◽  
Alexandr Stryutsky ◽  
Alexandr Shevchuk ◽  
Viktor Kravchenko ◽  
...  
Keyword(s):  
Absorption Band ◽  
Rhodamine B ◽  
Fluorescent Dyes ◽  
Hydroxyl Groups ◽  
Uv Spectrum ◽  
Absorption Bands ◽  
Organic Shell ◽  
Similar Band ◽  
Inorganic Nanocomposites ◽  
Epoxy Groups

A method for the synthesis of reactive oligomeric silsesquioxanes, combining fragments of azo dye 4-(phenylazo)phenol and fluorescent dye Rhodamine B in various proportions in an organic shell was developed. These compounds were obtained by the reaction between the oligosilsesquioxane nanoparticles consisting of a mixture of linear, branched, ladder and polyhedral structures with epoxy groups in an organic frame (OSS–Ep) and the dyes. The structure of the synthesized substances was characterized by the methods of IR and 1H NMR spectroscopy. The UV-Vis spectra of OSS–Pp–Rh in DMF solution contain absorption bands characteristic of both acidic (560 and 350 nm) and lactone (in the range of 318–326 nm) forms of Rhodamine B. The absorption band of 4-(phenylazo) phenol fragments corresponding to π−π* transition is observed at 348 nm and overlaps the absorption band of Rhodamine B at 350 nm.The intensity of the absorption bands of fragments of various dyes depends on their content in organic frame of the silsesquioxane core. The intensity of the absorption bands at 348 nm and at 560 nm increases with an increase in the content of 4-(phenylazo)phenol and Rhodamine B correspondingly.It should be noted that when using DMF as a solvent the absorption band corresponding to acidic form of Rhodamine B at 560 nm in the UV-Vis spectra of the compounds obtained is more intense than similar band in the spectrum of the original Rhodamine B. Therefore, the attachment of Rhodamine B to the silsesquioxane core of oligomeric silsesquioxanes mixture does not have a significant effect on the position of absorption maxima in the UV-spectrum and prevents dye’s fragments from converting to the colorless lactone form. In the fluorescence spectra of OSS–Pp–Rh obtained using DMF as a solvent a peak at λ max = 592 nm (λex= 520 nm) is observed. The position of the fluorescence peak and its intensity in the spectra at the same optical density of the medium practically do not depend on the ratio of fragments of 4-(phenylazo)phenol and Rhodamine B in organic frame of OSS–Pp–Rh.  The combination of two different chromophores in organic shell of the silsesquioxane core broadens the range of absorbed light and the change of their ratio allows to adjust the absorption intensity in a certain area. The presence of hydroxyl groups makes it possible to introduce the obtained compounds into the composition of polymeric organic-inorganic nanocomposites by covalent bonding.

Role of Aqueous-Phase Calcination in Synthesis of Ultra-Stable Dye-Embedded Fluorescent Nanoparticles for Cellular Probing

2021 ◽  
pp. 000370282110275
Author(s):  
Rachel Rex ◽  
Soumik Siddhanta ◽  
Ishan Barman
Keyword(s):  
Silica Nanoparticles ◽  
Cell Imaging ◽  
Fluorescent Dyes ◽  
Aqueous Media ◽  
Clinical Diagnostics ◽  
Live Cell ◽  
Metal Nanoparticle ◽  
Superior Performance ◽  
Fluorescent Nanoparticles

Fluorescence imaging is a major driver of discovery in biology, and an invaluable asset in clinical diagnostics. To overcome quenching limitations of conventional fluorescent dyes and further improve intensity, nanoparticle-based constructs have been the subject of intense investigation, and within this realm, dye-doped silica-coated nanoparticles have garnered significant attention. Despite their growing popularity in research, fluorescent silica nanoparticles suffer from a significant flaw. The degradation of these nanoparticles in biological media by hydrolytic dissolution is underreported, leading to serious misinterpretations, and limiting their applicability for live cell and in vivo imaging. Here, the development of an ultra-stable, dye-embedded, silica-coated metal nanoparticle is reported, and its superior performance in long-term live cell imaging is demonstrated. While conventional dye-doped silica nanoparticles begin to degrade within an hour in aqueous media, by leveraging a modified liquid calcination process, this new construct is shown to be stable for at least 24 h. The stability of this metal-enhanced fluorescent probe in biologically relevant temperatures and media, and its demonstrated utility for cell imaging, paves the way for its future adoption in biomedical research.

scholarly journals A Novel Ratiometric Probe Based on Nitrogen-Doped Carbon Dots and Rhodamine B Isothiocyanate for Detection of Fe3+in Aqueous Solution

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Lin Liu ◽  
Lu Chen ◽  
Jiangong Liang ◽  
Lingzhi Liu ◽  
Heyou Han
Keyword(s):  
Rhodamine B ◽  
Carbon Dots ◽  
Dynamic Range ◽  
Tap Water ◽  
Buffer Solution ◽  
Nitrogen Doped ◽  
Rhodamine B Isothiocyanate ◽  
Doped Carbon Dots ◽  
Nitrogen Doped Carbon ◽  
Ratiometric Probe

A ratiometric probe for determining ferric ions (Fe3+) was developed based on nitrogen-doped carbon dots (CDs) and rhodamine B isothiocyanate (RhB), which was then applied to selective detection of Fe3+in PB buffer solution, lake water, and tap water. In the sensing system, FePO4particles deposit on the surface of CDs, resulting in larger particles and surface passivation. The fluorescence (FL) intensity and the light scattering (LS) intensity of CDs can be gradually enhanced with the addition of Fe3+, while the FL intensity of RhB remains constant. The ratiometric light intensity of CDs LS and RhB FL was quantitatively in response to Fe3+concentrations in a dynamic range of 0.01–1.2 μM, with a detection limit as low as 6 nM. Other metal ions, such as Fe2+, Al3+, K+, Ca2+, and Co2+, had no significant interference on the determination of Fe3+. Compared with traditional probes based on single-signal probe for Fe3+detection, this dual-signal-based ratiometric probe exhibits a more reliable and stable response on target concentration and is characterized by easy operation in a simple fluorescence spectrophotometer.

scholarly journals Ratiometric pH Sensing and Imaging in Living Cells with Dual-Emission Semiconductor Polymer Dots

Molecules ◽  
2019 ◽  
Vol 24 (16) ◽  
pp. 2923
Author(s):  
Piaopiao Chen ◽  
Iqra Ilyas ◽  
Su He ◽  
Yichen Xing ◽  
Zhigang Jin ◽  
...  
Keyword(s):  
Fluorescent Dyes ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Fluorescein Isothiocyanate ◽  
Water Soluble ◽  
Ph Sensing ◽  
Dual Emission ◽  
Polymer Dots ◽  
Ratiometric Ph Sensing

Polymer dots (Pdots) represent newly developed semiconductor polymer nanoparticles and exhibit excellent characteristics as fluorescent probes. To improve the sensitivity and biocompatibility of Pdots ratiometric pH biosensors, we synthesized 3 types of water-soluble Pdots: Pdots-PF, Pdots-PP, and Pdots-PPF by different combinations of fluorescent dyes poly(9,9-dioctylfluorenyl-2,7-diyl) (PFO), poly[(9,9-dioctyl-fluorenyl-2,7-diyl)-co-(1,4-benzo-{2,1′,3}-thiadazole)] (PFBT), and fluorescein isothiocyanate (FITC). We found that Pdots-PPF exhibits optimal performance on pH sensing. PFO and FITC in Pdots-PPF produce pH-insensitive (λ = 439 nm) and pH-sensitive (λ = 517 nm) fluorescence respectively upon a single excitation at 380 nm wavelength, which enables Pdots-PPF ratiometric pH sensing ability. Förster resonance energy transfer (FRET) together with the use of PFBT amplify the FITC signal, which enables Pdots-PPF robust sensitivity to pH. The emission intensity ratio (I517/I439) of Pdots-PPF changes linearly as a function of pH within the range of pH 3.0 to 8.0. Pdots-PPF also possesses desirable reversibility and stability in pH measurement. More importantly, Pdots-PPF was successfully used for cell imaging in Hela cells, exhibiting effective cellular uptake and low cytotoxicity. Our study suggests the promising potential of Pdots-PPF as an in vivo biomarker.

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