scholarly journals Silica Nanoparticle Formation by Using Droplet-Based Microreactor

2017 ◽  
Author(s):  
Arsalan Nikdoost ◽  
Alican Ozkan ◽  
Yusuf Kelestemur ◽  
Hilmi Volkan Demir ◽  
E. Yegan Erdem
Keyword(s):  
Quantum Dots ◽  
Silica Nanoparticles ◽  
Size Distribution ◽  
Size Range ◽  
Silica Nanoparticle ◽  
Silica Particles ◽  
Cdse Nanoparticles ◽  
Synthesis Methods ◽  
Nanoparticle Formation ◽  
Comparable Size

This paper describes a method for the synthesis of silica nanoparticles that can be later used for coating of quantum dots inside a microfluidic reactor. Here, a droplet-based system is used where two reagents were mixed inside the droplets to obtain silica. Particles in the size range of 25±2.7 nm were obtained with comparable size distribution to controlled batch-wise synthesis methods. This method is suitable to be used later to coat CdSe nanoparticles inside the microreactor.

An Experimental Study on Synthesis and Characterization of Silica Nanoparticles Prepared by Sol-Gel Method

2007 ◽  
Vol 553 ◽  
pp. 245-251
Author(s):  
Ali Shokuhfar ◽  
Tolou Shokuhfar ◽  
M. Ghazinejad ◽  
R. Babazade ◽  
S. Tabatabae
Keyword(s):  
Electron Microscopy ◽  
Silica Nanoparticles ◽  
Size Distribution ◽  
Sol Gel ◽  
Sio2 Nanoparticles ◽  
Industrial Applications ◽  
Silica Particles ◽  
Narrow Size Distribution ◽  
Molar Ratios ◽  
Transmission Electron

Monodispersed nanometer-sized particles proved to be very important and advantageous in many industrial applications. One of the notable groups of these particles is silica (SiO2) nanoparticles which are widely utilized in developing numerous products such as electrical and thermal insulators, humidity sensors, varnish, etc. Since the quality of some of these products depends highly on the purity and size distribution of the silica particles, it is necessary to produce silica nanoparticles of narrow size distribution and very high purity. In this research silica nanoparticles, with a relatively narrow size distribution, have been synthesized via the hydrolysis reaction of tetraethoxisilane (TEOS) in the solution of deionized water and ethanol (C2H5OH), and in the presence of ammonia (NH3) as a catalyst. The nature, morphology and the size of the silica particles has been studied using Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and X-ray diffraction. Results indicate that the morphology, structure and the diameter of silica particles depend strongly on the molar ratios of the reactants.

scholarly journals Bright fluorescent silica-nanoparticle probes for high-resolution STED and confocal microscopy

2017 ◽  
Vol 8 ◽  
pp. 1283-1296 ◽  
Author(s):  
Isabella Tavernaro ◽  
Christian Cavelius ◽  
Henrike Peuschel ◽  
Annette Kraegeloh
Keyword(s):  
Silica Nanoparticles ◽  
Fluorescent Dyes ◽  
Organic Dyes ◽  
Imaging Techniques ◽  
A549 Cells ◽  
Water System ◽  
Silica Nanoparticle ◽  
Stimulated Emission ◽  
Synthesis Methods ◽  
Size Dispersion

In recent years, fluorescent nanomaterials have gained high relevance in biological applications as probes for various fluorescence-based spectroscopy and imaging techniques. Among these materials, dye-doped silica nanoparticles have demonstrated a high potential to overcome the limitations presented by conventional organic dyes such as high photobleaching, low stability and limited fluorescence intensity. In the present work we describe an effective approach for the preparation of fluorescent silica nanoparticles in the size range between 15 and 80 nm based on L-arginine-controlled hydrolysis of tetraethoxysilane in a biphasic cyclohexane–water system. Commercially available far-red fluorescent dyes (Atto647N, Abberior STAR 635, Dy-647, Dy-648 and Dy-649) were embedded covalently into the particle matrix, which was achieved by aminosilane coupling. The physical particle attributes (particle size, dispersion, degree of agglomeration and stability) and the fluorescence properties of the obtained particles were compared to particles from commonly known synthesis methods. As a result, the spectroscopic characteristics of the presented monodisperse dye-doped silica nanoparticles were similar to those of the free uncoupled dyes, but indicate a much higher photostability and brightness. As revealed by dynamic light scattering and ζ-potential measurements, all particle suspensions were stable in water and cell culture medium. In addition, uptake studies on A549 cells were performed, using confocal and stimulated emission depletion (STED) microscopy. Our approach allows for a step-by-step formation of dye-doped silica nanoparticles in the form of dye-incorporated spheres, which can be used as versatile fluorescent probes in confocal and STED imaging.

Application of Silica Nanoparticles in the Determination of Herbicides in Environmental Water Samples Using Liquid Chromatography-Mass Spectroscopy

2020 ◽  
Vol 16 (5) ◽  
pp. 748-756
Author(s):  
Mir Waqas Alam ◽  
Tentu Nageswara Rao ◽  
Yarasani Prashanthi ◽  
Vourse Sridhar ◽  
Adil Alshoaibi ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Liquid Chromatography ◽  
Silica Nanoparticles ◽  
Solid Phase ◽  
Silica Nanoparticle ◽  
Environmental Water ◽  
Phase Extraction ◽  
Functionalized Nanoparticles ◽  
Supporting Material

Background: Herbicides are very beneficial in the crop yield with the aid of controlling weeds within the agriculture, but several herbicides are chronic in soil. Objective: In this study, nanoparticles and the packages of synthesized novel silica nanoparticles were studied for the preconcentration of herbicides. Methods: These nanoparticles prepared by the Stöber mechanism were purified and functionalized. Nanoparticles thus prepared successfully were used as supporting material for the preconcentration of residues of herbicides in the water. Results: Preconcentration was achieved by preparing the silica-based solid-phase-extraction cartridges. Nanoparticles used for this purpose were within the range of 50-250 nm. An SPE cartridge was prepared by packing 200 mg of silica nanoparticle in the empty cartridge of diameter 5.5 cm and length 0.6 cm in between PTFE frits. Aqueous solutions of 0.1 μg/ml of herbicides were prepared separately, and 10 ml of the solution was passed through the cartridge at the rate of 0.2 ml/min. After passing 10 ml volume of the aqueous solution, residues adsorbed on the cartridge were eluted using 2 ml of acetonitrile. The eluate was injected to determine the herbicide residue adsorbed on the SPE cartridge. Conclusion: In the study, it was found that greater than 90% of the herbicide residues were trapped on silica nanoparticle-based SPE cartridge. An analytical method was developed for the simultaneous determination of these herbicides. The residues were quantified by LC-MS/MS with ESI mode.

Mesoporous Silica Nanoparticles of Hydroxyurea: Potential

2020 ◽  
Vol 10 ◽  
Author(s):  
Kumar Nishchaya ◽  
Swatantra K.S. Kushwaha ◽  
Awani Kumar Rai
Keyword(s):  
Drug Release ◽  
Silica Nanoparticles ◽  
Mesoporous Silica Nanoparticles ◽  
Release Kinetics ◽  
Average Particle Size ◽  
Silica Nanoparticle ◽  
Average Particle ◽  
Independent Variables ◽  
Lower Temperature

Background: Present malignant cancer medicines has the advancement of magnetic nanoparticles as delivery carriers to magnetically accumulate anticancer medication in malignant growth tissue. Aim: In the present investigation, a silica nanoparticles (MSNs) stacked with hydroxyurea were combined and was optimized for dependent and independent variables. Method: In this study, microporous silica nanoparticle stacked with neoplastic medication had been prepared through emulsification followed with solvent evaporation method. Prepared MSNs were optimized for dependent and independent variables. Different formulations were prepared with varying ratio of polymer, lipid and surfactant which affects drug release and kinetics of drug release pattern. The obtained MSNs were identified by FTIR, SEM, drug entrapment, in-vitro drug release, drug release kinetics study, stability testing in order to investigate the nanoparticle characteristics. Results: The percentage drug entrapment of the drug for the formulations F1, F2, F3, was found to be 27.78%, 65.52% and 48.26%. The average particle size for F2 formulation was found to be 520 nm through SEM. The cumulative drug release for the formulations F1, F2, F3 was found to be 64.17%, 71.82% and 32.68%. The formulations were found to be stable which gives controlled drug delivery for 6 hours. Conclusion: From the stability studies data it can be culminated that formulations are most stable when stored at lower temperature or in refrigerator i.e. 5˚C ± 3˚C. It can be concluded that MSN’s loaded with hydroxyurea is a promising approach towards the management of cancer due to its sustained release and less side effects.

scholarly journals Nucleation of Ga droplets self-assembly on GaAs(111)A substrates

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Artur Tuktamyshev ◽  
Alexey Fedorov ◽  
Sergio Bietti ◽  
Stefano Vichi ◽  
Riccardo Tambone ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Size Distribution ◽  
Self Assembly ◽  
Cluster Size ◽  
Droplet Size Distribution ◽  
Local Environment ◽  
The Self ◽  
Critical Cluster ◽  
Droplet Nucleation ◽  
High Degree

AbstractWe investigated the nucleation of Ga droplets on singular GaAs(111)A substrates in the view of their use as the seeds for the self-assembled droplet epitaxial quantum dots. A small critical cluster size of 1–2 atoms characterizes the droplet nucleation. Low values of the Hopkins-Skellam index (as low as 0.35) demonstrate a high degree of a spatial order of the droplet ensemble. Around $$350\,^{\circ }\hbox {C}$$ 350 ∘ C the droplet size distribution becomes bimodal. We attribute this observation to the interplay between the local environment and the limitation to the adatom surface diffusion introduced by the Ehrlich–Schwöbel barrier at the terrace edges.

Fully numerical analysis of III-nitride based quantum dot lasers considering the quantum dots size distribution

Optik ◽  
2015 ◽  
Vol 126 (1) ◽  
pp. 119-122 ◽  
Author(s):  
P. Navaeipour ◽  
A. Asgari
Keyword(s):  
Quantum Dots ◽  
Numerical Analysis ◽  
Quantum Dot ◽  
Size Distribution ◽  
Quantum Dot Lasers

Size distribution effects on self-assembled InAs quantum dots

2007 ◽  
Vol 18 (S1) ◽  
pp. 191-194 ◽  
Author(s):  
S. I. Jung ◽  
H. Y. Yeo ◽  
I. Yun ◽  
J. Y. Leem ◽  
I. K. Han ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Size Distribution ◽  
Inas Quantum Dots ◽  
Self Assembled

Computational modeling of expansion and deterioration due to alkali-silica reaction: Effects of size range, size distribution, and content of reactive aggregate

2021 ◽  
pp. 111220
Author(s):  
Lifu Yang ◽  
Madura Pathirage ◽  
Huaizhi Su ◽  
Mohammed Alnaggar ◽  
Giovanni Di Luzio ◽  
...  
Keyword(s):  
Computational Modeling ◽  
Size Distribution ◽  
Size Range ◽  
Range Size ◽  
Alkali Silica Reaction ◽  
Reactive Aggregate

One-pot synthesis and application of novel amino-functionalized silica nanoparticles using guanidine as amino group

2016 ◽  
Vol 40 (10) ◽  
pp. 8444-8450 ◽  
Author(s):  
Feng Guodong ◽  
Guan Mingming ◽  
Lai Qi ◽  
Mi Hongyu ◽  
Li Guanghua ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Silica Nanoparticles ◽  
Amino Group ◽  
Functionalized Silica ◽  
Henry Reaction ◽  
Modified Silica ◽  
One Pot ◽  
One Pot Synthesis ◽  
Modified Silica Nanoparticles ◽  
Functionalized Silica Nanoparticles

The preparation of modified silica nanoparticles with guanidine was developed and used to catalyze the Henry reaction and fix quantum dots.

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