scholarly journals A Study on Preparation and Stabilizing Mechanism of Hydrophobic Silica Nanofluids

Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1385 ◽  
Author(s):  
Mingwei Zhao ◽  
Wenjiao Lv ◽  
Yuyang Li ◽  
Caili Dai ◽  
Hongda Zhou ◽  
...  
Keyword(s):  
Particle Size ◽  
Zeta Potential ◽  
Silica Nanoparticles ◽  
Effect Of Ph ◽  
Hydrophobic Silica ◽  
The Stability

Nanofluids have increasingly drawn interest in recent years with their various applications in a number of fields. The method for the preparation of stable nanofluids is a key concern for extending the application of nanofluids. This study focuses on the effect of pH, dosage of surfactant (TX-100), and nanofluid concentration on the stability of a silica nanofluid. Particle size and zeta potential are two important factors to consider in evaluating the stability of the silica nanofluid. Results indicate that the stability of the silica nanofluid highly depends on pH, dosage of surfactant (TX-100), and nanofluid concentration. On the basis of these experiments, the best conditions for the preparation of a silica nanofluid are 0.1 wt. % for the concentration of silica nanoparticles and TX-100 and 10 for pH. A transparent and stable silica nanofluid can thus be obtained.

scholarly journals SYNTHESIS AND STABILITY OF RESVERATROL-CONJUGATED GOLD NANOPARTICLES MODIFIED WITH POLYETHYLENE GLYCOL

2020 ◽  
pp. 230-236
Author(s):  
RADITYA ISWANDANA ◽  
RICHA NURSELVIANA ◽  
SUTRIYO SUTRIYO
Keyword(s):  
Particle Size ◽  
Gold Nanoparticles ◽  
Polyethylene Glycol ◽  
Zeta Potential ◽  
High Performance ◽  
Entrapment Efficiency ◽  
Test Results ◽  
Novel Method ◽  
The Stability ◽  
Phosphate Buffered Saline

Objective: Gold nanoparticles (AuNPs) are highly useful for drug delivery, but their application is limited by their stability as they readily aggregate.This issue can be prevented by adding a stabilizing agent such as resveratrol (RSV), which is a polyphenol derived from plants, that is used to preventcancer. Therefore, we propose a novel method to prepare stable RSV-conjugated nanoparticles modified with polyethylene glycol (RSV-AuNP-PEG).Methods: In the first step, the Turkevich method was used to synthesize the AuNPs. Then, PEG was added as stabilizer agent and conjugated with RSV.The synthesized conjugates were characterized using ultraviolet-visible spectrophotometry, Fourier transform infrared spectroscopy, particle sizeanalysis, and high-performance liquid chromatography.Results: The obtained RSV-AuNP-PEG had a particle size of 83.93 nm with a polydispersity index (PDI) of 0.562 and formed a translucent purple-redfluid in solution. The zeta potential was −22.9 mV, and the highest entrapment efficiency was 75.86±0.66%. For comparison, the RSV-AuNP solutionwas purple and turbid, the particle size was 51.97 nm with a PDI of 0.694, and the zeta potential was −24.6 mV. The stability test results showed thatthe storage stability of RSV-AuNP-PEG was better than that of AuNP-RSV. Further, the RSV-AuNP-PEG was shown to be most stable in 2% bovine serumalbumin (BSA) while the AuNP-RSV was most stable in 2% BSA in phosphate-buffered saline pH 7.4.Conclusion: These results show that modification of RSV-conjugated AuNPs with PEG effectively prevents their aggregation in storage, but only incertain mediums.

scholarly journals Effect of Potato Pulp Pectic Polysaccharide on the Stability of Acidified Milk Drinks

Molecules ◽  
2020 ◽  
Vol 25 (23) ◽  
pp. 5632
Author(s):  
Weixuan Sun ◽  
Wenhan Yang ◽  
Yuxue Zheng ◽  
Huiling Zhang ◽  
Haitian Fang ◽  
...  
Keyword(s):  
Particle Size ◽  
Zeta Potential ◽  
Neutral Sugar ◽  
Lower Serum ◽  
Pectic Polysaccharide ◽  
Potato Pulp ◽  
Lower Viscosity ◽  
Stabilizing Effect ◽  
New Ideas ◽  
The Stability

In order to broaden the application of potato pulp pectic polysaccharide (PPP) in stabilizing acidified milk drinks (AMDs) and investigate the stabilizing effect and physical properties of AMDs prepared with PPP, a comparative study was made among PPP, commercial high methoxyl pectin (HMP) and low methoxyl pectin (LMP). The zeta potential, rheology, particle size and serum separation of AMDs were evaluated after preparing with PPP, HMP and LMP, respectively. Results indicated that PPP led to lower serum separation than LMP (14.65% for AMDs prepared with 0.5% PPP compared to 25.05% for AMDs prepared with 0.5% LMP), but still higher than HMP (9.09% for AMDs prepared with 0.5% HMP). However, narrower particle size distribution and lower viscosity of AMDs was achieved by PPP than by LMP and HMP. PPP can electrostatically adsorb on the surface of casein and its abundant neutral sugar side chains would provide steric hindrance to prevent casein flocculation in AMDs. Our results might provide some new ideas for the application of PPP in improving the stability of AMDs.

scholarly journals The Effect of the Liposomal Encapsulated Saffron Extract on the Physicochemical Properties of a Functional Ricotta Cheese

Molecules ◽  
2021 ◽  
Vol 27 (1) ◽  
pp. 120
Author(s):  
Zahra Siyar ◽  
Ali Motamedzadegan ◽  
Jafar Mohammadzadeh Milani ◽  
Ali Rashidinejad
Keyword(s):  
Particle Size ◽  
Zeta Potential ◽  
Encapsulation Efficiency ◽  
Textural Properties ◽  
Constant Concentration ◽  
Soy Lecithin ◽  
Significant Difference ◽  
Saffron Extract ◽  
The Stability ◽  
Potential Stability

In this study, the encapsulation of saffron extract (SE) was examined at four various concentrations of soy lecithin (0.5%–4% w/v) and constant concentration of SE (0.25% w/v). Particle size and zeta potential of liposomes were in the range of 155.9–208.1 nm and −34.6–43.4 mV, respectively. Encapsulation efficiency was in the range of 50.73%–67.02%, with the stability of nanoliposomes in all treatments being >90%. Encapsulated SE (2% lecithin) was added to ricotta cheese at different concentrations (0%, 0.125%, 1%, and 2% w/v), and physicochemical and textural properties of the cheese were examined. Lecithin concentration significantly (p ≤ 0.05) affected the particle size, zeta potential, stability, and encapsulation efficiency of the manufactured liposomes. In terms of chemical composition and color of the functional cheese, the highest difference was observed between the control cheese and the cheese enriched with 2% liposomal encapsulated SE. Hardness and chewiness increased significantly (p ≤ 0.05) in the cheeses containing encapsulated SE compared to the control cheese. However, there was no significant difference in the case of adhesiveness, cohesiveness, and gumminess among different cheeses. Overall, based on the findings of this research, liposomal encapsulation was an efficient method for the delivery of SE in ricotta cheese as a novel functional food.

Stability of nano-sized titanium dioxide in an aqueous environment: effects of pH, dissolved organic matter and divalent cations

2013 ◽  
Vol 68 (2) ◽  
pp. 276-282 ◽  
Author(s):  
X. N. Yang ◽  
F. Y. Cui
Keyword(s):  
Particle Size ◽  
Titanium Dioxide ◽  
Organic Matter ◽  
Zeta Potential ◽  
Dissolved Organic Matter ◽  
Ph Value ◽  
Divalent Cations ◽  
Aqueous Environment ◽  
Nano Tio2 ◽  
The Stability

Nano-sized titanium dioxide in the aquatic environment has a potential impact on the environment and human health. In this study, the impact of pH value, dissolved organic matter (DOM) and divalent cations (Ca2+) on the stability of titanium dioxide nanoparticles (nano-TiO2) in an aqueous environment was investigated in batch tests. The results showed that the particle size of nano-TiO2 was not sensitive to pH value but was inversely proportional to zeta potential. The nano-TiO2 becomes more stable with surface zeta potential, accompanied by small particle size and high dispersion. In the presence of DOM, the particle size was smaller and the stability of nano-TiO2 could be enhanced. This might be a synergistic effect of the ligand exchange and electrostatic force. Particle size increased with the addition of Ca2+ and the stability decreased.

The Influence of Groundwater on the Stability of Silica Colloids

2009 ◽  
Vol 1193 ◽  
Author(s):  
Pirkko Holtta ◽  
Mari Lahtinen ◽  
Martti Hakanen ◽  
Jukka Lehto ◽  
Piia Juhola
Keyword(s):  
Particle Size ◽  
Zeta Potential ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Colloidal Silica ◽  
Silica Sol ◽  
Low Salinity ◽  
Silica Concentration ◽  
Silica Colloids ◽  
The Stability

AbstractNon-cementitious grouts have been tested in Olkiluoto for the sealing of fractures with the small hydraulic apertures. A promising non-cementitious inorganic grout material for sealing the fractures with the apertures less than 0.05 mm is commercial colloidal silica called silica sol. The potential relevance of colloid-mediated radionuclide transport is highly dependent on their stability in different geochemical environments. The objective of this work was to follow stability of silica sol colloids in low salinity Allard and saline OLSO reference groundwater (pH 7–11) and in deionized milliQ water. Stability of silica sol colloids was followed by measuring particle size distribution, zeta potential, colloidal and reactive silica concentrations. The particle size distributions were determined applying the dynamic light scattering (DLS) method and zeta potential based on dynamic electrophoretic mobility. The colloidal silica concentration was calculated from DLS measurements applying a calibration using a standard series of silica sol. Dissolved reactive silica concentration was determined using the molybdate blue (MoO4) method.These results confirmed that the stability of silica colloids dependent significantly on groundwater salinity. In deionized water, particle size distribution and zeta potential was rather stable except the most diluted solution. In low salinity Allard, particle size distribution was rather constant and the mean particle diameter remained less than 100 nm. High negative zeta potential values indicated the existence of stable silica colloids. In saline OLSO, particle size distribution was wide from a nanometer scale to thousands of nanometers. The disappearance of large particles, decrease in colloidal particle concentration and zeta potential near zero suggest flocculation or coagulation. Under prevailing saline groundwater conditions in Olkiluoto silica colloids released from silica sol are expected to be instable but the possible influence of low salinity glacial melt water has to be considered.

Interlaboratory comparison for the measurement of particle size and zeta potential of silica nanoparticles in an aqueous suspension

2011 ◽  
Vol 13 (12) ◽  
pp. 7317-7329 ◽  
Author(s):  
Andrée Lamberty ◽  
Katrin Franks ◽  
Adelina Braun ◽  
Vikram Kestens ◽  
Gert Roebben ◽  
...  
Keyword(s):  
Particle Size ◽  
Zeta Potential ◽  
Silica Nanoparticles ◽  
Interlaboratory Comparison ◽  
Aqueous Suspension

scholarly journals FORMULATION AND OPTIMIZATION OF NIFEDIPINE LOADED NANOCARRIERS

2021 ◽  
pp. 311-317
Author(s):  
ASHWINI JADHAV ◽  
BINOY VARGHESE CHERIYAN
Keyword(s):  
Particle Size ◽  
Zeta Potential ◽  
Physical Stability ◽  
Entrapment Efficiency ◽  
Tween 80 ◽  
Physicochemical Characteristics ◽  
Good Choice ◽  
The Stability

Objective: The main aim of this study to formulate a nifedipine-loaded nanocarrier for improving solubility and bioavailability. Methods: To improve the solubility of drug, nifedipine-loaded nanocarrier (lipotomes) were prepared by using the film lipid hydration technique. lipotomes were prepared by using tween 80, which is used for increasing solubility and cetyl alcohol for lipophilic environment. Drug excipients interaction determined by FTIR. lipotomes were characterized for particle size, Entrapment efficiency and zeta potential. lipotomes were optimized by using Design-Expert 12 software. Optimized formula further lyophilized by using different cyroproyectant to improve the stability and oral administration of the drug. Results: FTIR shows there was no interaction between formulation ingredients. Mean particle size, entrapment efficiency, zeta potential was determined and found to be 308.1 nm, 96.7%, 20.1mV, respectively. Surface morphology of lipotomes was observed by a scanning electron microscope (SEM). Optimized lipotomes was lyophilized with Mannitol (8% w/v) was the ideal cryoprotectant to retain the physicochemical characteristics of the OLT formulation after lyophilization. Conclusion: Nifedipine loaded nanocarrier was successfully prepared, using film hydration method. Which have good particle size, EE% and zeta potential. After lyophilization no significant changes was observed in particle size with good physical stability, so it could be a good choice for conventional drug delivery system by doing further investigation as in vitro and in vivo study

scholarly journals Preparation and characterization of phospholipid stabilized nanoemulsions in small-scale

2019 ◽  
Author(s):  
Shila Gurung ◽  
Martin Holzer ◽  
Sabine Barnert ◽  
Rolf Schubert
Keyword(s):  
Particle Size ◽  
Zeta Potential ◽  
Sodium Cholate ◽  
Correlation Spectroscopy ◽  
Polydispersity Index ◽  
Small Scale ◽  
Polycarbonate Membrane ◽  
Polycarbonate Membranes ◽  
The Stability ◽  
The Cost

AbstractPhospholipids have been used to prepare liposomes. The use of phospholipids to stabilize nanoemulsions may cause spontaneous formation of liposomes. The main objective of this study is to develop a method to prepare phospholipid stabilized nanoemulsions in small scale (< 1 mL) and to minimize the formation of liposomes.A combination of hand extrusion and detergent removal methods was used in this study. Extrusion through polycarbonate membranes was performed in two steps, firstly using membranes of 400 nm followed by 200 nm membranes as the second step. Sodium cholate was used as a detergent to solubilize the formed liposomes which was later removed via dialysis. Nanoemulsions were characterized by measuring their particle size, polydispersity index and zeta-potential using Photon Correlation Spectroscopy and Cryo-TEM pictures. The stability of nanoemulsion stored under refrigeration was also studied.Fifty-one extrusion cycles through polycarbonate membrane of 400 nm pore size followed by one-hundred fifty-three cycles through polycarbonate membrane of 200 nm produced nanoemulsions having particle size below 200 nm (diameter). The nanoemulsions were found to be homogenous as depicted by polydispersity index (PDI) value below 0.1. Similarly, the zeta-potential was measured to be above −30 mV which is sufficient to keep nanoemulsions stable for as long as 7 months when stored under refrigeration. The Cryo-TEM pictures revealed 30 mM to be an optimum concentration of sodium cholate to prepare homogenous nanoemulsions with negligible proportion of liposomes.It was concluded that this method could be established as a small scale method of preparing nanoemulsions which will not only reduce the cost of preparation but also the disposal cost of toxic chemicals used for functionalizing nanoemulsions for scientific research.

Stability Analysis of Nano-Sized Titanium Dioxide in Aqueous Environment

2011 ◽  
Vol 374-377 ◽  
pp. 869-874 ◽  
Author(s):  
Xiao Nan Yang ◽  
Fu Yi Cui ◽  
Xiao Ying Mu ◽  
Zhi Wei Zhao
Keyword(s):  
Particle Size ◽  
Titanium Dioxide ◽  
Zeta Potential ◽  
Ph Value ◽  
Electrostatic Force ◽  
High Dispersion ◽  
Aqueous Environment ◽  
Tio2 Nps ◽  
The Stability ◽  
The Impact

Nano-sized titanium dioxide in aquatic environment poses potential impact on environment and human health. In this research, the impact of pH value, humic acid (HA) and divalent cations (Ca2+) on the stability of titanium dioxide nanoparticles(NPs) in the aqueous enviorment was investigated using a batch test. The results showed that the particle size of TiO2 NPs was not sensitive to the pH value but presented inversely proportional to zeta potential. The TiO2 NPs become more stable along with surface zeta potential, accompany with small particle size and high dispersion. In the presence of HA, the particle size was smaller and TiO2 NPs could be stabilized. This might be synergistic effect of the ligand exchange and electrostatic force. Meanwhile, NPs particle size increased with the addition of Ca2+ and the stability of TiO2 NPs became decreased.

scholarly journals Real-Time Analysis of the Stability of Oil-In-Water Pickering Emulsion by Electrochemical Impedance Spectroscopy

Molecules ◽  
2020 ◽  
Vol 25 (12) ◽  
pp. 2904
Author(s):  
Qiuyan Jiang ◽  
Ning Sun ◽  
Parveen Kumar ◽  
Qiuhong Li ◽  
Bo Liu ◽  
...  
Keyword(s):  
Particle Size ◽  
Impedance Spectroscopy ◽  
Silica Nanoparticles ◽  
Real Time ◽  
Electrical Impedance ◽  
Pickering Emulsion ◽  
Electrical Impedance Spectroscopy ◽  
Water Emulsion ◽  
Oil In Water ◽  
The Stability

In this paper, electrical impedance spectroscopy (EIS) was applied to investigate the stability of oil-in-water (O/W) Pickering emulsions prepared with negatively charged silica nanoparticles in combination with a trace amount of redox switchable fluorescent molecules, ferrocene azine (FcA). Electrical impedance values of emulsions obtained at different emulsification speeds were estimated according to the frequency response data with frequencies ranging from 1 MHz to 1 Hz. The equivalent circuit model of toluene-in-water emulsion was established by the resistor (RO/W) and capacitor (CO/W) in parallel connection. Nyquist diagrams for the emulsions prepared by toluene and water were characterized by the formation of one semi-circle. The droplet size distribution is one of the important factors that affect the stability of the emulsion, except for the volume fraction of water and oil, the size of stabilizing particles, etc. The average particle size of the emulsion droplets decreased as the emulsification speed increased, indicating the higher stability of the emulsion. It was found that the fitted impedance value RO/W of the emulsion decreased with decreasing particle size prepared at different emulsification speeds and storage time by performing real-time EIS detection techniques. The results suggested that EIS could be used to characterize the stability of a toluene-in-water emulsion stabilized by FcA modified silica nanoparticles. Moreover, based on the good electrochemical activity of the FcA molecule, the stability of the Pickering emulsion can be modulated by adding oxidant and reductant and detected by EIS in real-time.

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