Influence of particle size and dielectric environment on the dispersion behaviour and surface plasmon in nickel nanoparticles

2017 ◽  
Vol 19 (21) ◽  
pp. 14096-14106 ◽  
Author(s):  
Vikash Sharma ◽  
Chanderbhan Chotia ◽  
Tarachand Tarachand ◽  
Vedachalaiyer Ganesan ◽  
Gunadhor S. Okram

Schematic showing the effect of the dielectric environment on the zeta potential and UV-visible absorbance of monodispersed Ni nanoparticles.

2017 ◽  
Vol 19 (27) ◽  
pp. 18099-18099
Author(s):  
Vikash Sharma ◽  
Chanderbhan Chotia ◽  
Tarachand Tarachand ◽  
Vedachalaiyer Ganesan ◽  
Gunadhor S. Okram

Correction for ‘Influence of particle size and dielectric environment on the dispersion behaviour and surface plasmon in nickel nanoparticles’ by Vikash Sharma et al., Phys. Chem. Chem. Phys., 2017, 19, 14096–14106.


2007 ◽  
Vol 534-536 ◽  
pp. 117-120 ◽  
Author(s):  
Eun Hee Lee ◽  
Min Ku Lee ◽  
Chang Kyu Rhee

Colloid stability of the suspensions of Ni nanoparticles has been investigated with adding polymeric dispersant in various organic media. We characterized the dispersion stability of Ni nanoparticles by means of visual inspection, transmission profiles measured by Turbiscan, the particle size distribution, and the zeta potential. 0.01 wt% of Ni nanoparticles were found to be optimally dispersed in ethanol among various organic media employed in this study with adding the dispersant (0.6 wt%-2 wt%). As the concentration of the dispersant increased, the particle size decreased in size from 300 nm to 200 nm due to less coalescence. The zeta potential values of the Ni nanoparticles in suspensions with the dispersant were greater than -40mV. Such stable Ni nanoparticle suspensions are attributed to the electrosteric effect of the polymeric dispersant.


2017 ◽  
Author(s):  
Vikash Sharma ◽  
Tarachand ◽  
Chandrabhan Chotia ◽  
G. S. Okram

2020 ◽  
Vol 10 (1) ◽  
pp. 1981-1992

The biosynthesis of metallic nanoparticles with plant extract is a promising alternative method to traditional chemical methods. Artemisia annua L is a well-known Chinese herb for its potent therapeutic anti-malarial activity and antitumor effects. Artemisinin, a sesquiterpene lactone derived from Artemisia annua L. Although artemisinin's anticancer effect has been extensively reported, the precise mechanisms underlying its cytotoxicity remain under intensive study. In the present work rapid and simple method for green synthesis of silver nanoparticles with the leaf extract of the therapeutic plant Artemisia annua L.was carried-out. The biologically synthesized silver nanoparticles were analyzed using spectroscopic methods like UV–visible spectroscopy. Fourier transforms infrared spectroscopy (FT-IR), Zeta potential, and particle size. The green Aa-AgNPs are characterized by spectral analysis by Nanodrop-UV-visible spectroscopy. The surface Plasmon resonance peak of silver nanoparticles in colloidal solution showed maximum absorption 441nm. FT-IR spectroscopy results indicate the O-H phenolic group's participation, C=C aromatic stretching, N-H secondary amide stretching, and C-H methylene group stretching. Dynamic light scattering measurements of Aa-AgNPs revealed that the particle size is between 5-20 nm. The zeta potential of the green synthesized Aa-AgNPs was found to be -26.1 mV. The high negative potential indicates long-term stability. The antioxidant activity of Aa-AgNPs was evaluated by DPPH assay. The results revealed that they have very good antioxidant activity, which can be useful as a potential free radical scavenger. The biosynthesized Aa-AgNPs of Artemisia annua exhibited good antimicrobial activity. The Aa-AgNPs showed excellent catalytic activity in the reduction of lemon yellow and orange-red food dyes. The Aa-AgNPs can also act as an effective seed germination agent. Hence it is concluded that the green Aa-AgNPs can be useful for various biomedical and industrial applications.


NANO ◽  
2017 ◽  
Vol 12 (10) ◽  
pp. 1750124 ◽  
Author(s):  
Jingyuan Cao ◽  
Fei Wang ◽  
Shuai Liang ◽  
Xue Tong ◽  
Zhongnan Zhang ◽  
...  

Nickel nanoparticles embedded in mesoporous silica (Ni/SiO[Formula: see text] were successfully synthesized by microwave-assisted in situ self-assembly method using colloidal silica, urea and nickel nitrate as precursors and glucose as carbon template, which resulted in mesoporous structure of silica through removal of template. Ni nanoparticles were uniformly well-dispersed within mesoporous silica, which were 3.5–4.0[Formula: see text]nm in diameter and had a very narrow particle size distribution. In addition, particle size of Ni nanoparticles can be controllably adjusted by microwave power. As-prepared Ni/SiO2 catalyst exhibited better catalytic activity for reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) than Ni/SiO2-IM catalyst, which was mainly attributed to confinement effect of mesoporous silica support. This simple and versatile method can also be extended to cover many kinds of other supported catalysts for broad applications in many other catalytic reactions in the future.


Author(s):  
Aline Krindges ◽  
Vanusca Dalosto Jahno ◽  
Fernando Morisso

Incorporation studies of particles in different substrates with herbal assets growing. The objective of this work was the preparation and characterization of micro/nanoparticles containing cymbopogon nardus essential oil; and the incorporation of them on bacterial cellulose. For the development of the membranes was used the static culture medium and for the preparation of micro/nanoparticles was used the nanoprecipitation methodology. The incorporation of micro/nanoparticles was performed on samples of bacterial cellulose in wet and dry form. For the characterization of micro/nanoparticles were carried out analysis of SEM, zeta potential and particle size. For the verification of the incorporation of particulate matter in cellulose, analyses were conducted of SEM and FTIR. The results showed that it is possible the production and incorporation of micro/nanoparticles containing essential oil in bacterial cellulose membranes in wet form with ethanol.


Author(s):  
R. Preethi ◽  
P. Padma

The study focused on the green synthesis of silver nanobioconjugates (AgNPs) from phenolic-rich fruit source, Vitis vinifera seed extract and its major component phenolic, resveratrol respectively. Sunlight exposure for 20 minutes was the method of choice for the synthesis of AgNPs of the extract as well as the phenolic, resveratrol. The synthesized nanobioconjugates were characterized using UV-Visible spectroscopy, Transmission electron microscopy (TEM), Energy dispersive X-ray analysis (EDAX), X-ray diffraction (XRD), Polydispersity index, Zeta potential and Fourier transform infrared spectroscopy (FTIR). The reduction of silver ions was confirmed by UV-visible spectroscopy with peaks at 440nm for both nanobioconjugates synthesized from seed extract and compound. The nanobioconjugates showed the spherical in shape with 14-35nm in size and crystalline in nature. The conjugates are well dispersed with 0.301 and 0.287 polydispersity index and the zeta potential range at -13.6 and -14.3mV for stability. The FTRI data proved that the components in grape seeds act as good reductants and stabilizers for the silver nanobioconjugate synthesis. All the synthesized nanobioconjugates exhibited steady and sustained release of the medicinal components conjugated, proving their druggability, and were biocompatible with human cells, demonstrating their safety. The findings of the study validate the anticancer properties of silver nanobioconjugates of Vitis vinifera and its active component resveratrol.


Author(s):  
Kranti Singh ◽  
Surajpal Verma ◽  
Shyam Prasad ◽  
Indu Bala

Ciprofloxacin hydrochloride loaded Eudragit RS100 nanoparticles were prepared by using w/o/w emulsification (multiple emulsification) solvent evaporation followed by drying of nanoparticles at 50°C. The nanoparticles were further incorporated into the pH-triggered in situ gel forming system which was prepared using Carbopol 940 in combination with HPMC as viscosifying agent. The developed nanoparticles was evaluated for particle size, zeta potential value and loading efficiency; nanoparticle incorporated in situ gelling system was evaluated for pH, clarity, gelling strength, rheological studies, in-vitro release studies and ex-vivo precorneal permeation studies. The nanopaticle showed the mean particle size varying between 263.5nm - 325.9 nm with the mean zeta potential value of -5.91 mV to -8.13 mV and drug loading capacity varied individually between 72.50% to 98.70% w/w. The formulation was clear with no suspended particles, showed good gelling properties. The gelling was quick and remained for longer time period. The developed formulation was therapeutically efficacious, stable and non-irritant. It provided the sustained release of drug over a period of 8-10 hours.


Author(s):  
Rupali L. Shid ◽  
Shashikant N. Dhole ◽  
Nilesh Kulkarni ◽  
Santosh L Shid

Poor water solubility and slow dissolution rate are issues for the majority of upcoming and existing biologically active compounds. Simvastatin is poorly water-soluble drug and its bioavailability is very low from its crystalline form. The purpose of this study wasto increase the solubility and dissolution rate of simvastatin by the  preparation of nanosuspension by emulsification solvent diffusion method at laboratory scale. Prepared nanosus-pension was evaluated for its particle size and in vitro dissolution study and characterized by zeta potential,differential scanning calorimetry (DSC) and X-Ray diffractometry (XRD), motic digital microscopy, entrapment efficiency, total drug content, saturated solubility study and in vivo study. A 23 factorial design was employed to study the effect of independent variables, amount of SLS (X1), amount of PVPK-30 (X2) and poloxamer-188 (X3) and dependent variables are total drug content and polydispersity Index. The obtained results showed that particle size (nm) and rate of dissolution has been improved when nanosuspension prepared with the higherconcentration of PVPK-30 with the higher concentration of PVP K-30 and Poloxamer-188 and lower concentration of SLS. The particle size and zeta potential of optimized formulation was found to be 258.3 nm and 23.43. The rate of dissolution of the optimized nanosuspension was enhanced (90% in 60min), relative to plain simvastatin  (21% in 60 min), mainly due to the formation of nanosized particles. These results indicate the suitability of 23 factorial  design for preparation of simvastatin loaded nano-suspension significantly improved in vitro dissolution rate and thus possibly enhance fast onset of therapeutic drug effect. In vivo study shows increase in bioavailability in nanosuspension formulation than the plain simvastatin drug.


2020 ◽  
Vol 26 (14) ◽  
pp. 1543-1555 ◽  
Author(s):  
Meltem E. Durgun ◽  
Emine Kahraman ◽  
Sevgi Güngör ◽  
Yıldız Özsoy

Background: Topical therapy is preferred for the management of ocular fungal infections due to its superiorities which include overcoming potential systemic side effects risk of drugs, and targeting of drugs to the site of disease. However, the optimization of effective ocular formulations has always been a major challenge due to restrictions of ocular barriers and physiological conditions. Posaconazole, an antifungal and highly lipophilic agent with broad-spectrum, has been used topically as off-label in the treatment of ocular fungal infections due to its highly lipophilic character. Micellar carriers have the potential to improve the solubility of lipophilic drugs and, overcome ocular barriers. Objective: In the current study, it was aimed optimization of posaconazole loaded micellar formulations to improve aqueous solubility of posaconazole and to characterize the formulations and to investigate the physical stability of these formulations at room temperature (25°C, 60% RH), and accelerated stability (40°C, 75% RH) conditions. Method: Micelles were prepared using a thin-film hydration method. Pre-formulation studies were firstly performed to optimize polymer/surfactant type and to determine their concentration in the formulations. Then, particle size, size distribution, and zeta potential of the micellar formulations were measured by ZetaSizer Nano-ZS. The drug encapsulation efficiency of the micelles was quantified by HPLC. The morphology of the micelles was depicted by AFM. The stability of optimized micelles was evaluated in terms of particle size, size distribution, zeta potential, drug amount and pH for 180 days. In vitro release studies were performed using Franz diffusion cells. Results: Pre-formulation studies indicated that single D-ɑ-tocopheryl polyethylene glycol succinate (TPGS), a combination of it and Pluronic F127/Pluronic F68 are capable of formation of posaconazole loaded micelles at specific concentrations. Optimized micelles with high encapsulation efficiency were less than 20 nm, approximately neutral, stable, and in aspherical shape. Additionally, in vitro release data showed that the release of posaconazole from the micelles was higher than that of suspension. Conclusion: The results revealed that the optimized micellar formulation of posaconazole offers a potential approach for topical ocular administration.


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