Nanoparticle zeta potential

Each analytical instrument has a separate property, for example UV-visible spectroscopy helps to identify the surface plasmon resonance of synthesized nanoparticles. X-ray diffractometry identifies the crystaUine nature of synthesized nanoparticles and also using Scherrer s formula (D = K%l(3 cos 0) from which researchers are able to calculate the crystal size of synthesized nanoparticles. Fourier transform infrared spectroscopy finds the functional group which reduces metal salts into nanoparticles. The scanning electron microscope and transmission electron microscope indicate the exact size and shape of nanoparticles. Zeta potential plays a major role in nanoparticle characterization, which results in the stability and withstand property of nanoparticles. 

For the preparation of nanoparticles based on two aqueous phases at room temperature one phase contains chitosan and poly(ethylene oxide) and the other contains sodium tripolyphosphate. The particle size (200-1000 nm) and zeta potential (between -i- 20 mV and -l- 60 mV) could be modulated by varying the ratio chitosan/PEO-PPO. These nanoparticles have great proteinloading capacity and provide continuous release of the entrapped protein (particularly insulin) for up to one week [100,101]. 

Fig. 14.3 Zeta-potential of halloysite, and silica and alumina nanoparticles (for comparison).

Freitas C. and Muller R.H., Effect of light and temperature on zeta potential and physical stability in solid hpid nanoparticle (SLN) dispersions, Int. J. Pharm., 168, 221, 1998. 

Three different ways have been developed to produce nanoparticle of PE-surfs. The most simple one is the mixing of polyelectrolytes and surfactants in non-stoichiometric quantities. An example for this is the complexation of poly(ethylene imine) with dodecanoic acid (PEI-C12). It forms a solid-state complex that is water-insoluble when the number of complexable amino functions is equal to the number of carboxylic acid groups [128]. Its structure is smectic A-like. The same complex forms nanoparticles when the polymer is used in an excess of 50% [129]. The particles exhibit hydrodynamic diameters in the range of 80-150 nm, which depend on the preparation conditions, i.e., the particle formation is kinetically controlled. Each particle consists of a relatively compact core surrounded by a diffuse corona. PEI-C12 forms the core, while non-complexed PEI acts as a cationic-active dispersing agent. It was found that the nanoparticles show high zeta potentials (approximate to +40 mV) and are stable in NaCl solutions at concentrations of up to 0.3 mol l-1. The stabilization of the nanoparticles results from a combination of ionic and steric contributions. A variation of the pH value was used to activate the dissolution of the particles. 

Polymeric nanoparticles have attracted a lot of attention in the last years. Polymeric materials exhibit several advantageous properties including biodegradability and ease of functionalization. They also allow for a greater control of pharmacokinetic behavior of the loaded drug leading to more steady levels of drugs (Rawat et al. 2006). Furthermore, they enable the modulation of the physicochemical properties of the surface such as Zeta potential and hydro-phobicity/hydrophilicity. Many polymers used to develop nano- and... 

One can attribute the relative stability of colloids, or dispersed particles, to a theoretical electrokinetic potential, or zeta potential, or potential, which is defined as the potential difference between the bulk solvent and a very thin layer of the solvent (called the "slipping plane" and typically about lnm thick) that is tightly attached to the colloidal particle or nanoparticle. This potential cannot be measured directly, but... 

One phase contains the polysaccharide chitosan (CS) and a diblock copolymer of ethylene oxide and the polyanion sodium tripolyphosphate (TPP). It was stated that the size (200-1000 nm) and zeta potential (between + 20 mV and + 60 mV) of nanoparticles can be conventionally modulated by varying the ratio of CS/PEO to PPO. Furthermore, using BSA as a model protein, it was shown that these new nanoparticles have a high protein loading capacity (entrapment efficiency up to 80 % of the protein) and provide a continuous release of the entrapped protein for up to 1 week [56]. 

Fig. 15. Zeta potential (in mV SD, n = 4) of CT/PEO-PPO and CT/PEO nanoparticles as affected by concentration in the initial chitosan solution and molecular weight of surfactants (reproduced from Calvo et al. 1997, with permission of Wiley) [ 14]...

The selection of polymer is critical to the performance, properties, and application of nanoparticles. Further, the physicochemical properties of the polymer will determine the surface properties of nanoparticles with polymer molecular weight, hydro-phobicity, and glass transition temperature being particularly important. The surface properties that influence their biodistribution and cellular response include particle size, zeta potential, and surface hydrophilicity. 

The surface charge of nanoparticles is important because it determines the nature and extent of aggregation of colloids and their interaction with cells and other biological components within the body. The zeta potential is the potential at the solid-liquid interface and is commonly determined using light scattering [153], Decreasing the zeta potential of nanoparticles below a critical value increases the rate and... 

Drug-loaded nanoparticles were also evaluated for their safety and efficacy. Paclitaxel-encapsulated 6-O-CAPRO-p-CD nanospheres and nanocapsules were evaluated for their physical stability in a one-month period in aqueous dispersion form with repeated particle size and zeta potential measurements and AFM imaging to evaluate recrystallization in aqueous medium. Paclitaxel-loaded amphiphilic CD nanoparticles were found to be physically stable for a period of one month whereas recrystallization occurs within minutes when diluted for intravenous (IV) infusion [85], Finally, paclitaxel-loaded amphiphilic nanoparticles were demonstrated to show similar anticancer efficacy against MCF-7 cells when compared to paclitaxel solution in a cremophor vehicle [85],... 

The charge of the nanoparticle surface is usually evaluated by the measurement of their zeta potential, which gives information about the overall surface charge of the particles and how it is affected by changes in the environment. ° Zeta potential is affected by the surface composition of the nanoparticles, the presence or the absence of adsorbed compounds, and the composition of the dispersing phase, mainly the ionic strength and the pH. 

Fig. 10.10 Zeta potential of three-layered nanoparticles (3LNPs)...

Patil, S. et al.. Protein adsorption and cellular uptake of cerium oxide nanoparticles as a function of zeta potential. Biomaterials, 28, 4600, 2007. 

Sieger, H. et al., Gonlrolling surface composition and zeta potential of chemical vapor synthesized alumina-sihea nanoparticles, Chem. Vapor Depos., 10, 71, 2004. 

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