Preparation Of Nanosized Particles Research Articles

Utility of Biogenic Iron and Its Bimetallic Nanocomposites for Biomedical Applications: A Review

Nanotechnology mainly deals with the production and application of compounds with dimensions in nanoscale. Given their dimensions, these materials have considerable surface/volume ratios, and hence, specific characteristics. Nowadays, environmentally friendly procedures are being proposed for fabrication of Fe nanoparticles because a large amount of poisonous chemicals and unfavorable conditions are needed to prepare them. This work includes an inclusive overview on the economical and green procedures for the preparation of such nanoparticles (flower, fruits, tea, carbohydrates, and leaves). Pure and bimetallic iron nanoparticles, for instance, offer a high bandwidth and excitation binding energy and are applicable in different areas ranging from antibacterial, anticancer, and bioimaging agents to drug delivery systems. Preparation of nano-sized particles, such as those of Fe, requires the application of high quantities of toxic materials and harsh conditions, and naturally, there is a tendency to develop more facile and even green pathways (Sultana, Journal of Materials Science & Technology, 2013, 29, 795–800; Bushra et al., Journal of hazardous materials, 2014, 264, 481–489; Khan et al., Ind. Eng. Chem. Res., 2015, 54, 76–82). This article tends to provide an overview on the reports describing green and biological methods for the synthesis of Fe nanoparticles. The present review mainly highlights selenium nanoparticles in the biomedical domain. Specifically, this review will present detailed information on drug delivery, bioimaging, antibacterial, and anticancer activity. It will also focus on procedures for their green synthesis methods and properties that make them potential candidates for various biomedical applications. Finally, we provide a detailed future outlook.

Preparation of nano-sized particles from bacterial cellulose using ultrasonication and their characterization

As more applications for nano-sized natural particles are discovered, simple, environmentally friendly ways to produce these particles become more important. This work prepares and characterizes nano-size bacterial cellulose particles using ultrasonication. Pellicle from nata de coco containing nanofibers was broken up in an electrical blender, then sonicated using an ultrasonic probe at 20 kHz and 3 W/mL for 30, 60 and 90 min. Transmission electron microscope observations indicate the particles become nano-sized after 60 min ultrasound. The maximum decomposition temperature before sonication was 373 °C, decreased to 357 °C after 60 min ultrasonication. Moisture absorption of the 90 min sonicated particles film is 60% slower compared to non-sonicated particles. After ultrasonication, the crystallinity index of the cellulose decreases. The functional groups of non-sonicated and sonicated cellulose remain the same. This study promotes a potential method of fabrication of nano-sized particles from pure bacterial cellulose.

Generation of mucin gel particles with self-degradable and -releasable properties.

Herein, we focused on mucin, which is a large viscous glycoprotein in terms of materials science, and reported preparation of mucin gel particles and incorporation of enzymes to provide the particle with self-degradable and releasable properties. To expose the hydrophobic peptide cores, trimming of sugar moieties was carried out by β-elimination reaction under alkaline conditions (tMucin). Nano-sized tMucin particles were prepared by the assembly of tMucin with the aid of a cationic surfactant. Then, cross-linking of tMucin particles was carried out via heat treatment (annealing) to induce thermal aggregation of the polypeptide chains. The hydrodynamic diameter of tMucin particles reversibly changed in response to calcium ions. Next, in an attempt to render the particle degradable, lysozyme was incorporated into the tMucin particles for the hydrolysis of oligosaccharide chains. These particles were gradually degraded upon enzymatic cleavage of the mucin molecules, facilitating the release of their incorporated substances. Also, the degradation of the mucin particles and the release of lysozyme were tunable by environmental conditions, such as temperature and calcium ions, in addition to the degree of cross-linking of the particles.

The formation of nanosized molybdenum oxide particles in a hydrocarbon medium

This work is concerned with the preparation of nanosized particles of molybdenum oxides from an “inverted” emulsion of an aqueous ammonium paramolybdate solution in a pentadecane medium and in the presence of surfactants. The characteristics of disperse-phase particles and the factors, such as the metal concentration, the treatment temperature, and the water and surfactant contents, that affect these characteristics are analyzed.

Spray-drying preparation of microparticles containing cationic PLGA nanospheres as gene carriers for avoiding aggregation of nanospheres

Preparation of nano-sized particles using lyophilization, which is a standard drying technique for high-molecular-weight compounds such as bioactive peptides, proteins, plasmid DNA and siRNA, often results in particle aggregation. In this study, spray-drying was applied for preparation of cationic PLGA nanospheres as gene delivery vectors in order to minimize aggregation and loss of gene transfection efficiency. PLGA nanoparticle emulsions were prepared by dropping an acetone/methanol mixture (2/1) containing PLGA and a cationic material, such as PEI, DOTMA, DC-Chol or CTAB, into distilled water with constant stirring. The PLGA nanosphere emulsion was dried with mannitol by spray-drying, and mannitol microparticles containing PLGA nanospheres were obtained. Mean particle diameter of spray dried PLGA particles was 100–250 nm, which was similar to that of the nano-emulsion before drying, whereas the lyophilized PLGA particles showed increased particle diameter due to particle aggregation. PEI, DOTMA and DC-Chol were useful for maintaining nanoparticle size and conferring positive charge to nanospheres. Transfection of pDNA (pCMV-Luc) using these spray-dried cationic PLGA nanospheres yielded high luciferase activity in COS-7 cells, particularly with PLGA/PEI nanospheres. The present spray-drying technique is able to provide cationic PLGA nanospheres, and may improve redispersal and handling properties.

Preparation of nano-sized particles from collagen II by a high-voltage electrostatic field system

The pilot study describes a novel method for preparing nano-sized particles from collagen II using a high-voltage electrostatic field system. Observations from transmission electron microscopy showed that, in one of the cases, the nano-sized collagen II particles exhibited good sphericity, and the particles were in the range of 23.3+/-1.7 nm in diameter at the experimental setting of 3 kV cm(-1), for a 3 h treatment period and at 25 degrees C (with a collagen concentration of 0.2 mg ml(-1)). When the treatment temperature increased to 30 degrees C, the collagen II began to lose the tendency to form individually separated spherically shaped nano-particles. Moreover, a fibrous structure of collagen II was formed instead of a nano-particle shape at the temperature of 37 degrees C. This result is probably contributed to by an entropy-driven process that is termed fibrillogenesis, a larger force causing the collagen molecules to self-assemble and then form collagen fibrils. It is interesting to note that this is practically the first attempt to produce nano-particles directly from collagen II solution under the treatment of a high-voltage electrostatic field, together with a set of working parameters for the collagen concentration and low-temperature setting.

Characterization of Particle Surfaces

Recently, preparation of nano-sized particles and construction of nano-structure on particle surfaces have been vigorously studied. The effects of surface and interface on nano-sized particles are emphasized, and surface modification is useful to control the characteristics of particles. Information of structure and properties of particle surfaces is necessary to design the surfaces. In this review, characterizations of particle surfaces, especially oxide surfaces, has been discussed. Evaluations of functional groups on the surfaces, mainly hydroxyl groups, and adsorption properties observed by FT-IR have been reviewed. The problems in the specific surface area measurement by gas adsorption have been noted. Fractal analysis of solid surface that is a new concept of surface morphology has been explained.

Controlled colloid formation

Advances in controlled colloid formation have taken place for the preparation of suspensions from dry powders, the preparation of nanosized particles, the preparation of lattices using nonspherical particles, and for emulsion preparation.