Current Nanoscience - Volume 7, Issue 4, 2011

The aim of this study was to develop a delivery system to enable the promotion of the antitumor potential of fucoidan (FUC). FUC/N-trimethylchitosan (TMC) ion-complex submicron particles (FUC/TMC-SMP) were produced by ionic complexation, and their particle characteristics were investigated. Antitumor effect was examined in vivo using sarcoma 180-bearing mice by oral administration, and body weight loss was checked as an index of toxic side effects. FUC/TMC-SMP could be obtained by the complexation of negatively charged fucoidan with positively charged N-trimethylchitosan under aqueous conditions. The mean particle size was 325 nm and mean FUC content was 47 % (w/w). Oral administration was conducted using two treatment schedules, that is, pre- and post-tumor inoculation. As to pre-treatment, oral administration was performed from 13 days before inoculation to 1 day before inoculation every other day. For post-treatment, preparation samples were administered orally from 1 day after inoculation to 13 days after inoculation every other day. FUC/TMC-SMP were more effective than FUC solution and suppressed tumor growth significantly in both treatment schedules. FUC/TMC-SMP are suggested to be a useful oral delivery system enhancing the antitumor potential of FUC.

Nanoparticles based on poly(propylene succinate) copolymers with poly(ethyleneglycol) (PPSu-PEG) were prepared and evaluated in vitro for their potential for a more selective delivery of cisplatin to tumors using local hyperthermia. The copolymers were synthesized through one-pot melt-polymerization under vacuum. Their thermal properties were investigated using DSC. PPSu-PEG nanoparticles loaded with cisplatin were prepared by a double emulsion method. Their colloidal stability, drug release properties, and in vitro anticancer activity were assessed. The m.p. of the synthesized PPSu-PEG copolymers ranged between 40-45 °C. The PPSu-PEG nanoparticles were stable in aqueous media with high salt concentrations. The average size of the different compositions of the PPSu- PEG nanoparticles loaded with cisplatin ranged between 77 and 126 nm and all compositions exhibited low negative ζ-potential values. The PPSU-PEG/cisplatin nanoparticles released cisplatin much faster at 42 ° C than at 37 ° C and exhibited comparable to free cisplatin cytotoxicity against HT 29 cells, which was increased when the incubation temperature was increased from 37 ° C to 42 ° C. The results justify further investigation of the potential of PPSu-PEG copolymers for the development of temperature-sensitive, targetable cisplatin nanocarriers.

Nanomaterials are at the leading edge of the rapidly developing field of nanotechnology. Nanomaterials such as magnetic iron oxides and magnetic gold-coated iron oxides nanoparticles exhibit unusual optical, thermal, chemical, and physical properties, due to a combination of high-energy surface atoms compared to bulk solids. Their low toxicity, biocompatibility, and established protocols of synthesis have resulted in a tremendous upsurge of interest, and their applications as special biomolecule carriers via a stable immobilization process show promise as sensitive detection tools. This review provides a comprehensive analysis of new synthetic routes, characterization methodologies, and functionalization protocols of magnetic and gold-coated magnetic iron oxides nanoparticles. Applications of these materials as scaffolds for biosensing and detection are also discussed.

Cyclosporin-A is a drug of choice for the topical treatment of various dermatological diseases, however the drug failed to penetrate into intact skin barrier due to its high molecular weight, complex cyclic molecular structure and the barrier property of stratum corneum (SC). Less than 1% of the drug reaches skin upon systemic administration and it further causes systemic toxicity. So the aim of the present work was to develop cyclosporine-A loaded PLGA nanoparticles for enhancing its topical delivery. Spherical shaped nanoparticles with high entrapment efficiency (86%), low particle size (163 nm) and narrow polydispersity index (0.118) were prepared by emulsion diffusion evaporation technique. In vitro permeation studies were carried out using rat skin and 6.6 and 4.85 times higher amount of the drug was estimated in SC and dermis respectively as compared to free drug. No drug was detected in receptor compartment hence the system might be devoid of risk of any systemic toxicity. Histological examination and TEWL measurement exhibited no morphological changes upon application of nanoparticles on the skin. CLSM images suggested pilosebaceous route followed by nanoparticles for skin penetration. The system may be a promising carrier for topical delivery of cyclosporin.

The new bio-branch of nanotechnology is considered to be one of the fastest emerging fields often called as Nanobiotechnology. Recent studies on exploitation of the nature's secrets for the synthesis of inorganic materials are relatively new and exciting area of research with considerable potential for development. Among the inorganic materials, noble metals research is been always interesting, silver in particular. Nanoscale silver has been proved to be one of the potential antibacterial, antifungal and anti-inflammatory agents. Biologically synthesized silver nanoparticles can be more effective in the medicinal applications due to their diversified surface coatings (biomaterial). The present review gives an idea about the importance of biogenic metallic silver nanoparticles, their characterization and potential antimicrobial properties.

Penetration of PLGA nanoparticles in the hairless mouse skin petreated by microneedles was studied in vitro using nanoparticles containing coumarin 6 and R-phycoerythrin (R-PE) as fluorescent probe. Confocal laser scanning microscopy (CLSM) was used to visualize the distribution of nanoparticles and the high performance liquid chromatography (HPLC) was utilized to quantify the amount of the nanoparticles. The CLSM images revealed that nanoparticles (diameter 160.1± 1.97nm) could penetrate into the skin through the microconduits created with microneedles and reach the depth of more than 42.19µ m. The quantitative results showed that the amount of nanoparticles deposited in the skin increased by microneedles was about twice that in the control group in a period of 48h. However, the nanoparticle was not able to reach the receptor compartment. In additional, the penetration and the distribution of nanoparticles was significantly influenced by the particle size (diameter ranged from 160.1± 1.97nm to 288.2± 6.62nm). These results suggested that the combination of PLGA nanoparticles with microneedles could be a useful method to increase topical drug delivery and improving therapy by supplying drug reservoirs to the skin.

A simple and environmental friendly synthetic method for the preparation of polymer/clay nanocomposite was introduced. Poly(methyl methacrylate)/ montmorillonite nanocomposites with a high filling of clay were obtained by one step in situ redox polymerization in aqueous dispersion. Triethanolamine hydrochloride was used as intercalative modifier for montmorillonite via ion exchange reaction to introduce hydroxyl groups on the surface of montmorillonite layers which generated free radicals to initiate polymerization reaction with ceric ions. Exfoliation or intercalation structures are related to the clay content of nanocomposites and are evidenced by both X-ray diffraction spectroscopy (XRD) and transmission electron microscopy (TEM). Characterization results of extracted nanocomposite indicate the existence of polymer chain on the surface of montmorillonite layers. Effect of concentration of triethanolamine hydrochloride on the structure of poly(methyl methacrylate) nanocomposites was also investigated.

Polydiacetylene (PDA) vesicles with various cross-linking degree were prepared by adding different quantity of ethylenediamine. Ag nanoparticles were added into above systems to form the cross-linked PDA/Ag composite vesicles. UV-vis spectra and transmission electron microscopy (TEM) were used to confirm the formation of the cross-linked PDA/Ag composite vesicles. Their thirdorder nonlinear optical (NLO) properties were investigated in detail. A pronounced enhancement of the third-order nonlinear optical susceptibility χ(3) was observed with increasing of the cross-linking degree, which should be ascribed to the coupling effect of strong local field near the adjacent PDA/Ag composite vesicles.

Based on the electrostatic interaction between carboxymethylated chitosan (CMCH) and negatively charged CdTe quantum dots, and the selective crosslinking of CMCH using glutaraldehyde(GA), we demonstrated the formation of Fe3O4/SiO2/CMCH/CdTe microspheres. The dense silicate shells of Fe3O4 nano-particles (NPs) protect the luminescence quenching from Fe3O4 NPs, so the composite microspheres have great fluorescence and emulative magnetism. These multifunctional fluorescence/magnetic microspheres lead to robust and water dispersible nanoparticle colloidosomes, and should be of great importance for diagnostics application and specific biological applications.

In the present investigation a titania network encapsulating nano bioactive glass 58s (NBG) particulate phase is proposed as a bioceramic composite coating. The grain size of NBG particles was uniform and its nano scale (50 - 60 nm) confirmed with transmission electron microscopy (TEM). XRD pattern of NBG particles, calcinated at 600°C in air confirmed that the calcinated glass generally existed in amorphous state. Thermogravimetry (TG) curves for the bulk of NBG-Titania gel indicated that the organic and inorganic precursors have been decomposed completely before 600° C. Nickel-titanium alloy (Nitinol® ) Nails was dip-coated with NBG-Titania composite via the sol-gel route. The morphology, structure and component of the composites films were evaluated using environmental scanning electron microscope (SEM) and field emission scanning electron microscope (FESEM). Also, FTIR confirmed the presence of Si-OSi bands on the calcinated NBG-Titania films. The hardness of the prepared films was investigated using micro hardness test method. The results verified that the presence of NBG particles in titania matrix enhanced gradually the mechanical data of the prepared films (450 VHN). Direct pull-off test recorded a mean coating-substrate bonding strength larger than 16 MPa. The in vitro bioactivity of prepared films indicates that hydroxyapatite nuclei can form and grow on the surface of NBG-Titania films coated on Nitinol alloy. The present study shows that due to their excellent bioactivity, hardness and bonding strength to substrate, NBG-Titania coatings are practical biocomposite films in biomedical applications.

When the nanostructured materials were used as heterogeneous catalysts by comparing with traditional powder catalysts, the nanostructured materials exhibited special properties of nanoparticles and new effects caused by nanostructured combination, with many unmatchable improvements in the aspects of size, shape, surface structure, numbers of reaction active sites, catalytic selectivity and so on. Because of those advantages, the nanostructured materials have great potential application in the field of heterogeneous catalysis and have become the hotspot of materials science in the area of heterogeneous catalysis gradually. In this paper, the advantages of nanostructured materials for heterogeneous catalysis were concisely summarized; the nanostructured materials, which included supported nanostructured catalysts and non-supported nanostructured catalysts, were discussed as an emphasis in application of heterogeneous catalysis. Finally, the development trends of nanostructured catalysts were indicated.

The aim of the present study was to improve transfection efficiency using different combinations of cationic liposomes, linear polyethylenimine and DNA. A novel gene delivery system (lipopolyplex) was developed by premixing cationic liposomes containing cholesterol or oligoamine modified cholesterol (derivative I-III) and linear polyethyleneimines (PEIs) following addition of plasmid at three different C/P ratios. The resultant complexes were characterized for their size, zeta potential and ability of DNA condensation. Luciferase reporter gene was used for determination of transfection efficiency in Neuro2A cells. Mean particle size of prepared complexes was less than 200 nm and they showed positive surface charge. The transfection efficiency of vectors was reduced by increasing in carrier concentration/plasmid DNA ratio (C/P ratio) while gene expression of cationic liposome or PEI was increased at higher C/P ratios. Complexes composed of PEI 2.5 or 250 kDa and liposome containing derivative I had the highest transfection activity. Furthermore, non-viral vectors described in this study showed low cytotoxicity. The results show that small and large molecular weight linear PEI in combination with liposome have little toxicity and may enhance transfection efficiency.

GaN nanorods are fabricated with an AgO mask by a process of iodine-assisted focused ion beam etching (IFIBE). The transformation from GaN nanorod to GaN nanotip structure, the thermal treatment uses a high temperature of 800° C in air to increase the partial oxygen pressure resulting in the formation of a double mask, GaO and AgO. In addition, the Ag clusters react with the iodine gas to affect the etching rate and retain a GaO zone on the GaN nanotip arrays. Oxide-capped GaN nanotips can be applied as field emitter. The turn-on electric field was 2.2V/um when the current density was 0.1mA/cm2.

Flower-like amorphous silicon oxide nanostructures were synthesized by a metal-catalyzed chemical vapor deposition method on Si (111) wafers, using SiCl4 as the source of Si and Au as catalyst in a flowing H2-5% Ar atmosphere. The nanostructures were characterized using field-emission scanning electron microscopy, transmission electron microscopy equipped with electron energy dispersive X-ray spectroscopy. Each flower-like nanostructure consists of many silicon oxide nanorods with smooth surface and uniform diameter. At early stage, the growth of the flower-like silicon oxide nanostructures was controlled by solid-liquid-solid and solid-vapor-liquid-solid mechanisms, and solid-vapor-liquid-solid and vapor-liquid-solid mechanisms at later stage. The silicon oxide nanoflowers show a photoluminescence emission band at 339 nm, revealing that the nanoflowers might have potential applications in the future optoelectronic device.

Nanocrystalline zinc titanate powders were produced at the short sintering time by a sol-gel route. The effect of heat treatment was studied on the crystallization behavior of zinc titanates. The prepared sols showed a narrow particle size the average grain size of 68 nm. The resulting nanopowders were characterized by X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDAX), transmission electron microscopy (TEM), scanning electron microscope (SEM), ultra-violet diffuse reflectance (UV-DRS) and thermogravimetry thermal analysis (TG-DTA). Results of thermal analysis by DTA and TG suggest that decomposition of the precursor proceeded via dehydration reaction, decomposition, combustion reaction and Ecandrewsite phase formation. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) revealed that the optimum temperature for Ecandrewsite nanopowders calcination is 900 °C. With the increase of annealing temperature a new crystallite Ecandrewsite was formed and the ultraviolet light absorption efficiency was enhanced according to the UV-vis diffuse reflectance spectroscopy. The scanning electron microscope (SEM) observation shows that the nanopowders existed in the mode of polycrystalline structure and the average grain size 68 nm. A new absorption edge at higher wavelength (438 nm) for Ecandrewsite zinc titanate annealed at 900 °C is an indication that the nanopowder can absorb lights in the higher wavelength, and therefore they can more efficiently utilize lights for the photocatalytic purpose.

The aim of this study was design and development of colon-specific delivery system of satranidazole based on pectin microbeads formed by cross-linking with calcium chloride. Satranidazole loaded calcium-pectinate microbeads were prepared by ionotropic gelation method. Application of response surface methodology was used to study the effect of pectin concentration, calcium chloride concentration and stirring speed on drug release and encapsulation efficiency. Particle size of the calcium-pectinate microbeads was determined by particle size analyzer. The SEM was used to characterize the surface of these microbeads. In vitro drug-release studies were performed in conditions simulating stomach-to-colon transit in the presence and absence of rat cecal contents. The in vitro drug release studies exhibited low drug release at gastric pH, however continuous release of drug was observed from the formulation at colonic pH. Further, the release of drug from formulation was found to be higher in the presence of rat cecal contents, indicating the effect of colonic enzymes on the calcium pectinate microbeads. The significance of differences was evaluated by analysis of variance (ANOVA). Differences were considered statistically significant at P < 0.05. Thus, by experiment design important parameters affecting formulation characteristics of satranidazole loaded calcium-pectinate microbeads can be identified for colon specific delivery.

Ezetimibe is a poorly water-soluble drug with varying bioavailability. The main objective of present work was to develop self nanoemulsifying drug delivery system (SNEDDS) for enhancing solubility and bioavailability of ezetimibe, which is widely used in treatment of homozygous familial hypercholesterolemia and homozygous sitosterolemia. The formulation of ezetimibe SNEDDS was optimized by simplex lattice design, multiple regression analysis and ternary contour plot. The optimal formulation of SNEDDS comprised of 7.058% oil (Oleic acid), 82.94% surfactant (Tween-80) and 10.0% co-surfactant (PEG-400). Pseudo-ternary phase diagrams were constructed to identify the efficient self-emulsification region. The average globule size of SNEDDS containing ezetimibe was about 90.63 nm when diluted with water. No significant variations in globule size and ezetimibe content in SNEDDS were observed over a period of 3 months at 40 ± 2° C/75 ± 5% RH and 25 ± 3° C (room temperature). In vitro diffusion studies showed remarkable increase in diffusion of drug. In vivo studies (in rats) showed significant increase in absorption of drug as compared to plain drug and marketed formulation. The data suggested use of SNEDDS to provide great potential as alternative to traditional oral formulations of ezetimibe.

The infrared radiation from Nd:YAG laser (1604 nm, 8ns, 125mJ, 15.6MW) is focused by IR lens (20cm) to irradiate Cu and Al (99.99%) target in air. The angular distribution and arrival of ions are collected by Faraday Cups (FC). For anisotropic investigation, the cups are arranged at different positions (5cm and 10cm) from the targets at different angles (5° , 30° , 45° , 60° and 90° ) with respect to the normal on targets surface. Faraday Cups are biased at -100V and the ion current signals are obtained on Tektronix TDS 3054B Digital Storage oscilloscope (500 MHz) through integrated circuit. The average kinetic energy of ions is also calculated. Maximum arrival rate of ions is observed at angle 5° and minimum ions flux is at angle 90° to normal on the target surface. The results show that the plume is peaked strongly in forward direction. The laser matter interaction is good for the laser based ion sources generation, which can produce a collimated beam of ions because of forward peaking.

Textile processing industry generally requires significant amounts of process water for cleaning, rinsing, and dyeing purposes and therefore releases significant amounts of dye polluted waste streams into the environment. In recent years considerable attempts have been made to remove pollutants from these waste streams. One of the promising methods in this regard is membrane filtration. Utilizing this separation method would necessitate the manufacture of effective membranes, such as nanofibrous membranes. Electrospinning is a relatively simple method to produce nanofibers from solutions of different polymers and polymer blends. This paper presents the results of a research on manufacturing a membrane filter by electrospinning Nylon-6 nanofibers on a carbon coated polyurethane substrate and implementing this membrane for dye removal in a filtration system. The membrane sample contained nanofibers with an average diameter of 211 nm. Experiments were run with C.I. Direct yellow 12 as a typical dye pollutant. The effect of coating time, transmembrane pressure, and two different pretreatment methods were investigated and it was observed that by the application of 150ppm coagulant material at 0.75 bar pressure, a filtration efficiency of 98% was achieved.

Currently, 1.1 billion people are at risk due to lack of clean water and about 35 percent of people in the developing world die from water-related problem. To alleviate these problems water purification technology requires new approaches for effective management and conservation of water resources. Nanotechnology has the potential to contribute a long-term water quality, availability and viability of water resources, through the use of advanced filtration materials that enable greater water reuse, recycling and desalinization. Recent advances strongly suggest that many of the current problems involving water quality can be addressed and potentially resolved using nanosorbents, nanocatalysts, bioactive nanoparticles, nanostructured catalytic membranes, and nanoparticle enhanced filtration. This review highlights the uses of nanotechnology in areas relevant to water treatment including purification, separation, bioremediation and disinfection. Creating better disinfection and purification technologies could significantly reduce water borne diseases and further ensure continued economic prosperity of developed nations and create new economic opportunities for the developing world.