PVA-coated Nanoparticles Research Articles

Coating SiO2 nanoparticles with polyvinyl alcohol for interfacial tension alteration in the system CO2+polyethylen glycol+water

Interfacial tension (IFT) data were measured and correlated by a theoretical model for the system CO2/polyethylene glycol (PEG) (40 wt.%)+water (60 wt.%). The effect of both bare SiO2 nanoparticles (NPs) as well as their modified surface counterparts on the IFT alteration was investigated. SiO2 NPs were synthesized followed by coating with polyvinyl alcohol (PVA). IFT measurements based on a well-established pendant droplet technique were carried out in the presence of 0.00–0.05 wt.% NPs over the temperatures and pressures of 298–323 K and 0.1–4.0 MPa, respectively. The obtained results depict that IFT decreases with increasing pressure and increasing NPs concentration, and increases with increasing temperature. It was shown that increasing the SiO2 NPs concentration from 0.00 to 0.05 wt.% causes a 35.8% decrease at constant pressure and temperature of 3.0 MPa and 323 K, respectively. Increasing pressure from 2.0 to 4.0 MPa in the presence of 0.03 wt.% SiO2 NPs decreases the IFT of the system by 27% at a constant temperature of 313 K. Lower IFTs were observed (11.50–18.90%) when PVA-coated NPs were added to the fluid. Finally, the parameters of the employed theoretical model were determined using global and local parameters, the latter of which showed higher precisions in the representation of data.

Effects of PVA-coated nanoparticles on human T helper cell activity.

Superparamagnetic iron oxide nanoparticles (SPION) are used as high-sensitive enhancer for magnetic resonance imaging, where they represent a promising tool for early diagnosis of destructive diseases such as rheumatoid arthritis (RA). Since we could demonstrate that professional phagocytes are activated by amino-polyvinyl-alcohol-coated-SPION (a-PVA-SPION), the study here focuses on the influence of a-PVA-SPION on human T cells activity. Therefore, primary human CD4+ T cells from RA patients and healthy subjects were treated with varying doses of a-PVA-SPION for 20h or 72h. T cells were then analyzed for apoptosis, cellular energy, expression of the activation marker CD25 and cell proliferation. Although, we observed that T cells from RA patients are more susceptible to low-dose a-PVA-SPION-induced apoptosis than T cells from healthy subjects, in both groups a-PVA-SPION do not activate CD4+ T cells per se and do not influence mitogen-mediated T cells activation with regard to CD25 expression and cell proliferation. Nevertheless, our results demonstrate that CD4+ T cells from RA patients and healthy subjects differ in their response to mitogen stimulation and oxygen availability. We conclude from our data, that a-PVA-SPION do neither activate nor significantly influence mitogen-stimulated CD4+ T cells activation and have negligible influence on T cells apoptosis.

Application of polymeric nanoparticles prepared by an antisolvent diffusion with preferential solvation for iontophoretic transdermal drug delivery

Indomethacin-loaded poly(lactide-co-glycolide) (PLGA) nanoparticles with an average diameter of 100 nm were prepared by using a combination of an antisolvent diffusion method with preferential solvation (bare nanoparticles). Polyvinyl alcohol (PVA)-coated indomethacin-loaded PLGA nanoparticles with an average diameter of 100 nm were also prepared by emulsification and the solvent evaporation method (PVA-coated nanoparticles). Bare nanoparticles do not have a hydrophilic stabilizer on the surface; therefore, they have high hydrophobicity and negative charges. Electrophoretic mobility of bare nanoparticles at 5 mM NaCl solution was about 68 times higher than that of PVA-coated nanoparticles. Permeability of bare nanoparticles through rat skin was significantly higher than that of PVA-coated nanoparticles when iontophoresis was applied ex vivo. Indomethacin amount inside the skin after the permeation study by using bare nanoparticles was much higher than that by using PVA-coated nanoparticles. Indomethacin transition to circulation and accumulation in muscle by the transdermal delivery of indomethacin-loaded PLGA nanoparticles were significantly enhanced by using the combination of bare nanoparticles and iontophoresis in vivo. As for transdermal route of nanoparticles, both bare and PVA-coated nanoparticles were revealed to penetrate through the transfollicular pathway, and the migration of nanoparticles to follicles was enhanced by the application of iontophoresis. PLGA nanoparticles prepared by the antisolvent diffusion with preferential solvation are beneficial for iontophoretic transdermal delivery of therapeutic agents.

Surfactant free preparation of PLGA nanoparticles: The combination of antisolvent diffusion with preferential solvation

Indomethacin-loaded PLGA nanoparticles with an average diameter of 100nm were prepared by using a combination of an antisolvent diffusion method with preferential solvation (bare nanoparticles). For bare nanoparticles, the number density of negative charges on their surfaces was calculated to be −47.57mM, while the number density of negative charges on the surfaces of indomethacin-loaded PLGA nanoparticles prepared by emulsification and the solvent evaporation method (PVA-coated nanoparticles) was −0.23mM. The bare nanoparticles do not have a hydrophilic stabilizer on the surface; therefore, they have high hydrophobicity and negative charges. On the other hand, PVA-coated nanoparticles have a hydrophilic stabilizer (polyvinyl alcohol; PVA) on the surface. Thus the degree of hydrophobicity is low by the amphiphilic property of PVA, and the negative charge is also low by charge shielding effect of PVA. Electrophoretic mobilities of bare nanoparticles were 59–68 times higher than those of PVA-coated nanoparticles, at the measurement range of ionic strength of PBS buffer (pH 7.4) in this experiment. These results suggest that nanoparticles prepared by the antisolvent diffusion method with preferential solvation have a higher potential to be affected by electrical energy than nanoparticles prepared by emulsification with the solvent evaporation method. Skin permeability test ex vivo confirmed that the bare nanoparticles can be more affected by iontophoresis than the PVA-coated nanoparticles. Thus the nanoparticles prepared by the antisolvent diffusion method with preferential solvation are beneficial for the iontophoretic transdermal delivery of therapeutic agents.

Biodegradable Nanoparticles Meet the Bronchial Airway Barrier: How Surface Properties Affect Their Interaction with Mucus and Epithelial Cells

Despite the wide interest raised by lung administration of nanoparticles (NPs) for the treatment of various diseases, little information is available on their effect toward the airway epithelial barrier function. In this study, the potential damage of the pulmonary epithelium upon exposure to poly(lactide-co-glycolide) (PLGA) NPs has been assessed in vitro using a Calu-3-based model of the bronchial epithelial barrier. Positively and negatively charged as well as neutral PLGA NPs were obtained by coating their surface with chitosan (CS), poloxamer (PF68), or poly(vinyl alcohol) (PVA). The role of NP surface chemistry and charge on the epithelial resistance and mucus turnover, using MUC5AC as a marker, was investigated. The interaction with mucin reduced the penetration of CS- and PVA-coated NPs, while the hydrophilic PF68-coated NPs diffused across the mucus barrier leading to a higher intracellular accumulation. Only CS-coated NPs caused a transient but reversible decrease of the trans-epithelial electrical resistance (TEER). None of the NP formulations increased MUC5AC mRNA expression or the protein levels. These in vitro results highlight the safety of PLGA NPs toward the integrity and function of the bronchial airway barrier and demonstrate the crucial role of NP surface properties to achieve a controlled and sustained delivery of drugs via the pulmonary route.

Nanostructural origin of the spin and orbital contribution to the magnetic moment in Fe3−xO4 magnetite nanoparticles

5 nm Fe3−xO4 nanoparticles were synthesized either by high-temperature decomposition in organic phase or in low-temperature aqueous conditions. In the first case oleic acid was covalently bonded to the nanoparticles; in the second case polyvinyl alcohol (PVA) yielded a protective coating without chemical bond. Magnetization measurements and x-ray magnetic circular dichroism showed a saturation magnetization close to bulk magnetite and an orbital moment effectively quenched in covalently bonded nanoparticles. PVA-coated nanoparticles showed a reduced value of the magnetization and ∼3 fold increase in the orbital moment. High resolution electron microscopy suggested that this was related to the nanostructure of the samples.