Papers by Keyword: Polyethyleneimine

Abstract: Polymeric compounds are of great interest as corrosion inhibitors in acidic environment due to their inherent stability. Polymeric film is effectively used for the protection of metals partly owing to their capacity to act as a physical barrier between the metal surface and the corrosive environment. In this paper, a cation polyelectrolyte inhibitor (Quaternary Polyethyleneimine, QPEI) was prepared. The quality and inhibition efficiency of QPEI self-adsorbed films were studied by polarization curve and electrochemical impedance spectroscopy, respectively. The compositions and morphologies of the polymer film on the steel surface were examined with the aids of SEM and XPS, respectively. The results showed that QPEI could greatly retard the corrosion of iron in sulfuric acid, which was attributed mainly to the protective QPEI film formed on the surface. Meanwhile, the inhibition of QPEI could be supposed as a mixed process, in which both cathodic and anodic corrosions were simultaneously restrained. Based on the results of XPS and SEM, it could be evidenced that the QPEI can form a protective polymer layer on the metal surface by adsorption.

Abstract: Ultrasmall superparamagnetic iron oxide nanoparticles (USPION) as magnetic resonance imaging were synthesized through a sonochemical co-precipitation method with poly (ethyleneimine) (PEI). The size of the USPION was controlled by poly (ethyleneimine) (PEI) contents, ultrasonic exposure time, and Na4OH concentration. The characteristics of PEI-USPION were studied by X-ray diffractometry, magnetic property measurement system, scanning electron microscopy, transmission electron microscopy, and particle size analysis. The PEI-USPION had an average size of 5~10nm with a narrow size distribution, a perfect magnetite crystal structure, and high saturation magnetization.

Abstract: Polyethylenimine-graft-poly(L-lactide-co-glycolide) (PEI-g-PLGA) block copolymers were prepared by a ring-opening polymerization of L-lactide and glycolide using PEI as a macroinitiator and stannous octoate as a catalyst in dimethylformamide at 100 °C. The molecular structure of the block copolymers was evaluated with 1H-NMR, and the molecular weight of the block copolymers was determined with gel permeation chromatography. The thermal properties were investigated using differential scanning calorimetery and thermogravimetric analysis. The zetapotential of the pDNA/copolymer complexes was evaluated with dynamic laser light scattering. Cytotoxicity and gene transfection efficiency of PEI-g-PLGA were tested in vitro using human embryonic kidney 293 cell culture. The pDNA/copolymer complexes (N/P = 10) showed a lower zeta-potential than pDNA/PEI25kDa complex, suggesting the lower toxicity of the pDNA/copolymer complexes. The copolymer composition was found to significantly affect the gene transfection efficiency of the pDNA/copolymer complexes. The copolymers with lower contents of PLGA showed higher gene transfection efficiency. These results indicate that these block copolymers are promising candidates for gene delivery vehicles, featuring good biocompatibility, potential biodegradability, and relatively high gene transfection efficiency.

Abstract: Novel, biodegradable poly(ester amine)s (PEAs) were synthesized using hydrophobic polycaprolactone diacrylate (PCLDA) and highly cationic polyethylenimine (PEI). This novel gene carrier can form stable DNA complexes with particle sizes around 200 nm, and showing excellent transfection efficiency and relatively low cytotoxicity compared with PEI 25K. Effect of hydrophobicity on transfection efficiency and cytotoxicity was profound and was relatively important parameter for the success of gene delivery.

Abstract: The objective of this study is to develop a new type of cationic nanoparticles for the intracellular drug delivery to breast cancer. Poly(ester amine) (PEA) based on polyethylenimine and polycaprolactone was synthesized to make cationic PEA nanoparticles for all-trans retinoic acid (RA). In the 1H-NMR study, the proton signals of RA appeared in the spectrum of RA-loaded PEA nanoparticles in CDCL3, whereas they disappeared in D2O, suggesting that hydrophobic inner-core with hydrophilic outer-shell formed in water. RA release was faster at lower drug content and RA was released over a period of 20 days. RA-loaded PEA nanoparticles showed enhanced cytotoxicity compared with RA itself, whereas nanoparticles of PEA themselves did not show it. These results indicated that the cationic PEA provided an efficient intracellular delivery of RA.

Abstract: Acknowledging the supportive influence of matrix molecules on the chondrocytic phenotype, we combined heparin and chitosan to develop a novel biomaterial, supporting chondrogenesis. Chitosan had been shown as a promising structural material for a number of tissue engineering applications. Similar to heparin, one of the glycosamino-glycans (GAGs) had been known to exert various influences on the biological activities. In this study we evaluated the potential of heparin/chitosan polyelectrolyte complex materials for controlling the proliferation and differentiation of chondrocytes. The heparin/chitosan polyelectrolyte complex was coated over the polyethyleneimine (PEI) layer precoated on the commercial polystyrene dish. When examined by using human chondrocyte cell line (C28/I2), the heparin/chitosan surfaces supported well not only the cell proliferation but also the chondrocytic functions, such as expression of collagen type II. These results indicated that the heparin/chitosan complex could be used to modulate the activity of chondrocytes in vitro.

Abstract: Hydrolysis and dispersing behavior of aqueous ZrB2 slurry were investigated. The isoelectric point (IEP) of ZrB2 slurry was measured to be pH 6.3. The acid and base slurry underwent rather rapid change of pH after fabrication for one and three hours, respectively. The oxygen content of the boride powder increased slowly with static ageing time in acid and neutral slurries, while the value decreased in base slurry. Application of poly(ethyleneimine) changed IEP of the boride slurry to pH 10.4. Sedimentation test informed that stability of the slurry was improved when increasing the molecular weight of poly(ethyleneimine) to 70,000 and in acid slurry (pH 3).

Abstract: We present the preparation and Cu(II) adsorption characteristics of a new and innovative composite which was composed of a carboxymethylated polyethyleneimine (CM-PEI) and an activated carbon with a nanopore less than 2 nm in diameter. In this study, we examined the adsorption phenomena of Cu(II) on the CM-PEI/F400 composite and evaluated the adsorption data using three kinds of isotherm models (Langmuir, Freundlich, and Temkin isotherms). It was found that the adsorption of Cu(II) on the CM-PEI/F400 composite obeys the Langmuir isotherm model. Furthermore, The Cu element mapping results showed that Cu was well distributed throughout all the surface of the composite particle, suggesting that the surface of the F400 particle was uniformly covered with CM-PEI.