scholarly journals Colloidal Stability of Positively Charged Dispersions of Styrene and Acrylic Copolymers in the Presence of TiO2 and CaCO3

2019 ◽  
Vol 3 (1) ◽  
pp. 20 ◽  
Author(s):  
Kamil Wojciechowski ◽  
Małgorzata Gutarowicz ◽  
Kamil Janke ◽  
Ilona Jurek ◽  
Marcin Kaczorowski ◽  
...  
Keyword(s):  
Cetyltrimethylammonium Bromide ◽  
Colloidal Stability ◽  
Antimicrobial Properties ◽  
Ethyl Acrylate ◽  
Ζ Potential ◽  
Bacterial Diseases ◽  
Latex Dispersions ◽  
Acrylic Copolymers ◽  
Alternative Approaches ◽  
Positively Charged

Increasing antibiotic resistance of several pathogenic microorganisms calls for alternative approaches to prevent spreading of bacterial diseases. We propose to employ for this purpose coatings obtained from positively charged latex dispersions. In this contribution we characterize aqueous mixed dispersions containing TiO2 or CaCO3 and methyl methacrylate-ethyl acrylate or styrene-ethyl acrylate copolymers synthesized using a cationic surfactant, cetyltrimethylammonium bromide as an emulsifier. Particle size, electrokinetic (ζ) potential of the mixed dispersions and the resulting thin films, as well as antimicrobial properties of the latter are described. The TiO2 and CaCO3 dispersions were stabilised with polyethyleneimine (PEI) and optimum pH for the mixed dispersions were chosen on the basis of ζ-potential measurements. For TiO2, the maximum ζ = +35 mV was found at pH 7.5, and for CaCO3, pH was set at 8.2 (ζ = +38 mV), to prevent its dissolution. In most 1:1 mixtures of TiO2 or CaCO3 with the cetyltrimethylammonium bromide (CTAB)-stabilised latex dispersions, two distinct particles populations were observed, corresponding to the bare latex and bare TiO2 or CaCO3 fractions. Films made of the mixed dispersions remained positively charged and showed antimicrobial activity similar or reduced with respect to the bare polymer films.

Hydrogel supported positively charged ultrathin polyamide layer with antimicrobial properties via Ag modification

2021 ◽  
pp. 120295
Author(s):  
Pengrui Jin ◽  
Victor Mattelaer ◽  
Shushan Yuan ◽  
Mohamed Bassiouni ◽  
Kenneth Simoens ◽  
...  
Keyword(s):  
Antimicrobial Properties ◽  
Positively Charged ◽  
Ag Modification

scholarly journals Copper Kills Escherichia coli Persister Cells

Antibiotics ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 506
Author(s):  
Paula Maria Moreira Martins ◽  
Ting Gong ◽  
Alessandra A. de Souza ◽  
Thomas K. Wood
Keyword(s):  
Escherichia Coli ◽  
Copper Ions ◽  
Copper Alloys ◽  
Control Plant ◽  
Antimicrobial Properties ◽  
Bacterial Strains ◽  
Persister Cells ◽  
Independent Manner ◽  
Bacterial Diseases ◽  
Antimicrobial Treatments

Due to their reduced metabolism, persister cells can survive most antimicrobial treatments, which usually rely on corrupting active biochemical pathways. Therefore, molecules that kill bacterial persisters should function in a metabolism-independent manner. Some anti-persister compounds have been found previously, such as the DNA-crosslinkers mitomycin C and cisplatin, but more effective and lower cost alternatives are needed. Copper alloys have been used since ancient times due to their antimicrobial properties, and they are still used in agriculture to control plant bacterial diseases. By stopping transcription with rifampicin and by treating with ampicillin to remove non-persister cells, we created a population that consists solely of Escherichia coli persister cells. Using this population of persister cells, we demonstrate that cupric compounds kill E. coli persister cells. Hence, copper ions may be used in controlling the spread of important bacterial strains that withstand treatment with conventional antimicrobials by forming persister cells.

scholarly journals Effect of Hydrophobic and Hydrophilic Metal Oxide Nanoparticles on the Performance of Xanthan Gum Solutions for Heavy Oil Recovery

Nanomaterials ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 94 ◽  
Author(s):  
Laura Corredor ◽  
Maen Husein ◽  
Brij Maini
Keyword(s):  
Metal Oxide ◽  
Oil Recovery ◽  
Heavy Oil ◽  
Xanthan Gum ◽  
Colloidal Stability ◽  
Metal Oxide Nanoparticles ◽  
Oxide Nanoparticles ◽  
Heavy Oil Recovery ◽  
Tio2 Nps ◽  
Ζ Potential

Recent studies revealed higher polymer flooding performance upon adding metal oxide nanoparticles (NPs) to acrylamide-based polymers during heavy oil recovery. The current study considers the effect of TiO2, Al2O3, in-situ prepared Fe(OH)3 and surface-modified SiO2 NPs on the performance of xanthan gum (XG) solutions to enhance heavy oil recovery. Surface modification of the SiO2 NPs was achieved by chemical grafting with 3-(methacryloyloxy)propyl]trimethoxysilane (MPS) and octyltriethoxysilane (OTES). The nanopolymer sols were characterized by their rheological properties and ζ-potential measurements. The efficiency of the nanopolymer sols in displacing oil was assessed using a linear sand-pack at 25 °C and two salinities (0.3 wt % and 1.0 wt % NaCl). The ζ-potential measurements showed that the NP dispersions in deionized (DI) water are unstable, but their colloidal stability improved in presence of XG. The addition of unmodified and modified SiO2 NPs increased the viscosity of the XG solution at all salinities. However, the high XG adsorption onto the surface of Fe(OH)3, Al2O3, and TiO2 NPs reduced the viscosity of the XG solution. Also, the NPs increased the cumulative oil recovery between 3% and 9%, and between 1% and 5% at 0 wt % and 0.3 wt % NaCl, respectively. At 1.0 wt % NaCl, the NPs reduced oil recovery by XG solution between 5% and 12%, except for Fe(OH)3 and TiO2 NPs. These NPs increased the oil recovery between 2% and 3% by virtue of reduced polymer adsorption caused by the alkalinity of the Fe(OH)3 and TiO2 nanopolymer sols.

Change of Multiple-Layered Phospholipid Vesicles Produced by Electrostatic Deposition of Polymers during Storage

2016 ◽  
Vol 12 (8) ◽  
pp. 763-771 ◽  
Author(s):  
Ji-Yeon Chun ◽  
Jochen Weiss ◽  
Monika Gibis ◽  
Mi-Jung Choi ◽  
Geun-Pyo Hong
Keyword(s):  
Particle Size ◽  
Layer By Layer ◽  
Ζ Potential ◽  
Electrostatic Deposition ◽  
Sedimentation Behavior ◽  
Physicochemical Stability ◽  
Release Study ◽  
Calcein Release ◽  
Liposome Surface ◽  
Positively Charged

Abstract In this study, 1 wt% lecithin (–), chitosan (+), and λ-carrageenan (–) were prepared to manufacture multiple-layered liposomes with optimal formulations developed in a previous study by using layer-by-layer electrostatic deposition. We observed their particle size, ζ-potential, sedimentation behavior, and microstructure for 6 weeks. Multiple-layered liposomes were quenched with calcein to evaluate stability in terms of factors such as encapsulation efficiency and released amount of calcein. The particle size of multi-layered liposomes increased with storage periods and the ζ-potential of multiple-layered liposomes gained a neutral charge. Interestingly, negatively charged layered liposomes were smaller than positively charged layered liposomes and showed a lower polydispersity index. Moreover, the ζ-potential did not apparently change compared to positively charged layered liposomes. For the calcein release study, multiple-layered liposomes significantly sustained quenched calcein more than that observed using non-layered liposomes. This study showed that it was possible to increase the thickness of the liposome surface and to manipulate its charge using chitosan and λ-carrageenan through electrostatic deposition. Results showed that manufacturing negatively charged multiple-layer (over 4-layer) liposomes with charged biopolymer improved the physicochemical stability of liposomes.

Nanocomposites Based on Acrylic Copolymer, Iron Lignosulfonate and ZnO Nanoparticles Used as Wood Preservatives

2009 ◽  
Vol 151 ◽  
pp. 139-144 ◽  
Author(s):  
Lucia Dumitrescu ◽  
Dana Perniu ◽  
Ileana Manciulea
Keyword(s):  
Zno Nanoparticles ◽  
Sol Gel ◽  
Ethyl Acrylate ◽  
Wood Preservation ◽  
Acrylic Copolymer ◽  
Water Emulsion ◽  
Afm Analysis ◽  
Acrylic Copolymers ◽  
Inorganic Nanomaterials

The paper presents research concerning the synthesis and characterization of some new nanocomposite used as wood coating nanomaterials, consisting of a hybrid of organic (functionalized acrylic copolymers with iron lignosulfonate) and inorganic nanomaterials (ZnO nanoparticles obtained by sol-gel process). The presence of acrylic copolymers in water emulsion (based on monomers ethyl acrylate, butyl acrylate, acrylonitrile and the lignin derivative iron lignosulfonate) and ZnO nanoparticles enables the formation of a crosslinked nanometric network of inorganic and organic domains, emphasized by AFM analysis. The interphase characterization of the nanostructured materials synthesized was performed using FT-IR analysis. Considering the biocide activity for the acrylic copolymers, the lignin derivative iron lignosulfonate and ZnO nanoparticles, the obtained nanocomposites were biologically investigated and proposed as wood preservation agents.

Magneto-Structural and Antimicrobial Properties of Sodium Doped Lanthanum Manganite Magnetic Nanoparticles for Biomedical Applications: Influence of Silica Coating

2018 ◽  
Vol 37 ◽  
pp. 117-127 ◽  
Author(s):  
Cyril O. Ehi-Eromosele ◽  
J.A.O. Olugbuyiro ◽  
A. Edobor-Osoh ◽  
A.A. Adebisi ◽  
O.A. Bamgboye ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Magnetic Nanoparticles ◽  
Structural Properties ◽  
Biomedical Applications ◽  
Colloidal Stability ◽  
Antimicrobial Properties ◽  
Silica Coating ◽  
Coated Sample ◽  
Lanthanum Manganites ◽  
Doped Lanthanum Manganites

Coating of magnetic nanoparticles (MNPs) is usually a requirement prior to their utilization in biomedical applications. However, coating can influence the magneto-structural properties of MNPs thereby imparting their applications. The present work highlights the combustion synthesis of Na-doped lanthanum manganites (LNMO) and the influence of silica coatings on the magneto-structural properties, colloidal stability and antimicrobial properties of LNMO MNPs with their biomedical applications in mind. The crystalline perovskite structure was the same both for the bare and silica coated LNMO samples while there was a slight increase in crystallite size after coating. The FTIR spectral analysis, reduction in agglomeration of the particles and the elemental composition of the coated nanoparticles confirmed the presence of silica. The magnetization values of 34 emu/g and 29 emu/g recorded for bare and coated LNMO samples, respectively show that LNMO MNPs retained its ferromagnetic behaviour after silica coating. The pH dependent zeta potentials of the coated sample is-22.20 mV at pH 7.4 (physiological pH) and-18 mV at pH 5.0 (cell endosomal pH). Generally, silica coating reduced the antibacterial activity of the sample except forBacillussppwhere the antibacterial activity was the same with the bare sample. These results showed that while silica coating had marginal effect on the crystalline structure, size and magnetization of LNMO MNPs, it reduced the antibacterial activity of LNMO MNPs and enhanced greatly the colloidal stability of LNMO nanoparticles. Keywords: Na-doped lanthanum manganites, Silica coating, magnetic nanoparticles, biomedical applications, antimicrobial properties, colloidal stability

scholarly journals Self‐Assembly of Proteinaceous Shells around Positively Charged Gold Nanomaterials Enhances Colloidal Stability in High‐Ionic‐Strength Buffers

ChemBioChem ◽  
2019 ◽  
Vol 21 (1-2) ◽  
pp. 74-79
Author(s):  
Eita Sasaki ◽  
Ryan M. Dragoman ◽  
Shiksha Mantri ◽  
Dmitry N. Dirin ◽  
Maksym V. Kovalenko ◽  
...  
Keyword(s):  
Ionic Strength ◽  
Self Assembly ◽  
Colloidal Stability ◽  
High Ionic Strength ◽  
Gold Nanomaterials ◽  
Positively Charged
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