Anionic Poly Acrylic Acid Research Articles

Preparation of Antimicrobial Agents: From Interpolyelectrolyte Complexes to Silver-Containing Metal–Polymer Complexes and Nanocomposites

In order to control pathogenic microorganisms, three polymer compositions were prepared and tested. First, a water-soluble positively charged polycomplex was synthesized via the electrostatic binding of anionic polyacrylic acid to an excess of polyethylenimine to enhance the biocidal activity of the polycation. Second, an aqueous solution of AgNO3 was added to the polycomplex, thus forming a ternary polycation-polyanion-Ag1+ complex with an additional antimicrobial effect. Third, the resulting ternary complex was subjected to UV irradiation, which ensured the conversion of Ag1+ ions into Ag nanoparticles ranging in size mainly from 10 to 20 nm. Aqueous solutions of the polymer compositions were added to suspensions of the Gram-positive bacteria S. aureus and the Gram-negative bacteria P. aeruginosa, with the following main results: (a) Upon the addition of the binary polycomplex, 30% or more of the cells survived after 20 h. (b) The ternary complex killed S. aureus bacteria but was ineffective against P. aeruginosa bacteria. (c) When the ternary complex with Ag nanoparticles was added, the percentage of surviving cells of both types did not exceed 0.03%. The obtained results are valuable for the development of antibacterial formulations.

Synthesis of salt-resistant hyperbranched waterborne polyurethane associative thickener and its application in textile printing

To improve the thickening effect of polyurethane thickener, hyperbranched waterborne polyurethane associative thickener (HWPUAT) was successfully synthesized and the 3 wt% HWPUAT aqueous solution (HAS) was prepared. The viscosity of HAS at the rotating speed of 6 and 60 rpm was 12,118 and 4207 mPa·s, respectively. After adding 1.3 wt% NaCl, the viscosity retention rates of HAS and anionic polyacrylic acid thickener (APAT) aqueous solution with the same mass fraction were 90.5% and 27.5%, respectively. In addition, HWPUAT was used in textile printing with three different reactive dyes. The penetration ratios (PRs) and the paste removing rates (PRRs) of the cotton fabrics were equal to or greater than 75.91% and 74.23%, respectively. And the color unevenness (CU) of the cotton fabrics was equal to or less than 0.19. The comprehensive performance of the printed fabric was good.

Boosting the Photodynamic Degradation of Islet Amyloid Polypeptide Aggregates Via a “Bait-Hook-Devastate” Strategy

Photosensitizers that can generate reactive oxygen species (ROS) upon irradiation have emerged as promising agents for photodynamic degradation of toxic amyloid aggregates that are linked to many amyloidogenic diseases. However, due to the ultrastable β-sheet structure in amyloid aggregates and inefficient utilization of the generated ROS, it usually requires high stoichiometric concentration of the photosensitizer and/or intensive light irradiation to fully dissociate aggregates. In this work, we have developed a "bait-hook-devastate" strategy to boost the efficiency of the photodynamic degradation of amyloid aggregates. This strategy employs anionic polyacrylic acid as a bait to accumulate cationic human islet amyloid polypeptide (IAPP) aggregates and positively charged photosensitizer TPCI in a confined area through electronic interactions. Multiple characterization studies proved that the utilization rate of ROS generated by TPCI was remarkably improved via this strategy, which amplified the ability of TPCI to dissociate IAPP aggregates. Rapid and complete degradation of IAPP aggregates could be achieved by irradiating the system under very mild conditions for less than 30 min, and the IAPP-mediated cytotoxicity was also largely alleviated, providing a new paradigm to accelerate photodynamic degradation of amyloid aggregates for further practical applications.

Investigation of surface structure, electrokinetic and stability properties of highly dispersed Ho2O3–Yb2O3/SiO2 nanocomposites

A series of highly dispersed Ho2O3–Yb2O3/SiO2 nanocomposites was synthesized using a liquid-phase method and examined using Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), nitrogen adsorption–desorption, transmission electron microscopy (TEM), Scanning Electron Microscopy (SEM), and photon correlation spectroscopy (PCS). X-ray fluorescence spectrometry (XRF) confirmed a similar amount of weight percentage of Ho, Yb and Si oxides in the prepared samples. Samples HoYbSi1 (Ho2O3:Yb2O3:SiO2 = 0.5:10:89.5, wt. %), HoYbSi2 (Ho2O3:Yb2O3:SiO2 = 1:10:89, wt. %) and HoYbSi3 (Ho2O3:Yb2O3:SiO2 = 2:10:88, wt. %) calcined at 550 °C are amorphous. TEM and SEM analysis confirm a sphere-like morphology with a quite homogeneous size and shape. As compared with the initial silica, the agglomerated particles of nanocomposites in the aqueous medium are in the range from 200 to 850 nm according to PCS data. The effect of anionic polyacrylic acid (PAA) adsorption on fumed silica (SiO2) and Ho2O3–Yb2O3/SiO2 nanocomposite surfaces on suspension stability was studied. The turbidymetry method was used to monitor the initial silica and triple nanooxides suspensions stability as a function of time.

Colloidal stabilization of CeO2 nanomaterials with polyacrylic acid, polyvinyl alcohol or natural organic matter

Engineered nanomaterials (ENM) such as nano-sized cerium dioxide (CeO2) are increasingly applied. Meanwhile, concerns on their environmental fate are rising. Understanding the fate of ENM within and between environmental compartments such as surface water and groundwater is crucial for the protection of drinking water resources. Therefore, the colloidal stability of CeO2 ENM (2 mg L−1) was assessed with various surface coatings featuring different physico-chemical properties such as weakly anionic polyvinyl alcohol (PVA), strongly anionic polyacrylic acid (PAA) or complex natural organic matter (NOM) at various water compositions in batch experiments (pH 2–12, ionic strength 0–5 mM KCl or CaCl2). While uncoated CeO2 ENM aggregate in the range of pH 4–8 in 1 mM KCl solution, the results show that PAA, PVA and NOM surface coatings stabilize CeO2-ENM at neutral and alkaline pH in 1 mM KCl solution. Stabilization by PAA and NOM is associated with strongly negative zeta potentials below −20 mV, suggesting electrostatic repulsion as stabilization mechanism. No aggregation was detected up to 5 mM KCl for PAA- and NOM-coated CeO2 ENM. In contrast, CaCl2 induced aggregation at >2.2 mM CaCl2 for PAA and NOM-coated CeO2 ENM respectively. PVA-coated ENM showed zeta potentials of −15 mV to −5 mV in the presence of 0–5 mM ionic strength, suggesting steric effects as stabilization mechanism. The hydrodynamic diameter of PVA-coated ENM was larger compared to PAA and NOM at low ionic strength, but the size did not increase with ionic strength of the suspensions. The effect of ionic strength and counter ion valency (pH 7) on the colloidal stability of ENM depends on the prevailing stabilization mechanism of the organic coating. NOM can be similarly effective in colloidal stabilization of CeO2-ENM as PAA. Our results suggest natural Ca-rich waters will lead to ENM agglomeration even of coated CeO2-ENM.

Polyelectrolyte-protected Dual-color-quantum-dot Assembled Silica Nanoparticles and Their Application in Simultaneous Fluorescence Determination of e Antigen and Surface Antigen of Hepatitis B.

Cationic poly-diallyldimethylammonium (PDADMAC), green CdTe quantum dots (QDs) or red CdS coated CdTe QDs, and anionic polyacrylic acid (PAA) were respectively assembled on the nano-carrier SiO2 to prepare green fluorescence composite nanoparticles (GF-QDs) and red ones (RF-QDs) with the structure SiO2/PDADMAC/QD/PDADMAC/PAA. The sandwich structure "PDADMAC/QD/PDADMAC" on the nano-carrier not only realized the protection to fluorescence of QDs but also avoided the fluorescence shielding of silica shell for the assembled QDs. In 7 days, the diluent solutions of GF-QD and RF-QD all have a very stable fluorescence. On the contrary, the fluorescence of diluent solutions of red and green QDs reduced by 75.99 and 94.35%, respectively. Indeed, they have not fluorescent shielding and have a very slight fluorescent enhancement. Based on GF-QD and RF-QD, the simultaneous determination of Hepatitis B e antigen and surface antigen has been established. Their determination in buffer and plasma all showed good precision and accuracy.

Understanding the Colloidal Behaviour or 45S5 Bioactive Glass Particles to Obtain Bioactive-Glass Based Composite Coatings by EPD

The interaction between bioactive glass particles and polymers with different functional groups has been established in this work to better understand and control the colloidal processing of the bioactive glass phase. Cationic polyvinylpyrrolidone (PVP), anionic polyacrylic acid (PAA) and neutral polyvinyl alcohol (PVA) were selected and the surface reactions in alcoholic media and between bioactive glass particles and polymers were considered. All three polymers were successfully employed to obtain soft composite coatings incorporating bioactive glass particles.

Self-assembly of polyelectrolytes for the removal of metal cations from aqueous solutions

Interactions between polyacrylic acid (PAA) and polyethyleneimine (BPEI) were investigated in the absence and in the presence of metal cations (M) over a large pH-range. These interactions led to the formation of complexes with sizes in the range from colloids to particles. The sizes of the complexes, structures of the resulting media and free metal concentrations were strongly dependent on the way reactants were put into contact. Best conditions for metal separation were obtained when the polycation was used to neutralise the anionic PAA–M complex since it resulted in fast gravity separation of metals and low residual concentrations. A single-step ultrafiltration (UF) treatment was also studied and compared to a two-step treatment made of gravity separation and UF of supernatants in terms of quality and volumetric rates for treated wastewater.

Layer-by-layer assembly of chitosan stabilized multilayered liposomes for paclitaxel delivery

Paclitaxel (PTX) loaded multilayered liposomes were prepared using layer-by-layer assembly in an effort to improve the stabilization of the liposomal compositions for PTX delivery. Stearyl amine was used to provide positive charge to the PTX-liposomes, and subsequently coated with anionic polyacrylic acid (PAA) followed by cationic chitosan. Various process variables were optimized and the optimum formulation was found to have particle size of 215±17nm, zeta potential of +27.9±3.4mV and encapsulation efficiency of 70.93±2.39%. The lyophilized chitosan–PAA–PTX–liposomes formulation was stable in simulated gastrointestinal fluids and at different environmental conditions (4°C and 25°C). In vitro drug release experiments demonstrated that chitosan–PAA–PTX-liposomes formulation exhibited obvious sustained release behaviors compared to PTX-liposomes. Furthermore, chitosan–PAA–PTX-liposomes formulation revealed enhanced PTX induced cytotoxicity in human cervical cancer cell culture experiments compared to PTX-liposomes. In conclusion, the approach presented herein will provide a promising solution for PTX delivery.

Inorganic–Organic Hybrid Nanoparticles with Biocompatible Calcium Phosphate Thin Shells for Fluorescence Enhancement

Polymeric micelles consisting of asymmetric triblock copolymers were successfully used for fabrication of robust hybrid nanoparticles with highly biocompatible calcium phosphate shells. The hydrophobic polystyrene core encapsulates hydrophobic fluorescent dyes such as Nile red. The anionic polyacrylic acid provides the site for the mineralization reaction of calcium phosphate. The polyethylene glycol corona stabilizes the hybrid nanoparticles. Fluorescent dyes can be used as imaging agents for determining the location of the nanoparticles and to give an observable indication of drug delivery, while the calcium phosphate shell can enhance the fluorescence of the encapsulated dye.

Effect of Organic Polymer Addition on the Microstructure of Magnetite-Polymer Hybrid

This study is concerning hybrid materials composed of the magnetite and the organic polymer such as dextran. They are useful for hyperthermia of cancer. In the preparation of this material, chemical structure or molecular weight of the added polymer is expected to affect ionic interaction between polymer and iron salts, and consequently the grain size and morphology of the prepared magnetite core. Therefore, we have synthesized magnetite-polymer hybrids using various polymers. Various polymers were dissolved in iron (II) chloride aqueous solution, and then NaOH aqueous solution was added to this mixed solution. As a result, in the case of neutral and cationic polymer crystalline magnetite was precipitated in the hybrid. On the other hand, in the case of anionic polyacrylic acid, lepidocrocite was precipitated rather than magnetite. It is known that the magnetite formation progresses through intermediate Fe (OH)2 formation and oxidation of the Fe (OH)2 by dissolved O2. Therefore it is considered that tight ionic interaction is constructed between the iron ions and the carboxyl group in the polyacrylic acid to form a complex, and the Fe (OH)2 formation is inhibited. When the hybrid was prepared by addition of NaOH aqueous solution to iron (II) chloride solution, and subsequent addition of the different polymers, magnetite formation was not inhibited irrespective of kind of polymer. The present results indicate that crystalline structure of the magnetite phase in magnetite-polymer hybrid is strongly affected by the chemical structure of polymer additives or the order of addition.

Direct measurement of alkaline phosphatase kinetics on bioactive paper

The reaction kinetics of alkaline phosphatase (ALP) adsorbed on paper was quantified by image analysis using a colorimetric technique under conditions of excess enzyme. A classical reaction kinetics approach integrated with image processing technique was used to analyse the coloured product formation from the enzyme substrate reaction against time. The order of reaction and rate constant of enzyme activities on paper surface were calculated. ALP was either physisorbed directly on paper or adsorbed on paper treated with a monolayer of a high molecular weight cationic polyacrylamide (CPAM), an anionic polyacrylic acid (PAA) or a high molecular weight polyethylene oxide (PEO). The reaction rate of enzymatic paper follows a first order reaction with respect to the concentration of enzyme–substrate complex. ALP immobilized on paper has a reaction rate 2 to 3 orders of magnitude lower than the free ALP enzyme in buffer solution. This might be due to a critical loss of enzyme flexibility upon adsorption. No increase in reaction rate was achieved by immobilizing ALP on paper treated with a high molecular weight cationic polyacrylamide (CPAM) or a highly charged anionic polyacrylic acid oligomer (PAA), which suggests the enzyme orientation was not significantly affected. However, the reaction rate for ALP on PEO treated paper was lower than that on CPAM or PAA treated papers. That is probably due to some PEO-enzyme interaction affecting the tertiary structure of the ALP enzyme.

Effect of the type of polymer functional groups on the structure of its film formed on the alumina surface – Suspension stability

The effects of polymer functional group and solution pH on stability of colloidal Al2O3 water suspension were studied. Both the nonionic polymers: polyethylene glycol (PEG), polyethylene oxide (PEO) and the ionic ones: polyacrylic acid (PAA), polyacrylamide (PAM), polyvinyl alcohol (PVA) were used in the experiments. The following methods were applied: turbidimetry (stability measurements), spectrophotometry (determination of polymer adsorption), viscosimetry (thickness of polymer adsorption layer), potentiometric titration (solid surface charge density) and microelectrophoresis (potential zeta). It was shown that anionic polyacrylic acid is both the most effective stabilizer (at pH 9) and flocculant (at pH 3) of the alumina suspension. Its carboxyl groups have the greatest affinity for the surface active sites (the largest adsorption) of all functional groups present in the other examined polymers. The latter, i.e. hydroxyl (PEG, PEO, and PVA) and acetate (PVA) show a much lower affinity for the Al2O3 surface (negligible adsorption) and minimally affect the stability of the alumina-solution system.

Interaction between Eudragit® E100 and anionic drugs: Addition of anionic polyelectrolytes and their influence on drug release performance

In this work, we report results concerning the study of solid complexes compounded by a cationic polymethacrylate (Eudragit® E100, Eu) and mesalazine (M) (Eu–Mx complex). The influence of an anionic polyacrylic acid polymer (carbomer, C) on dissolution behavior of M from the complex was evaluated (Eu–MxCy complex). The dissolution profiles and solvent front movements of solid matrices in different media (water, buffer pH 7.4, 0.9% NaCl) were investigated and ionic interactions among Eu, M, and C were determined through Fourier transform infrared (FT‐IR) spectroscopy. For Eu–Mx complexes, the affinity between M and Eu modulated the delivery of free M in solution, with the dissolution media affecting the delivery rate mainly due to an ionic interchange process between M and anionic electrolytes (i.e., Cl−). FTIR spectroscopy allowed the ionic interaction between Eu and M to be verified. The addition of C (Eu–MxCy) influenced the dissolution behavior of these matrices. As the amount of C was increased, the release mechanism changed from diffusion (Eu–M50) or anomalous (Eu–M100) to zero order (Eu–MxC50). This variation in rate delivery was also affected by the dissolution media, as occurred with Eu–Mx complexes. The formation of the gel layer during the dissolution process, as consequence of Eu–MxCy matrices hydration, was influenced by C amount and dissolution media. © 2011 Wiley‐Liss, Inc. and the American Pharmacists Association J Pharm Sci 100:4664–4673, 2011

Temperature effect on adsorption properties of silica-polyacrylic acid interface

The temperature influence on the adsorption mechanism of anionic polyacrylic acid (PAA) macromolecules on the silica surface was studied. For this purpose, the following techniques were applied: spectrophotometry, thermogravimetry, potentiometric titration and microelectrophoresis. This method allowed to determine the adsorbed amounts of polymer, changes in thermal characteristic of silica surface with adsorbed PAA, surface charge density of the solid as well as zeta potential of SiO2 particles in the presence and absence of polyacrylic acid. All measurements were carried out in the temperature range 15-35 °C. The free energies of adsorption were calculated from the adsorption data fitted by the Langmuir model. The obtained results of increase of PAA adsorption and its adsorption free energies with the rising temperature suggest that adsorbed polymer conformation changes from the coiled structure to more stretched one. Moreover, the polymer adsorption on the silica surface at 25 °C leads to changes in the course of thermogravimetric curves as a result of surface properties modification of the solid by bonded macromolecules.

Effect of polymers on the retention and aging of enzyme on bioactive papers

The effect of polymer on the retention and the thermal stability of bioactive enzymatic papers was measured using a colorimetric technique quantifying the intensity of the enzyme–substrate product complex. Alkaline phosphatase (ALP) was used as model enzyme. Three water soluble polymers: a cationic polyacrylamide (CPAM), an anionic polyacrylic acid (PAA) and a neutral polyethylene oxide (PEO) were selected as retention aids. The model polymers increased the enzyme adsorption on paper by around 50% and prevented enzyme desorption upon rewetting of the papers. The thermal deactivation of ALP retained on paper with polymers follows two sequential first order reactions. This was also observed for ALP simply physisorbed on paper. The retention aid polymers instigated a rapid initial deactivation which significantly decreased the longevity of the enzymatic papers. This suggests some enzyme–polymer interaction probably affecting the enzyme tertiary structure. A deactivation mathematical model predicting the enzymatic paper half-life was developed.

Adsorption of ethoxylated styrene oxide and polyacrylic acid and mixtures there of on organic pigment

The adsorption of two polymeric surfactants on an organic pigment was investigated. As surfactants the anionic polyacrylic acid sodium salt (PANa, M W = 15 , 000 ) and a non-ionic block copolymer surfactant based on styrene oxide (SO) and ethylene oxide (EO) ( M W = 1500 ) were used. The adsorption behavior was analyzed by size exclusion chromatography of the supernatant after centrifugation of the pigment dispersions. It was found that PANa has no affinity to the pigment, whereas SO–EO has a strong affinity to the pigment surface. Competitive adsorption of PANa and SO–EO was not observed. Addition of SO–EO yields stable dispersions.

Adhesion of Gibberella fujikuroi cells on surfaces of carriers by radiation polymerization

The adhesion of Gibberella fujikuroi cells on the covered polymers which were prepared by radiation polymerization technique was investigated. The adhesion of the cells was related to the surface free energy and polar component force. The copolymer resulted from hydrophillic and hydrophobic monomer and porous structure were favorable to the adhesion of the cells. However, the anionic poly-acrylic acid was not unfavorable to the adhesion of the cells. The adhesion process of the cells on the carrier covered with copolymer was observed by scanning electron microscopy.

Lack of inhibition of adhesion of an enteropathogenic Escherichia coli by polycarbophil.

Anionic polyacrylic acid polymers, such as polycarbophil, have a number of properties that would make them suitable carriers for sustained antibiotic release formulations in the intestinal tract. However, little is known with regards to possible microbial adhesion to polycarbophil. The aim of this study was to evaluate for such an interaction using the rabbit enteric pathogen Escherichia coli RDEC-1 (serotype O15:H-). RDEC-1 mediates attaching and effacing binding to intestinal epithelium in a manner morphologically identical to that observed in both human enteropathogenic E. coli and enterohemorrhagic E. coli infections. RDEC-1 bacteria were grown to promote the expression of the mannose-resistant AF/R1 adhesion pili. A nonpiliated mutant, strain M34, was used as a negative control. Using radioactive labeling of bacteria, we quantitated adhesion of piliated RDEC-1 in the presence of polycarbophil using an in vitro adhesion assay system. Binding of piliated RDEC-1 in the adhesion assay was greater than for nonpiliated M34 for all concentrations of bacteria greater than 10(9) (P < .05). Polycarbophil did not cause concentration-dependent inhibition of piliated RDEC-1 binding (P > .05). We conclude polycarbophil does not interfere with the AF/R1 adhesin ligand of RDEC-1. Use of this polymer as a mucoadhesive drug delivery vehicle for nonabsorbable antibiotics in the treatment of gastrointestinal infections would not be expected to interfere with the protective effects of intestinal mucins.