Cationic Water-soluble Polymers Research Articles

Analysis of polydisperse polymer adsorption on porous cellulose fibers.

The adsorption of cationic water-soluble polymers onto negatively charged porous wood pulp fibers is an essential aspect of papermaking. Adsorption data can be displayed as a direct plot of the amount adsorbed, Γ, versus the amount of polymer added or as an isotherm plot showing the amount adsorbed versus the residual unadsorbed polymer. In either data presentation, the analysis is more transparent if the units of each axis are the same (e.g., mg/g or meq/g), giving dimensionless slopes. Values for Γmax, ΓI, f I , and Γme can be extracted from many isotherms where: Γmax is the maximum capacity of the fibers to adsorb polymer; ΓI is the y-axis isotherm intercept and gives the maximum dose that can be fully adsorbed; f I is the slope of the direct plot at ΓI, and f I is the mass fraction of the added polymer that can access interior (pore) surfaces; and, Γme is the saturated amount of polymer adsorbed on exterior surfaces. Additionally, the molecular weight distribution of theadsorbing polymer in conjunction with the adsorption isotherm can be used to estimate the molecular weight distributions of adsorbed polymer on interior and exterior fiber surfaces as functions of the polymer dose.

Polyquaternium polymers cause inflammatory response and alterations of the lipidome in Danio rerio larvae

Polyquaternium polymers are widely used in various applications, such as personal care products and wastewater treatment plants, and eventually end up in the aquatic environment. While polymers have been perceived of low toxicological concern due to their size, several studies have pointed towards water-soluble cationic polymers being toxic towards aquatic organisms – and that the toxicity largely is determined by the polymer charge density. The present study investigated the polyquaternium toxicological mechanism of action throughout lipidomic analysis and changes in immune-gene expression (qPCR) of zebrafish larvae exposed continuously to two water-soluble polymers; a high charge density polyquaternium-6 and a low charge density polyquaternium-10, for 5 and 12 days upon fertilization. The results showed that the investigated polyquaterniums cause both inflammatory responses and significant alterations of the zebrafish larvae lipidome. Depending on polyquaternium polymer and larvae development stage, the gene expression showed an inflammatory response (e.g. significant up-regulation of il8, il1β and tnfα) in the exposed zebrafish. Alterations of the lipidome were additionally observed, with severe depletion of lipids (e.g. lyso-glycerophosphocholines and ceramides) in the 12 days old larvae exposed to high charge density polymer. The findings furthermore support a hypothetical mechanism of action to be non-specific and lethality potentially to be narcosis-like driven.

Antifouling and Water Flux Enhancement in Polyethersulfone Ultrafiltration Membranes by Incorporating Water-Soluble Cationic Polymer of Poly [2-(Dimethyl amino) ethyl Methacrylate

Novel ultrafiltration (UF) polymer membranes were prepared to enhance the antifouling features and filtration performance. Several ultrafiltration polymer membranes were prepared by incorporating different concentrations of water-soluble cationic poly [2-(dimethyl amino) ethyl methacrylate] (PDMAEMA) into a homogenous casting solution of polyethersulfone (PES). After adding PDMAEMA, the effects on morphology, hydrophilicity, thermal stability, mechanical strength, antifouling characteristics, and filtration performance of these altered blended membranes were investigated. It was observed that increasing the quantity of PDMAEMA in PES membranes in turn enhanced surface energy, hydrophilicity, and porosity of the membranes. These new modified PES membranes, after the addition of PDMAEMA, showed better filtration performance by having increased water flux and a higher flux recovery ratio (FRR%) when compared with neat PES membranes. For the PES/PDMAEMA membrane, pure water flux with 3.0 wt.% PDMAEMA and 0.2 MPa pressure was observed as (330.39 L·m-2·h-1), which is much higher than that of the neat PES membrane with the value of (163.158 L·m-2·h-1) under the same conditions. Furthermore, the inclusion of PDMAEMA enhanced the antifouling capabilities of PES membranes. The total fouling ratio (TFR) of the fabricated PES/PDMAEMA membranes with 3.0 wt.% PDMAEMA at 0.2 MPa applied pressure was 36 percent, compared to 64.9 percent for PES membranes.

In vivo surface-enhanced Raman scattering nanosensor for the real-time monitoring of multiple stress signalling molecules in plants.

When under stress, plants release molecules to activate their defense system. Detecting these stress-related molecules offers the possibility to address stress conditions and prevent the development of diseases. However, detecting endogenous signalling molecules in living plants remains challenging due to low concentrations of these analytes and interference with other compounds; additionally, many methods currently used are invasive and labour-intensive. Here we show a non-destructive surface-enhanced Raman scattering (SERS)-based nanoprobe for the real-time detection of multiple stress-related endogenous molecules in living plants. The nanoprobe, which is placed in the intercellular space, is optically active in the near-infrared region (785 nm) to avoid interferences from plant autofluorescence. It consists of a Si nanosphere surrounded by a corrugated Ag shell modified by a water-soluble cationic polymer poly(diallyldimethylammonium chloride), which can interact with multiple plant signalling molecules. We measure a SERS enhancement factor of 2.9 × 107 and a signal-to-noise ratio of up to 64 with an acquisition time of ~100 ms. To show quantitative multiplex detection, we adopted a binding model to interpret the SERS intensities of two different analytes bound to the SERS hot spot of the nanoprobe. Under either abiotic or biotic stress, our optical nanosensors can successfully monitor salicylic acid, extracellular adenosine triphosphate, cruciferous phytoalexin and glutathione in Nasturtium officinale, Triticum aestivum L. and Hordeum vulgare L.-all stress-related molecules indicating the possible onset of a plant disease. We believe that plasmonic nanosensor platforms can enable the early diagnosis of stress, contributing to a timely disease management of plants.

Preparation of Magnetic Hydrogel Microparticles with Cationic Surfaces and Their Cell-Assembling Performance.

Cationic magnetic hydrogel microparticles with high retention on cell surfaces were prepared using a two-step procedure. Using these magnetic hydrogel microparticles, cells were clustered with each other, and cell aggregates were prepared effectively. Cross-linked poly(vinyl alcohol) (PVA) hydrogel microparticles containing iron oxide nanoparticles were prepared. The diameter of the microparticles was in the range of 200-500 nm. Water-soluble cationic polymers containing both trimethyl ammonium (TMA) groups and phenylboronic acid (PBA) groups were synthesized for the surface modification of the microparticles. To regulate the composition, electrically neutral phosphorylcholine groups were introduced into the polymer. Covalent bonds were formed between the hydroxy groups of PVA microparticles and PBA groups in the polymer. The surface zeta potential of the microparticles reflected the composition of the TMA groups. The particles responded to an external magnetic field and clustered rapidly. Microparticles were adsorbed on the floating cell surface and induced cell aggregation quickly when a magnetic field was applied. Under the most effective conditions, the diameter of the cell aggregates increased to approximately 1 mm after 30 min. Denser cell aggregates were formed by the synergistic effects of the magnetic field and the properties of the microparticles. The formed cell aggregates continued to grow for more than 4 days under an applied magnetic field, indicating that the ability of the cells in the aggregate to proliferate was well maintained.

Enhanced dewatering of oil sands tailings by a novel water-soluble cationic polymer

This work investigates how poly(vinylbenzyl trimethylammonium chloride)–poly(VBTMAC)–flocculates oil sands mature fine tailings (MFT). This water-soluble cationic polymer contains pendant benzene rings that make it partially hydrophobic. The positive charges on the poly(VBTMAC) backbone neutralize the negatively-charged MFT clays while the hydrophobic benzene rings help expel the water trapped in the aggregates. Vinylbenzyl trimethylammonium chloride can be polymerized to produce long chains (comparable to anionic polyacrylamide) with fast polymerization rates. Focused beam reflectance measurement (FBRM) experiments showed that larger aggregates were formed using higher molecular weight poly(VBTMAC), which is evidence of the bridging mechanism. The flocculation performance of poly(VBTMAC) was tested against commercially available anionic polyacrylamides for undiluted MFT by measuring the extent of dewatering in filtration tests and the rheological properties of the sediments. Our results showed that poly(VBTMAC) is a better flocculant in terms of ease of production, fast dewatering rate, and formation of sediments with high shear strength, but required substantially higher dosages to perform better than commercially available anionic polyacrylamides.

UV-Curable Surface-Attached Antimicrobial Polymeric Onium Coatings: Designing Effective, Solvent-Resistant Coatings for Plastic Surfaces.

Contact-active ammonium and phosphonium antimicrobial polymeric coatings grafted to plastic surfaces by UV treatment are described. Robust, antimicrobial styrenic polymeric scaffolds copolymerized with a low loading of UV-curable benzophenone were prepared by nitroxide-mediated polymerization (NMP). Similar reversible addition-fragmentation chain-transfer (RAFT)-controlled radical polymerizations were attempted for comparison. These random styrenics were further functionalized into partially quaternarized water-soluble cationic polymers. UV-cured polymeric thin film coatings possessing cationic groups with n-alkyl substituents of n ≤ 2 demonstrate antimicrobial properties against both Gram-positive and Gram-negative bacteria, while species containing bulkier or longer substituents were biologically inactive. The UV-cured cationic antimicrobial polymeric onium thin films also demonstrate enhanced abrasion and chemical resistance.

Reinforcing Paper Strength by Dual Treatment of a Cationic Water-soluble Polymer and Cellulose Nanofibril

Reinforcing Paper Strength by Dual Treatment of a Cationic Water-soluble Polymer and Cellulose Nanofibril

Targeting tuberculosis infection in macrophages using chitosan oligosaccharide nanoplexes

Targeting bacterial infections using RNA interference (RNAi) has been a relatively nascent area of research as compared with cancer and viral infections. Exploring this area is especially vital due to the prevalence of numerous challenging bacterial infections that have been persistent despite treatment with antibiotics or antibiotic-loaded delivery systems. In this investigation, we formulate siRNA nanoparticle complexes, using cationic water-soluble chitosan polymer, for intracellular delivery into macrophages that serve as reservoirs of numerous pathogenic bacteria, including Mycobacterium tuberculosis (Mtb). Cationic chitosan oligosaccharide nanoparticles of size 215.3 ± 4.19 nm were formulated by ionotropic gelation and were effectively delivered along with siRNA into the macrophages, without any obvious cytotoxicity. The siRNA-loaded nanoparticles resulted in more than two-fold down-regulation of the host gene, Bfl1/A1, as compared with untreated controls. Since the over expression of host gene Bfl1/A1 favours for survival of Mtb within macrophages, the nanoparticles present a promising potential for developing anti-tuberculosis therapy.

Chitosan Coating Applications in Probiotic Microencapsulation

Nowadays, probiotic bacteria are extensively used as health-related components in novel foods with the aim of added-value for the food industry. Ingested probiotic bacteria must resist gastrointestinal exposure, the food matrix, and storage conditions. The recommended methodology for bacteria protection is microencapsulation technology. A key aspect in the advancement of this technology is the encapsulation system. Chitosan compliments the real potential of coating microencapsulation for applications in the food industry due to its physicochemical properties: positive charges via its amino groups (which makes it the only commercially available water-soluble cationic polymer), short-term biodegradability, non-toxicity and biocompatibility with the human body, and antimicrobial and antifungal actions. Chitosan-coated microcapsules have been reported to have a major positive influence on the survival rates of different probiotic bacteria under in vitro gastrointestinal conditions and in the storage stability of different types of food products; therefore, its utilization opens promising routes in the food industry.

Flocculation of kaolin particles with cationic lignin polymers

Currently, lignin of black liquor is incinerated to generate energy in pulp mills; but it has potential to be valorized through different modification methods. In this work, kraft lignin (KL) was polymerized with 2-[(methacryloyloxy) ethyl] trimethylammonium chloride (DMC) to produce cationic water soluble polymers. After producing five polymers with different molecular weights and charge densities, their flocculation efficiency in kaolin suspensions was investigated. The adsorption, zeta potential and flocculation results confirmed that the polymer with the highest charge density and molecular weight (KLD5) was a more effective flocculant than other polymers. The structure and size of flocs formed from the interaction of kaolin with KLD were determined by a focused beam reflectance measurement (FBRM). The sedimentation studies, conducted under gravitational (by vertical scan analyzer) and centrifugal force (by Lumisizer analytical centrifuge), revealed that KLD5 was very effective in flocculating kaolin particles.

Application of the liquid-phase polymer-based retention technique to the sorption of molybdenum(VI) and vanadium(V)

This research is focused on molybdate and vanadate removal from aqueous solutions by the liquid-phase polymer-based retention (LPR) technique. In this technique, a cationic water-soluble polymer based on the ammonium quaternary group poly(diallyldimethylammonium chloride), PDDA, was used as a polymeric sorbent, and a regenerated cellulose ultrafiltration membrane was used as a filter. The removal of molybdenum and vanadium using the LPR technique was analyzed by both the washing and enrichment methods. The removal experiments using the washing method were conducted by varying the pH, polymer/metal molar ratio, concentration of metal ions, pressure and presence of interfering ions. In addition, the enrichment method was used to determine the maximum retention capacity of PDDA. The obtained results showed the highest retention capacity of molybdate (100%, using 30 mg/L in the feed) for PDDA at pH 3 and 9. The optimum molar ratio was 20:1 polymer/Mo(VI). The efficient vanadate retention (approximately 90%) was obtained at pH 6 with 10:1 polymer/V(V) molar ratio. The effect of metal concentration on the retention showed a higher retention of Mo(VI) independent of its concentrations. In the case of V(V), the maximum retention was reached when 60 mg/L of vanadium was used in the feed. The enrichment method showed the maximum retention capacities of 370 mg Mo(VI)/g PDDA and 520 mg V(V)/g PDDA. The presence of interfering ions did not affect the retention capacity of PDDA. These results showed that the combination of PDDA with ultrafiltration membranes could represent an alternative method for the removal of molybdate and vanadate from water.

Acid-tolerant cyclodextrin-based ruthenium nanoparticles for the hydrogenation of unsaturated compounds in water

Ru NPs, stabilized by a water soluble cationic β-cyclodextrin polymer, proved to be efficient for the hydrogenation of acid substrates.

Toward an Understanding of How the Optical Property of Water-Soluble Cationic Polythiophene Derivative Is Altered by the Addition of Salts: The Hofmeister Effect

Hofmeister ion-specific effects on optical properties of a water-soluble cationic polymer, poly(3-alkoxy-4-methylthiophene) (PMNT), are investigated by means of absorption, resonance Raman spectroscopy, and molecular dynamic simulations. It is found that the ionochromism of conjugated polyelectrolytes PMNT obeys Hofmeister series with high optical sensitivity, while the spectral changes result from the different electrostatic interactions and the conformational change of the cationic PMNT in different salt solutions. As a result, UV–vis absorption spectra exhibit almost no shift of absorption of PMNT in the presence of SO42–, F–, etc., whereas a red-shifted absorption of PMNT with I–, SCN– is clearly observed. To gain a deeper understanding of the nature of these anion-dependent chromic phenomena, ab initio calculations and molecular dynamics (MD) simulations are carried out to present the microscopic insights, that the Hofmeister effect occurs at the PMNT/water interface through the direct (hydrophobic, hydrophilic, and electrostatic) interactions between the anions and PMNT backbone. It is found that the salting-in anions like I– strongly suppress the hydrophobic collapse of PMNT backbone, leading to more extended and ordered PMNT backbone with red-shifted absorption, and the salting-out anions like F– strongly avoid the hydrophobic PMNT backbone, keeping a random-coiled configuration of PMNT backbone without obvious absorption changes in KF solution. The existence of ordered and disordered backbone configurations is further verified by monitoring the main in-plane skeleton Raman modes (C═C and C–C stretch) of PMNT in various salt solutions. The results presented here could provide a fundamental understanding of salt effects on chemical and biological processes occurring at the macromolecular/water interface, and then may potentially stimulate many chemical and biological applications.

Research of Salt-Free Dyeing of Reactive Dyes on Chitosan Quaternary Ammonium Salt Treated <i>Bombyx mori</i> Silk Fabric

Chitosan quaternary ammonium salt (short for HTCC) was a strong cationic water-soluble polymer. The bombyx Mori silk fabric was treated by HTCC solution and the salt-free reactive dyeing process and properties of modified silk fabric were investigated in this paper. The results showed that salt-free dyeing effect of silk fabric treated with Cibacron Blue FN-G was better when HTCC concentration was 8g/L, the processing temperature was 60°C and the processing time was 35min; the optimum salt-free reactive dyeing process of silk fabric treated by HTCC was: dyeing pH was 8.0, dyeing temperature was 90°C and dyeing time was 70 min; HTCC had obviously promoted dyeing effect, after salt-free dyeing, the dyeing rate, the color fixing rate and the dyeing depth of silk fabric modified by HTCC solution were all increased obviously, and the washing fastness and rubbing fastness were both improved slightly; the smaller molecular weight of chitosan was used to modify to HTCC, the higher dyeing rate and color fixing rate of the treated silk fabric were obtained.

Simultaneous electrochemical determination of ascorbic acid, dopamine and uric acid with helical carbon nanotubes

In this study we develop a sensor based on helical carbon nanotubes (HCNTs) for the simultaneous electrochemical determination of ascorbic acid (AA), dopamine (DA), and uric acid (UA). A water soluble cationic polymer, poly(diallyl dimethylammonium chloride) (PDDA), is used to functionalize the nanotubes’ surface, aiming to improve the HCNTs dispersibility and adhesion to substrates. After electrochemical pre-treatment, the PDDA@HCNTs coated glassy carbon electrodes can separate the anodic oxidation potential of AA, DA and UA with well-defined peak separation in the presence of each other. The calibration curves were obtained in the range of 25–1045μML−1 for AA, 2.5–10μML−1 for DA, and 5.0–175μML−1 for UA. Detection limits of 0.12μML−1, 0.08μML−1, and 0.22μML−1 were obtained for AA, DA, and UA at pH 7.4, respectively. The analytical performance of this sensor has been evaluated for simultaneous detection of AA, DA, and UA in the fetal bovine serum samples.

Retinal drug delivery using eyedrop preparations of poly-l-lysine-modified liposomes

The purpose of this study was to develop surface-modified liposomes that enhance the efficiency of eye drop drug delivery to the retina. Various molecular weights and concentrations of the water-soluble cationic polymer poly-l-lysine (PLL) were used to modify the surface of submicronized (100nm) liposomes. Physicochemical properties of surface-modified liposomes were determined in vitro, and the efficiency of drug delivery to the retina was investigated in vivo. Using coumarin-6 as a model drug and fluorescent marker, we show that liposome surface modification by PLL dramatically increased delivery to mouse retina segments after eye drop administration. However, when PLL of high molecular weight (>30,000) was used at higher concentrations (>0.05%), aggregation of surface-modified liposomes increased particle size and hampered distribution to inner ocular tissues. As a result, the efficiency of drug delivery of these aggregated surface-modified liposomes was the same as unmodified liposomes. The optimal molecular weight and concentration of PLL in drug-delivering liposomes were 15,000–30,000 and 0.005%, respectively. Under these conditions, PLL-modified liposomes were not cytotoxic in corneal or conjunctival cells. In conclusion, surface-modified liposomes have great potential as effective retinal drug delivery carriers in eye drop formulations.

Cationic Hybrid Hydrogels from Amino‐Acid‐Based Poly(ester amide): Fabrication, Characterization, and Biological Properties

AbstractA family of biodegradable, biocompatible, water soluble cationic polymer precursor, arginine‐based unsaturated poly (ester amide) (Arg‐UPEA), is reported. Its incorporation into conventional Pluronic diacrylate (Pluronic‐DA) to form hybrid hydrogels for a significant improvement of the biological performance of current synthetic hydrogels is shown. The gel fraction (Gf), equilibrium swelling ratio (Qeq), compressive modulus, and interior morphology of the hybrid hydrogels as well as their interactions with human fibroblasts and bovine endothelial cells are fully investigated. It is found that the incorporation of Arg‐UPEA into Pluronic‐DA hydrogels significantly changes their Qeq, mechanical strength, and interior morphology. The structure–property relationship of the newly fabricated hybrid hydrogels is studied in terms of the chemical structure of the Arg‐UPEA precursor, i.e., the number of methylene groups in the Arg‐UPEA repeating unit. The results indicate that increasing methylene groups in the Arg‐UPEA repeating unit increases Qeq and decreases the compressive modulus of hydrogels. When compared with a pure Pluronic hydrogel, the cationic Arg‐UPEAs/Pluronic hybrid hydrogels greatly improve the attachment and proliferation of human fibroblasts on hydrogel surfaces. A bovine aortic endothelial cells (BAEC) viability test in the interior of the hydrogels shows that the positively charged hybrid hydrogels can significantly improve the viability of the encapsulated endothelial cell over a 2 week study period when compared with a pure Pluronic hydrogel.

Star-branched cationic light-emitting dot with silsesquioxane core, synthesis, and light scattering studies

Novel star-like hydrophobic (M) and hydrophilic (W) hybrid light-emitting dots were synthesized by grafting conjugated arms at eight vertexes of polyhedral oligomeric silsesquioxane (POSS) cage. The water-soluble cationic polymer W contains POSS as a core and two layers shell—an inner layer shell consists of the conjugated organic chain and a long chain of hydrophilic polymer as outer layer shell for solubilization in water. The 3D structure renders non-aggregation properties of W in solution as the wavelength for the absorption and luminescence spectra remains unchanged over different concentrations. The effects of ionic strength and pH on the properties of cationic polymer W were studied using UV, dynamic- and static-light scattering (DLS and SLS).

Detection of native chondroitin sulfate impurities in heparin sodium with a colorimetric micro-plate based assay

We have recently described a 96-well plate format assay for visually detecting oversulfated chondroitin sulfate A (OSCS) in heparin that uses a water soluble cationic polythiophene polymer (3-(2-(N-(N′-methylimidazole))ethoxy)-4-methylthiophene (LPTP)) and heparinase digestion. Because dermatan sulfate (DS, a.k.a. chondroitin sulfate B (CSB)) and, to a lesser degree, chondroitin sulfate A (CSA) are the most common native impurities of heparin active pharmaceutical ingredients (APIs) we adapted the previously established micro-plate assay for the visual detection of DS and CSA in heparin sodium. We describe a naked-eye detection test of these common heparin impurities with sensitivity appropriate for the United States Pharmacopeia (USP) 1% percent galactosamine in total hexosamine specification. For example, the test detects DS ≥ 1.0% w/w visually and 0.5% using a plate reader, or CSA ≥ 1.0 to 2.0% w/w visually and at ≥1.0% with a plate reader. In contrast to the test developed for oversulfated glycosaminoglycans such as OSCS, the LPTP–chondroitinase test developed here utilizes chondroitinase ABC instead of heparinases and requires a centrifugal filtration step to remove un-digested heparin. The test takes advantage of the sensitivity of the LPTP chemosensor to low molecular weight glycosaminoglycan (GAG) fragments formed by digesting DS or CSA. Importantly, the LPTP–chondroitinase method detects DS and CSA in heparin sodium in a format potentially amenable to high throughput screening.