Anionic Agents Research Articles

Antimicrobial finishing of wool fabric using ionic liquids

This work aims to study the effect of pretreatment of wool fabrics with two imidazolium-based ionic liquids to impart durable antimicrobial properties. The used ionic liquids, cationic in nature, were ionically bonded to the anionic sites along the keratin macromolecules. These anionic sites have been enriched via treatment with the presynthesized anionic agent (AA) (sodium 4-(4,6-dichloro-1,3,5-triazinylamino)-benzenesulfonate). The effect of the treatment temperature of wool fabric with the AA, liquor ratio as well as the pH on the exhaustion percentage was studied. Antibacterial activity of the treated wool fabric towards Gram –ve bacteria (Escherichia coli), and fastness to washing were examined. The chemical structure of the synthesized AA was elucidated using liquid chromatography mass spectrometry.

Making a Match for Valinomycin: Steroidal Scaffolds in the Design of Electroneutral, Electrogenic Anion Carriers

The natural product Valinomycin is a well-known transmembrane cation carrier. Despite being uncharged, this molecule can extract potassium ions from water without counterions and ferry them through a membrane interior. Because it only transports positive ions, it is electrogenic, mediating a flow of charge across the membrane. Equivalent agents for anions would be valuable research tools and may have therapeutic applications, especially in the treatment of "channelopathies" such as cystic fibrosis. However, no such molecules have been found in nature. In this Account, we describe our research toward synthetic and rationally designed "anti-Valinomycins". As our core approach to this problem, we used the steroid nucleus, provided by cholic acid, as a scaffold for the assembly of anion receptors. By positioning H-bond donors on this framework, especially urea and thiourea groups in conformationally constrained axial positions, we created binding sites capable of exceptionally high affinities (up to 10(11) M(-1) for R4N(+)Cl(-) in chloroform). The extended hydrocarbon surface of the steroid helped to maintain compatibility with nonpolar media. When we tested these "cholapods" for chloride transport in vesicles, they provided the first evidence for electrogenic anion transport mediated by electroneutral organic carriers: in other words, they are the first authenticated anti-Valinomycins. They also proved active in live cells that we grew and assayed in an Ussing chamber. In subsequent work, we have shown that the cholapods can exhibit very high activities, with transport observed down to carrier/lipid ratios of 1:250,000. We also understand some of the effects of structure on the activity of these molecules. For example, in most cases, powerful transporters also act as powerful receptors. On the other hand, some modifications which favor binding do not promote transport. We gained functional advantages by cyclizing the cholapod architecture, which encloses the anion binding site. We could also simplify the structure without compromising function. A steroid-inspired trans-decalin framework has proved highly effective and may lead to agents with practical advantages. Changing an ester side-chain in this system revealed a surprising effect, whereby increased length and/or lipophilicity resulted in substantially raised activity. Although much remains to be discovered about these anionophores, their high activities and intrinsic tuneabilities bode well for applications. In future work, we plan to develop and exploit these molecules as tools for biophysical research and to explore the possibility of useful biological activity.

Chemical Modification of Cellulosic Fibers Using Eco-Friendly Compounds to Improve Dyeing with Cationic Dyes

In order to improve their affinity to the cationic dyes, cotton and jute cellulosic fibres were chemically modified using natural compounds such as: Tannic acid, Mimosa and cactus juice and commercialized compounds such as Clarite Com, Albatex and Albaflow. Cellulose modifications were performed using physiochemical analysis such as Bohem titration, spectroscopic analysis (FTIR spectroscopy and UV-Vis), the Point of Zero Charge (pHPZC) and the Cationic Exchange Capacity (CEC) determination. The dyeing performance were evaluated by controlling the percentage of the dye bath exhaustion (E %), the color yield (k/s), the brightness index BI (%) and the dyeing fastness to light, washing and rubbing. Two cationic dyes CI Basic Red 46 and CI Basic Blue 3 with a delocalised cationic charge were checked for dyeing properties. The pHPZC of modified samples varied from 2.98 to 5.7. The CEC varied from 43meq/g to 82meq/g. This study showed that the color yield and the dyeing fastness were improved for modified cellulosic fabrics. The Bohem titration and FTIR spectrum showed that the acidic sites number on the fabrics increased after using anionic agents.

Simultaneous intercalation and release of 2,4-dichloro- and 4-chloro-phenoxy acetates into Zn/Al layered double hydroxide

A new nanohybrid compound was formed by the concurrent insertion of 2,4-dichlorophenoxy acetate (DPA) used as herbicides and 4-chlorophenoxy acetate (CPA) as plant growth regulator, the two guest anions into the interlamellar space of the host Zn/Al layered double hydroxide (LDH) using co-precipitation or spontaneous self-assembly method. Two different basal spacings of 2.54 and 1.97nm were detected by PXRD of the nanohybrid accounting for the presence of two distinct intercalated phases. Direct insertion mass spectroscopy (DIMS) analyses confirm that both anions are intercalated to give a biphasic well ordered nanohybrid material. The study of the release properties shows that both ions were released, but with different rates. This opens up the possibility of using such a biphasic nanohybrid for controlled release of more than one active anionic agent at different controlled rates.

Electrification of antistatic-treated polymeric surface

Nylon and polypropylene surfaces were treated with three different finishes (nonionic, cationic, and anionic) at four different solution concentrations (weight percentage of active finish to solution), 0.025%, 0.05%, 0.075%, and 0.1%. Contact electrification tests showed that charge accumulated on polypropylene decreased as the concentration of nonionic and anionic solutions increased, and charge could be controlled when the concentration reached 0.1%. The same effect was realized when the concentration of the cationic solution was only 0.025%. No contact charging was observed on nylon after treating with any solutions. Rubbing electrification (tribo‐charging) of nylon treated with the nonionic solution showed that charge decreased as the solution concentration increased, and no charge was observed as the solution concentration reached 0.1%. Furthermore, no tribo‐charging of nylon was observed at any level of the cationic or anionic agents applied to the surface.

Sulfosalicylate mediates improved vinorelbine loading into LUVs and antineoplastic effects

Liposomal vinorelbine formulation is desirable, as it might improve the therapeutic activity of vinorelbine. However, because of its lipophilic and membrane-permeable properties, vinorelbine is hard to be formulated into liposomes using conventional drug-loading technologies. To improve vinorelbine retention, ammonium salts of several anionic agents were employed to prepare liposomal vinorelbine formulations. It was found that 5-sulfosalicylate (5ssa) could form stable complexes with vinorelbine and stabilize entrapped vinorelbine. The resultant vesicles had an in vitro release t1/2 of ~12.49 hours in NH3-containing media, which is longer than those of sulfate and phytate vesicles (~0.57 hours). The circulation half-life of vinorelbine after the injection of 5ssa vesicles into normal mice was ~13.01 hours, accounting for ~2-fold increase relative to that of sulfate vesicles. Improved drug retention correlated with enhanced antitumor efficacy. In the RM-1/c57 model, 5ssa vesicles were more efficacious than sulfate vesicles (P < 0.05). In RM-1/BDF1 and Lewis lung cancer/c57 models, antitumor efficacy was also considerably improved after vinorelbine encapsulation into 5ssa vesicles. For instance, in the RM/BDF1 model, liposomal vinorelbine was at least 4-fold more therapeutically active than free vinorelbine. Our results demonstrated that 5ssa could stabilize vinorelbine relative to other anions, resulting in the formulation with improved drug retention and efficacy. Improved vinorelbine retention might be associated with the formation of insoluble precipitate, which could be proved by precipitation study and decreased drug-release rate at a high D/L ratio.

The absorption from the gut of quinine and chlorpheniramine given with various anionic agents.

Abstract The absorption of quinine and chlorpheniramine with anionic agents was examined in the rat rectum, small intestine and stomach. The enhancement of absorption was related to partition behaviour, to the organic solvent, and surface activity of ion-pair complexes, but it seems that with results from these properties alone it is not possible to explain the apparent increase in the in situ absorption of amines. In the presence of anionic agents, the absorption of amines was enhanced at all sites examined and kinetically the uptake to the mucosal membrane was increased in the rectum and small intestine. The effect of anionic agents on the uptake of amines was greater in the rectum than in the small intestine and this may be related to differences in the nature of the gut wall.

5-(3-Bromo-4-hydroxy-5-methoxyphenyl)-7,7-dimethyl-7H-indolo[1,2-a]quinolinium Perchlorate as a New Indicator for Anionic Surface Active Agents Determination

Abstract The work refers to the already published modification of widely used method for anionic active agents determination which concerns the replacement of the mixed indicator, consisting of Acid Blue 1 and carcinogenic Dimidium Bromide, applied in the International Standard ISO 2271:1989 with solvatochromic dye i.e. 5-(3-bromo-4-hydroxy-5-methoxyphenyl)-7,7-dimethyl-7H-indolo[1,2-a]quinolinium perchlorate (1). The value of pKa for examined dye (1) amounts to 6.59 thus the influence of different pH values of the probes on the analysis results was studied i.e. precision of determination of titration endpoint and the same the result of the quantitative analysis. The change of pH for aqueous and apparent pH for organic phase were determined during the titration process. It was shown that there is no effect of the pH change in its range varying from 3.5 to 5 on the results. The modification of the method for the probes which pH do not fit to the range mentioned above is presented.

Cationic contrast agents improve quantification of glycosaminoglycan (GAG) content by contrast enhanced CT imaging of cartilage

Minimally invasive and non-destructive methods to quantify glycosaminoglycans (GAGs) in articular cartilage extracellular matrix are of significant interest for the biochemical analysis of cartilage and diagnosis and tracking of osteoarthritis in vivo. Here, we report the use of cationic iodinated contrast agents in comparison to conventional anionic contrast agents for the quantitative monitoring of GAG concentrations with peripheral quantitative computed tomography. Using an ex vivo bovine osteochondral plug model, the cationic contrast agents were evaluated for their ability to distribute into articular cartilage and generate a positive relationship with GAG content. The cationic agents resulted in much higher equilibrium X-ray attenuations in cartilage extracellular matrix (ECM) than anionic agents. Experiments with samples subjected to enzymatic GAG degradation demonstrated that the cationic agents were up to five times more sensitive (p = 0.0001) to changes in GAG content and had a 24% higher correlation (p = 0.002) compared to the anionic agent (R(2) = 0.86, p < 0.0001 compared with R(2) = 0.62, p = 0.004). The natural inhomogeneous distribution of GAGs in the ECM could clearly be identified in undegraded samples.

10.1007/s11449-008-1007-z

The data on the influence of polyelectrolytes on the photon emission probability of water-soluble CdSe/ZnS nanoparticles are obtained. The decrease in the photoluminescence quantum yield of nanoparticles occurring upon their transfer to aqueous solutions from toluene (in the course of solubilization) depends on the ionic nature of an agent applied for the replacement of trioctylphosphine oxide residues on the surface of nanoparticles. It turns out that such a cationic modifying agent as cysteamine leads to an insignificant (∼10%) decrease in the photoluminescence quantum yield of nanoparticles. The use of such an anionic agent as mercaptoacetic acid causes a significant (∼80%) decrease in the quantum yield and the average decay time of photoluminescence. For nanoparticles modified by mercaptoacetic acid (anionic nanoparticles), this decrease is partially compensated if these particles interact with polyelectrolytes whose backbone is oppositely charged (cationic polyelectrolytes), such as polyallylamine and polydiallyldimethylammonium chloride. In this case, the photoluminescence quantum yield shows a reverse increase by 40%, remaining the same within a matter of months or longer. In contrast to this, cationic nanoparticles, only slightly quenched by cysteamine at the stage of solubilization, are appreciably degraded in complexes with anionic polyelectrolytes in solutions and upon immobilization of complexes on a substrate, so that their photoluminescence quantum yield irreversible decreases to zero within a few days. Possible mechanisms of the effects observed are discussed and their consideration in polyelectrolyte-based molecular lithography.

Development of a Bioactive Paper Sensor for Detection of Neurotoxins Using Piezoelectric Inkjet Printing of Sol−Gel-Derived Bioinks

There is an increasing interest in new strategies to rapidly detect analytes of clinical and environmental interest without the need for sophisticated instrumentation. As an example, the detection of acetylcholinesterase (AChE) inhibitors such as neurotoxins and organophosphates has implications for neuroscience, drug assessment, pharmaceutical development, and environmental monitoring. Functionalization of surfaces with multiple reagents, including enzymes and chromogenic reagents, is a critical component for the effective development of "dipstick" or lateral flow biosensors. Herein, we describe a novel paper-based solid-phase biosensor that utilizes piezoelectric inkjet printing of biocompatible, enzyme-doped, sol-gel-based inks to create colorimetric sensor strips. For this purpose, polyvinylamine (PVAm, which captures anionic agents) was first printed and then AChE was overprinted by sandwiching the enzyme within two layers of biocompatible sol-gel-derived silica on paper. AChE inhibitors, including paraoxon and aflatoxin B1, were detected successfully using this sensor by measuring the residual activity of AChE on paper, using Ellman's colorimetric assay, with capture of the 5-thio-2-nitrobenzoate (TNB(-)) product on the PVAm layer. The assay provided good detection limits (paraoxon, approximately 100 nM; aflatoxin B1, approximately 30 nM) and rapid response times (<5 min). Detection could be achieved either by eye or using a digital camera and image analysis software, avoiding the need for expensive and sophisticated instrumentation. We demonstrate that the bioactive paper strip can be used either as a dipstick or a lateral flow-based biosensor. The use of sol-gel-based entrapment produced a sensor that retained enzyme activity and gave reproducible results after storage at 4 degrees C for at least 60 days, making the system suitable for storage and use in the field.

Design of high payload PLGA nanoparticles containing melittin/sodium dodecyl sulfate complex by the hydrophobic ion-pairing technique

The water-soluble peptide, melittin, was modified with an anionic agent, sodium dodecyl sulfate by hydrophobic ion-pairing. Investigations showed that the formed complex was very soluble in organic solvent, especially, in dimethylsulfoxide and dehydrated alcohol. Furthermore, the physiochemical properties of the complex in the solid state or in an aqueous medium were characterized using octanol/water partition measurement, Fourier transform infrared spectroscopy, and differential scanning calorimetry. The complex was formulated into poly(d,l-lactide–co-glycolide acid) nanoparticles by an emulsion solvent diffusion method. It was found that the nanoparticles of about 130 nm in size can be produced with a high encapsulation efficiency, and the entrapment of nanoparticles prepared with the formed complex increased from about 50% to nearly 100% compared with that for pure melittin. Moreover, the growth inhibitory effects of modified melittin and melittin-loaded nanoparticles in breast cancer MCF-7 cells were not changed comparing with free melittin as determined by (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay.

Improvement on Hydrophobicity of Synthetic Textiles by Plasma Treatment – A Review

Cationic dyes exhibit high exhaustion towards protein fibres, such as wool and silk, due to ionic interactions but they show little substantivity onto cellulosic and hemicellulosic fibres. In order to apply cationic dyes to mill scoured and bleached linen fibers, a new approach employing anionic agents containing a reactive monochloro-S- triazinyl group is synthesized and used to import a negative charge to the fibre surface. Two cationic dyes show considerable substantivity towards anionic agent modified fabrics. Four different anionic agents are covalently bounded to the linen substrate to provide an electrostatic interaction with cationic dyes. The anionic agent treated fabrics are monitored for nitrogen content, and the reaction efficiency is determined as a K/S value of the dyed samples. Different factors that affect the pretreatment and dyeing process are investigated, and an overall improvement in the effectiveness of the anionic agent on the dyeability using cationic dyes is achieved. The reaction efficiency for the four anionic agents follows the order: anionic agent III &gt; I &gt; II &gt; IV &gt; untreated fabric. The treated dyed fabrics also exhibit good fastness properties.

Development of berberine attraction sites onto cellulosic substrates modified by reactive bridging agent: Statistical optimization and analysis

Statistical method of experimentation for berberine adsorption onto reactive bridging agent modified cellulosic fibers has been successfully studied for determining the optimal values of three important parameters. Synthesis, reaction mechanism and application of reactive anionic agent and effect of three important parameters were discussed in detail in our previous publications [T.K. Kim, Y.A. Son, Dyes and Pigments 64 (2005) 85; T.K. Kim, S.H. Yoon, Y.A. Son, Dyes and Pigments 60 (2004) 121]. In this article, experiments were conducted by a standard design of experimental analysis called as central composite design (CCD). Experimental results were thoroughly analyzed by ANOVA (analysis of variance) statistical concepts. Optimum process conditions were obtained by surface plot as well as Monte Carlo technique to achieve high % exhaustion.

Evaluating the Use of Tricationic Reagents for the Detection of Doubly Charged Anions in the Positive Mode by ESI-MS

The analysis of anions remains an important task for many areas of science, and new sensitive analytical methods continue to be of great interest. In this study, we present the use of 17 tricationic reagents for use as gas-phase ion pairing agents for divalent anions. When the anion pairs with the tricationic reagent, an overall positive charge is retained and enables detection by ESI-MS in the positive mode. The 17 tricationic reagents were made from 1 of 4 core structures and 7 terminal charged groups. The effect of these structural elements on the detection sensitivity of the complex is examined empirically. A comparison of signal-to-noise ratios achieved in positive and negative modes also is presented.

Biophysical Properties of CDAN/DOPE‐Analogue Lipoplexes Account for Enhanced Gene Delivery

Typically, cationic liposomes are formulated from the combination of a synthetic cationic lipid (cytofectin) and a neutral, biologically available co-lipid. However, the use of cationic liposome formulations to mediate gene delivery to cells is hampered by a paradox. Cationic lipids, such as N(1)-cholesteryloxycarbonyl-3-7-diazanonane-1,9-diamine (CDAN), are needed to ensure the formation of cationic liposome-DNA (lipoplex, LD) particles by plasmid DNA (pDNA) condensation, as well as for efficient cell binding of LD particles and intracellular trafficking of pDNA post-intracellular delivery by endocytosis. However, the same cationic lipids can exhibit toxicity, and also promote LD particle colloidal instability, leading to aggregation. This results from electrostatic interactions with anionic agents in biological fluids, particularly in vivo. One of the most commonly used neutral, bioavailable co-lipids, dioleoyl L-alpha-phosphatidylethanolamine (DOPE), has been incorporated into many cationic liposome formulations owing to its fusogenic characteristics that are associated with a preference for the inverted hexagonal (H(II)) phase-a phase typical of membrane-membrane fusion events. However, these same fusogenic characteristics also destabilize LD particles substantially with respect to aggregation, in vitro and especially in vivo. Therefore, there is a real need to engineer more stable cationic liposome systems with lower cellular toxicity. We hypothesize that one way to achieve this goal should be to find the means to reduce the mol fraction of cationic lipid in cationic liposomes without impairing the overall transfection efficiency, by replacing DOPE with an alternative co-lipid with fusogenic properties "tuned" with a greater preference for the more stable lamellar phases than DOPE is able to achieve. Herein, we document the syntheses of triple bond variants of DOPE, and their formulation into a range of low charge, low cationic lipid containing LD systems. The first indications are that our hypothesis is correct in vitro.

Photoluminescence of water-soluble CdSe/ZnS nanoparticles in complexes with cationic and anionic polyelectrolytes

The data on the influence of polyelectrolytes on the photon emission probability of water-soluble CdSe/ZnS nanoparticles are obtained. The decrease in the photoluminescence quantum yield of nanoparticles occurring upon their transfer to aqueous solutions from toluene (in the course of solubilization) depends on the ionic nature of an agent applied for the replacement of trioctylphosphine oxide residues on the surface of nanoparticles. It turns out that such a cationic modifying agent as cysteamine leads to an insignificant (∼10%) decrease in the photoluminescence quantum yield of nanoparticles. The use of such an anionic agent as mercaptoacetic acid causes a significant (∼80%) decrease in the quantum yield and the average decay time of photoluminescence. For nanoparticles modified by mercaptoacetic acid (anionic nanoparticles), this decrease is partially compensated if these particles interact with polyelectrolytes whose backbone is oppositely charged (cationic polyelectrolytes), such as polyallylamine and polydiallyldimethylammonium chloride. In this case, the photoluminescence quantum yield shows a reverse increase by 40%, remaining the same within a matter of months or longer. In contrast to this, cationic nanoparticles, only slightly quenched by cysteamine at the stage of solubilization, are appreciably degraded in complexes with anionic polyelectrolytes in solutions and upon immobilization of complexes on a substrate, so that their photoluminescence quantum yield irreversible decreases to zero within a few days. Possible mechanisms of the effects observed are discussed and their consideration in polyelectrolyte-based molecular lithography.

Preparation of Chitosan Nanoparticles for Protein Delivery by w/o/w Emulsion Solvent Evaporation and Simple Ionotropic Gelation Techniques

The purpose of this study was to prepare chitosan nanoparticles (CS NP) for controlled protein delivery. Two techniques, simple ionotropic gelation (method [I]) and w/o/w emulsion solvent evaporation containing ionotropic gelation (method [II]), were used to prepare CS NP. Tripolyphosphate (TPP) and Eudragit L100-55 (Eud) were used as anionic agents to form complex with cationic chitosan. Bovine serum albumin (BSA) was encapsulated into NP. The morphological characteristics, particle size and size distribution, protein entrapment efficiency, zeta potential, in vitro release, protein secondary structure and its integrity were investigated. The results showed that CS NP could be prepared by appropriate cationic and anionic ratios in both methods. Excess anionic agents resulted in particle aggregation of micron size. The median sizes of particles were between 0.127-0.273 mcm with method [I] provided the smallest size. The 0.02-0.10% BSA loaded preparations showed the same particle sizes and size distributions as blank preparations. SEM photomicrographs revealed that the obtained NP were spherical. Protein entrapment efficiency was between 47-84% and increased when decreasing the percentage of drug loading. The method [II] with TPP exhibited the highest protein entrapment efficiency, following by the method [II] with Eud and method [I] with TPP, respectively. The zeta potentials were positive. Prolonged in vitro protein release profiles were observed from all preparations of CS NP. After 10 days, the release was between 53-72%. Circular dichroism and SDS-polyaceylamide gel electrophoresis techniques confirmed that these processes did not have any destructive effect on the protein structure. Therefore these preparation techniques could be used to encapsulate water-soluble drugs, proteins, DNA, or antigens into CS NP as effective delivery carriers.

Magnetic composites obtainment based on styrene polymers

AbstractThree styrene‐based matrices for hybrid composites with ferrite have been obtained by emulsion polymerization in the presence of a tensioactive system: sodium n‐dodecylbenzene sulfate (C12H25C6H4SO3Na) as anionic agent and poly(oxyethylene) nonylphenyl ether [C9H19C6H4(OCH2CH2)30OH] as nonionic tensioactive agent. The system assures the steadiness of the emulsion during the reaction and the stability of the latices. The surfactants act as a protective colloid component and thickening agents determining an optimum viscosity and conditions for the further catching of the inorganic oxide with magnetic properties. The obtained polystyrene and styrene copolymers with acrylamide and methacrylamide were analyzed by elemental analysis, IR spectroscopy, DSC, and their viscosity data have been characterized. The size as well as the magnetic properties of composites were also appreciated. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4133–4141, 2006

Synthesis, magnetic measurement and spectroscopic studies on cobalt (II) complexes in thiosemicarbazones derived from P-anisaldehyde, P-tolualdehyde, P-vanillin and 9-fluorenone

Cobalt(II) complexes, Co(ATSC) 2 Co(TTSC) 2 CO(VTSC) 2 and Co(FTSC) 2 were prepared by reacting Cobalt(II)acetate and bidenlate thiosemicarbazones derived from p-anisaldehyde (ATSCH), p-tolualdehyde (TTSCH), p-vanillin (VTSCH), and 9-fluorenone (FTSCH) and were characterized by IR, uv-visible spectra, molar conductance, magnetic moment and elemental analysis. The, observed spectral data on thiosemicarbonzones indicate thione form for the ligands and they act as anionic bidentate chelating agents. The coordination takes place through thiolato sulphur and azonmethine /imine nitrogen atoms. The tetrahedral flattened structures have been suggested for the cobalt(II) complexes under investigation. KEYWORD: Thiosemicarbazone; Cobalt(II) complex; IR; uv-visible; spectra; molar conductance; magnetic moment. Global Jnl Pure and Applied Sciences Vol.10(3) 2004: 391-395