Amidoxime copolymer beads containing Cu/Cu2O microparticles as a biocidal material for water disinfection

Macroporous crosslinked acrylonitrile‐divinylbenzene copolymer beads were synthesized by suspension polymerization technique. The beads were chemically modified to have amidoxime functional group, which was used as a solid support for anchoring copper microparticles. The copper ions loaded on the copolymer beads were reduced using strong reducing agent to have copper microparticles on the amidoxime copolymer beads. The size of copper particles formed depends upon the amount of copper ions loaded on the beads. The formation of copper microparticles on the copolymer was confirmed by instrumental analysis. The copper containing amidoxime copolymer beads were investigated for the biocidal activity. The size and the distribution of copper particles on the amidoxime copolymer beads influenced their biocidal activity. The biocidal activity was tested against two Gram‐positive bacteria, Bacillus subtilis and Staphylococcus aureus, and against two Gram‐negative bacteria, Pseudomonas aeruginosa and Escherichia coli. The beads containing copper particles showed better biocidal activity against the Gram‐negative bacteria when compared with the Gram‐positive organisms. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Preparation,characterization, and properties of crosslinked hydroxylated poly(styrene‐b‐butadiene‐b‐styrene) triblock copolymer

Acrylic acid was crosslinked with N,N′‐methylenebisacrylamide and converted to bioactive hydrogels by neutralization with different amino containing compounds. Several amino containing compounds were used such as 2‐aminopyridine, triethanol amine, hexamethylenetetramine (HMTA), pyridine, and imidazole. The best crosslinker ratio was determined in addition to the maximum absorbed water in different mediums. The antibacterial activity of the prepared gels were examined against examples of Gram‐positive (Staphylococcus aureus) and Gram‐negative bacteria (Escherichia coli) using agar plate method. The study was extended by evaluating one of prepared gels in columns as models for water filters. All prepared gels showed antibacterial action in agar plate method against both bacterium and the column method using one of the prepared gels showed excellent filtration and biocidal action. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Macroscopic N‐halamine biocidal polymeric beads

The particle size of N‐halamine biocidal polymers was methodically modified forming beads of different sizes by blending water‐insoluble N‐halamine polyurethane with sodium alginate as the matrix and loading heterocyclic rings onto modified silica gels. The biological activity of the prepared beads and halogenated modified silica derivatives was evaluated against examples of Gram‐positive (Staphylococcus aureus) and Gram‐negative (Escherichia coli) bacteria. The recycling possibilities and the optimum preparation conditions of the blended beads were investigated; blending prehalogenated polyurethane (5%, w/v) with sodium alginate (3%, w/v) followed by crosslinking with CaCl₂ (10%, w/v) at 40°C are the optimum preparation conditions for the alginate beads. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Silver nanoparticle incorporated poly(l‐lactide‐co‐glycolide) nanofibers: Evaluation of their biocompatibility and antibacterial properties

The objective of this work is the fabrication of poly(l ‐lactide‐co‐glycolide) or PLGA (with LA/GA ratios of 50/50 and 75/25) nanofibers containing silver nanoparticles (AgNPs) by the method of electrospinning. The incorporation of AgNPs in PLGA was carried out in three different concentrations (1, 3, 6 w/w %).The electrospun nanofibers were evaluated for their morphology by scanning electron microscopy and their fiber diameters ranged between 487 and 781 nm. Integration of AgNPs within the fibers was verified by spectroscopy studies, while the mechanical properties of the developed fibers were found comparable to the mechanical properties of the human skin. Proliferation of human dermal fibroblasts (HDF) demonstrated minimal cytotoxicity on fibers containing 1 wt % and 3 wt % of AgNPs, while 6 wt % of AgNPs inhibited cell proliferation. Antimicrobial activity was studied using three different strains of Gram‐positive and Gram‐negative bacteria. Results of the HDF proliferation and antimicrobial studies showed that the electrospun PLGA75/25 containing 3 wt % AgNP can function as a suitable substrate for wound dressing, compared to the other scaffolds of this study. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42686.     

Cationization of cellulose/polyamide on UV protection,bio‐activity,and electro‐conductivity of graphene oxide‐treated fabric

In this work, cationized cotton/nylon fabric was treated with reduced graphene oxide (rGO) to produce highly conductive fabric. The fabric was cationized with 3‐chloro‐2‐hydroxy propyl trimethyl ammonium chloride to attract more anionic GO. The fabric was then treated with GO followed by reduction with sodium dithionite. The results of energy‐dispersive X‐ray spectroscopy, X‐ray diffraction, and X‐ray photoelectron spectroscopy indicated entire coverage of the fabric surface with rGO. The color of fabrics changed to gray‐black and the electrical resistance decreased to 0.6 × 103 Ω sq^?1. The washing fastness was measured according to ISO 105‐CO5 for color change and also electrical resistance of the samples demonstrated well stability of rGO on the fabric surface. The antibacterial activities of the treated fabrics improved against Gram‐negative bacteria including Escherichia coli (84.8%) and Pseudomonas aeruginosa (96.4%) and also Gram‐positive bacteria consisting Staphylococcus aureus (100%) and Enterococcus faecalis (98.4%). Further, the treated fabrics indicated an excellent UV reflectance of 100%. Finally heating of the cationized rGO fabric at 220 °C displayed a lower electrical resistance of 0.5 × 103 Ω sq^?1. The thermogravimetric analysis showed that heating has a slight effect on the dimensional thermal stability of the treated fabric as shrunk 2.43%. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 45493.     

Synthesis of novel pyridinium N‐chloramine precursors and its antimicrobial application on cotton fabrics

To control pathogenic microbial contamination on polymeric material surface, it is pivotal to develop materials with efficacious antimicrobial activity. Two pyridinium N‐chloramine precursors containing a siloxane handle were synthesized, characterized, and grafted onto cotton fabrics. The attenuated total reflectance spectra and scanning electron microscope photo analysis indicated that the cotton fabric surface was successfully modified. The resultant chlorinated fabric samples were challenged against bacteria Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 25923. Results showed that: (1) the surface modified cotton fabrics displayed satisfactory biocidal efficacy; (2) the precursor structure played a major role on surface grafting and antibacterial activity. This work provides two promising pyridinium N‐chloramine precursors which hold potential application for preparing antibacterial textile materials. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45323.     

Multicomponent Petasis‐borono Mannich Preparation of Alkylaminophenols and Antimicrobial Activity Studies

In this work we report the antibacterial activity of alkylaminophenols. A series of such compounds was prepared by a multicomponent Petasis‐borono Mannich reaction starting from salicylaldehyde and its derivatives. The obtained compounds were tested against a large panel of microorganisms, Gram‐positive and Gram‐negative bacteria, and a yeast. Among the several tertiary amine derivatives tested, indoline‐derived aminophenols containing a nitro group at the para‐phenol position showed considerable activity against bacteria tested with minimal inhibitory concentrations as low as 1.36 μm against Staphyloccocus aureus and Mycobacterium smegmatis. Cytotoxicity of the new para‐nitrophenol derivatives was observed only at concentrations much higher than those required for antibacterial activity.     

Antibacterial finishing of polyester/cotton blend fabrics using neem (Azadirachta indica): A natural bioactive agent

The study focused on the development of biofunctional polyester/cotton blend fabric using a natural product. An antimicrobial agent extracted from the seeds of Neem tree (Azadirachta indica) was used for imparting antibacterial property to the blend fabric. Resin and catalyst concentrations were optimized to get the maximum crosslinking in the fabric blends using glyoxal/glycol as a crosslinking agent. The optimized concentrations were used to treat the fabric with the antimicrobial agent along with the crosslinking agent. Quantitative analysis was carried out to measure the antimicrobial activity against Gram‐positive and Gram‐negative bacteria. The results showed that the treated fabrics inhibited the growth of Gram‐positive bacteria (Bacillus subtilis) by more than 90% as compared to the control sample. Antimicrobial activity against Gram‐ positive bacteria was retained up to five machine washes and decreased thereafter. The antibacterial activity was higher against Gram‐positive bacteria as compared to Gram‐ negative bacteria (Proteus vulgaris). The treated fabrics also showed improved crease recovery property although the tensile property showed a marginal decrease. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Antimicrobial activity of some new 4‐arylazo‐3‐methylthiophene disperse dyes on polyester fabrics

A series of novel 4‐arylazo‐3‐methylthiophenes was synthesized by the heterocyclization of 2‐arylhydrazono‐2‐acetyl thioacetanilide derivatives with a variety of α‐halogenated reagents, such as chloroacetone, phenacyl bromide, ethyl chloroacetate, and chloroacetonitrile. The structures of the synthesized thiophene derivatives were confirmed by ultraviolet–visible, IR, and ¹H‐NMR spectroscopic techniques and elemental analysis. The synthesized dyes were applied to polyester fabrics as disperse dyes, and their fastness properties were evaluated. The dyed polyester fabrics displayed antibacterial efficacy against Gram‐positive (Staphylococcus aureus) and Gram‐negative (Escherichia coli) bacteria. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

N‐(hydroxymethyl) acrylamide as a multifunctional finish to cotton and a tether for grafting methacrylamide for biocidal coatings

N‐(hydroxymethyl) acrylamide (NMA) was immobilized on cotton surfaces through etherification, and then methacrylamide (MA) was grafted onto the treated surface. The coatings were characterized by ATR‐IR spectroscopy and were rendered biocidal upon exposure to dilute household bleach. The treated fabrics were challenged with Gram‐negative and Gram‐positive bacteria; both NMA and NMA/MA‐treated fabrics inactivated about 8 logs of Escherichia coli O157:H7 and Staphylococcus aureus within only 5 min of contact time. The coatings were also quite stable toward ultraviolet (UVA) light exposure and repeated laundering. Moreover, a substantial improvement in wrinkle recovery angle was obtained for the NMA/MA‐treated fabrics. The new acyclic acrylamide N‐halamine coating should be less expensive to produce and use than previous cyclic N‐halamine coatings developed in these laboratories. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Synthesis and biocidal efficacy of self‐spreading polydimethylsiloxane oligomers possessing oxyethylene‐functionalized quaternary ammoniums

In an effort to develop a more versatile creeping biocide that is capable of self‐spreading and self‐decontaminating of pathogenic bacteria, we report the development of two new homologous series of hybrid PDMS molecules. These oligomers were synthesized with terminal quaternary ammonium functionalities bearing variable length oxyethylene moieties. It is shown that the ionic interaction of the ammonium groups with the surface onto which it spreads can be tempered by the oxyethylene segments through close association of the polar chains with the cationic centers within the hydrophobic PDMS environment, thereby promoting self‐spreading of the molecule. Once the compounds spread to a humid environment, the oxyethylene chains “blossom” and subsequently expose the biocidal centers, at which point, function as broad spectrum versatile antimicrobials. While biological evaluation showed antimicrobial activity against both Gram‐positive and Gram‐negative bacteria for all samples, one series was found to be much more effective due to lower steric hindrance surrounding the biocidal cationic termini. However, this increased exposure of the cationic center also altered the physical properties of the compounds except those isolated as a waxy solid. Self‐spreading abilities with increasing oxyethylene chain length correlating to a decreasing spread rate. The decontaminating ability of the two most active compounds was demonstrated by allowing samples to spread to pools of water contaminated with S. aureus, yielding log reductions as high as 5.7 in less than two hours without external influences. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Synthesis and characterization of novel biocidal cyclodextrin inclusion complexes grafted onto polyamide‐6 fabric by a redox method

The synthesis of immobilized β‐cyclodextrin derivatives onto polyamide‐6 fabric is presented. These novel fabrics were prepared by graft‐copolymerization of glycidyl methacrylate (GMA) onto polyamide 6 fabric, using a chemical redox system K₂S₂O₈/CuSO₄·5H₂O, followed by reaction of β‐cyclodextrins (CD) or monochlorotriazinyl (MCT β‐CD) with the GMA epoxy group. Some biocidal guests were complexed into CD cavity including p‐hydroxy benzoic acid, AgNO₃–ethanolamine mixture, iodine, N,N‐diethyltoluamide (DETA), citronella, jasmine, and sweet basil. Characterization of the novel fabrics was done by Fourier transform infrared spectroscopy (IR), electron scanning microscopy (SEM), and thermo gravimetric analysis (TGA). The biocidal activity of the grafted fabrics was tested against five strains of microorganisms. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 2586–2593, 2006     

Citric acid used as a crosslinking agent for the grafting of chitosan onto woolen fabric

Modification of woolen fabrics was done by the grafting of low‐molecular‐weight deacetylated chitosan in the presence of citric acid as a crosslinking agent with the pad–dry cure method at different conditions (times and temperatures). The add‐on of chitosan and the optimum conditions were determined. The improved properties of modified wool by chitosan were evaluated with the urea bisulfite solubility test, crease recovery angle, yellowness index, and scanning electron microscopy. The dyeing properties of modified wool fabrics were studied with acid and reactive dyes. The biocidal activities of the modified and unmodified wool samples were evaluated and compared against some species of microorganisms, including Escherichia coli (Gram negative), Staphylococcus aureus (Gram positive), Candida albicans, and Aspergillus flavus. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Synthesis of (R)‐ and (S)‐Ricinoleic Acid Amides and Evaluation of Their Antimicrobial Activity

A series of fatty acid amides derived from (R)‐ and (S)‐ricinoleic acid and 4 cyclic and acyclic amines were synthesized in a proecological solvent‐free process with yields ranging from 43 to 88%. All S‐configured compounds and both enantiomers of amide with 2‐amino‐2‐methyl‐1‐propanol were obtained and studied in terms of biological activity for the first time. The evaluation of antimicrobial activity of (R)‐ and (S)‐ricinoleic acid derivatives against 13 different microorganisms representing Gram‐negative and Gram‐positive bacteria, yeast, and molds showed significant inhibitory activity against Gram‐positive bacteria, especially Micrococcus luteus and Bacillus subtilis, and against selected molds. Ethanolamine‐ and pyrrolidine‐derived amides showed the most promising antibacterial and antimold potential. Derivatives from ricinoleic acid and pyrrolidine were the most active against both selected molds, Aspergillus brasiliensis and Penicillium expansum. Moreover, the R‐configured analog was the most potent against B. subtilis. The amides of ricinoleic acid with ethanolamine exhibited significant potential to Staphylococcus aureus, which distinguished them from the rest of tested derivatives to which this bacterium was very resistant.     

Structural characterization and antimicrobial activity of chitosan (CS‐40)/nisin complexes

A complex of chitosan (CS‐40) and nisin (CS‐40/nisin) was prepared and characterized with Fourier transform infrared spectroscopy and thermal analysis (thermogravimetry, differential thermogravimetry, and differential scanning calorimetry). The results show that the complex formed mainly by electrostatic interaction between the protonated amino group in CS‐40 backbone with the carboxylate ion of nisin. Minimum inhibitory concentrations (MICs) were evaluated against Gram‐positive bacteria (Staphylococcus aureus, Bacillus subtilis, and Bacillus stearothermophilus), Gram‐negative bacteria (Escherichia coli, Salmonella enteritidis, and Proteus vulgaris), and fungi (Fusarium oxysporum). The results show that the CS‐40/nisin solution did inhibit or even more strongly inhibited the growth of all the tested microorganisms, whereas CS‐40 did not inhibit the growth of F. oxysporum and nisin did not inhibit the growth of Gram‐negative bacteria (E. coli, S. enteritidis, and P. vulgaris). The relative inhibition times of CS‐40/nisin solutions with different concentrations and ratios of CS‐40 and nisin were also investigated against the seven microorganisms. The results showed that CS‐40/nisin solutions with CS‐40/nisin concentration ratios of 0.05/0.005, 0.05/0.0025, 0.05/0.00125, and 0.025/0.0001% had higher antimicrobial activity against all tested bacteria and fungi. The relationship between complex formation and antimicrobial activity is discussed. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Novel anti‐bacterial acid dyes derived from naphthalimide: synthesis,characterisation and evaluation of their technical properties on nylon 6

As an attempt to combine the dyeing and functional finishing steps into one process, two novel anti‐bacterial monoazo acid dyes based on N‐ester‐1,8‐naphthalimide were synthesised. To do this, 4‐amino‐N‐ethyl glycinate‐1,8‐naphthalimide was prepared, diazotised and then coupled to thiosalicylic acid or salicylic acid to produce anti‐bacterial dyes. The synthesised dyes were purified and then fully characterised using Fourier Transform–infrared spectrometry, proton nuclear magnetic resonance spectroscopy and melting point analysis. Dispersion of the dyes was prepared in water and applied to nylon 6 fabrics. The novel dyes offered good build‐up properties on the substrate. The anti‐bacterial efficacy of the synthesised dyes was assessed, with the dyes showing activity against both Gram‐positive and Gram‐negative bacteria.     

Synthesis and Characterization of Cationic Surfactants Based on N‐Hexamethylenetetramine as Active Microfouling Agents

Four cationic surfactants of quaternary hexammonium silane chloride based on hexamethylenetetramine and alkyl chloride were synthesized. The chemical structures of the prepared cationic surfactants were elucidated using Fourier transform infrared (FT‐IR) spectroscopy and mass spectrometry analysis. The surface and thermodynamic properties of the prepared surfactants were also studied. The performance of these cationic surfactants as microfouling agents against two strains of Gram‐negative bacteria, namely, Pseudomonas aeruginosa and Escherichia coli, and two strains of Gram‐positive bacteria, namely, Staphylococcus aureus and Bacillus subtilis, were evaluated as antimicrobial agents. The results showed that the maximum antimicrobial activity was detected for N‐hexamethylenetetramine‐N‐ethyl silane ammonium trichloride (Ah). The maximum and minimum antimicrobial activities were 73 and 60 % against S. aureus and E. coli, respectively, at a concentration of 5 mg/l, pH 7, and 37 °C.     

Using Chemical Probes to Assess the Feasibility of Targeting SecA for Developing Antimicrobial Agents against Gram‐Negative Bacteria

With the widespread emergence of drug resistance, there is an urgent need to search for new antimicrobials, especially those against Gram‐negative bacteria. Along this line, the identification of viable targets is a critical first step. The protein translocase SecA is commonly believed to be an excellent target for the development of broad‐spectrum antimicrobials. In recent years, we developed three structural classes of SecA inhibitors that have proven to be very effective against Gram‐positive bacteria. However, we have not achieved the same level of success against Gram‐negative bacteria, despite the potent inhibition of SecA in enzyme assays by the same inhibitors. In this study, we use representative inhibitors as chemical probes to gain an understanding as to why these inhibitors were not effective against Gram‐negative bacteria. The results validate our initial postulation that the major difference in effectiveness against Gram‐positive and Gram‐negative bacteria is in the additional permeability barrier posed by the outer membrane of Gram‐negative bacteria. We also found that the expression of efflux pumps, which are responsible for multidrug resistance (MDR), have no effect on the effectiveness of these SecA inhibitors. Identification of an inhibitor‐resistant mutant and complementation tests of the plasmids containing secA in a secAts mutant showed that a single secA‐azi‐9 mutation increased the resistance, providing genetic evidence that SecA is indeed the target of these inhibitors in bacteria. Such results strongly suggest SecA as an excellent target for developing effective antimicrobials against Gram‐negative bacteria with the intrinsic ability to overcome MDR. A key future research direction should be the optimization of membrane permeability.     

Novel feature of nano‐titanium dioxide on textiles: Antifelting and antibacterial wool

In this study, the antifelting and antibacterial features of wool samples treated with nanoparticles of titanium dioxide (TiO₂) were evaluated. To examine the antifelting properties of the treated samples, the fabric shrinkage after washing was determined. The antimicrobial activity was assessed through the calculation of bacterial reduction against Escherichia coli (Gram‐negative) and Staphylococcus aureus (Gram‐positive) bacteria. TiO₂ was stabilized on the wool fabric surface by means of carboxylic acids, including citric acid (CA) and butane tetracarboxylic acid (BTCA). Both oxidized samples with potassium permanganate and nonoxidized wool fabrics were used in this study. The relations between both the TiO₂ and carboxylic acid concentrations in the impregnated bath and the antifelting and antibacterial properties are discussed. With increasing concentration in the impregnated bath, the amount of TiO₂ nanoparticles on the surface of the wool increased; subsequently, lower shrinkage and higher antibacterial properties were obtained. The existence of TiO₂ nanoparticles on the surface of the treated samples was proven with scanning electron microscopy images and energy‐dispersive spectrometry. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Antibacterial activities of novel nanocomposite biofilms of chitosan/phosphoramide/Ag NPs

Novel nanocomposite films of chitosan/phosphoramide/Ag NPs were prepared containing 1–5% of silver nanoparticles. The Ag NPs were synthesized according to the citrate reduction method. The XRD and SEM analysis of Ag NPs, chitosan (CS), phosphoramide (Ph), CS/Ph, CS/Ag NPs films and the nanocomposite films 1–5 containing CS/Ph/1–5% Ag NPs were investigated. The in vitro antibacterial activities were evaluated against four bacteria including two Gram‐positive Staphylococcus aureus (S. aureus), Bacillus cereus (B. cereus) and two Gram‐negative Escherchia coli (E. coli), Pseudomonas aeruginosa (P. aeruginosa) bacteria. Results revealed greater antibacterial effects of the films against Gram‐positive bacteria. Also, nanocomposite films containing higher percent of Ag NPs showed more antibacterial activities. POLYM. COMPOS. 36:454–466, 2015. © 2014 Society of Plastics Engineers