Polymeric phosphonium salts as a novel class of cationic biocides. III. Immobilization of phosphonium salts by surface photografting and antibacterial activity of the surface-treated polymer films

Immobilized polycationic biocides with phosphonium salt on the surface of poly(propylene) film were prepared by surface photografting and surface antibacterial activity of the resulting films against Staphylococcus aureus and Escherichia coli was explored by the viable cell counting method. These films with phosphonium salts were found to exhibit high antibacterial activity against S. aureus and E. coli—particularly against E. coli. Furthermore, morphological changes of the cells of S. aureus and E. coli in contact with the immobilized phosphonium salt were estimated by scanning electron microscopy. It was found that the immobilized biocides exhibited surface bactericidal activity against both strains as evidenced by shrunken and deformed cells of these species in contact with the immobilized biocides. © 1993 John Wiley & Sons, Inc.     

Polymeric phosphonium salts as a novel class of cationic biocides. IV. Synthesis and antibacterial activity of polymers with phosphonium salts in the main chain

Polymers with phosphonium salts and different alkyl spacers in the main chain were prepared, and their antibacterial activities against Staphylococcus aureus and Escherichia coli were explored by the viable cell counting method in sterile distilled water. The antibacterial activity of the polymers was found to be higher than that of the corresponding model compounds against each strain, and the effect of the molecular weight on the antibacterial activity was also observed for the compounds with the same spacer length. The antibacterial activity of the polymer samples bonded with different spacer lengths was found to increase with increasing the spacer length against both strains. © 1993 John Wiley & Sons, Inc.     

Polymeric phosphonium salts as a novel class of cationic biocides. IX. Effect of side-chain length between main chain and active group on antibacterial activity

Polymeric phosphonium salts with different side-chain length between the main chain and the active group, poly[4-2-tributyl-phosphonioethyl)styrene chloride-co-4-(2-chloroethyl)styrene] and poly[4-(3-tributylphosphoniopropyl)styrene chloride-co-4-(3-chloropropyl)styrene], were prepared and their antibacterial activities against Staphylococcus aureus and Escherichia coli were examined by the viable cell counting method in sterile distilled water. The antibacterial activity was found to decrease as the side-chain length increased. The most significant finding is a peculiar concentration dependence of the antibacterial activity, which demonstrated the presence of an optimal concentration. The observed specific effects of the side chain length and the concentration on the antibacterial activity seem to be ascribed to the state of aggregation of the polycationic biocides in aqueous solution. © 1994 John Wiley & Sons, Inc.     

Novel polycationic biocides: Synthesis and antibacterial activity of polymeric phosphonium salts

Various polymeric phosphonium salts and the corresponding low-molecular-weight model compounds were prepared and their antibacterial activities against Staphylococcus aureus and Escherichia coli were explored by the viable cell counting method in sterile distilled water. Antibacterial activity of the polymers was found to be higher than that of the corresponding model compounds, particularly against S. aureus. Furthermore, the polymeric phosphonium salt exhibited a higher activity by 2 orders of magnitude than the polymeric quaternary ammonium salt with the same structure except the cationic part. Compounds with the longest alkyl chain (octyl) studied were found to exhibit particularly high activity, and this finding may be ascribed to the contribution of the increased hydrophobicity of the compounds to the cidal activity. © 1993 John Wiley & Sons, Inc.     

Polymeric phosphonium salts as a novel class of cationic biocides. II. Effects of counter anion and molecular weight on antibacterial activity of polymeric phosphonium salts

Various poly[tributyl(4-vinylbenzyl)phosphonium salt]s with different counter anions were prepared and their antibacterial activities against Staphylococcus aureus were explored by the viable cell counting method in sterile distilled water. Antibacterial activity was found to be affected by the structure of the counter anions. The activity was low for a counter anion which tends to form a tight ion-pair with phosphonium ion, while it was high for those facilitating ionic dissociation to free ions. Furthermore, the molecular weight dependence of the antibacterial activity was investigated for poly[tributyl(4-vinylbenzyl) phosphonium chloride] with various molecular weights against S. aureus. Antibacterial activity was found to increase with molecular weight. Various copolymers were prepared in which the compositional ratio of tributyl(4-vinylbenzyl)phosphonium chloride to acrylamide, N-vinyl-2-pyrrolidone, or styrene was altered, and the effect of the positive charge density on the antibacterial activity was investigated against S. aureus. Antibacterial activity of the copolymers was much higher than that of the low-molecular-weight model compound and enhanced with the molar fraction of the phosphonium units in the copolymers. © 1993 John Wiley & Sons, Inc.     

Preparation and properties of antibacterial ABS plastics based on polymeric quaternary phosphonium salts antibacterial agents

Antibacterial acrylonitrile‐butadiene‐styrene (ABS) plastics were prepared by adding polymeric quaternary phosphonium salts as antibacterial agents through a double screw extruder. The novel polymeric quaternary phosphonium salts (PBrMAP‐n) with alkyl chain length ranging from 3 to 11 were synthesized, and their chemical structures were confirmed by Nuclear magnetic resonance hydrogen spectroscopy (¹H‐NMR) and Fourier transform infrared spectroscopy (FT‐IR) spectra. The thermogravimetric analysis (TGA) results showed that all of the antibacterial agents had good thermal stability. The influence of addition amount as well as the alkyl chain length on mechanical properties and antibacterial properties was investigated. Compared with the pure ABS, all of PBrMAP‐n containing specimens had comparable tensile strength and flexural properties but reduced impact strength. Only samples with 10 wt% of PBrMAP‐11 exhibited more than 90% antibacterial efficiency against Escherichia coli and Staphylococcus aureus.     

Preparation and antibacterial activity of hybrid materials containing quaternary ammonium salts via sol-gel process

Organic-inorganic hybrid coatings containing quaternary ammonium salts (QAS) bonded to the organic-inorganic network were prepared from tetraethoxysilane and triethoxysilane terminated poly(ethylene glycol)-block-poly(ethylene) using a sol-gel process. They were applied as a thin layer (0.6-1 μm) to PE films and the antibacterial activity of the coated films was tested against both Gram-negative (Escherichia coli ATCC 25922) and Gram-positive (Staphylococcus aureus ATCC 6538) bacteria. Measurements at different contact times showed a rapid decrease of the viable count for both the tested strains. In particular, after 48 h of contact, a decrease of 96.4% and 99.1% of E. coli and S. aureus, respectively, was observed. The permanence of the antibacterial activity of the coated films was demonstrated through repeated washings and prolonged immersion in physiological saline solutions at 37 °C. Indeed, due to the removal of QAS moieties by the nucleophilic attack of water, the antibacterial activity after 24 h was strongly reduced when measured on samples submitted to several washings. However, a quite good antibacterial activity was observed even on the same samples after 96 h, probably due to a spontaneous partial restoring of the QAS on the surface. Very good transparency, quite good adhesion and high wettability are further features of these hybrid coatings.     

Biologically active polymers. V. Synthesis and antimicrobial activity of modified poly(glycidyl methacrylate‐co‐2‐hydroxyethyl methacrylate) derivatives with quaternary ammonium and phosphonium salts

Antimicrobial copolymers bearing quaternary ammonium and phosphonium salts based on a copolymer of glycidyl methacrylate and 2‐hydroxyethyl methacrylate were synthesized. Poly(glycidyl methacrylate‐co‐2‐hydroxyethyl methacrylate) was modified for the introduction of chloromethyl groups by its reaction with chloroacetyl chloride. The chloroacetylated copolymer was modified for the production of quaternary ammonium or phosphonium salts. The antimicrobial activity of the obtained copolymers was studied against gram‐negative bacteria (Escherichia coli, Pseudomonas aeruginosa, Shigella sp., and Salmonella typhae), gram‐positive bacteria (Bacillus subtilus and B. cereus), and the fungus Trichophyton rubrum by the cut‐plug method. The results showed that the three copolymers had high antimicrobial activity. A control experiment was carried out on the main polymer without ammonium or phosphonium groups. The copolymer bearing quaternary salt made from tributyl phosphine was the most effective copolymer against both gram‐negative and gram‐positive bacteria and the fungus T. rubrum. The diameters of the inhibition zones ranged between 20 and 60 mm after 24 h. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2384–2393, 2002     

Combination of analytical and microbiological techniques to study the antimicrobial activity of a new active food packaging containing cinnamon or oregano against E. coli and S. aureus

The aim of this work is the optimization and application of a group of analytical and microbiological techniques in the study of the activity of essential oils (EOs) incorporated in a new antimicrobial packaging material and the research in depth of the interaction between the microbial cells and the individual compounds present in the active material. For this purpose the antimicrobial activity of the active packaging containing cinnamon or oregano was evaluated against E. coli and S. aureus. The vapour phase activity and the direct contact between the antimicrobial agents themselves, or once incorporated in the packaging material, and the microbial cells have been studied. The direct contact was studied using a broth dilution method. The vapour phase was evaluated by using a new method which involves the use of a filter disk containing the EOs. Furthermore, the kill time assay was used to determine the exposure time for the maximum efficiency in packaging, and transmission electron microscopy was used to investigate the antimicrobial activity and the possible mechanism of action against E. coli and S. aureus. Finally, the compounds absorbed by cells were identified. The results showed that the techniques used provide relevant information about the antibacterial activity of cinnamon and oregano in direct contact as well as in the vapour phase. The antimicrobial packaging showed a fast efficiency which supports its likely application as a food packaging material. Bacteria treated with EOs exhibit a wide range of significant abnormalities; these include formation of blebs, coagulation of cytoplasmatic constituents, collapse of the cell structure and lack of cytoplasmatic material. Some of these observations are correlated to the ability of some of these substances to disrupt envelop structure, especially the inner membrane. After an extraction from dead cells, cinnamaldehyde was detected by GC-MS in E. coli exposed to the active packaging containing cinnamon.     

Novel naphthalene-based bis-pyridinium compounds with pronounced antibacterial activity

Novel para-substituted bis-pyridinium compounds containing 2,7-dioxynaphthalene spacer were synthesized in two simple steps from the corresponding dihydroxy-naphthalene. The microbiological study on five reference (E. coli ATCC 25922, K. pneumoniae ATCC 70060, S. aureus ATCC 43300, P. aeruginosa ATCC27853, and A. baumannii ATCC 15308) and five clinical (E. coli B-3421/19,K. pneumoniae B-2523/18, S. aureus B-8648, P. aeruginosa B-2099/18 and A. baumannii B-2926/18) bacterial strains showed promising range of antibacterial properties for these biocides, compared to modern sanitizers.     

Surprising Antibacterial Activity and Selectivity of Hydrophilic Polyphosphoniums Featuring Sugar and Hydroxy Substituents

There is currently an urgent need for the development of new antibacterial agents to combat the spread of antibiotic‐resistant bacteria. We explored the synthesis and antibacterial activities of novel, sugar‐functionalized phosphonium polymers. While these compounds exhibited antibacterial activity, we unexpectedly found that the control polymer poly(tris(hydroxypropyl)vinylbenzylphosphonium chloride) showed very high activity against both Gram‐negative Escherichia coli and Gram‐positive Staphylococcus aureus and very low haemolytic activity against red blood cells. These results challenge the conventional wisdom in the field that lipophilic alkyl substituents are required for high antibacterial activity and opens prospects for new classes of antibacterial polymers.     

Preparation of antifog and antibacterial coatings by photopolymerization

This paper contains a kind of ultraviolet‐cured antifogging and antibacterial coating. A quaternary ammonium salt (14QAS), which was synthesized in this paper, has been implemented as a monomer. The chemical structure of 14QAS has been confirmed by Fourier transform infrared spectroscopy and nuclear magnetic resonance. The nitrogen atom on the surface of the coatings with 14QAS was observed by X‐ray photoelectron spectroscopy. The Surface wettability of the polymer film was studied by contact angle analysis, which confirmed the hydrophilicity of the coatings with low water contact angle (~25°). The antifog properties were evaluated under different conditions. The antibacterial activity of coatings with 14QAS reached 99.9% against S. aureus and E. coli. Copyright © 2014 John Wiley & Sons, Ltd.     

Intercation spacing and side chain effects on phosphonium polymers: Thermal,supramolecular, and bactericidal properties

The properties of phosphonium polyelectrolytes (PELs) were evaluated in an effort to assess the influence of both side chain and main chain composition. The influence of side chain was examined by comparing properties of a series of PELs having hydrophobic octyloxy side chains to those of structural analogues lacking the side chains. The influence exerted by backbone flexibility/length of spacer between charges was revealed by comparing properties of two series of polymers with a variable number of methylene units between phosphonium charge‐bearing sites. Side chain composition and spacing between phosphonium units lead to noteworthy influence on thermal stability, glass transition, and crystallinity. The molecular structure of PELs also correlates with trends in film morphology and critical surface energy of PEL dip‐cast films. Sensitivity of morphology to humidity or water in the casting solvent was observed. Supramolecular assembly of films via layer‐by‐layer deposition of PELs alternating with anionic polythiophene derivative layers was also undertaken. The linearity of film growth, amount of material deposited in each bilayer, polycation:polyanion ratio, and film roughness all show noteworthy trends that depend on both the presence/absence of side chains and on spacing between ionic centers. The relationship between side chain and spacer on bactericidal activity against Staphylococcus aureus and Escherichia coli was assessed. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 24–34     

Synthesis of n-alkylated quaternary ammonium chitosan and its long-term antibacterial finish for rabbit hair fabric

In this work, n-alkyl chitosan (N-CTS) was obtained by alkylation modification of chitosan with n-butylaldehyde using Schiff alkali method. The etherifying agent 3-chloro-2-hydroxypropyl triethylammonium chloride (CHPTAC-ethyl) was synthesized from triethylamine and epichlorohydrin. The N-CTS and CHPTAC-ethyl were etherized to finally synthesize n-alkyl quaternary ammonium chitosan (N-CCTS). Scanning electron microscope, X-ray diffractometer, Fourier transform infrared, X-ray photoelectron spectroscopy, and ¹³CNMR were used to characterize the surface morphology and chemical structure. Viscosity method and spectrophotometry were used to determine its physical and chemical properties. The etherification reaction mechanism was studied systematically and the influence of reaction conditions on the degree of substitution and solubility of N-CCTS was investigated. The minimum inhibitory concentration (MIC) of N-CCTS against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) was both 0.15 g/L, which was superior to the MIC value of natural chitosan. N-CCTS was used to finish rabbit hair fabric with citric acid as cross-linking agent and sodium hypophosphite as catalyst. The antibacterial and washing resistance of the product were investigated. After 25 times of washing, the antibacterial rate of N-CCTS against E. coli and S. aureus remained stable at about 90%, and the antibacterial rate was higher than that of N-CTS and natural chitosan, and it was a kind of natural polymer long-acting antibacterial finishing agent for rabbit hair fabric.     

Preparation of antimicrobial polycaprolactone‐silica composite films with nanosilver rods and triclosan using roll‐milling method

In this study, antimicrobial polycaprolactone composite films containing 12.5% silica and 0.15% silver nanorods were prepared using the roll‐milling method. The destruction of E. coli and S. aureus on the surface of the composite films was evaluated after 6 hr of incubation at 37°C. For the E. Coli, no bacterial contamination was detected after 6 hr and the film surface was completely disinfected with 100% reduction of the microbial contamination. For the S. aureus, 94% reduction of the bacterial contamination was observed after 6 hr. The results were compared with the composite films containing triclosan, a broad‐spectrum antimicrobial agent. The antimicrobial activity tests with 0.25% triclosan incorporated polycaprolactone‐silica composite films showed only 70% reduction of E. coli and 95% reduction of S. aureus after 6 hr. The results demonstrated that the use of silver nanoparticles in the biopolymer industry has huge potential for the self‐cleaning applications. Copyright © 2009 John Wiley & Sons, Ltd.     

Closing one of the last gaps in polyionene compositions: alkyloxyethylammonium ionenes as fast-acting biocides

Alkyloxyethylammonium ionenes are reported as biocompatible biocides with a time of biocidal action within a few minutes. The presence of both ethoxyethyl and aliphatic spacers besides long alkyl chain substituents on the quaternary nitrogen atom differentiates these biocides structurally from the known polyionenes. The influence of alkyl spacer length, counter ion and length of the pendant alkyl groups on the antibacterial properties is studied. E. coli is adopted as a test organism. MIC and MBC values are determined via broth dilution methods; time-dependent tests are accomplished by determining the number of viable cells with the spread-plate method after different contact times. Structural characterization is conducted via NMR and mass spectrometry techniques.     

Green Synthesized Silver Nanoparticles Immobilized on Activated Carbon Nanoparticles: Antibacterial Activity Enhancement Study and Its Application on Textiles Fabrics

This research aimed to enhance the antibacterial activity of silver nanoparticles (AgNPs) synthesized from silver nitrate (AgNO₃) using aloe vera extract. It was performed by means of incorporating AgNPs on an activated carbon nanoparticle (ACNPs) under ultrasonic agitation (40 kHz, 2 × 50 watt) for 30 min in an aqueous colloidal medium. The successful AgNPs synthesis was clarified with both Ultraviolet-Visible (UV-Vis) and Fourier Transform Infrared (FTIR) spectrophotometers. The successful AgNPs–ACNPs incorporation and its particle size analysis was performed using Transmission Electron Microscope (TEM). The brown color suspension generation and UV-Vis’s spectra maximum wavelength at around 480 nm confirmed the existence of AgNPs. The particle sizes of the produced AgNPs were about 5 to 10 nm in the majority number, which collectively surrounded the aloe vera extract secondary metabolites formed core-shell like nanostructure of 8.20 ± 2.05 nm in average size, while ACNPs themselves were about 20.10 ± 1.52 nm in average size formed particles cluster, and 48.00 ± 8.37 nm in average size as stacking of other particles. The antibacterial activity of the synthesized AgNPs and AgNPs-immobilized ACNPs was 57.58% and 63.64%, respectively (for E. coli); 61.25%, and 93.49%, respectively (for S. aureus). In addition, when the AgNPs-immobilized ACNPs material was coated on the cotton and polyester fabrics, the antibacterial activity of the materials changed, becoming 19.23% (cotton; E. coli), 31.73% (polyester; E. coli), 13.36% (cotton; S. aureus), 21.15% (polyester; S. aureus).     

Light-Activated Rhenium Complexes with Dual Mode of Action against Bacteria

New antibiotics and innovative approaches to kill drug-resistant bacteria are urgently needed. Metal complexes offer access to alternative modes of action but have only sparingly been investigated in antibacterial drug discovery. We have developed a light-activated rhenium complex with activity against drug-resistant S. aureus and E. coli. The activity profile against mutant strains combined with assessments of cellular uptake and synergy suggest two distinct modes of action.     

Effect of the topology on the antibacterial activity of cationic polythioether synthesized by all-click chemistry

Cationic compounds often serve as antibacterial materials for a wide range of applications. However, the relationship of topology−antibacterial activity has been rarely revealed. Herein, three cationic polythioethers (CPTEs) with hyperbranched topologies are well designed and facilely synthesized via an all-click chemistry strategy (including thiol-ene and epoxy-amine additions). These as-prepared CPTEs were found to exhibited outstanding antibacterial activity against Escherichia coli and Staphylococcus aureus with minimum inhibitory concentrations against E. coli of 7.3, 14.6, and 14.6 μg ml⁻¹, and against S. aureus of 14.6, 29.2, and 29.2 μg ml⁻¹, respectively. The antibacterial activity is coincident with their degree of branching (DB, their DB values of 0.81, 0.48, and 0.27), which is mainly attributed to the inherent three-dimensional structure. The present strategy reveals the relationship of polymer topology and antibacterial activity, providing a novel possibility for designing and/or synthesis of high-efficiency antibacterial agents.     

Zn or O? An Atomic Level Comparison on Antibacterial Activities of Zinc Oxides

For the first time, the influence of different types of atoms (Zn and O) on the antibacterial activities of nanosized ZnO was quantitatively evaluated with the aid of a 3D‐printing‐manufactured evaluation system. Two different outermost atomic layers were manufactured separately by using an ALD (atomic layer deposition) method. Interestingly, we found that each outermost atomic layer exhibited certain differences against gram‐positive or gram‐negative bacterial species. Zinc atoms as outermost layer (ZnO?Zn) showed a more pronounced antibacterial effect towards gram‐negative E. coli (Escherichia coli), whereas oxygen atoms (ZnO?O) showed a stronger antibacterial activity against gram‐positive S. aureus (Staphylococcus aureus). A possible antibacterial mechanism has been comprehensively discussed from different perspectives, including Zn²⁺ concentrations, oxygen vacancies, photocatalytic activities and the DNA structural characteristics of different bacterial species.