Special Issue "Antimicrobial Polymers"

A special issue of Polymers (ISSN 2073-4360).

Deadline for manuscript submissions: closed (31 March 2018)

Special Issue Editors

Guest Editor
Prof. Huining Xiao

Department of Chemical Engineering, University of New Brunswick, 15 Dineen Drive, Fredericton, N.B. E3B 3B4, Canada
Website | E-Mail
Interests: antimicrobial polymers; functinoal-modified cellulose fibres; nanoparticles; green adsorbents; responsive polymers and hydrogels; multiple-barrier and biodegradable packaging materials
Guest Editor
Prof. Yuanfeng Pan

School of Chemistry & Chemical Engineering, Guangxi University, 100 Daxue East Road, Nanning, Guangxi 530004, P.R.China
Website | E-Mail
Interests: functional polymers; carbohydrate polymers; green materials; adsorbent; hydrogel

Special Issue Information

Dear Colleagues,

With increasing public health awareness regarding the effects of bacteria and microorganisms, developing antibacterial or antimicrobial polymers has attracted substantial interest. Improving the health of human being via reducing the infection caused by various bacteria has become increasingly important. Nowadays, the rapid growth of harmful pathogens and their serious health effects pose a significant challenge to modern society. Infections by pathogenic microorganisms are of great concern in a number of areas, such as medical devices, drugs, hospital surfaces/furniture, dental restoration, surgery equipment, health care products, and hygienic applications including water purification systems, food packaging and major or domestic appliances. Antimicrobial polymers are the materials having the capability to kill/inhibit the growth of microbes on their surface or surrounding environment. Moreover, with unique chain structures and functional groups, antimicrobial polymers often generate high antimicrobial activity without inducing drug resistance; and meanwhile eliminate the leaching-out effects that are encountered by conventional antimicrobial agents with low molecular weights. The high retention and effective grafting of antimicrobial polymers render various substrates or materials antimicrobial, such as cellulose fibres, textiles, composites and coating materials.

This Special Issue, "Antimicrobial Polymers", includes research and review papers concerning the recent advances on the preparation of antimicrobial polymers, antimicrobial mechanisms, various factors influencing antimicrobial activity, and applications of antimicrobial polymers in food packaging, biomedicine, health-care and environmental material field. Antimicrobial polymers have recently emerged as a new weapon material to combat microbial contamination owing to their unique properties. In this Special Issue, the main strategies pursued for developing antimicrobial polymers, including polymer impregnation with antimicrobial agents or synthesis of polymers bearing antimicrobial moieties to address the health and environmental concerns will be discussed.  The future application of these polymers, either in industrial or healthcare sectors, is anticipated to lead to extremely positive impacts, not only at the economic level, but also for the improvement of quality of life.

Prof. Dr. Huining Xiao
Prof. Dr. Yuanfeng Pan
Guest Editors

Manuscript Submission Information

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Keywords

  • Antimicrobial polymers
  • Biocide polymers
  • Microbial biofilms
  • Hybrid antimicrobial materials
  • Antimicrobial activity
  • Non-leaching antimicrobial effect
  • Antimicrobial packaging materials
  • Medical-related antimicrobial polymers

Published Papers (15 papers)

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Research

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Open AccessArticle
Antibacterial Superabsorbent Polymers from Tara Gum Grafted Poly(Acrylic acid) Embedded Silver Particles
Polymers 2018, 10(9), 945; https://doi.org/10.3390/polym10090945
Received: 27 June 2018 / Revised: 22 August 2018 / Accepted: 23 August 2018 / Published: 24 August 2018
Cited by 1 | PDF Full-text (3900 KB) | HTML Full-text | XML Full-text
Abstract
Tara gum/silver composite superabsorbent polymers were synthesized with tara gum grafted poly(acrylic acid), using K2S2O8 (KPS) as an initiator and N,N′-methylenebisacrylamide (MBA) as a cross-linker. The products were characterized by Fourier transform infrared spectroscopy (FTIR), [...] Read more.
Tara gum/silver composite superabsorbent polymers were synthesized with tara gum grafted poly(acrylic acid), using K2S2O8 (KPS) as an initiator and N,N′-methylenebisacrylamide (MBA) as a cross-linker. The products were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS). The results showed that the silver ions were partially reduced to Ag0 and the amorphous nanoparticles containing Ag0 and Ag2O were around 10~50 nm in size The tara gum/silver composite superabsorbent polymers exhibited an interconnected porous structure with strong water absorption capacity. The swelling ratio of each product could reach 473 g/g in distilled water and 62 g/g in 0.9% NaCl solution. The antimicrobial activity of the samples against Staphylococcus aureus and Escherichia coli increased with the addition of AgNO3 from 0 to 125 mg. This work indicates that the developed tara gum/silver composite superabsorbent polymers can be potentially used for biomedical applications. Full article
(This article belongs to the Special Issue Antimicrobial Polymers)
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Open AccessArticle
Polyhexamethylene Biguanide and Nadifloxacin Self-Assembled Nanoparticles: Antimicrobial Effects against Intracellular Methicillin-Resistant Staphylococcus aureus
Polymers 2018, 10(5), 521; https://doi.org/10.3390/polym10050521
Received: 24 March 2018 / Revised: 29 April 2018 / Accepted: 9 May 2018 / Published: 12 May 2018
Cited by 1 | PDF Full-text (3029 KB) | HTML Full-text | XML Full-text
Abstract
The treatment of skin and soft tissue infections caused by methicillin-resistant Staphylococcus aureus (MRSA) remains a challenge, partly due to localization of the bacteria inside the host’s cells, where antimicrobial penetration and efficacy is limited. We formulated the cationic polymer polyhexamethylene biguanide (PHMB) [...] Read more.
The treatment of skin and soft tissue infections caused by methicillin-resistant Staphylococcus aureus (MRSA) remains a challenge, partly due to localization of the bacteria inside the host’s cells, where antimicrobial penetration and efficacy is limited. We formulated the cationic polymer polyhexamethylene biguanide (PHMB) with the topical antibiotic nadifloxacin and tested the activities against intracellular MRSA in infected keratinocytes. The PHMB/nadifloxacin nanoparticles displayed a size of 291.3 ± 89.6 nm, polydispersity index of 0.35 ± 0.04, zeta potential of +20.2 ± 4.8 mV, and drug encapsulation efficiency of 58.25 ± 3.4%. The nanoparticles killed intracellular MRSA, and relative to free polymer or drugs used separately or together, the nanoparticles displayed reduced toxicity and improved host cell recovery. Together, these findings show that PHMB/nadifloxacin nanoparticles are effective against intracellular bacteria and could be further developed for the treatment of skin and soft tissue infections. Full article
(This article belongs to the Special Issue Antimicrobial Polymers)
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Open AccessArticle
Controlled Levofloxacin Release and Antibacterial Properties of β-Cyclodextrins-Grafted Polypropylene Mesh Devices for Hernia Repair
Polymers 2018, 10(5), 493; https://doi.org/10.3390/polym10050493
Received: 31 March 2018 / Revised: 29 April 2018 / Accepted: 1 May 2018 / Published: 3 May 2018
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Abstract
Mesh infection is a major complication of hernia repair. After knitted mesh implantation, bacteria can grow within textile structures causing infection. In this work, polypropylene (PP) mesh devices were two-step grafted with hexamethylene diisocyanate (HDI) and β–cyclodexrins (CD) and then loaded with suitable [...] Read more.
Mesh infection is a major complication of hernia repair. After knitted mesh implantation, bacteria can grow within textile structures causing infection. In this work, polypropylene (PP) mesh devices were two-step grafted with hexamethylene diisocyanate (HDI) and β–cyclodexrins (CD) and then loaded with suitable antimicrobial levofloxacin HCL for hernia mesh-infection prevention. First, oxygen plasma was able to create surface roughness, then HDI was successfully grafted onto PP fiber surfaces. Afterwards, CD was covalently grafted onto the HDI treated PP meshes, and levofloxacin HCL (LVFX) was loaded into the CD cavity of the modified meshes. The modified devices were evaluated for sustained antibiotic properties and drug-release profiles in a phosphate buffer, and sustained drug release was observed between interfaces of meshes and aqueous environment. The antibiotic-loaded PP mesh samples demonstrated sustained antibacterial properties for 7 and 10 days, respectively, against both Gram-negative and Gram-positive bacteria. The CD-captured levofloxacin HCL showed burst release after 6 h but later exhibited sustained release for the next 48 h. Among all samples, the modified mesh LVFX-6 was more stable and showed more sustained drug release and could be employed in future clinical applications. Full article
(This article belongs to the Special Issue Antimicrobial Polymers)
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Open AccessArticle
Antifungal Paper Based on a Polyborneolacrylate Coating
Polymers 2018, 10(4), 448; https://doi.org/10.3390/polym10040448
Received: 13 March 2018 / Revised: 12 April 2018 / Accepted: 14 April 2018 / Published: 17 April 2018
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Abstract
Paper documents and products are very susceptible to microbial contamination and damage. Fungi are mainly responsible for those biodeterioration processes. Traditional microbicidal strategies constitute a serious health risk even when microbes are dead. Ideal methods should not be toxic to humans and should [...] Read more.
Paper documents and products are very susceptible to microbial contamination and damage. Fungi are mainly responsible for those biodeterioration processes. Traditional microbicidal strategies constitute a serious health risk even when microbes are dead. Ideal methods should not be toxic to humans and should have no adverse effects on paper, but should own a broad spectrum, good chemical stability and low cost. In this work, we utilize an advanced antimicrobial strategy of surface stereochemistry by applying a coating of a shallow layer of polyborneolacrylate (PBA), resulting in the desired antifungal performance. The PBA-coated paper is challenged with the most common air-borne fungi growing on paper, Aspergillus niger and Penicillium sp. Ten percent by weight of the coating concentration or a 19-μm infiltration of PBA is sufficient to keep the paper spotless. The PBA coating also exhibits significant inhibition of spores’ germination. After PBA coating, both physicochemical properties (paper whiteness, pH, mechanical strength) and inking performance display only slight changes, which are acceptable for general utilization. This PBA coating method is nontoxic, rapid and cost-effective, thus demonstrating great potential for applications in paper products. Full article
(This article belongs to the Special Issue Antimicrobial Polymers)
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Open AccessArticle
The Discovery of an Iridium(III) Dimer Complex as a Potent Antibacterial Agent against Non-Replicating Mycobacterium smegmatis
Polymers 2018, 10(3), 297; https://doi.org/10.3390/polym10030297
Received: 12 February 2018 / Revised: 4 March 2018 / Accepted: 6 March 2018 / Published: 9 March 2018
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Abstract
Novel agents are urgently needed to rapidly kill drug-resistant Mycobacterium tuberculosis. Noble metal complexes, particularly polypyridyl iridium complexes serving as therapeutic agents, have attracted considerable interest recently, due to their significant cytotoxic or antimicrobial activities. Here, we reported an polypyridyl iridium dimer [...] Read more.
Novel agents are urgently needed to rapidly kill drug-resistant Mycobacterium tuberculosis. Noble metal complexes, particularly polypyridyl iridium complexes serving as therapeutic agents, have attracted considerable interest recently, due to their significant cytotoxic or antimicrobial activities. Here, we reported an polypyridyl iridium dimer complex [Ir(ppy)2Cl]2 (3), with ppy = phenylpyridine, which was found to be active against both exponential growing and non-replicating M. smegmatis, with minimum inhibitory concentration values of 2 μg/mL, and exhibited rapid bactericidal kinetics, killing pathogens within 30–60 min. Moreover, 3 was demonstrated to generate a large amount of reactive oxygen species and to be effective in drug-resistant strains. Taken together, the selectively active iridium(III) dimer complex showed promise for use as a novel drug candidate for the treatment of M. tuberculosis infection. Full article
(This article belongs to the Special Issue Antimicrobial Polymers)
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Open AccessArticle
Tailoring Macromolecular Structure of Cationic Polymers towards Efficient Contact Active Antimicrobial Surfaces
Polymers 2018, 10(3), 241; https://doi.org/10.3390/polym10030241
Received: 25 January 2018 / Revised: 19 February 2018 / Accepted: 23 February 2018 / Published: 27 February 2018
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Abstract
The aim of this work is the preparation of contact active antimicrobial films by blending copolymers with quaternary ammonium salts and polyacrylonitrile as matrix material. A series of copolymers based on acrylonitrile and methacrylic monomers with quaternizable groups were designed with the purpose [...] Read more.
The aim of this work is the preparation of contact active antimicrobial films by blending copolymers with quaternary ammonium salts and polyacrylonitrile as matrix material. A series of copolymers based on acrylonitrile and methacrylic monomers with quaternizable groups were designed with the purpose of investigating the influence of their chemical and structural characteristics on the antimicrobial activity of these surfaces. The biocide activity of these systems was studied against different microorganisms, such as the Gram-positive bacteria Staphylococcus aureus and the Gram-negative bacteria Pseudomona aeruginosa and the yeast Candida parapsilosis. The results confirmed that parameters such as flexibility and polarity of the antimicrobial polymers immobilized on the surfaces strongly affect the efficiency against microorganisms. In contrast to the behavior of copolymers in water solution, when they are tethered to the surface, the active cationic groups are less accessible and then, the mobility of the side chain is critical for a good contact with the microorganism. Blend films composed of copolymers with high positive charge density and chain mobility present up to a more than 99.999% killing efficiency against the studied microorganisms. Full article
(This article belongs to the Special Issue Antimicrobial Polymers)
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Open AccessArticle
Novel Antibacterial Polyglycidols: Relationship between Structure and Properties
Polymers 2018, 10(1), 96; https://doi.org/10.3390/polym10010096
Received: 4 December 2017 / Revised: 17 January 2018 / Accepted: 18 January 2018 / Published: 20 January 2018
Cited by 1 | PDF Full-text (1968 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Antimicrobial polymers are an attractive alternative to low molecular weight biocides, because they are non-volatile, chemically stable, and can be used as non-releasing additives. Polymers with pendant quaternary ammonium groups and hydrophobic chains exhibit antimicrobial properties due to the electrostatic interaction between polymer [...] Read more.
Antimicrobial polymers are an attractive alternative to low molecular weight biocides, because they are non-volatile, chemically stable, and can be used as non-releasing additives. Polymers with pendant quaternary ammonium groups and hydrophobic chains exhibit antimicrobial properties due to the electrostatic interaction between polymer and cell wall, and the membrane disruptive capabilities of the hydrophobic moiety. Herein, the synthesis of cationic–hydrophobic polyglycidols with varying structures by post-polymerization modification is presented. The antimicrobial properties of the prepared polyglycidols against E. coli and S. aureus are examined. Polyglycidol with statistically distributed cationic and hydrophobic groups (cationic–hydrophobic balance of 1:1) is compared to (i) polyglycidol with a hydrophilic modification at the cationic functionality; (ii) polyglycidol with both—cationic and hydrophobic groups—at every repeating unit; and (iii) polyglycidol with a cationic–hydrophobic balance of 1:2. A relationship between structure and properties is presented. Full article
(This article belongs to the Special Issue Antimicrobial Polymers)
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Open AccessArticle
Antimicrobial Carvacrol-Containing Polypropylene Films: Composition, Structure and Function
Polymers 2018, 10(1), 79; https://doi.org/10.3390/polym10010079
Received: 3 December 2017 / Revised: 10 January 2018 / Accepted: 11 January 2018 / Published: 16 January 2018
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Abstract
Significant research has been directed toward the incorporation of bioactive plant extracts or essential oils (EOs) into polymers to endow the latter with antimicrobial functionality. EOs offer a unique combination of having broad antimicrobial activity from a natural source, generally recognized as safe [...] Read more.
Significant research has been directed toward the incorporation of bioactive plant extracts or essential oils (EOs) into polymers to endow the latter with antimicrobial functionality. EOs offer a unique combination of having broad antimicrobial activity from a natural source, generally recognized as safe (GRAS) recognition in the US, and a volatile nature. However, their volatility also presents a major challenge in their incorporation into polymers by conventional high-temperature-processing techniques. Herein, antimicrobial polypropylene (PP) cast films were produced by incorporating carvacrol (a model EO) or carvacrol, loaded into halloysite nanotubes (HNTs), via melt compounding. We studied the composition-structure-property relationships in these systems, focusing on the effect of carvacrol on the composition of the films, the PP crystalline phase and its morphology and the films’ mechanical and antimicrobial properties. For the first time, molecular dynamics simulations were applied to reveal the complex interactions between the components of these carvacrol-containing systems. We show that strong molecular interactions between PP and carvacrol minimize the loss of this highly-volatile EO during high-temperature polymer processing, enabling semi-industrial scale production. The resulting films exhibit outstanding antimicrobial properties against model microorganisms (Escherichia coli and Alternaria alternata). The PP/(HNTs-carvacrol) nanocomposite films, containing the carvacrol-loaded HNTs, display a higher level of crystalline order, superior mechanical properties and prolonged release of carvacrol, in comparison to PP/carvacrol blends. These properties are ascribed to the role of HNTs in these nanocomposites and their effect on the PP matrix and retained carvacrol content. Full article
(This article belongs to the Special Issue Antimicrobial Polymers)
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Open AccessArticle
Preparation of Antibacterial Cellulose Paper Using Layer-by-Layer Assembly for Cooked Beef Preservation at Ambient Temperature
Polymers 2018, 10(1), 15; https://doi.org/10.3390/polym10010015
Received: 9 November 2017 / Revised: 11 December 2017 / Accepted: 20 December 2017 / Published: 23 December 2017
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Abstract
Positively-charged ε-poly(l-lysine) (ε-PL) and negatively-charged carboxymethyl cellulose (CMC) were alternately deposited on a cellulose paper surface by the layer-by-layer (LBL) assembly technique. The formation of ε-PL/CMC multilayers was confirmed by X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectra (FTIR), and zeta [...] Read more.
Positively-charged ε-poly(l-lysine) (ε-PL) and negatively-charged carboxymethyl cellulose (CMC) were alternately deposited on a cellulose paper surface by the layer-by-layer (LBL) assembly technique. The formation of ε-PL/CMC multilayers was confirmed by X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectra (FTIR), and zeta potential measurement. The morphologies of the multilayer-modified cellulose paper were observed by scanning electron microscopy (SEM). The ε-PL/CMC multilayers effectively improved not only the antibacterial activity of cellulose paper against both Escherichia coli and Staphylococcus aureus, but also the cellulose paper tensile strength property. Cellulose paper modified with a (ε-PL/CMC)4.5 multilayer exhibited the strongest antibacterial activity, selected for preserving cooked beef for nine days at ambient temperature, could extend the shelf-life of beef for about three days compared with common commercial PE films. The prepared antibacterial paper did not show any evidence of the cytotoxic effect since it could not increase the cytoplasmic lactate dehydrogenase release from L-929 fibroblast cells in contact with the antibacterial paper, suggesting the possibility of utilization in food packaging field. Full article
(This article belongs to the Special Issue Antimicrobial Polymers)
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Open AccessArticle
Preparation of Copolymer-Based Nanoparticles with Broad-Spectrum Antimicrobial Activity
Polymers 2017, 9(12), 717; https://doi.org/10.3390/polym9120717
Received: 31 October 2017 / Revised: 1 December 2017 / Accepted: 10 December 2017 / Published: 15 December 2017
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Abstract
Polyacrylate and guanidine-based nanoparticles which involve acrylate monomers and glycidyl methacrylate modified oligo-guanidine were prepared by a seeded semi-continuous emulsion polymerization. The results from transmission electron microscope and dynamic light scattering measurements showed that the nanoparticles were spherical in shape and the particle [...] Read more.
Polyacrylate and guanidine-based nanoparticles which involve acrylate monomers and glycidyl methacrylate modified oligo-guanidine were prepared by a seeded semi-continuous emulsion polymerization. The results from transmission electron microscope and dynamic light scattering measurements showed that the nanoparticles were spherical in shape and the particle size was in the range of 80–130 nm. Antimicrobial experiments were performed with two types of bacteria, Gram-negative (Escherichia coli, ATCC 8739) and Gram-positive (Staphylococcus aureus, ATCC 6538). The as-synthesized cationic nanoparticles exhibited effective antimicrobial activities on Escherichia coli and Staphylococcus aureus with the minimal inhibitory concentrations at 8 μg/mL and 4 μg/mL, respectively. The mechanism of action of the resulted nanoparticles against these bacteria was revealed by the scanning electron microscopic observation. In addition, the films consisting of latex nanoparticles are non-leaching antimicrobial materials with excellent antimicrobial activity, which indicates the polymers could preserve their antimicrobial activity for long-term effectiveness. Full article
(This article belongs to the Special Issue Antimicrobial Polymers)
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Open AccessArticle
Microwave Assisted Preparation of Antimicrobial Chitosan with Guanidine Oligomers and Its Application in Hygiene Paper Products
Polymers 2017, 9(12), 633; https://doi.org/10.3390/polym9120633
Received: 12 October 2017 / Revised: 9 November 2017 / Accepted: 13 November 2017 / Published: 24 November 2017
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Abstract
Guanidinylated chitosan (GCS) was prepared by grafting guanidine oligomers onto chitosan under microwave irradiation. The structure of GCS characterized by FT-IR and 1H NMR verified the covalent bonding between the guanidine oligomers and chitosan; the effects of molar ratio, reaction temperature, and [...] Read more.
Guanidinylated chitosan (GCS) was prepared by grafting guanidine oligomers onto chitosan under microwave irradiation. The structure of GCS characterized by FT-IR and 1H NMR verified the covalent bonding between the guanidine oligomers and chitosan; the effects of molar ratio, reaction temperature, and time were investigated and the degree of substitution of GCS reached a maximum of 25.5% under optimized conditions in this work. The resulting GCS showed significantly enhanced antimicrobial activities. The results obtained from the dynamic UV absorption of Escherichia coli (E. coli) and atomic force microscopy (AFM) revealed that the deactivation of E. coli by GCS was due to the destructing of the cell membrane and the prompt release of cytoplasm from the bacterial cells. The adsorption of GCS onto cellulose fibers and the antimicrobial efficiency of the hygiene papers with GCS were also investigated. Microwave irradiation as a green assisted method was applied to promote this reaction. This facile approach allowed chitosan to be guanidinylated without tedious preparation procedures and thus broadened its application as a biocompatible antimicrobial agent. Full article
(This article belongs to the Special Issue Antimicrobial Polymers)
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Open AccessArticle
Interactions of Biocidal Polyhexamethylene Guanidine Hydrochloride and Its Analogs with POPC Model Membranes
Polymers 2017, 9(10), 517; https://doi.org/10.3390/polym9100517
Received: 14 September 2017 / Revised: 5 October 2017 / Accepted: 11 October 2017 / Published: 17 October 2017
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Abstract
The bacterial membrane-targeted polyhexamethylene guanidine hydrochloride (PHGH) and its novel analog polyoctamethylene guanidine hydrochloride (POGH) had excellent antimicrobial activities against antibiotics-resistant bacteria. However, the biocompatibility aspects of PHGH and POGH on the phospholipid membrane of the eukaryotic cell have not yet been considered. [...] Read more.
The bacterial membrane-targeted polyhexamethylene guanidine hydrochloride (PHGH) and its novel analog polyoctamethylene guanidine hydrochloride (POGH) had excellent antimicrobial activities against antibiotics-resistant bacteria. However, the biocompatibility aspects of PHGH and POGH on the phospholipid membrane of the eukaryotic cell have not yet been considered. Four chemically synthesized cationic oligoguanidine polymers containing alkyl group with different carbon chain lengths, including PHGH, POGH, and their two analogs, were used to determine their interactions with zwitterionic 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) phospholipids vesicles mimicking the eukaryotic cell membrane. Characterization was conducted by using bactericidal dynamics, hemolysis testing, calcein dye leakage, and isothermal titration calorimetry. Results showed that the gradually lengthened alkyl carbon chain of four oligoguanidine polymers increased the biocidal activity of the polymer, accompanied with the increased hemolytic activity, calcein dye leakage rate and the increased absolute value of the exothermic effect of polymer-POPC membrane interaction. The thermodynamic curve of the polymer-POPC membrane interaction exhibited a very weak exothermic effect and a poorly unsaturated titration curve, which indicated that four guanidine polymers had weak affinity for zwitterionic POPC vesicles. Generally, PHGH of four guanidine polymers had high biocidal activity and relatively high biocompatibility. This study emphasized that appropriate amphiphilicity balanced by the alkyl chain length, and the positive charge is important factor for the biocompatibility of cationic antimicrobial guanidine polymer. Both PHGH and POGH exhibited destructive power to phospholipid membrane of eukaryotic cell, which should be considered in their industry applications. Full article
(This article belongs to the Special Issue Antimicrobial Polymers)
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Open AccessArticle
pH-Mediated Antibacterial Dyeing of Cotton with Prodigiosins Nanomicelles Produced by Microbial Fermentation
Polymers 2017, 9(10), 468; https://doi.org/10.3390/polym9100468
Received: 19 August 2017 / Revised: 15 September 2017 / Accepted: 20 September 2017 / Published: 23 September 2017
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Abstract
This study developed a novel pH-mediated antimicrobial dyeing process of cotton with prodigiosins nanomicelles produced by microbial fermentation. The average diameter of the pigment nanomicelles was 223.8 nm (range of 92.4–510.2 nm), and the pigment concentration was 76.46 mg/L. It was found that [...] Read more.
This study developed a novel pH-mediated antimicrobial dyeing process of cotton with prodigiosins nanomicelles produced by microbial fermentation. The average diameter of the pigment nanomicelles was 223.8 nm (range of 92.4–510.2 nm), and the pigment concentration was 76.46 mg/L. It was found that the superior dyeing effect of cotton fabric was achieved by adjusting the dye bath pH. When the pH was three, dyed cotton under 90 °C for 60 min exhibited the greatest color strength with good rubbing, washing and perspiration color fastness. By the breaking strength test and XRD analysis, it was concluded that the cotton dyed under the optimum condition almost suffered no damage. In addition, due to the presence of prodigiosins, dyed cotton fabric under the optimal process showed outstanding bacteriostatic rates of 99.2% and 85.5% against Staphylococcus aureus and Escherichia coli, respectively. This research provided an eco-friendly and widely-applicable approach for antimicrobial intracellular pigments with the property of pH-sensitive solubility in water to endow cellulose fabric with color and antibacterial activity. Full article
(This article belongs to the Special Issue Antimicrobial Polymers)
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Open AccessArticle
Microscopic Examination of Polymeric Monoguanidine, Hydrochloride-Induced Cell Membrane Damage in Multidrug-Resistant Pseudomonas aeruginosa
Polymers 2017, 9(9), 398; https://doi.org/10.3390/polym9090398
Received: 23 July 2017 / Revised: 21 August 2017 / Accepted: 26 August 2017 / Published: 31 August 2017
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Abstract
Advances in antimicrobial activities of molecule-containing, multiple guanidinium groups against antibiotics-resistant bacteria should be noted. The synthesized polyoctamethylene monoguanidine hydrochloride (POGH), carrying cationic amphiphilic moieties, display excellent activity against multidrug-resistant Pseudomonas aeruginosa (MDR-PA) and other antibiotics-resistant bacteria. The membrane damage effects of POGH [...] Read more.
Advances in antimicrobial activities of molecule-containing, multiple guanidinium groups against antibiotics-resistant bacteria should be noted. The synthesized polyoctamethylene monoguanidine hydrochloride (POGH), carrying cationic amphiphilic moieties, display excellent activity against multidrug-resistant Pseudomonas aeruginosa (MDR-PA) and other antibiotics-resistant bacteria. The membrane damage effects of POGH on MDR-PA were clarified using beta-lactamase activity assay, confocal fluorescence microscopy, scanning electron microscopy, and transmission electron microscopy. The results showed that POGH disrupted both the outer and inner membranes and the intracellular structure of MDR-PA to different extents depending on the dose. All concentrations of POGH within 3–23 μg/mL increased the outer membrane permeability, which facilitated the release of beta-lactamase across the inner membrane. A median dose (10 μg/mL) of POGH led to the separation of the inner and outer membrane, an increase in the membrane gap, and outer membrane structure damage with still maintained overall cytoskeletal structures. The application of a 30 μg/mL dose of POGH led to the collapse of the outer membrane, cellular wrinkling, and shrinkage, and the formation of local membrane holes. The disruption of the outer and inner membranes and the formation of the local membrane holes by a relative high dose were probably the main bactericidal mechanism of POGH. The microscopic evidence explained the strong outer-membrane permeation ability of guanidine-based antimicrobial polymers, which could be considered for the molecular design of novel guanidine-based polymers, as well as the damaged membrane structure and intracellular structure of MDR-PA. Full article
(This article belongs to the Special Issue Antimicrobial Polymers)
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Review

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Open AccessReview
Recent Advances on Octahedral Polypyridyl Ruthenium(II) Complexes as Antimicrobial Agents
Polymers 2018, 10(6), 650; https://doi.org/10.3390/polym10060650
Received: 1 April 2018 / Revised: 15 May 2018 / Accepted: 7 June 2018 / Published: 10 June 2018
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Abstract
Recent developments of therapeutic agents based on transition metals have attracted a great deal of attention. Metal drugs have advantages over other small molecule drugs, and it was demonstrated that, in a number of studies, they played an important role in pharmaceutical chemical [...] Read more.
Recent developments of therapeutic agents based on transition metals have attracted a great deal of attention. Metal drugs have advantages over other small molecule drugs, and it was demonstrated that, in a number of studies, they played an important role in pharmaceutical chemical research and clinical chemotherapy of cancers. It is worthwhile mentioning that octahedral polypyridyl ruthenium(II) complexes have shown remarkable applications in chemical biology and medicinal chemistry over the last decade. However, only very recently has there been comprehensive interest in their antimicrobial properties due to metal-related toxic concerns or neglected potential roles in microbiological systems. Our review will highlight the recent developments in octahedral polypyridyl ruthenium(III) complexes that have exhibited significant antimicrobial activities and will discuss the relationship between the chemical structure and biological process of ruthenium complexes, in both bacterial and fungal cells. Full article
(This article belongs to the Special Issue Antimicrobial Polymers)
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