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Special Issue "Polymeric Systems as Antimicrobial or Antifouling Agents"

A special issue of International Journal of Molecular Sciences (ISSN 1422-0067). This special issue belongs to the section "Materials Science".

Deadline for manuscript submissions: 30 June 2019

Special Issue Editors

Guest Editor
Dr. Antonella Piozzi

Department of Chemistry, Sapienza, University of Rome, Piazzale A. Moro 5, 00185, Rome, Italy
Website | E-Mail
Interests: antimicrobial polymers; polyurethanes; drug delivery systems; functionalization of polymers; microbial biofilms; nanocomposites
Guest Editor
Dr. Iolanda Francolini

Department of Chemistry, University “La Sapienza”, Piazzale Aldo Moro 5, 00185, Rome, Italy
Website | E-Mail
Interests: antimicrobial polymers; polyurethanes; drug delivery systems; functionalization of polymers; microbial biofilms; nanocomposites

Special Issue Information

Dear Colleagues,

Research concerning the development of antimicrobial polymers represents a great challenge for both the academic world and industry, as microbial contamination is a serious issue that involves many areas, such as the health and biomedical field, water purification systems, food packaging and storage. Microbial adhesion to surfaces results in the formation of a tick microbial biofilm, difficulty eradicable, in which microbes are protected from the action of common antimicrobial agents. Antimicrobial polymers can help to prevent biofilm development and solve the problems associated with the use of conventional antimicrobial agents, such as residual toxicity, short term antimicrobial activity and development of resistant microorganisms. The microbial adhesion is a problem particularly felt in the field of medical devices since it can lead to serious infections and device failure. Different types of polymer systems have been designed to prevent microbial adhesion among which the most investigated are: (a) antifouling polymers; (b) amphiphilic polymers mimicking antibacterial peptides occurring in nature; (c) functionalized polymers able to load and release bioactive molecules such as antibiotics, heavy metals and other antiseptic agents. We particularly take an interest in manuscripts that report relevance of antimicrobial polymers in the design and fabrication of medical devices, packaging materials and water purification systems.

Potential topics include, but are not limited to:

  • Antimicrobial polymers for medical devices
  • Antimicrobial polymers for food packaging
  • Polymers made antimicrobial by silver loading
  • Release of antimicrobial agents from polymers
  • Biomimetic polymers
  • Antifouling polymers

Dr. Antonella Piozzi
Dr. Iolanda Francolini
Guest Editors

Manuscript Submission Information

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Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. International Journal of Molecular Sciences is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1800 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • antimicrobial polymers
  • drug delivery systems
  • silver
  • microbial biofilms
  • medical devices
  • antimicrobial packaging
  • water purification systems

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Published Papers (16 papers)

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Research

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Open AccessArticle
Olive Mill Wastewater Valorization in Multifunctional Biopolymer Composites for Antibacterial Packaging Application
Int. J. Mol. Sci. 2019, 20(10), 2376; https://doi.org/10.3390/ijms20102376
Received: 4 April 2019 / Revised: 3 May 2019 / Accepted: 11 May 2019 / Published: 14 May 2019
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Abstract
Olive mill wastewater (OMW) is the aqueous waste derived from the production of virgin olive oil. OMW typically contains a wide range of phenol-type molecules, which are natural antioxidants and/or antibacterials. In order to exploit the bioactive molecules and simultaneously decrease the environmental [...] Read more.
Olive mill wastewater (OMW) is the aqueous waste derived from the production of virgin olive oil. OMW typically contains a wide range of phenol-type molecules, which are natural antioxidants and/or antibacterials. In order to exploit the bioactive molecules and simultaneously decrease the environmental impact of such a food waste stream, OMW has been intercalated into the host structure of ZnAl layered double hydroxide (LDH) and employed as an integrative filler for the preparation of poly(butylene succinate) (PBS) composites by in situ polymerization. From the view point of the polymer continuous phase as well as from the side of the hybrid filler, an investigation was performed in terms of molecular and morphological characteristics by gel permeation chromatography (GPC) and X-ray diffraction (XRD); also, the thermal and mechanical properties were evaluated by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and dynamic thermomechanical analysis (DMTA). Antibacterial properties have been assessed against a Gram-positive and a Gram-negative bacterium, Staphylococcus aureus and Escherichia coli, respectively, as representatives of potential agents of foodborne illnesses. Full article
(This article belongs to the Special Issue Polymeric Systems as Antimicrobial or Antifouling Agents)
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Open AccessArticle
Use of Materials Based on Polymeric Silica as Bone-Targeted Drug Delivery Systems for Metronidazole
Int. J. Mol. Sci. 2019, 20(6), 1311; https://doi.org/10.3390/ijms20061311
Received: 26 February 2019 / Revised: 9 March 2019 / Accepted: 11 March 2019 / Published: 15 March 2019
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Abstract
Mesostructured ordered silica-based materials are the promising candidates for local drug delivery systems in bone disease due to their uniform pore size and distribution, and high surface area which affect their excellent adsorption properties, good biocompatibility and bioactivity, and versatile functionalization so that [...] Read more.
Mesostructured ordered silica-based materials are the promising candidates for local drug delivery systems in bone disease due to their uniform pore size and distribution, and high surface area which affect their excellent adsorption properties, good biocompatibility and bioactivity, and versatile functionalization so that their properties can be controlled. Ordered mesoporous silica (MCM-41 type) was synthesized by a surfactant-assisted sol-gel process using tetraethoxysilane as a silica precursor and hexadecyltrimethylammonium bromide as the structure-directing agent. Functionalized silica materials containing various types of organic groups (3-aminopropyl, 3-mercaptopropyl, or 3-glycidyloxypropyl groups) were synthesized by the post-grafting method onto pre-made mesoporous silica. Comparative studies of their structural characteristics, the surface mineralization activity and release properties for the model drug Metronidazole (MT) were then conducted. It has been found that porosity parameters, mineralization activity and adsorption/release of metronidazole from mesoporous channels of silica can be regulated using functional groups which are chemically bounded with an outer silica surface. The preferential mineral nucleation was found on negatively charged surfaces—MCM-41, and mercaptopropyl and glycidyloxypropyl functionalized silica (MCM-SH and MCM-epoxy, respectively) in simulated body fluid (SBF solution), as well as a sustained release of MT. In contrast to them, aminopropyl-functionalized samples (MCM-NH2) achieved a high MT release rate. These results confirm the potential of silica-based materials for local therapeutic applications (as drug carriers and bone substitutes) in bone disease. Full article
(This article belongs to the Special Issue Polymeric Systems as Antimicrobial or Antifouling Agents)
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Open AccessArticle
Synthesis, Characterization, and Bacterial Fouling-Resistance Properties of Polyethylene Glycol-Grafted Polyurethane Elastomers
Int. J. Mol. Sci. 2019, 20(4), 1001; https://doi.org/10.3390/ijms20041001
Received: 25 January 2019 / Revised: 15 February 2019 / Accepted: 20 February 2019 / Published: 25 February 2019
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Abstract
Despite advances in material sciences and clinical procedures for surgical hygiene, medical device implantation still exposes patients to the risk of developing local or systemic infections. The development of efficacious antimicrobial/antifouling materials may help with addressing such an issue. In this framework, polyethylene [...] Read more.
Despite advances in material sciences and clinical procedures for surgical hygiene, medical device implantation still exposes patients to the risk of developing local or systemic infections. The development of efficacious antimicrobial/antifouling materials may help with addressing such an issue. In this framework, polyethylene glycol (PEG)-grafted segmented polyurethanes were synthesized, physico-chemically characterized, and evaluated with respect to their bacterial fouling-resistance properties. PEG grafting significantly altered the polymer bulk and surface properties. Specifically, the PEG-grafted polyurethanes possessed a more pronounced hard/soft phase segregated microstructure, which contributed to improving the mechanical resistance of the polymers. The better flexibility of the soft phase in the PEG-functionalized polyurethanes compared to the pristine polyurethane (PU) was presumably also responsible for the higher ability of the polymer to uptake water. Additionally, dynamic contact angle measurements evidenced phenomena of surface reorganization of the PEG-functionalized polyurethanes, presumably involving the exposition of the polar PEG chains towards water. As a consequence, Staphylococcus epidermidis initial adhesion onto the surface of the PEG-functionalized PU was essentially inhibited. That was not true for the pristine PU. Biofilm formation was also strongly reduced. Full article
(This article belongs to the Special Issue Polymeric Systems as Antimicrobial or Antifouling Agents)
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Open AccessArticle
Interaction of Halictine-Related Antimicrobial Peptides with Membrane Models
Int. J. Mol. Sci. 2019, 20(3), 631; https://doi.org/10.3390/ijms20030631
Received: 27 December 2018 / Revised: 24 January 2019 / Accepted: 28 January 2019 / Published: 1 February 2019
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Abstract
We have investigated structural changes of peptides related to antimicrobial peptide Halictine-1 (HAL-1) induced by interaction with various membrane-mimicking models with the aim to identify a mechanism of the peptide mode of action and to find a correlation between changes of primary/secondary structure [...] Read more.
We have investigated structural changes of peptides related to antimicrobial peptide Halictine-1 (HAL-1) induced by interaction with various membrane-mimicking models with the aim to identify a mechanism of the peptide mode of action and to find a correlation between changes of primary/secondary structure and biological activity. Modifications in the HAL-1 amino acid sequence at particular positions, causing an increase of amphipathicity (Arg/Lys exchange), restricted mobility (insertion of Pro) and consequent changes in antimicrobial and hemolytic activity, led to different behavior towards model membranes. Secondary structure changes induced by peptide-membrane interaction were studied by circular dichroism, infrared spectroscopy, and fluorescence spectroscopy. The experimental results were complemented by molecular dynamics calculations. An α-helical structure has been found to be necessary but not completely sufficient for the HAL-1 peptides antimicrobial action. The role of alternative conformations (such as β-sheet, PPII or 310-helix) also seems to be important. A mechanism of the peptide mode of action probably involves formation of peptide assemblies (possibly membrane pores), which disrupt bacterial membrane and, consequently, allow membrane penetration. Full article
(This article belongs to the Special Issue Polymeric Systems as Antimicrobial or Antifouling Agents)
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Open AccessArticle
Functionalized Polymeric Materials with Bio-Derived Antimicrobial Peptides for “Active” Packaging
Int. J. Mol. Sci. 2019, 20(3), 601; https://doi.org/10.3390/ijms20030601
Received: 20 December 2018 / Revised: 25 January 2019 / Accepted: 28 January 2019 / Published: 30 January 2019
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Abstract
Food packaging is not only a simple protective barrier, but a real “active” component, which is expected to preserve food quality, safety and shelf-life. Therefore, the materials used for packaging production should show peculiar features and properties. Specifically, antimicrobial packaging has recently gained [...] Read more.
Food packaging is not only a simple protective barrier, but a real “active” component, which is expected to preserve food quality, safety and shelf-life. Therefore, the materials used for packaging production should show peculiar features and properties. Specifically, antimicrobial packaging has recently gained great attention with respect to both social and economic impacts. In this paper, the results obtained by using a polymer material functionalized by a small synthetic peptide as “active” packaging are reported. The surface of Polyethylene Terephthalate (PET), one of the most commonly used plastic materials in food packaging, was plasma-activated and covalently bio-conjugated to a bactenecin-derivative peptide named 1018K6, previously characterized in terms of antimicrobial and antibiofilm activities. The immobilization of the peptide occurred at a high yield and no release was observed under different environmental conditions. Moreover, preliminary data clearly demonstrated that the “active” packaging was able to significantly reduce the total bacterial count together with yeast and mold spoilage in food-dairy products. Finally, the functionalized-PET polymer showed stronger efficiency in inhibiting biofilm growth, using a Listeria monocytogenes strain isolated from food products. The use of these “active” materials would greatly decrease the risk of pathogen development and increase the shelf-life in the food industry, showing a real potential against a panel of microorganisms upon exposure to fresh and stored products, high chemical stability and re-use possibility. Full article
(This article belongs to the Special Issue Polymeric Systems as Antimicrobial or Antifouling Agents)
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Open AccessArticle
Antibacterial Composites of Cuprous Oxide Nanoparticles and Polyethylene
Int. J. Mol. Sci. 2019, 20(2), 439; https://doi.org/10.3390/ijms20020439
Received: 28 December 2018 / Revised: 17 January 2019 / Accepted: 18 January 2019 / Published: 21 January 2019
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Abstract
Cuprous oxide nanoparticles (Cu2ONPs) were used for preparing composites with linear low-density polyethylene (LLDPE) by co-extrusion, thermal adhesion, and attachment using ethyl cyanoacrylate, trimethoxyvinylsilane, and epoxy resin. The composites were examined by Scanning electron microscope and tested for their antibacterial activity [...] Read more.
Cuprous oxide nanoparticles (Cu2ONPs) were used for preparing composites with linear low-density polyethylene (LLDPE) by co-extrusion, thermal adhesion, and attachment using ethyl cyanoacrylate, trimethoxyvinylsilane, and epoxy resin. The composites were examined by Scanning electron microscope and tested for their antibacterial activity against Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli. All of these composites—except for the one obtained by extrusion—eradicated cells of both bacteria within half an hour. The composite prepared by thermal adhesion of Cu2ONPs on LLDPE had the highest external exposure of nanoparticles and exhibited the highest activity against the bacteria. This composite and the one obtained using ethyl cyanoacrylate showed no leaching of copper ions into the aqueous phase. Copper ion leaching from composites prepared with trimethoxyvinylsilane and epoxy resin was very low. The antibacterial activity of the composites can be rated as follows: obtained by thermal adhesion > obtained using ethyl cyanoacrylate > obtained using trimethoxyvinylsilane > obtained using epoxy resin > obtained by extrusion. The composites with the highest activity are potential materials for tap water and wastewater disinfection. Full article
(This article belongs to the Special Issue Polymeric Systems as Antimicrobial or Antifouling Agents)
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Open AccessArticle
Antibacterial Activities of Lipopeptide (C10)2-KKKK-NH2 Applied Alone and in Combination with Lens Liquids to Fight Biofilms Formed on Polystyrene Surfaces and Contact Lenses
Int. J. Mol. Sci. 2019, 20(2), 393; https://doi.org/10.3390/ijms20020393
Received: 11 December 2018 / Revised: 9 January 2019 / Accepted: 14 January 2019 / Published: 17 January 2019
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Abstract
The widespread use of biomaterials such as contact lenses is associated with the development of biofilm-related infections which are very difficult to manage with standard therapies. The formation of bacterial biofilms on the surface of biomaterials is associated with increased antibiotic resistance. Owing [...] Read more.
The widespread use of biomaterials such as contact lenses is associated with the development of biofilm-related infections which are very difficult to manage with standard therapies. The formation of bacterial biofilms on the surface of biomaterials is associated with increased antibiotic resistance. Owing to their promising antimicrobial potential, lipopeptides are being intensively investigated as novel antimicrobials. However, due to the relatively high toxicity exhibited by numerous compounds, a lot of attention is being paid to designing new lipopeptides with optimal biological activities. The principal aim of this study was to evaluate the potential ophthalmic application of lipopeptide (C10)2-KKKK-NH2. This lipopeptide was synthesized according to Fmoc chemistry using the solid-phase method. The antibiofilm activities of the lipopeptide, antibiotics used in ocular infections, and commercially available lens liquids were determined using the broth dilution method on polystyrene 96-well plates and contact lenses. Resazurin was applied as the cell-viability reagent. The effectiveness of the commercially available lens liquids supplemented with the lipopeptide was evaluated using the same method and materials. (C10)2-KKKK-NH2 exhibited stronger anti-biofilm properties compared to those of the tested conventional antimicrobials and showed the ability to enhance the activity of lens liquids at relatively low concentrations (4–32 mg/L). Estimation of the eye irritation potential of the lipopeptide using Toxtree software 2.6.13 suggests that the compound could be safely applied on the human eye. The results of performed experiments encourage further studies on (C10)2-KKKK-NH2 and its potential application in the prophylaxis of contact lens-related eye infections. Full article
(This article belongs to the Special Issue Polymeric Systems as Antimicrobial or Antifouling Agents)
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Open AccessCommunication
Additives for Efficient Biodegradable Antifouling Paints
Int. J. Mol. Sci. 2019, 20(2), 361; https://doi.org/10.3390/ijms20020361
Received: 20 December 2018 / Revised: 11 January 2019 / Accepted: 13 January 2019 / Published: 16 January 2019
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Abstract
The evolution of regulations concerning biocidal products aims to increase protection of the environment (e.g., EU Regulation No 528/2012) and requires the development of new non-toxic anti-fouling (AF) systems. The development of these formulations implies the use of ingredients (polymers, active substances, additives) [...] Read more.
The evolution of regulations concerning biocidal products aims to increase protection of the environment (e.g., EU Regulation No 528/2012) and requires the development of new non-toxic anti-fouling (AF) systems. The development of these formulations implies the use of ingredients (polymers, active substances, additives) that are devoid of toxicity towards marine environments. In this context, the use of erodable antifouling paints based on biodegradable polymer and authorized biocides responds to this problem. However, the efficiency of paints could be improved by the use of specific additives. For this purpose, three additives acting as surface modifiers were studied (Tween 80, Span 85 and PEG-silane). Their effects on parameters involved in antifouling efficiency as hydrophobicity, hydration and copper release were studied. Results showed that the addition of 3% of additives modulated hydrophobicity and hydration without an increase of copper release and significantly reduced microfouling development. Efficient paints based on biodegradable polymer and with no organic biocide could be obtained by mixing copper thiocyanate and additives. Full article
(This article belongs to the Special Issue Polymeric Systems as Antimicrobial or Antifouling Agents)
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Open AccessArticle
Antibiofilm Activity of Polyamide 11 Modified with Thermally Stable Polymeric Biocide Polyhexamethylene Guanidine 2-Naphtalenesulfonate
Int. J. Mol. Sci. 2019, 20(2), 348; https://doi.org/10.3390/ijms20020348
Received: 9 December 2018 / Revised: 30 December 2018 / Accepted: 8 January 2019 / Published: 16 January 2019
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Abstract
The choice of efficient antimicrobial additives for polyamide resins is very difficult because of their high processing temperatures of up to 300 °C. In this study, a new, thermally stable polymeric biocide, polyhexamethylene guanidine 2-naphtalenesulfonate (PHMG-NS), was synthesised. According to thermogravimetric analysis, PHMG-NS [...] Read more.
The choice of efficient antimicrobial additives for polyamide resins is very difficult because of their high processing temperatures of up to 300 °C. In this study, a new, thermally stable polymeric biocide, polyhexamethylene guanidine 2-naphtalenesulfonate (PHMG-NS), was synthesised. According to thermogravimetric analysis, PHMG-NS has a thermal degradation point of 357 °C, confirming its potential use in joint melt processing with polyamide resins. Polyamide 11 (PA-11) films containing 5, 7 and 10 wt% of PHMG-NS were prepared by compression molding and subsequently characterised by FTIR spectroscopy. The surface properties were evaluated both by contact angle, and contactless induction. The incorporation of 10 wt% of PHMG-NS into PA-11 films was found to increase the positive surface charge density by almost two orders of magnitude. PA-11/PHMG-NS composites were found to have a thermal decomposition point at about 400 °C. Mechanical testing showed no change of the tensile strength of polyamide films containing PHMG-NS up to 7 wt%. Antibiofilm activity against the opportunistic bacteria Staphylococcus aureus and Escherichia coli was demonstrated for films containing 7 or 10 wt% of PHMG-NS, through a local biocide effect possibly based on an influence on the bacterial eDNA. The biocide hardly leached from the PA-11 matrix into water, at a rate of less than 1% from its total content for 21 days. Full article
(This article belongs to the Special Issue Polymeric Systems as Antimicrobial or Antifouling Agents)
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Open AccessArticle
Providing Antibacterial Activity to Poly(2-Hydroxy Ethyl Methacrylate) by Copolymerization with a Methacrylic Thiazolium Derivative
Int. J. Mol. Sci. 2018, 19(12), 4120; https://doi.org/10.3390/ijms19124120
Received: 28 November 2018 / Revised: 14 December 2018 / Accepted: 16 December 2018 / Published: 19 December 2018
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Abstract
Antimicrobial polymers and coatings are potent types of materials for fighting microbial infections, and as such, they have attracted increased attention in many fields. Here, a series of antimicrobial copolymers were prepared by radical copolymerization of 2-hydroxyethyl methacrylate (HEMA), which is widely employed [...] Read more.
Antimicrobial polymers and coatings are potent types of materials for fighting microbial infections, and as such, they have attracted increased attention in many fields. Here, a series of antimicrobial copolymers were prepared by radical copolymerization of 2-hydroxyethyl methacrylate (HEMA), which is widely employed in the manufacturing of biomedical devices, and the monomer 2-(4-methylthiazol-5-yl)ethyl methacrylate (MTA), which bears thiazole side groups susceptible to quaternization, to provide a positive charge. The copolymers were further quantitatively quaternized with either methyl or butyl iodide, as demonstrated by nuclear magnetic resonance (NMR) and attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR). Then, the polycations were characterized by zeta potential measurements to evaluate their effective charge and by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) to evaluate their thermal properties. The ζ-potential study revealed that the quaternized copolymers with intermediate compositions present higher charges than the corresponding homopolymers. The cationic copolymers showed greater glass transition temperatures than poly(2-hydroxyethyl methacrylate) (PHEMA), with values higher than 100 °C, in particular those quaternized with methyl iodide. The TGA studies showed that the thermal stability of polycations varies with the composition, improving as the content of HEMA in the copolymer increases. Microbial assays targeting Gram-positive and Gram-negative bacteria confirmed that the incorporation of a low number of cationic units into PHEMA provides antimicrobial character with a minimum inhibitory concentration (MIC) of 128 µg mL−1. Remarkably, copolymers with MTA molar fractions higher than 0.50 exhibited MIC values as low as 8 µg mL−1. Full article
(This article belongs to the Special Issue Polymeric Systems as Antimicrobial or Antifouling Agents)
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Open AccessArticle
α-Chymotrypsin Immobilized on a Low-Density Polyethylene Surface Successfully Weakens Escherichia coli Biofilm Formation
Int. J. Mol. Sci. 2018, 19(12), 4003; https://doi.org/10.3390/ijms19124003
Received: 5 November 2018 / Revised: 23 November 2018 / Accepted: 10 December 2018 / Published: 12 December 2018
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Abstract
The protease α-chymotrypsin (α-CT) was covalently immobilized on a low-density polyethylene (LDPE) surface, providing a new non-leaching material (LDPE-α-CT) able to preserve surfaces from biofilm growth over a long working timescale. The immobilized enzyme showed a transesterification activity of 1.24 nmol/h, confirming that [...] Read more.
The protease α-chymotrypsin (α-CT) was covalently immobilized on a low-density polyethylene (LDPE) surface, providing a new non-leaching material (LDPE-α-CT) able to preserve surfaces from biofilm growth over a long working timescale. The immobilized enzyme showed a transesterification activity of 1.24 nmol/h, confirming that the immobilization protocol did not negatively affect α-CT activity. Plate count viability assays, as well as confocal laser scanner microscopy (CLSM) analysis, showed that LDPE-α-CT significantly impacts Escherichia coli biofilm formation by (i) reducing the number of adhered cells (−70.7 ± 5.0%); (ii) significantly affecting biofilm thickness (−81.8 ± 16.7%), roughness (−13.8 ± 2.8%), substratum coverage (−63.1 ± 1.8%), and surface to bio-volume ratio (+7.1 ± 0.2-fold); and (iii) decreasing the matrix polysaccharide bio-volume (80.2 ± 23.2%). Additionally, CLSM images showed a destabilized biofilm with many cells dispersing from it. Notably, biofilm stained for live and dead cells confirmed that the reduction in the biomass was achieved by a mechanism that did not affect bacterial viability, reducing the chances for the evolution of resistant strains. Full article
(This article belongs to the Special Issue Polymeric Systems as Antimicrobial or Antifouling Agents)
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Open AccessArticle
Antibacterial and Antibiofilm Activity and Mode of Action of Magainin 2 against Drug-Resistant Acinetobacter baumannii
Int. J. Mol. Sci. 2018, 19(10), 3041; https://doi.org/10.3390/ijms19103041
Received: 6 September 2018 / Revised: 28 September 2018 / Accepted: 28 September 2018 / Published: 5 October 2018
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Abstract
Antimicrobial peptides (AMPs) are promising therapeutic agents for treating antibiotic-resistant bacterial infections. Previous studies showed that magainin 2 (isolated from African clawed fogs Xenopus laevis) has antimicrobial activity against gram-positive and gram-negative bacteria. The present study was conducted to investigate the antibacterial [...] Read more.
Antimicrobial peptides (AMPs) are promising therapeutic agents for treating antibiotic-resistant bacterial infections. Previous studies showed that magainin 2 (isolated from African clawed fogs Xenopus laevis) has antimicrobial activity against gram-positive and gram-negative bacteria. The present study was conducted to investigate the antibacterial activity of magainin 2 against Acinetobacter baumannii. Magainin 2 showed excellent antibacterial activity against A. baumannii strains and high stability at physiological salt concentrations. This peptide was not cytotoxic towards HaCaT cells and showed no hemolytic activity. Biofilm inhibition and elimination were significantly induced in all A. baumannii strains exposed to magainin 2. We confirmed the mechanism of magainin 2 on the bacterial outer and inner membranes. Collectively, these results suggest that magainin 2 is an effective antimicrobial and antibiofilm agent against A. baumannii strains. Full article
(This article belongs to the Special Issue Polymeric Systems as Antimicrobial or Antifouling Agents)
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Open AccessArticle
Antimicrobial Coatings from Hybrid Nanoparticles of Biocompatible and Antimicrobial Polymers
Int. J. Mol. Sci. 2018, 19(10), 2965; https://doi.org/10.3390/ijms19102965
Received: 17 August 2018 / Revised: 20 September 2018 / Accepted: 26 September 2018 / Published: 28 September 2018
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Abstract
Hybrid nanoparticles of poly(methylmethacrylate) synthesized in the presence of poly (diallyldimethyl ammonium) chloride by emulsion polymerization exhibited good colloidal stability, physical properties, and antimicrobial activity but their synthesis yielded poor conversion. Here we create antimicrobial coatings from casting and drying of the nanoparticles [...] Read more.
Hybrid nanoparticles of poly(methylmethacrylate) synthesized in the presence of poly (diallyldimethyl ammonium) chloride by emulsion polymerization exhibited good colloidal stability, physical properties, and antimicrobial activity but their synthesis yielded poor conversion. Here we create antimicrobial coatings from casting and drying of the nanoparticles dispersions onto model surfaces such as those of silicon wafers, glass coverslips, or polystyrene sheets and optimize conversion using additional stabilizers such as cetyltrimethyl ammonium bromide, dioctadecyldimethyl ammonium bromide, or soybean lecithin during nanoparticles synthesis. Methodology included dynamic light scattering, determination of wettability, ellipsometry of spin-coated films, scanning electron microscopy, and determination of colony forming unities (log CFU/mL) of bacteria after 1 h interaction with the coatings. The additional lipids and surfactants indeed improved nanoparticle synthesis, substantially increasing the conversion rates by stabilizing the monomer droplets in dispersion during the polymerization. The coatings obtained by spin-coating or casting of the nanoparticles dispersions onto silicon wafers were hydrophilic with contact angles increasing with the amount of the cationic polymer in the nanoparticles. Against Escherichia coli and Staphylococcus aureus, bacteria cell counts were reduced by approximately 7 logs upon interaction with the coatings, revealing their potential for several biotechnological and biomedical applications. Full article
(This article belongs to the Special Issue Polymeric Systems as Antimicrobial or Antifouling Agents)
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Open AccessArticle
Synthesis, Characterization, and Antimicrobial Properties of Peptides Mimicking Copolymers of Maleic Anhydride and 4-Methyl-1-pentene
Int. J. Mol. Sci. 2018, 19(9), 2617; https://doi.org/10.3390/ijms19092617
Received: 9 August 2018 / Revised: 27 August 2018 / Accepted: 29 August 2018 / Published: 4 September 2018
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Abstract
Synthetic amphiphilic copolymers with strong antimicrobial properties mimicking natural antimicrobial peptides were obtained via synthesis of an alternating copolymer of maleic anhydride and 4-methyl-1-pentene. The obtained copolymer was modified by grafting with 3-(dimethylamino)-1-propylamine (DMAPA) and imidized in a one-pot synthesis. The obtained copolymer [...] Read more.
Synthetic amphiphilic copolymers with strong antimicrobial properties mimicking natural antimicrobial peptides were obtained via synthesis of an alternating copolymer of maleic anhydride and 4-methyl-1-pentene. The obtained copolymer was modified by grafting with 3-(dimethylamino)-1-propylamine (DMAPA) and imidized in a one-pot synthesis. The obtained copolymer was modified further to yield polycationic copolymers by means of quaternization with methyl iodide and dodecyl iodide, as well as by being sequentially quaternized with both of them. The antimicrobial properties of obtained copolymers were tested against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus epidermidis, and Staphylococcus aureus. Both tested quaternized copolymers were more active against the Gram-negative E. coli than against the Gram-positive S. aureus. The copolymer modified with both iodides was best when tested against E. coli and, comparing all three copolymers, also exhibited the best effect against S. aureus. Moreover, it shows (limited) selectivity to differentiate between mammalian cells and bacterial cell walls. Comparing the minimum inhibitory concentration (MIC) of Nisin against the Gram-positive bacteria on the molar basis instead on the weight basis, the difference between the effect of Nisin and the copolymer is significantly lower. Full article
(This article belongs to the Special Issue Polymeric Systems as Antimicrobial or Antifouling Agents)
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Review

Jump to: Research

Open AccessReview
Antimicrobial Polymers for Additive Manufacturing
Int. J. Mol. Sci. 2019, 20(5), 1210; https://doi.org/10.3390/ijms20051210
Received: 15 February 2019 / Revised: 27 February 2019 / Accepted: 5 March 2019 / Published: 10 March 2019
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Abstract
Three-dimensional (3D) printing technologies can be widely used for producing detailed geometries based on individual and particular demands. Some applications are related to the production of personalized devices, implants (orthopedic and dental), drug dosage forms (antibacterial, immunosuppressive, anti-inflammatory, etc.), or 3D implants that [...] Read more.
Three-dimensional (3D) printing technologies can be widely used for producing detailed geometries based on individual and particular demands. Some applications are related to the production of personalized devices, implants (orthopedic and dental), drug dosage forms (antibacterial, immunosuppressive, anti-inflammatory, etc.), or 3D implants that contain active pharmaceutical treatments, which favor cellular proliferation and tissue regeneration. This review is focused on the generation of 3D printed polymer-based objects that present antibacterial properties. Two main different alternatives of obtaining these 3D printed objects are fully described, which employ different polymer sources. The first one uses natural polymers that, in some cases, already exhibit intrinsic antibacterial capacities. The second alternative involves the use of synthetic polymers, and thus takes advantage of polymers with antimicrobial functional groups, as well as alternative strategies based on the modification of the surface of polymers or the elaboration of composite materials through adding certain antibacterial agents or incorporating different drugs into the polymeric matrix. Full article
(This article belongs to the Special Issue Polymeric Systems as Antimicrobial or Antifouling Agents)
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Open AccessReview
Novel Bioactive and Therapeutic Dental Polymeric Materials to Inhibit Periodontal Pathogens and Biofilms
Int. J. Mol. Sci. 2019, 20(2), 278; https://doi.org/10.3390/ijms20020278
Received: 19 December 2018 / Revised: 9 January 2019 / Accepted: 9 January 2019 / Published: 11 January 2019
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Abstract
Periodontitis is a common infectious disease characterized by loss of tooth-supporting structures, which eventually leads to tooth loss. The heavy burden of periodontal disease and its negative consequence on the patient’s quality of life indicate a strong need for developing effective therapies. According [...] Read more.
Periodontitis is a common infectious disease characterized by loss of tooth-supporting structures, which eventually leads to tooth loss. The heavy burden of periodontal disease and its negative consequence on the patient’s quality of life indicate a strong need for developing effective therapies. According to the World Health Organization, 10–15% of the global population suffers from severe periodontitis. Advances in understanding the etiology, epidemiology and microbiology of periodontal pocket flora have called for antibacterial therapeutic strategies for periodontitis treatment. Currently, antimicrobial strategies combining with polymer science have attracted tremendous interest in the last decade. This review focuses on the state of the art of antibacterial polymer application against periodontal pathogens and biofilms. The first part focuses on the different polymeric materials serving as antibacterial agents, drug carriers and periodontal barrier membranes to inhibit periodontal pathogens. The second part reviews cutting-edge research on the synthesis and evaluation of a new generation of bioactive dental polymers for Class-V restorations with therapeutic effects. They possess antibacterial, acid-reduction, protein-repellent, and remineralization capabilities. In addition, the antibacterial photodynamic therapy with polymeric materials against periodontal pathogens and biofilms is also briefly described in the third part. These novel bioactive and therapeutic polymeric materials and treatment methods have great potential to inhibit periodontitis and protect tooth structures. Full article
(This article belongs to the Special Issue Polymeric Systems as Antimicrobial or Antifouling Agents)
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Int. J. Mol. Sci. EISSN 1422-0067 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
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