Antimicrobial Poly Research Articles

Antioxidant and antimicrobial poly(vinyl alcohol)-based films incorporated with grapefruit seed extract and curcumin

PVOH-based multifunctional films were fabricated by blending with grapefruit seed extract (GSE) and curcumin using a solvent casting technique. Both fillers (GSE and curcumin) were mixed well and evenly spread in the polymer matrix to form a compatible composite with PVOH. The addition of GSE and curcumin improved the UV-barrier (>95 %) and mechanical properties (30 %) of the PVOH film. Besides, functional properties like antioxidant and antibacterial actions were increased meaningfully by incorporating GSE and curcumin. However, the incorporation of GSE and curcumin slightly reduced the water vapor barrier property of the film without changing the thermal stability. When the combination of GSE and curcumin was used in a composite film, a unique effect was seen on the film properties. The PVOH/GSE/curcumin film with enhanced mechanical and functional properties can be used for active food packaging applications.

Nonleaching antimicrobial poly(vinyl alcohol)/polyhexamethylene guanidine hydrochloride hydrogels reinforced by hydrogen bond

Antimicrobial poly(vinyl alcohol) (PVA) hydrogels attracted much attentions in the last decade. In this work, a novel antimicrobial PVA hydrogel was prepared through compounding PVA with polyhexamethylene guanidine hydrochloride (PHMG) and freezing‐thawing method. These composite hydrogels behaved above 99.9% of antimicrobial rates against both Escherichia coli and Staphylococcus aureus even at 0.003 wt% of PHMG, and the nonleaching characteristic of PHMG as well as long‐acting antimicrobial activities. The PVA/0.100 wt% PHMG hydrogel had 120% higher tensile strength than pure PVA hydrogel, and its water vapor transmission rate was 4530 ± 245 g/m2/d, which was at an optimal range for injured skin (279‐5138 g/m2/d). This work provides a simple approach to develop nonleaching antimicrobial PVA hydrogels with extremely few PHMG for wound dressing and other potential applications in biomedical field.

Anti-staphylococcal hydrogels based on bacterial cellulose and the antimicrobial biopolyester poly(3-hydroxy-acetylthioalkanoate-co-3-hydroxyalkanoate)

Polymeric hydrogels from bacterial cellulose (BC) have been widely used for the development of wound dressings due to its water holding capacity, its high tensile strength and flexibility, its permeability to gases and liquids, but lacks antibacterial activity. In this work, we have developed novel antimicrobial hydrogels composed of BC and the antimicrobial poly(3-hydroxy-acetylthioalkanoate-co-3-hydroxyalkanoate) (PHACOS). Hydrogels based on different PHACOS contents (20 and 50 wt%) were generated and analysed through different techniques (IR, DSC, TGA, rheology, SEM and EDX) and their bactericidal activity was studied against Staphylococcus aureus. PHACOS20 (BC 80%-PHACOS 20%) hydrogel shows mechanical and thermal properties in the range of human skin and anti-staphylococcal activity (kills 1.8 logs) demonstrating a huge potential for wound healing applications. Furthermore, the cytotoxicity assay using fibroblast cells showed that it keeps cell viability over 85% in all the cases after seven days.

Breaking or following the membrane-targeting mechanism: Exploring the antibacterial mechanism of host defense peptide mimicking poly(2-oxazoline)s

Peptides exert important biological functions but their application is hindered by their susceptibility to proteolysis and poor stability in vivo. Thus, functional peptide mimics have drawn a great deal of attention to address this challenge. Poly(2-oxazoline)s, a class of biocompatible and proteolysis-resistant polymer, can work as host defense peptide mimics without following the general membrane-targeting mechanism as shown in our previous work. This observation encouraged us to figure out if poly(2-oxazoline)s are special and break the general membrane-targeting mechanism of host defense peptides and their mimics. In this study, we aimed at the connection between structure and antibacterial mechanism of poly(2-oxazoline)s. A new γ-aminobutyric acid (GABA)-pendent poly(2-oxazoline) was synthesized and investigated to compare with glycine-pendent poly(2-oxazoline) in our previous study, with the former polymer has two extra CH2 groups in the sidechain to increase the hydrophobicity and amphiphilicity. Membrane depolarization assay suggested that incorporating two more CH2 groups into the sidechain of poly(2-oxazoline) resulted in a mechanism switch from DNA-targeting to membrane-targeting, which was supported by the slow time-kill kinetics and slightly distorted and sunken membrane morphology. Besides, GABA-pendent poly(2-oxazoline) showed potent activity against methicillin-resistant S. aureus and low hemolysis on human red blood cells. Moreover, repeated use of the antimicrobial poly(2-oxazoline) did not stimulate bacteria to obtain resistance, which was an obvious advantage of membrane-targeting antimicrobial agents.

Antimicrobial Poly (methyl methacrylate) with Silver Nanoparticles for Dentistry: A Systematic Review

Poly(methyl methacrylate) (PMMA) is a widely used polymer for dental applications, and it is mainly used in the fabrication of dental prostheses. In an increasing number of these applications, the risk of suffering bacterial or fungal infection is higher than 60% among oral-prosthesis users. Some authors have reported the failure of other implants in the human body due to biofilm formation on the surface (mainly for total hip implants). In the dental field, the formation of bacterial and fungal biofilms on prosthesis’s surface is the etiologic factor for stomatitis, mainly caused by Candida albicans and bacteria such as Staphylococcus epidermidis, Staphylococcus aureus, Pseudomonas aeruginosa and Enterococcus faecalis, as well as many others. The antibacterial and antifungal properties of silver nanoparticles (AgNPs) have been widely reported, and their use in dental materials can prevent oral infections, such as candidiasis and stomatitis, and promote better oral health in dental-prosthesis users. They can even be used in other biomedical applications that require controlling biofilm formation on surfaces. In this review, the reported studies that use composites of PMMA and AgNPs (PMMA-AgNPs) for dental applications are listed and checked, with the aim of gaining a wider perspective of the use and application of this approach in the dental field.

Permanent Antimicrobial Poly(vinylidene fluoride) Prepared by Chemical Bonding with Poly(hexamethylene guanidine).

Biofouling is one of the major obstacles in the application of poly(vinylidene fluoride) (PVDF) membrane in water and wastewater treatment. Developing antimicrobial PVDF could kill the attached microbe in the initial stage, thus theoretically inhibiting the formation of biofilm and delaying the occurrence of biofouling. However, the leaching of the antimicrobial component and deterioration of antimicrobial properties remain a concern. In this work, an antimicrobial PVDF (PVDF-g-AGE-PHMG) was developed by chemical bonding PVDF with poly(hexamethylene guanidine hydrochloride) (PHMG). The obtained PVDF-g-AGE-PHMG was blended with pristine PVDF to prepare an antimicrobial PVDF membrane. The results of Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) confirmed that PHMG was successfully grafted into the PVDF membrane. The morphologies, membrane porosity, water contact angles, antimicrobial properties, mechanical properties, and thermostability of the as-prepared membranes were investigated. When the content of PVDF-g-AGE-PHMG reached 10.0 wt %, the inhibition rates of both antimicrobial PVDF membrane against Escherichia coli and Staphylococcus aureus were above 99.99%. Due to the increased hydrophilicity, excellent antimicrobial activity, nonleaching of antimicrobial component, good mechanical properties, and thermostability, the as-prepared PVDF membrane has promising applications in the field of water treatment.

Development of active antimicrobial poly (l-glutamic) acid-poly (l-lysine) packaging material to protect probiotic bacterium

The main objective of our research was development of a modified poly glutamic acid (PG) films by polylysine (PL) at different PL content (0, 2, 4 and 6%) as a microbioreactor to growth and protect Gamma-aminobutyric acid (GABA) producing bacteria. The addition of PL groups between the PG backbones was completely corroborated using FTIR analysis. Scanning electron micrographs confirmed the high changes in the microstructure of PG films by PL. Density, thickness, moisture content, L* (lightness), b*(yellowness-blueness), WI (whiteness index), opacity, and elongation at break were increased with increasing the PL content. Whereas ΔE (Total color difference) and tensile strength were decreased, simultaneously. The change of water vapor permeability and a* (redness-greenness) value of PG-PL were independent from PL content. The PG-PL films were active packaging material against food borne pathogens (i.e. Bacillus cereus and Escherichia coli). But they had not any side effects on viability of probiotic bacterium (i.e. Lactobacillus brevis G42) after drying process. It is inferable that PG-PL is a suitable candidate for the development of edible coating and film with high antimicrobial properties against food borne pathogen without any side effect on probiotic viability.

Preparation and biological characterization of plasma functionalized poly(ethylene terephthalate) antimicrobial sutures

The present investigation describes a method for the development of antimicrobial poly(ethylene terephthalate) (PET) sutures by employing plasma functionalization and immobilization of bioactive agents silver (Ag) and its combination with Aloe vera (AV). Plasma functionalized PET surface has carboxyl functionality that binds the bioactive agent and makes them antimicrobial in nature. The PET, PET-Ag, and PET-Ag-AV sutures were investigated by means of elemental analysis, mechanical properties, and surface topography study. The in-vitro release profile of Ag from the PET-Ag-AV suture exhibit an initial burst followed by sustained release over 72 h. The resulting sutures have excellent bacteriostatic and bactericidal properties against both Escherichia coli and Staphylococcus aureus. In-vivo wound healing studies were carried out over a period of 7 d on Swiss albino mice. Histopathology study was suggested the rapid healing in PET-Ag-AV suture treated wounds without any inflammatory response on the newly generated skin, as compared to other groups. Our study suggests that developed sutures shows excellent antimicrobial behavior with the improved healing process and appears to be a promising material as sutures.

Antibacterial nano biocomposite poly(ε-caprolactone) films with nano Ag-hydroxyapatite filler particles

ABSTRACTThis study describes the development of new antimicrobial nanocomposite poly(ε-caprolactone) (PCL) films by using the nanosilver coated hydroxyapatite particles. Firstly, the synthesis of hydroxyapatite (HAP) powder was performed using the chemical precipitation method. Next, the nanosilver coating of HAP powder was performed in acetone at 20°C using the poly(dimethylsiloxane) fluid as the reducing agent. Then, the nano Ag-HAP-PCL composite materials containing 30% HAP and 0.13–1.90% Ag were prepared by incorporating nano Ag-HAP powder into the poly(ε-caprolactone) (PCL) melt at 100°C. Finally, the nano Ag-HAP-PCL films were prepared by using the roll mill process. The nano Ag-HAP powder and the nanocomposite films were characterized by XRD, SEM, TEM, ICP-OES, UV-vis and FTIR analysis. The TEM analysis of the nano Ag-HAP powder showed that the size of the nanosilver particles is about 0–30 nm. The use of 0.13% nano-Ag in HAP-PCL composite films provided 100% effective antibacterial surface against Escherichia coli and Staphylococcus epidermidis. On the other hand, the use of 1.9% nano-Ag in HAP-PCL composite films provided 100% antibacterial effectiveness against Escherichia coli, Staphylococcus aureus and Staphylococcus epidermidis. The prepared antibacterial nano Ag-HAP-PCL biocomposites are promising materials for biomedical applications, implants and reconstructive orthopedic parts.

Surface enrichment and nonleaching antimicrobial performance of polypropylene grafted poly(hexamethylene guanidine) (PP-g-PHMG) in poly(ethylene terephthalate)/PP-g-PHMG

Antimicrobial poly(ethylene terephthalate) (PET) materials are highly demanding in various applications in the industry. However, the combination of large-scale preparation, cost-effective and nonleaching characteristic still remains challenges. Herein, antimicrobial PET materials were prepared by an easy-to-scale-up melting blending between neat PET and polypropylene grafted poly(hexamethylene guanidine) (PP-g-PHMG). Such PET materials exhibited excellent antimicrobial activities, such as above 98.0% and 99.9% of inhibition rates against Escherichia coli and Staphylococcus aureus, respectively. Nonleaching characteristic was confirmed by the inhibition zone test. More importantly, the antimicrobial component enriched on the surfaces of PET materials due to the difference in the compatibility between PET matrix and PP-g-PHMG and the heterogeneous repulsive effect of crystallization. This work provides a facile and easy-to-scale-up way to obtain nonleaching antimicrobial PET.

Electrospun Ribbon‐Like Microfiber Films of a Novel Guanidine‐Based ABA Triblock Copolymer: Fabrication, Antibacterial Activity, and Cytotoxicity

AbstractGuanidine‐based polymers have emerged as potential candidates for antibacterial agents and materials due to their high antibacterial property, no cytotoxicity, no bacterial resistance, and so on. A novel antimicrobial poly(methacryl guanidine hydrochloride)‐block‐polystyrene‐block‐poly(methacryl guanidine hydrochloride) (PMAGH‐b‐PS‐b‐PMAGH) is electrospun to ribbon‐like microfiber films for the first time. The electrospinning process parameters affecting structure and morphology of the ribbon‐like microfibers, including concentration, voltage, and feeding rate are systematically investigated. The mechanism inducing the formation of ribbon‐like fibers with a positively charged polymer is proposed and verified. PMAGH‐b‐PS‐b‐PMAGH microfiber films can inhibit 96% of Escherichia coli and 92% of Bacillus subtilis, and are not cytotoxic to mouse embryonic fibroblasts, but instead, provide a larger surface area for cell adherent growth.

A novel high-strength poly(ionic liquid)/PVA hydrogel dressing for antibacterial applications

Antibacterial wound dressings play an important role in wound healing and infection treatment. However, traditional antibacterial wound dressings uncontrollably release antibiotics or silver ions through passive diffusion. The overuse of antibiotics and silver ions may cause drug resistance, side effects, and argyrism, thereby hindering the healing process and creating other health hazards. To overcome these shortcomings, this paper reports an easy approach to synthesize non-releasing antimicrobial Poly(ionic liquid)/PVA hydrogel dressing with high-strength through chemical polymerization and physical cross-linking. The hydrogel dressing exhibited effective antibacterial ability against bacteria (E. coli, S. aureus and B. subtilis), fungus (C. albicans), and mold (Asp. niger, Asp. oryzae, and Rhizopus). Furthermore, in a murine model, the hydrogel dressing efficiently accelerated cutaneous wound healing. After 15 days of healing process, histological tests indicated that this hydrogel dressing can promote the reconstruction of intact epidermis faster than the control. Therefore, this Poly(ionic liquid)/PVA hydrogel has potential as an antibacterial wound-healing dressing.

Behaviours of poly(ε-caprolactone)/silver-montmorillonite nanocomposite in membrane ultrafiltration for wastewater treatment

ABSTRACTThe scope of this work consists in studying the possibility of using the long-lasting antimicrobial poly(ε-caprolactone)/silver-montmorillonite (PCL/Ag-MMT) materials which we have developed in our previous research, as new class of nanocomposite membranes, finding their application in the wastewater treatment. The surface properties of these hybrid membranes were investigated by scanning electron microscopy (SEM) analysis and contact angle measurements. The SEM results showed that the synthesized membranes exhibited homogeneous sponge microstructures. It was found that the gradual inclusion of nanoparticles (2, 3 and 5 wt. %) into PCL matrix induced a remarkable increase of the membrane thickness. Moreover, these hybrid materials exhibited an enhancement of the surface hydrophilicity attributed to the hydrophilic nature of clay incorporated. The water contact angle of the PCL membrane surface noticeably decreased after the Ag-MMT addition: dropping from 82.60° for PCL 0%Ag-MMT to 64.28° for PCL 5%Ag-MMT membrane. The antimicrobial properties of the membranes were confirmed using Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative) as the model bacteria. Quality parameters including total suspended solids (TSS), electric conductivity (EC), nitrates, chlorides, bicarbonates, heavy metals and other trace elements, were determined before and after treatment of real wastewater. A decrease of nitrates by 15.12%, a diminution of sulphates by 45.61% and a removal of 41.38%, 53.57% and61.11% for heavy metals Pb, Zn and Cd respectively indicating clearly that the ultrafiltration process using PCL/AgMMT nanocomposite membranes is an effective way to eliminate the wastewater effluents.

Preparation of antibacterial poly(lactide)/poly(butylene adipate-co-terephthalate) composite films incorporated with grapefruit seed extract

Antimicrobial poly(lactide) (PLA)/poly(butylene adipate-co-terephthalate) (PBAT) blend films incorporated with grapefruit seed extract (GSE) were prepared using a solvent casting method. Effect of GSE on the morphological, water vapor barrier, thermostability, color, optical, and antimicrobial properties of PLA/PBAT composite films was investigated. The composite films showed a yellowish tint after incorporation of GSE and exhibited a high UV-light barrier property. Incorporation of GSE increased the flexibility and tensile strength of the composite films. Films incorporated with 7 wt% of GSE exhibited potent antibacterial activity against Listeria monocytogenes, but they showed only bacteriostatic activity against Escherichia coli. The PLA/PBAT-GSE composite film with UV-light barrier and antibacterial properties has a high potential for an active food packaging application.

Development of antimicrobial active films based on poly(vinyl alcohol) containing nano-TiO2and its application inmacrobrachium rosenbergiipackaging

The antimicrobial poly(vinyl alcohol) (PVA) films incorporated with nano-TiO2 were prepared by solution blending-casting method. The effects of different nano-TiO2 addition of 0%, 0.5%, 1%, 3%, 5%, and 7% on the characterization of PVA films were studied. The tensile strength of the film incorporated with 0.5% nano-TiO2 was highest. Compared with the pure PVA film, the oxygen transmission rate, swelling ratio and water vapor uptake ratio of the films containing 0.5%–7% nano-TiO2 reduced 0.4%–0.8%, 22.82%–81.79%, and 3.59%–10.7%, respectively. The transparency reduced significantly. The thermal stability and antimicrobial activity against Staphylococcus aureus and Escherichia coli were improved. The storage study of macrobrachium rosenbergii indicated that the Shewanella spp., Pseudomonas putida and Aeromonas hydrophila could be inhibited by PVA films added with nano-TiO2 and their shelf-life was extended for 1–2 days. It was indicated that there's a good prospect for application of these PVA films in the antimicrobial food packaging. Practical applications Poly(vinyl alcohol) (PVA) is a biodegradability and nontoxicity synthetic polymer, which has been widely used in food packaging materials. This paper proved that the PVA films incorporated with nano-TiO2 showed good antimicrobial activity. For the application in macrobrachium rosenbergii packaging, it showed that the Shewanella spp., Pseudomonas putida and Aeromonas hydrophila could be inhibited by PVA films added with nano-TiO2 and their shelf-life could be extended for 1–2 days. There is a great advantage that the antimicrobial activity of the films could be motivated by UV-light irradiating before packaging process to avoid that the common active packaging films are in the excited state after prepared. This antimicrobial packaging film could be used as inner layer of the composite packaging film to improve the food quality and prolong the shelf-life of the food.

Antimicrobial poly(lactic acid)/cellulose bionanocomposite for food packaging application: A review

Abstract Conventional food packaging materials are derived from nonrenewable fossil resources and face difficulties in disposal and recycling. The development of green and ecologically balanced food packaging materials has received much attention as a prospective solution that can partially substitute for the imperishable fossil fuel-derived plastic. Polylactic acid (PLA) is known as a promising biopolymer, and the incorporation of nanocellulose can further enhance the properties of this biopolymer. The combination of PLA and nanocellulose enables the development of a sustainable eco-friendly food packaging as PLA can be obtained from agricultural resources and nanocellulose can be extracted from agricultural waste. This critical review demonstrates the current developments, and the advantages of PLA and nanocellulose for the purpose of food packaging are introduced. The nanocellulose produced from agricultural waste is summarized along with specific references to food packaging applications. In addition, the antimicrobial agents used in PLA/nanocellulose-based packaging are discussed. Overall, greener food packaging with enhanced antimicrobial properties with a suitable combination of bio-based nanocellulose is highlighted in this review.

From Antimicrobial Peptides to Antimicrobial Poly(α-amino acid)s.

Conventional small-molecule antibiotics are facing a significant challenge of the rapidly developed drug resistance of pathogens. In contrast, antimicrobial peptides (AMPs), an important component for innate host defenses, are now under intensive investigation as a promising antimicrobial agent for combating drug resistant pathogens. Most AMPs can effectively kill a broad spectrum of pathogens via physical disruption of microbial cellular membranes, which is identified to be difficult to develop resistance. However, the clinical applications of AMPs are still greatly limited by several inherent impediments, such as high cost of production, potential hemolysis or toxicity, and liability to proteinase degradation. Recently, cationic poly(α-amino acid)s with structures mimicking the AMPs are found to have excellent antimicrobial activity. These polymers, termed "antimicrobial poly(α-amino acid)s (APAAs)," have some advantages over AMPs, such as easy production and modification, prolonged antimicrobial activity, low cytotoxicity, and enhanced stability to protease degradation. Here, a brief introduction of mechanisms and affecting factors of microbial killing by AMPs is first presented, followed by a systematic illustration of recent advances in design and preparation of biomimetic APAAs and a perspective in this field.

Structural Determinants of the Stability of Enzyme-Responsive Polyion Complex Nanoparticles Targeting Pseudomonas aeruginosa's Elastase.

Here, we report how the stability of polyion complex (PIC) particles containing Pseudomonas aeruginosa’s elastase (LasB) degradable peptides and antimicrobial poly(ethylene imine) is significantly improved by careful design of the peptide component. Three LasB‐degradable peptides are reported herein, all of them carrying the LasB‐degradable sequence −GLA− and for which the number of anionic amino acids and cysteine units per peptide were systematically varied. Our results suggest that while net charge and potential to cross‐link via disulfide bond formation do not have a predictable effect on the ability of LasB to degrade these peptides, a significant effect of these two parameters on particle preparation and stability is observed. A range of techniques has been used to characterize these new materials and demonstrates that increasing the charge and cross‐linking potential of the peptides results in PIC particles with better stability in physiological conditions and upon storage. These results highlight the importance of molecular design for the preparation of PIC particles and should underpin the future development of these materials for responsive drug delivery.

Synthesis of Antimicrobial Poly(guanylurea)s

Bacterial infections are serious health threats. Emerging drug resistance in bacteria further poses serious challenges to the treatment options involving traditional antibiotics. Antimicrobial polymers disrupt the physical cell membrane integrity of bacteria to address the drug resistance problems. Here, we introduce a conceptually new class of antimicrobial polymers containing positively charged guanylurea backbones for enhanced antimicrobial effects. The initial structure-activity relationship studies demonstrate that poly(guanylurea piperazine)s (PGU-Ps) exhibit excellent antimicrobial activity against different types of bacteria with high selectivity. The new design concept of using a positively charged guanylurea backbone will contribute to the development of future biocompatible, specific, and selective antimicrobial polymers.

Telechelic, Antimicrobial Hydrophilic Polycations with Two Modes of Action

Telechelic antimicrobial poly(2-oxazoline)s with quaternary ammonium (quat) end groups are shown to be potent antimicrobial polymers against Gram-positive bacterial strains. In this study, the activity against the Gram-negative bacterium Escherichia coli is additionally implemented by hydrolyzing the poly(2-methyl-2-oxazoline) with two quart end groups to poly(ethylene imine) (PEI). The resulting telechelic polycations are active against Staphylococcus aureus and E. coli. The contribution of the PEI backbone is determined by measuring the antimicrobial activity in the presence of calcium ions. The influence of PEI on the overall activity strongly depends on the molecular weight and increases with higher mass. The PEI dominates the activity against E. coli at lower masses than against S. aureus. The quart end groups require an alkyl substituent of dodecyl or longer to dominate the antimicrobial activity. Additionally, PEI and quart end groups act synergistically.