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Wounds display particular vulnerability to microbial invasion and infections by pathogenic bacteria. Therefore, to reduce the risk of wound infections, researchers have expended considerable energy on developing advanced therapeutic dressings, such as electrospun membranes containing antimicrobial agents. Among the most used antimicrobial agents, medicinal plant extracts demonstrate considerable potential for clinical use, due primarily to their efficacy allied to relatively low incidence of adverse side-effects. In this context, the present work aimed to develop a unique dual-layer composite material with enhanced antibacterial activity derived from a coating layer of Poly(vinyl alcohol) (PVA) and Chitosan (CS) containing Agrimonia eupatoria L. (AG). This novel material has properties that facilitate it being electrospun above a conventional cotton gauze bandage pre-treated with 2,2,6,6-tetramethylpiperidinyl-1-oxy free radical (TEMPO). The produced dual-layer composite material demonstrated features attractive in production of wound dressings, specifically, wettability, porosity, and swelling capacity. Moreover, antibacterial assays showed that AG-incorporated into PVA_CS's coating layer could effectively inhibit Staphylococcus aureus ( S. aureus ) and Pseudomonas aeruginosa ( P. aeruginosa ) growth. Equally important, the cytotoxic profile of the dual-layer material in normal human dermal fibroblast (NHDF) cells demonstrated biocompatibility. In summary, these data provide initial confidence that the TEMPO-oxidized cotton/PVA_CS dressing material containing AG extract demonstrates adequate mechanical attributes for use as a wound dressing and represents a promising approach to prevention of bacterial wound contamination.

Despite a large number of wound dressing materials in the market, an ideal dressing able to re‐establish both the features and functions of the native skin remains a challenge. Concerning this, the present study aimed to produce a new double‐layer nanofibrous dressing material. The upper layer was fabricated by using Poly(l‐lactic acid; PLLA) to act as a hydrophobic protective barrier, while the highly porous lower layer composed of a blend of Poly(ethylene) oxide (PEO) and Chitosan (CS) containing Hypericum perforatum L. (HP) was produced to be used in the wound site, reduce the risk of infection, and enhance the healing process. The produced double‐layer material exhibited the required chemical, physical, and mechanical properties. Besides, the results showed an inhibitory effect on Staphylococcus aureus and Pseudomonas aeruginosa growth without providing any cytotoxicity on normal human dermal fibroblast (NHDF) cells. Therefore, these findings emphasize the potential use of this material as an antimicrobial wound dressing to treat skin lesions. [ABSTRACT FROM AUTHOR]

In recent years, the damaging effects of antimicrobial resistance relating to wound management and infections have driven the ongoing development of composite wound dressing mats containing natural compounds, such as plant extracts and their derivatives. The present research reports the fabrication of novel electrospun Polycaprolactone (PCL)/Polyvinyl Alcohol (PVA)/Chitosan (CS) fiber mats loaded with Eugenol (EUG), an essential oil, known for its therapeutic properties. The electrospun fiber mats were prepared via electrospinning from either water-in-oil (W/O) or oil-in-water (O/W) emulsions and characterized using scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FT-IR), total porosity measurements, and water contact angle. The in vitro EUG release profile and antibacterial activity against Staphylococcus aureus and Pseudomonas aeruginosa were also evaluated. The obtained results proved that the EUG was loaded efficiently into electrospun PCL/PVA/CS fiber mats and the two W/O and O/W emulsions prepared from the PCL/PVA/CS (7 : 3 : 1) and PCL/PVA/CS (3 : 7 : 1) revealed porosity within the ideal range of 60–90%, even when EUG was loaded. The measured contact angle values showed that the O/W emulsion exhibited a more hydrophilic character and the wettability noticeably decreased after adding EUG in both emulsion blends. Furthermore, the electrospun PCL/PVA/CS fiber mats demonstrated a rapid release of EUG during the first 8 hours, which enhanced gradually afterward (up to 120 hours). Moreover, an efficient antibacterial activity against S. aureus (inhibition ratios of 92.43% and 83.08%) and P. aeruginosa (inhibition ratios of 94.68% and 87.85%) was displayed and the in vitro cytotoxic assay demonstrated that the normal human dermal fibroblasts (NHDF) remained viable for at least 7 days, after direct contact with the produced electrospun fiber mats. Therefore, such findings support the biocompatibility and suitability of using these EUG-loaded electrospun PCL/PVA/CS fiber mats as a new innovative wound dressing material with potential for preventing and treating microbial wound infections. [ABSTRACT FROM AUTHOR]

ABSTRACT The aim of this study was to investigate a method of embedding l-cysteine ( l-cys), an antimicrobial agent, between layers of chitosan (CH) and sodium alginate (ALG) onto cotton samples obtained via a layer-by-layer electrostatic deposition technique via several embedding methods. The results show that the best way to incorporate l-cys into the layers was the one that used the property of gelling ALG. To monitor the l-cys embedding into the CH/ALG multilayer film, different methods were used: energy-dispersive X-ray spectrometry analysis to assess the presence of sulfur on the sample, Ellman's reagent method to analyze l-cys release from the sample, and attenuated total reflectance (ATR) Fourier transform infrared spectroscopy (FTIR) to compare the ATR-FTIR spectra of the pure l-cys and l-cys embedded in the CH/ALG multilayer film to study the interaction between the l-cys and the CH/ALG multilayer films. Functionalized CH/ALG cotton samples were also investigated for their antibacterial properties toward Staphylococcus aureus and Klebsiella pneumonia with the Japanese Industrial Standard method JIS L 1902:2002, and the results show an enhancement of the antibacterial effect due to the presence of l-cys. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40519. [ABSTRACT FROM AUTHOR]

In recent years, there has been an increase of infectious diseases caused by different microorganisms and the development of antibiotic resistance. In this way, the search for new and efficient antibacterial materials is imperative. The main polysaccharides currently used in the biomedical and pharmaceutical domains are chitin and its derivative chitosan (CH) and alginates (ALG). In this study, a simple technique of Layer by Layer (LbL) of applying polycation CH and polyanion ALG was used to prepare CH/ALG multilayers on cotton samples via the electrostatic assembly with success. The CH/ALG cotton samples (functionalized) were investigated for their antibacterial properties towards Staphylococcus aureus and Klebsiella pneumonia using the international standard method JIS L 1902:2002. The antibacterial activity of the functionalized samples was tested in terms of bacteriostatic and bactericidal activity, and results showed that the samples exhibited a bacteriostatic effect on the two bacteria tested, as expected. In addition, samples with five layers (CH/ALG/CH/ALG/CH) were more effective in inhibiting bacterial growth. This new coating for cellulosic fibers is a new strategy and may open new avenues for the development of antimicrobial polymers with potential application in health-care field. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Nowadays, food packaging systems have shifted from a passive to an active role in which the incorporation of antimicrobial compounds into biopolymers can promote a sustainable way to reduce food spoilage and its environmental impact. Accordingly, composite materials based on oxidized-bacterial cellulose (BC) and poly(vinyl alcohol)-chitosan (PVA-CH) nanofibers were produced by needleless electrospinning and functionalized with the bacterial pigment prodigiosin (PG). Two strategies were explored, in the first approach PG was incorporated in the electrospun PVA-CH layer, and TEMPO-oxidized BC was the substrate for nanofibers deposition (BC/PVA-CH_PG composite). In the second approach, TEMPO-oxidized BC was functionalized with PG, and afterward, the PVA-CH layer was electrospun (BC_PG/PVA-CH composite). The double-layer composites obtained were characterized and the nanofibrous layers displayed smooth fibers with average diameters of 139.63 ± 65.52 nm and 140.17 ± 57.04 nm, with and without pigment incorporation, respectively. FTIR-ATR analysis confirmed BC oxidation and revealed increased intensity at specific wavelengths, after pigment incorporation. Moreover, the moderate hydrophilic behavior, as well as the high porosity exhibited by each layer, remained mostly unaffected after PG incorporation. The composites' mechanical performance and the water vapor transmission rate (WVTR) evaluation indicated the suitability of the materials for certain food packaging solutions, especially for fresh products. Additionally, the red color provided by the bacterial pigment PG on the external surface of a food packaging material is also a desirable effect, to attract the consumers' attention, creating a multifunctional material. Furthermore, the antimicrobial activity was evaluated and, PVA-CH_PG, and BC_PG layers exhibited the highest antimicrobial activity against Staphylococcus aureus and Pseudomonas aeruginosa. Thus, the fabricated composites can be considered for application in active food packaging, owing to PG antimicrobial potential, to prevent foodborne pathogens (with PG incorporated into the inner layer of the food packaging material, BC/PVA-CH_PG composite), but also to prevent external contamination, by tackling the exterior of food packaging materials (with PG added to the outer layer, BC_PG/PVA-CH composite). [ABSTRACT FROM AUTHOR]

Wounds display particular vulnerability to microbial invasion and infections by pathogenic bacteria. Therefore, to reduce the risk of wound infections, researchers have expended considerable energy on developing advanced therapeutic dressings, such as electrospun membranes containing antimicrobial agents. Among the most used antimicrobial agents, medicinal plant extracts demonstrate considerable potential for clinical use, due primarily to their efficacy allied to relatively low incidence of adverse side-effects. In this context, the present work aimed to develop a unique dual-layer composite material with enhanced antibacterial activity derived from a coating layer of Poly(vinyl alcohol) (PVA) and Chitosan (CS) containing Agrimonia eupatoria L. (AG). This novel material has properties that facilitate it being electrospun above a conventional cotton gauze bandage pre-treated with 2,2,6,6-tetramethylpiperidinyl-1-oxy free radical (TEMPO). The produced dual-layer composite material demonstrated features attractive in production of wound dressings, specifically, wettability, porosity, and swelling capacity. Moreover, antibacterial assays showed that AG-incorporated into PVA_CS's coating layer could effectively inhibit Staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa (P. aeruginosa) growth. Equally important, the cytotoxic profile of the dual-layer material in normal human dermal fibroblast (NHDF) cells demonstrated biocompatibility. In summary, these data provide initial confidence that the TEMPO-oxidized cotton/PVA_CS dressing material containing AG extract demonstrates adequate mechanical attributes for use as a wound dressing and represents a promising approach to prevention of bacterial wound contamination. [ABSTRACT FROM AUTHOR]