Electrospun polyvinyl alcohol/cinnamon essential oil/β-cyclodextrin (PVA/CEO/β-CD) antimicrobial nanofibrous film with average diameter 240 ± 40 nm was successfully fabricated under the optimal ...conditions. The data of attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) and thermogravimetric analysis (TGA) indicated that CEO was encapsulated into β-CD cavity and there existed molecular interaction among PVA, CEO and β-CD, which enhanced the thermal stability of CEO. Water contact angle analysis showed that addition of CEO/β-CD made the nanofibrous film more hydrophilic. The PVA/CEO/β-CD nanofibrous film exhibited excellent antimicrobial activity, and its minimum inhibitory concentration (MIC) against Staphylococcus aureus and Escherichia coli was approximate 0.9–1 mg/mL (corresponding CEO concentration 8.9–9.9 μg/mL) and minimum bactericidal concentration (MBC) was approximate 7–8 mg/mL (corresponding CEO concentration 69.3–79.2 μg/mL). Furthermore, the mild electrospinning process was favorable for maintaining greater CEO in the film resulting in an improved antimicrobial activity compared with that of casting film. In addition, the PVA/CEO/β-CD nanofibrous film can effectively prolong the shelf-life of strawberry, indicating it is potential for the application in active food packaging.
•The electrospun PVA/CEO/β-CD nanofibrous film was successfully fabricated.•Electrospinning is favorable for keeping CEO in nanofilm compared with casting method.•PVA/CEO/β-CD nanofilm has strong antimicrobial activity against E. coli and S. aueus.•PVA/CEO/β-CD nanofilm can effectively prolong the shelf-life of strawberry.
As demand on the safety and quality of the product in food packaging is increased, nanocellulose based transparent paper with resistance against microbial activity becomes more important. In this ...study, transparent cellulose film was prepared from ginger nanofiber with chemicals and ultrasonication. After purification using acid hydrolysis, ginger fiber had high cellulose content (88%). Ultrasonication of the suspension of the chemically treated fibers for 1 h decreased their diameter to 54.3 nm. Drying of the nano-sized fiber suspension resulted in a transparent film with 5 μm thickness. This film transmitted 83.3% of the light at 650 nm and showed antimicrobial activity. It had high thermal stability with the maximum decomposition temperature peak at 353 °C. This was 17% higher than that of raw ginger fiber (302 °C). The transparent film had a crystallinity index of 48%, and lower moisture resistance than film from chemically treated cellulose fiber. This study promoted transparent nanocellulose film with good antimicrobial properties from abundant and available ginger fibers.
Drying of the nano-sized fiber suspension resulted in an optically transparent film showing antimicrobial activity. Display omitted
•Ginger nanofibers were prepared with chemical treatment and ultrasonication.•Drying of the nano-sized fiber suspension resulted in an optically transparent film.•This transparent film had high thermal stability and showed antimicrobial activity.
Edible coatings and films (ECF) are employed as matrixes for incorporating antimicrobial nanoparticles (NPs), and then they are applied on the fruits and vegetables to prolong shelf life and enhance ...storage quality. This paper provides a comprehensive review on the preparation, antimicrobial properties and mechanisms, surface and physical qualities of ECF containing antimicrobial NPs, and its efficient application to vegetables and fruits as well. Following an introduction on the properties of the main edible coating materials, the preparation technologies of ECF with NPs are summarized. The antimicrobial activity of ECF with NPs against the tested microorganism was observed by many researchers. This might be mainly due to the electrostatic interaction between the cationic polymer or free metal ions and the charged cell membrane, the photocatalytic reaction of NPs, the detachment of free metal ion, and partly due to the antimicrobial activity of edible materials. Moreover, their physical, mechanical and releasing properties are discussed in detail, which might be influenced by the concentration of NPs. The preservation potential on the quality of fruits and vegetables indicates that various ECF with NPs might be used as the ideal materials for food application. Following the introduction on these characteristics, an attempt is made to predict future trends in this field.
Recent data suggest that NETosis plays a crucial role in the innate immune response and disturbs the homeostasis of the immune system. NETosis is a form of neutrophil-specific cell death ...characterized by the release of large web-like structures referred to as neutrophil extracellular traps (NETs). NETs are composed of DNA strands associated with histones and decorated with about 20 different proteins, including neutrophil elastase, myeloperoxidase, cathepsin G, proteinase 3, high mobility group protein B1, and LL37. Reportedly, NETosis can be induced by several microbes, and particulate matter including sterile stimuli, via distinct cellular mechanisms. Meanwhile, suicidal NETosis and vital NETosis are controversial. As we enter the second decade of research on NETosis, we have partly understood NETs as double-edged swords of innate immunity. In this review, we will discuss the mechanisms of NETosis, its antimicrobial action, and role in autoimmune diseases, as well as the relatively new field of NET-associated mitochondrial DNA.
Currently, the emergence and ongoing dissemination of antimicrobial resistance among bacteria are critical health and economic issue, leading to increased rates of morbidity and mortality related to ...bacterial infections. Research and development for new antimicrobial agents is currently needed to overcome this problem. Among the different approaches studied, bacteriocins seem to be a promising possibility. These molecules are peptides naturally synthesized by ribosomes, produced by both Gram-positive bacteria (GPB) and Gram-negative bacteria (GNB), which will allow these bacteriocin producers to survive in highly competitive polymicrobial environment. Bacteriocins exhibit antimicrobial activity with variable spectrum depending on the peptide, which may target several bacteria. Already used in some areas such as agro-food, bacteriocins may be considered as interesting candidates for further development as antimicrobial agents used in health contexts, particularly considering the issue of antimicrobial resistance. The aim of this review is to present an updated global report on the biology of bacteriocins produced by GPB and GNB, as well as their antibacterial activity against relevant bacterial pathogens, and especially against multidrug-resistant bacteria.
Neutrophils are immune cells with unusual biological features that furnish potent antimicrobial properties. These cells phagocytose and subsequently kill prokaryotic and eukaryotic organisms very ...efficiently. Importantly, it is not only their ability to attack microbes within a constrained intracellular compartment that endows neutrophils with antimicrobial function. They can unleash their effectors into the extracellular space, where, even post-mortem, their killing machinery can endure and remain functional. The antimicrobial activity of neutrophils must not be misconstrued as being microbe specific and should be viewed more generally as biotoxic. Outside of fighting infections, neutrophils can harness their noxious machinery in other contexts, like cancer. Inappropriate or dysregulated neutrophil activation damages the host and contributes to autoimmune and inflammatory disease. Here we review a number of topics related to neutrophil biology based on contemporary findings.
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Neutrophils kill microbes and communicate with other cells to orchestrate immune responses. Besides fighting infections, neutrophils are relevant in other contexts, like cancer, and, when dysregulated, contribute to autoimmune and inflammatory diseases. Burn et al. review recent findings and provide insight into the roles of these cells in immunity.
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•A novel strategy was described to fabricate bimetallic-ZIF@silicate derived Co/NC@mSiO2 hollow sphere.•Co/NC@mSiO2 exhibited an excellent performance toward PMS activation with low ...cobalt leaching.•Both radical and non-radical based mechanisms were efficacious for CFL degradation.•Antibiotic degradation route and catalytic mechanism predicted.
Bimetallic-ZIF@silicate derived Co/NC@mSiO2 hollow sphere was developed as an excellent peroxymonosulfate (PMS) activator for ciprofloxacin (CFL) antibiotic and parabens degradation. First, bimetallic Zn-Co/ZIF frameworks were prepared by a solvothermal method and then coated with a silica layer. Subsequently, Zn-Co/ZIF@mSiO2 was carbonized under nitrogen gas to obtain the Co, N co-doped porous carbon material. The evaporation of zinc metal in Zn-Co/ZIF@mSiO2 by inert gas flow played an important role in the formation of porous carbon material. In the presence of a small quantity of PMS, this hollow sphere material acts as a highly efficient catalyst for the degradation of CFL with a rate constant of 0.07 min−1. The findings obtained from the quenching radical test and electron paramagnetic resonance (EPR) reveal that Co site within the hollow sphere nanoreactor catalyzed PMS to the generation of the HO, SO4−, and 1O2 for CFL degradation. Notably, the presence of Co NPs in the hollow sphere material enables the facile separation of the catalyst from the reaction mixtures using an external magnet. Furthermore, the as-prepared catalysts exhibited antibacterial activity in Staphylococcus aureus (S. aureus). The current study provides new horizons to develop ZIF-derived hybrid hollow materials in eliminating organic pollutants.
In the present study, zinc oxide nanoparticles (ZnO NPs) were synthesized using leaf extract of
(
) under different physical parameters. Biosynthesis of ZnO NPs was confirmed by UV-Visible ...spectrophotometer and further, characterized by X-Ray Diffraction (XRD), Fourier Transform Infrared spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Energy-Dispersive X-ray spectroscopy (EDX), Atomic Force Microscopy (AFM), Photoluminescence study and Dynamic Light Scattering (DLS). We have also confirmed that several physical parameters such as pH, temperature, concentration of metal ions and reaction time were able to regulate shape and size of synthesized ZnO NPs. XRD and TEM analysis provided the information about the average size and hexagonal morphology of ZnO NPs. FTIR spectra analysis suggested that phenolic compounds played crucial role in the biosynthesis of ZnO NPs. The significant antibacterial activity of ZnO NPs was observed against
MTCC 9760 (
),
MTCC 1926 (
),
MTCC 430 (
),
MTCC 424
,
MTCC 3310
and
MTCC 40 (
). The synthesized ZnO NPs have shown antibacterial efficacy against both Gram-positive and Gram-negative pathogens. Synergistic effects of ZnO NPs and streptomycin showed increased efficacy as indicated by the increased zone of clearance in comparison to their individual effects (either ZnO NPs or streptomycin). Overall, the results elucidated a rapid, cost-effective, environmentally friendly and convenient method for ZnO NPs synthesis, which could be used as a potential antimicrobial agent against drug resistant microbes.
The Cover Feature shows the stepwise synthesis of oligomeric phosphoramidates. A series of compounds having P–N, N–P‐N, P–N–P and P–N–P–N–P linkages were prepared via salt elimination and lithiation ...strategies and characterized using various spectroscopic techniques. These are postulated to be biocompatible, hydrolytically degradable at low pH and flame retardant – useful properties for many applications. A selection of the P–N compounds were screened for antimicrobial activity at various concentrations. The authors acknowledge Blake Laing‐Smith for this creative artwork. More information can be found in the Full Paper by E. M. Leitao et al.
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