scholarly journals Effect of Cellulose Microfiber Silylation Procedures on the Properties and Antibacterial Activity of Polydimethylsiloxane

Coatings ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 567
Author(s):  
Virginija Jankauskaitė ◽  
Aistė Balčiūnaitienė ◽  
Radostina Alexandrova ◽  
Nijolė Buškuvienė ◽  
Kristina Žukienė
Keyword(s):  
Mechanical Properties ◽  
Vapor Phase ◽  
Chemical Reduction ◽  
Antibacterial Properties ◽  
Crosslinking Density ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Cellulose Microfibers ◽  
Microscopy Techniques

In this study, the liquid phase and vapor phase procedures for silylating cellulose microfibers by hexamethyldisilazane (HMDS) were compared in terms of efficiency. The influence of functionalization degree on the morphology of microfibers and their interaction with polydimethylsiloxane (PDMS) matrix has been investigated. The antibacterial properties of silylated cellulose microfibers hybridized with Ag nanoparticles, obtained by in situ chemical reduction, were also studied. Sample morphology investigations were carried out using spectroscopy and microscopy techniques (FTIR, XPS, TEM, SEM, EDS, XPS). Trimethylsilyl moieties appear on the surface of the cellulose microfibers after modification and improve the dispersibility of the microfibers, allowing strong interaction with the PDMS matrix and favoring its crosslinking density. Microfibers functionalized by the vapor phase of HMDS show smoother surfaces with higher concentrations of Si-containing groups, resulting in a more hydrophobic wetting behavior and a greater influence on the mechanical properties of the polymer. The silylated cellulose microfiber–Ag nanohybrid shows stronger antimicrobial activity towards Gram-positive and Gram-negative bacteria strains compared to that of the untreated hybrid. A PDMS composite loaded with this hybrid exhibits the ability to inhibit bacterial growth.

scholarly journals Rational Design of Ag/ZnO Hybrid Nanoparticles on Sericin/Agarose Composite Film for Enhanced Antimicrobial Applications

2020 ◽  
Vol 22 (1) ◽  
pp. 105
Author(s):  
Wanting Li ◽  
Zixuan Huang ◽  
Rui Cai ◽  
Wan Yang ◽  
Huawei He ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Antimicrobial Activity ◽  
Composite Film ◽  
Water Absorption ◽  
Rational Design ◽  
Hybrid Nanoparticles ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
X Ray

Silver-based hybrid nanomaterials are receiving increasing attention as potential alternatives for traditional antimicrobial agents. Here, we proposed a simple and eco-friendly strategy to efficiently assemble zinc oxide nanoparticles (ZnO) and silver nanoparticles (AgNPs) on sericin-agarose composite film to impart superior antimicrobial activity. Based on a layer-by-layer self-assembly strategy, AgNPs and ZnO were immobilized on sericin-agarose films using the adhesion property of polydopamine. Scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray powder diffraction spectroscopy were used to show the morphology of AgNPs and ZnO on the surface of the composite film and analyze the composition and structure of AgNPs and ZnO, respectively. Water contact angle, swelling ratio, and mechanical property were determined to characterize the hydrophilicity, water absorption ability, and mechanical properties of the composite films. In addition, the antibacterial activity of the composite film was evaluated against Gram-positive and Gram-negative bacteria. The results showed that the composite film not only has desirable hydrophilicity, high water absorption ability, and favorable mechanical properties but also exhibits excellent antimicrobial activity against both Gram-positive and Gram-negative bacteria. It has shown great potential as a novel antimicrobial biomaterial for wound dressing, artificial skin, and tissue engineering.

scholarly journals In situ identification of Gram-negative bacteria in human lungs using a topical fluorescent peptide targeting lipid A

2018 ◽  
Vol 10 (464) ◽  
pp. eaal0033 ◽  
Author(s):  
Ahsan R. Akram ◽  
Sunay V. Chankeshwara ◽  
Emma Scholefield ◽  
Tashfeen Aslam ◽  
Neil McDonald ◽  
...  
Keyword(s):  
Lipid A ◽  
Respiratory Infections ◽  
Bacterial Species ◽  
Water Soluble ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Human Lungs ◽  
Fluorescent Peptide ◽  
Bacterial Lipid

Respiratory infections in mechanically ventilated patients caused by Gram-negative bacteria are a major cause of morbidity. Rapid and unequivocal determination of the presence, localization, and abundance of bacteria is critical for positive resolution of the infections and could be used for patient stratification and for monitoring treatment efficacy. Here, we developed an in situ approach to visualize Gram-negative bacterial species and cellular infiltrates in distal human lungs in real time. We used optical endomicroscopy to visualize a water-soluble optical imaging probe based on the antimicrobial peptide polymyxin conjugated to an environmentally sensitive fluorophore. The probe was chemically stable and nontoxic and, after in-human intrapulmonary microdosing, enabled the specific detection of Gram-negative bacteria in distal human airways and alveoli within minutes. The results suggest that pulmonary molecular imaging using a topically administered fluorescent probe targeting bacterial lipid A is safe and practical, enabling rapid in situ identification of Gram-negative bacteria in humans.

scholarly journals Bactericidal Silver Nanoparticles by Atmospheric Pressure Solution Plasma Processing

Nanomaterials ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 874 ◽  
Author(s):  
Janith Weerasinghe ◽  
Wenshao Li ◽  
Rusen Zhou ◽  
Renwu Zhou ◽  
Alexander Gissibl ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Atmospheric Pressure ◽  
Chemical Reduction ◽  
Cost Effective ◽  
Pressure Solution ◽  
Gram Negative Bacteria ◽  
Promising Alternative ◽  
Gram Negative ◽  
Transmission Electron ◽  
Solution Plasma Processing

Silver nanoparticles have applications in plasmonics, medicine, catalysis and electronics. We report a simple, cost-effective, facile and reproducible technique to synthesise silver nanoparticles via plasma-induced non-equilibrium liquid chemistry with the absence of a chemical reducing agent. Silver nanoparticles with tuneable sizes from 5.4 to 17.8 nm are synthesised and characterised using Transmission Electron Microscopy (TEM) and other analytic techniques. A mechanism for silver nanoparticle formation is also proposed. The antibacterial activity of the silver nanoparticles was investigated with gram-positive and gram-negative bacteria. The inhibition of both bacteria types was observed. This is a promising alternative method for the instant synthesis of silver nanoparticles, instead of the conventional chemical reduction route, for numerous applications.

scholarly journals Antimicrobial Polymeric Materials; Cellulose and m-Aramid Composite Fibers

2007 ◽  
Vol 2 (4) ◽  
pp. 155892500700200 ◽  
Author(s):  
Jaewoong Lee ◽  
R. M. Broughton ◽  
S. D. Worley ◽  
T. S. Huang
Keyword(s):  
Mechanical Properties ◽  
Antimicrobial Activity ◽  
Polymeric Materials ◽  
Composite Fiber ◽  
Wet Spinning ◽  
Gram Negative Bacteria ◽  
Composite Fibers ◽  
Aramid Fibers ◽  
Gram Negative ◽  
Chlorine Bleach

Cellulose and m-aramid were dissolved in an ionic liquid, and dry-jet wet spinning was employed to prepare composite fibers which could be rendered antimicrobial through exposure to chlorine bleach. The small domains of the m-aramid allowed a much higher accessibility and degree of chlorination than has been reported even for 100% m-aramid fibers. The mechanical properties including denier, tenacity, and strain at break were evaluated. The chlorinated composite fiber inactivated both Gram-positive and Gram-negative bacteria. The antimicrobial activity was retained after repeated washing and recharging.

scholarly journals Antimicrobial effect of essential oils of some Fijian medicinal plant leaves on pathogenic bacteria

2016 ◽  
Vol 34 (2) ◽  
pp. 35
Author(s):  
Prayna P. P. Maharaj ◽  
Riteshma Devi ◽  
Surendra Prasad
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antimicrobial Agent ◽  
Essential Oils ◽  
Pathogenic Bacteria ◽  
Antibacterial Properties ◽  
Antimicrobial Activities ◽  
Diffusion Method ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative

Fiji is highly populated with plants containing essential oils (EO). The essential oils extracted from the leaves of the selected Fijian leafy plants were screened against two Gram-negative bacteria (Salmonella typhimurium, Pseudomonas aeruginosa) and three Gram-positive bacteria (Staphylococcus aureus, Enterococcus faecalis and Bacillus subtilis). The agar diffusion method was used to examine the antimicrobial activities of the extracted EO. All the EO tested showed antibacterial properties against one or more strains while none of the EO was active against Pseudomonas aeruginosa. Viburnum lantana (Wayfaring tree), Annona muricata (Soursop), Coleus amboinicus (Spanish thyme) and Cinnamomum zeylancium (Cinnamon) showed good inhibition against both Gram-positive and Gram-negative bacteria and proved as worthy source of antimicrobial agent. These findings will help the Pacific population to use the studied plants leaves as antimicrobial agent.

scholarly journals Physicochemical and Antibacterial Properties of Chitosan Extracted from Waste Shrimp Shells

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
José Carlos Vilar Junior ◽  
Daylin Rubio Ribeaux ◽  
Carlos Alberto Alves da Silva ◽  
Galba Maria De Campos-Takaki
Keyword(s):  
Antibacterial Activity ◽  
Antibacterial Properties ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Degree Of Deacetylation ◽  
Shrimp Shells ◽  
Shrimp Shell ◽  
Ft Ir ◽  
High Degree

This research aims to study the production of chitosan from shrimp shell (Litopenaeus vannamei) of waste origin using two chemical methodologies involving demineralization, deproteinization, and the degree of deacetylation. The evaluation of the quality of chitosan from waste shrimp shells includes parameters for the yield, physical chemistry characteristics by infrared spectroscopy (FT-IR), the degree of deacetylation, and antibacterial activity. The results showed (by Method 1) extraction yields for chitin of 33% and for chitosan of 49% and a 76% degree of deacetylation. Chitosan obtained by Method 2 was more efficient: chitin (36%) and chitosan (63%), with a high degree of deacetylation (81.7%). The antibacterial activity was tested against Gram-negative bacteria (Stenotrophomonas maltophiliaandEnterobacter cloacae) and Gram-positiveBacillus subtilisand the Minimum Inhibitory Concentrations (MIC) and the Minimum Bactericidal Concentration (MBC) were determined. Method 2 showed that extracted chitosan has good antimicrobial potential against Gram-positive and Gram-negative bacteria and that the process is viable.

Antibacterial properties and cytocompatibility of bio-based nanostructured carbon aerogels derived from silver nanoparticles deposited onto bacterial cellulose

RSC Advances ◽  
2015 ◽  
Vol 5 (118) ◽  
pp. 97467-97476 ◽  
Author(s):  
Ning Yan ◽  
Yabin Zhou ◽  
Yudong Zheng ◽  
Shuang Qiao ◽  
Qun Yu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Silver Nanoparticles ◽  
Controlled Release ◽  
Bacterial Cellulose ◽  
Antibacterial Properties ◽  
Carbon Aerogels ◽  
Nanostructured Carbon

p-BC/AgNP carbon aerogels with excellent reabsorption capacities and mechanical properties were prepared by in situ reduction and carbonization. The aerogels had better antibacterial behavior and biocompatibility due to their slow controlled release of silver.

Gram-Negative and Gram-Positive Antibacterial Properties of the Whole Plant Extract of Willow Herb (Epilobium angustifolium)

2011 ◽  
Vol 14 (1) ◽  
pp. 85-89 ◽  
Author(s):  
Wally J. Bartfay ◽  
Emma Bartfay ◽  
Julia Green Johnson
Keyword(s):  
Plant Extract ◽  
Micrococcus Luteus ◽  
Antibacterial Properties ◽  
Health Concern ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Whole Plant ◽  
Epilobium Angustifolium ◽  
Herb Extract

The emergence of new pathogens and the increase in the number of multidrug-resistant strains in well-established pathogens during the past decade represent a growing public health concern globally. With the current lack of research and development of new antibiotics by large pharmaceutical companies due to poor financial returns, new alternatives need to be explored including natural herbal or plant-based extracts with reported antibacterial properties. Willow herb ( Epilobium angustifolium) preparations have been used in traditional aboriginal and folk medicine preparations externally as an antiphlogistic to treat prostate and gastrointestinal disorders and as an antiseptic to treat infected wounds. The authors hypothesized that a whole plant extract of willow herb would exhibit antimicrobial properties on a variety of both Gram-positive and gram-negative bacteria in culture. The authors found that, in comparison to growth controls, willow herb extract significantly inhibited the growth of Micrococcus luteus ( p < .01), Staphylococcus aureus ( p < .05), Escherichia coli ( p < .001), and Pseudomonas aeruginosa ( p < .001). They also found that willow herb extract inhibited the growth of bacteria in culture more effectively than vancomycin ( p < .05) or tetracycline ( p < .004). These results provide preliminary support for the traditional folkloric claim that the plant willow herb possesses antibacterial properties against a variety of gram-positive and gram-negative bacteria. Given that whole plant extract was utilized for this study, further investigations are warranted to determine which specific part of the plant (i.e., leaves, stem, roots, and flowers) possess the antibacterial properties.

scholarly journals Improving Antibacterial and Anti-biofilmic properties of urological catheters with Eucalyptus, Rosemary, Green tea and Ziziphora extracts by impregnation method

2021 ◽  
Author(s):  
Najme Akhlaghi-Ardekani ◽  
Davod Mohebbi-Kalhori ◽  
Abdolreza samimi ◽  
Reza Karazhyan
Keyword(s):  
Green Tea ◽  
Biofilm Formation ◽  
Antibacterial Agents ◽  
Antibacterial Properties ◽  
Polymer Materials ◽  
Gram Negative Bacteria ◽  
Impregnation Method ◽  
Herbal Extracts ◽  
Urinary Catheters ◽  
Gram Negative

Abstract The main complications of urinary catheters are the bacteria's biofilm formation and the urinary tract infection caused by gram-positive and gram-negative bacteria. In the recent years, the attention has changed its direction toward the antimicrobial, anti-biofilmic, and hydrophobicity effects of herbal extracts. Some of these extracts can inhibit the colonization of the two bacteria Staphylococcus aureus and Escherichia coli which are resistant to antibiotics. These bacteria can stick to the surface of polymer materials due to their hydrophobicity. Thus, antibacterial hydrophilic herbal extracts are supposed to help reduce the risk of the surficial infection if they are used to impregnate the urinary catheters. In this research, the extracts of these four plants eucalyptus, rosemary, green tea and ziziphora were used as the antibacterial agents. After the impregnation and modification of the sample catheters, they were tested by AFM, FE-SEM, ATR-FTIR methods to measure their mechanical, chemical, and hydrophilic properties, during the 21-day experiment period, compared to non-impregnated ones. The tests showed the silicone catheters impregnated by the herbal extracts have some significant anti-biofilmic and antibacterial properties (P˂0.0001) due to the increase in their hydrophilic property. The impregnated catheters could be release the extracts and killed bacteria in 21 days Therefore; some herbal extracts can be good alternatives to chemical drugs.

scholarly journals Asymmetric one-pot synthesis of cyclopropanes

2016 ◽  
Vol 35 (1) ◽  
pp. 45
Author(s):  
Naoufel Ben Hamadi ◽  
Ahlem Guesmi ◽  
Wided Nouira
Keyword(s):  
Escherichia Coli ◽  
Water Soluble ◽  
Gram Negative Bacteria ◽  
Protecting Group ◽  
Gram Positive ◽  
One Pot ◽  
Gram Negative ◽  
Activity Screening ◽  
High Yields

Cycloaddition of the diazoalkanes to electron-deficient olefins (in situ) affords polysubstituted cyclopropanes in high yields (up to 85%). Deprotection of the ketal protecting group provided water-soluble cyclopropane-bearing carbohydrate in good yields. Antimicrobial activity screening of the synthesized compounds 8 and 9, utilizing a variety of Gram-positive (Staphylococcus aureus and Enterococcus fecalis), Gram-negative bacteria (Escherichia coli and Klebsiella pneumoniae) and yeast (Candida albicans), exhibited that all the prepared analogues acquire promising activities against both Gram-positive and Gram-negative bacteria especially compounds 9b and 9c (antimicrobial active agents against Gram-negative bacteria).

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