Organic additives as antimicrobial agents in thermoplastics compounds

2016 ◽  
Vol 1817 ◽  
Author(s):  
Daiane Tomacheski ◽  
Michele Pittol ◽  
Vanda F. Ribeiro ◽  
Ruth M. C. Santana
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Antimicrobial Agents ◽  
Antimicrobial Properties ◽  
Organic Additives ◽  
Bacterial Strains ◽  
Melt Mixing ◽  
Polymeric Matrices ◽  
E Coli ◽  
Scanning Electron

ABSTRACTDevelopment of polymers with antimicrobial characteristics can avoid deterioration and assist in containing spread of pathogens harmful to human health. This study aimed to compare the antimicrobial and mechanical properties of polymeric matrices containing organic antimicrobial additives. Silver organomodified bentonite (Ag_bentonite) and organochlorine molecule in a masterbatch based polyethylene (Cl_PE) were tested in proportion of 2% in a thermoplastic elastomeric formulation. The polymeric matrices were prepared by melt mixing and evaluated in tensile and antimicrobial properties against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) strains. The additives were characterized by thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). The nanoscale of Ag_bentonite was verified by SEM. TGA assay showed that Cl_PE is more sensitive to heat than Ag_bentonite. As a result of this lower thermal stability, the addition of Cl_PE reduced the tensile properties of the compound. The sample with Cl_PE was effective against both bacterial strains, reducing the populations of S. aureus and E. coli in 99 and 96%, respectively. The addition of Ag_bentonite did not affect the tensile strength and decreased in 97 and 40% S. aureus and E. coli populations, respectively. The results indicate that the use of organic additives is promissory, but further modifications in processing must be necessary.

scholarly journals Synthesis of Hydroxyapatite-Ag Composite as Antimicrobial Agent

Dose-Response ◽  
2020 ◽  
Vol 18 (3) ◽  
pp. 155932582095134
Author(s):  
Pamela Nair Silva-Holguín ◽  
Simón Yobanny Reyes-López
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Drug Resistance ◽  
Silver Nanoparticles ◽  
Antimicrobial Agents ◽  
Sol Gel ◽  
Antimicrobial Properties ◽  
Low Concentrations ◽  
Silver Nanocomposite ◽  
Scanning Electron

Innovative and improved antimicrobial agents by nanotechnology are developed to control and mitigation of resistant microorganisms. Nanoparticles of metals or oxide metals be able to be toxic to bacteria, demonstrating biocidal behaviors at low concentrations. The integration of silver nanoparticles in ceramic matrices has enhanced the antimicrobial performance, resulting in the search for new composites with improved bactericidal properties. The aim of this study was to prepare and characterize hydroxyapatite-silver nanocomposite and evaluate its antimicrobial properties against various Gram-positive and negative bacteria related to drug-resistance infections. Hydroxyapatite nanopowders were produced by sol-gel and silver nanoparticles were synthesized by reduction of Ag+ions with the simple addition of gallic acid. Hydroxyapatite-silver composite (HAp-AgNPs) was prepared by adsorption of AgNPs at several concentrations. The results of UV–visible spectroscopy, dynamic light scattering, and transmission scanning electron microscopy revealed the existence of AgNPs with diameters around 6 nm. Scanning electron microscopy and energy dispersive X-ray spectroscopy corroborated the presence of silver disseminated over the surface of hydroxyapatite nanopowders. All HAp-AgNPs composites demonstrated excellent antibacterial effect even at lower silver concentration. HAp-AgNPs composites have a higher possibility for medical applications focused no the control of microorganisms with drug-resistance.

scholarly journals Functionalized Magnetic Nanoparticles and Their Effect onEscherichia coliandStaphylococcus aureus

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Mohamed S. A. Darwish ◽  
Nhung H. A. Nguyen ◽  
Alena Ševců ◽  
Ivan Stibor
Keyword(s):  
Electron Microscopy ◽  
Magnetite Nanoparticles ◽  
Biological Effect ◽  
Bacterial Strains ◽  
Gram Negative ◽  
E Coli ◽  
Functionalized Magnetic Nanoparticles ◽  
Nanoparticle Morphology ◽  
Average Size ◽  
Scanning Electron

Magnetite (Fe3O4) nanoparticles were prepared using coprecipitation and subsequently surface-functionalized with 3-aminopropyltriethoxysilane (APTS), polyethylene glycol (PEG), and tetraethoxysilane (TEOS). Nanoparticle morphology was characterized using scanning electron microscopy, while structure and stability were assessed through infrared spectroscopy and zeta potential, respectively. Average size of the nanoparticles analysed by dynamic light scattering was 89 nm, 123 nm, 109 nm, and 130 nm for unmodified magnetite and APTS-, PEG-, and TEOS-modified magnetite nanoparticles, respectively. Biological effect was studied on two bacterial strains: Gram-negativeEscherichia coliCCM 3954 and Gram-positiveStaphylococcus aureusCCM 3953. Most of modified magnetite nanoparticles had a significant effect onS. aureusand not onE. coli, whereas PEG-magnetite nanoparticles displayed no significant effect on the growth rate of either bacteria.

scholarly journals Surface Modification of Sodium Montmorillonite Nanoclay by Plasma Polymerization and Its Effect on the Properties of Polystyrene Nanocomposites

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Rosa Idalia Narro-Céspedes ◽  
María Guadalupe Neira-Velázquez ◽  
Luis Fernando Mora-Cortes ◽  
Ernesto Hernández-Hernández ◽  
Adali Oliva Castañeda-Facio ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Plasma Polymerization ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Melt Mixing ◽  
Sodium Montmorillonite ◽  
X Ray ◽  
Montmorillonite Nanoclay ◽  
Scanning Electron

Sodium montmorillonite nanoclay (Na+-MMT) was modified by plasma polymerization with methyl methacrylate (MMA) and styrene (St) as monomers and was denominated as Na+-MMT/MMA and Na+-MMT/St, respectively. This plasma modified nanoclay was used as reinforcement for polystyrene (PS) nanocomposites that were prepared by melt mixing. Pristine and modified Na+-MMT nanoclay were analyzed by the dispersion in various solvents, Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The results confirmed a change in hydrophilicity of the modified Na+-MMT, as well as the presence of a polymeric material over its surface. The pristine PS/Na+-MMT and modified PS/Na+-MMT/MMA and PS/Na+-MMT/St nanocomposites were studied with X-ray diffraction (XRD), differential scanning calorimetry (DSC), and TGA, as well as mechanical properties. It was found that the PS/Na+-MMT/St nanocomposites presented better thermal properties and an improvement in Young’s modulus (YM) in compared to PS/Na+-MMT/MMA nanocomposites.

scholarly journals The Synthesis and Evaluation of Aminocoumarin Peptidomimetics as Cytotoxic Agents on Model Bacterial E. coli Strains

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5725
Author(s):  
Paweł Kowalczyk ◽  
Monika Wilk ◽  
Parul Parul ◽  
Mateusz Szymczak ◽  
Karol Kramkowski ◽  
...  
Keyword(s):  
Antimicrobial Agents ◽  
Free Acid ◽  
Antimicrobial Properties ◽  
Acid Group ◽  
Ester Group ◽  
Biological Properties ◽  
Cytotoxic Agents ◽  
Coumarin Derivatives ◽  
Bacterial Strains ◽  
E Coli

This work presents the successful synthesis of a library of novel peptidomimetics via Ugi multicomponent reaction. Most of these peptidomimetics contain differently substituted aminocoumarin; 7-amino-4-methylcoumarin and 7-amino-4-(trifluoromethyl) coumarin. Inspired by the biological properties of coumarin derivatives and peptidomimetics, we proposed the synthesis of coumarin incorporated peptidomimetics. We studied the potential of synthesized compounds as antimicrobial drugs on model E. coli bacterial strains (k12 and R2–R4). To highlight the importance of coumarin in antimicrobial resistance, we also synthesized the structurally similar peptidomimetics, using benzylamine. Preliminary cellular studies suggest that the compounds with coumarin derivatives have more potential as antimicrobial agents compared to the compounds without coumarin. We also analyzed the effect of aldehyde, free acid group and ester group on the course of their antimicrobial properties.

Bioceramic Materials Show Reduced Pathological Biofilm Formation

2014 ◽  
Vol 631 ◽  
pp. 448-453 ◽  
Author(s):  
Corrado Piconi ◽  
Andrei Cristian Ionescu ◽  
Andrea Cochis ◽  
Erica Iasi ◽  
Eugenio Brambilla ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Biofilm Formation ◽  
Bacterial Biofilm ◽  
Morphological Data ◽  
Alumina Matrix ◽  
Bacterial Strains ◽  
E Coli ◽  
Viable Biomass ◽  
Alumina Matrix Composite ◽  
Scanning Electron

The aim of the present work was to assess the surface ability of three bioceramic materials (A: alumina BIOLOX®forte; B: Si3N4; C: alumina matrix composite BIOLOX®delta) to inhibit bacterial biofilm formation. For this purpose, ceramic disks at standardized roughness (Ra = 0,25 μm) were used as test materials while commercial polystyrene was considered as control. Two biofilm-producing bacterial strains (S. epidermidis ATCC14990, Escherichia coli ATCC25922) were used for experiments. The viable biomass was assessed by the metabolic MTT assay after 24h incubation. Morphological data regarding biofilms structure were obtained by scanning electron microscopy. In general, results revealed that all bioceramics materials were significantly less colonized compared to polystyrene. The degree of biofilm formation onto bioceramics ranged between about 30 to 60% less than the polystyrene control. Moreover, some differences were noticed by comparing the three bioceramics inhibition ratio: bioceramic A showed significanlty less S. epidermidis biofilm formation (p<0.005) compared to B and C that showed similar performance. Conversely, no difference were noted for E. coli biofilm amount for A, B and C. In conclusion, the tested materials showed capability to reduce biofilm formation to a different extent depending on the tested bacterial strains.

Flexible mats as promising antimicrobial systems via integration of Thymus capitatus (L.) essential oil into PLA

2020 ◽  
Vol 15 (14) ◽  
pp. 1379-1392
Author(s):  
Roberto Scaffaro ◽  
Andrea Maio ◽  
Manuela D'Arrigo ◽  
Francesco Lopresti ◽  
Andreana Marino ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Essential Oil ◽  
Antimicrobial Properties ◽  
Poly Lactic Acid ◽  
Viable Cells ◽  
Thymus Capitatus ◽  
Microbial Infections ◽  
Petri Dishes ◽  
Scanning Electron

Aim: To develop electrospun mats loaded with Thymus capitatus (L.) essential oil ( ThymEO) and to study their morpho-mechanical and antimicrobial properties. Materials & methods: Poly(lactic acid) (PLA) mats containing ThymEO were prepared by electrospinning. The effect of ThymEO on the morpho-mechanical properties of fibers was assayed by scanning electron microscopy and dynamometer measurements. The antimicrobial activity of ThymEO delivered either in liquid or vapor phase was assessed through killing curves and invert Petri dishes method. The cytotoxicity was also investigated. Results: The mechanical properties were enhanced by integrating ThymEO into PLA. Both liquid and vapors of ThymEO released from mats caused reductions of microbial viable cells. Negligible cytotoxicity was demonstrated. Conclusion: PLA/ ThymEO delivery systems could be suitable for treating microbial infections.

scholarly journals Synthesis and study on mechanical properties of the polypropylene/TiO2 - nano Ag composite for antibacterial application

2015 ◽  
Vol 18 (1) ◽  
pp. 70-80
Author(s):  
Luan Nguyen Thanh Huynh ◽  
Cuong Chi Huynh ◽  
Nhan Thuc Chi Ha ◽  
Vinh Quang Lam ◽  
Hieu Van Le
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Average Particle Size ◽  
Chemical Compositions ◽  
Average Particle ◽  
Melt Mixing ◽  
E Coli ◽  
Transmission Electron ◽  
Mixing Method ◽  
Polypropylene Matrix

In this study, PP/TiO2 – nano Ag composite were successfully prepared by melt mixing method. The composites TiO2 – nano Ag and PP/TiO2 – nano Ag with different silver content were characterized by scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Xray diffraction (XRD) and IR spectrum to investigate their morphology and chemical compositions. It was found that the silver nanoparticles in TiO2 matrix were uniformly distributed and strongly attached to the polypropylene matrix and the average particle size of TiO2 – nano Ag was from 30 to 60 nm. As the result, the antibacterial property was obtained via microorganism test by showing the elimination of more than 99 % of E. coli bacteria. And UV protection behavior was also observed by UV-Vis characterization. In the other hand, the mechanical properties of polypropyleneTiO2-nano Ag composite were noticeably improved as compared to the neat polypropylene.

Electron Microscopic Observation of the Longitudinal Organization of Poly (p-Phenylene Terephthalamide) Fibers

1982 ◽  
Vol 40 ◽  
pp. 680-681
Author(s):  
Li Li-Sheng ◽  
L.F. Allard ◽  
W.C. Bigelow
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Microscopic Observation ◽  
Electron Microscopic Observation ◽  
Electron Microscopic ◽  
Aromatic Polyamides ◽  
Radial Arrangement ◽  
Scanning Electron ◽  
Better Than

The aromatic polyamides form a class of fibers having mechanical properties which are much better than those of aliphatic polyamides. Currently, the accepted morphology of these fibers as proposed by M.G. Dobb, et al. is a radial arrangement of pleated sheets, with the plane of the pleats parallel to the axis of the fiber. We have recently obtained evidence which supports a different morphology of this type of fiber, using ultramicrotomy and ion-thinning techniques to prepare specimens for transmission and scanning electron microscopy.

SYNTHESIS, CHARACTERIZATION AND BIOLOGICAL EVALUATION OF 3-FORMYL INDOLE BASED SCHIFF BASES

2018 ◽  
Vol 7 (6) ◽  
Author(s):  
Singh Gurvinder ◽  
Singh Prabhsimran ◽  
Dhawan R. K.
Keyword(s):  
Antimicrobial Activity ◽  
Spectral Analysis ◽  
Schiff Bases ◽  
Antimicrobial Agents ◽  
Biological Evaluation ◽  
Fungal Strain ◽  
Bacterial Strains ◽  
Standard Drug ◽  
Gram Negative ◽  
E Coli

In order to develop new antimicrobial agents, a series of 3-formyl indole based Schiff bases were synthesized by reacting 3-formyl indole(indole-3-carboxaldehyde) with substituted aniline taking ethanol as solvent. The reaction was carried in the presence of small amount of p-toluene sulphonic acid as catalyst.All the synthesized compounds were characterized by IR, 1H-NMR spectral analysis. All the synthesized compounds were evaluated for antimicrobial activity against two gram positive bacterial strains (B. subtilisand S. aureus) and two gram negative bacterial strains (P. aeruginosaand E. coli) and one fungal strain (C. albicans). All the synthesized compounds were found to have moderate to good antimicrobial activity. The  standard drug amoxicillin, fluconazole were used for antimicrobial activity. Among the synthesized compounds, the maximum antimicrobial activity was shown by compounds GS04, GS07, GS08 and GS10.

Biological Evaluation of Selected 1,2,3-triazole Derivatives as Antibacterial and Antibiofilm Agents

2020 ◽  
Vol 20 (24) ◽  
pp. 2186-2191
Author(s):  
Lialyz Soares Pereira André ◽  
Renata Freire Alves Pereira ◽  
Felipe Ramos Pinheiro ◽  
Aislan Cristina Rheder Fagundes Pascoal ◽  
Vitor Francisco Ferreira ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Staphylococcus Aureus ◽  
Biofilm Formation ◽  
Antimicrobial Agents ◽  
Public Health Problem ◽  
Biological Evaluation ◽  
Major Public Health Problem ◽  
Community Environments ◽  
Scanning Electron

Background: Resistance to antimicrobial agents is a major public health problem, being Staphylococcus aureus prevalent in infections in hospital and community environments and, admittedly, related to biofilm formation in biotic and abiotic surfaces. Biofilms form a complex and structured community of microorganisms surrounded by an extracellular matrix adhering to each other and to a surface that gives them even more protection from and resistance against the action of antimicrobial agents, as well as against host defenses. Methods: Aiming to control and solve these problems, our study sought to evaluate the action of 1,2,3- triazoles against a Staphylococcus aureus isolate in planktonic and in the biofilm form, evaluating the activity of this triazole through Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) tests. We have also performed cytotoxic evaluation and Scanning Electron Microscopy (SEM) of the biofilms under the treatment of the compound. The 1,2,3-triazole DAN 49 showed bacteriostatic and bactericidal activity (MIC and MBC 128 μg/mL). In addition, its presence interfered with the biofilm formation stage (1/2 MIC, p <0.000001) and demonstrated an effect on young preformed biofilm (2 MICs, p <0.05). Results: Scanning Electron Microscopy images showed a reduction in the cell population and the appearance of deformations on the surface of some bacteria in the biofilm under treatment with the compound. Conclusion: Therefore, it was possible to conclude the promising anti-biofilm potential of 1,2,3-triazole, demonstrating the importance of the synthesis of new compounds with biological activity.

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