scholarly journals Surface Characterization and Anti-Biofilm Effectiveness of Hybrid Films of Polyurethane Functionalized with Saponite and Phloxine B

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7583
Author(s):  
Nitin Chandra Teja Dadi ◽  
Juraj Bujdák ◽  
Veronika Medvecká ◽  
Helena Pálková ◽  
Martin Barlog ◽  
...  
Keyword(s):  
Composite Materials ◽  
Surface Characterization ◽  
Cell Damage ◽  
Control Sample ◽  
Visible Region ◽  
Antimicrobial Properties ◽  
Layered Silicate ◽  
Composite Membranes ◽  
Biofilm Growth ◽  
Optimal Material

The main objective of this work was to synthesize composites of polyurethane (PU) with organoclays (OC) exhibiting antimicrobial properties. Layered silicate (saponite) was modified with octadecyltrimethylammonium cations (ODTMA) and functionalized with phloxine B (PhB) and used as a filler in the composites. A unique property of composite materials is the increased concentration of modifier particles on the surface of the composite membranes. Materials of different compositions were tested and investigated using physico-chemical methods, such as infrared spectroscopy, X-ray diffraction, contact angle measurements, absorption, and fluorescence spectroscopy in the visible region. The composition of an optimal material was as follows: nODTMA/mSap = 0.8 mmol g−1 and nPhB/mSap = 0.1 mmol g−1. Only about 1.5% of present PhB was released in a cultivation medium for bacteria within 24 h, which proved good stability of the composite. Anti-biofilm properties of the composite membranes were proven in experiments with resistant Staphylococcus aureus. The composites without PhB reduced the biofilm growth 100-fold compared to the control sample (non-modified PU). The composite containing PhB in combination with the photodynamic inactivation (PDI) reduced cell growth by about 10,000-fold, thus proving the significant photosensitizing effect of the membranes. Cell damage was confirmed by scanning electron microscopy. A new method of the synthesis of composite materials presented in this work opens up new possibilities for targeted modification of polymers by focusing on their surfaces. Such composite materials retain the properties of the unmodified polymer inside the matrix and only the surface of the material is changed. Although these unique materials presented in this work are based on PU, the method of surface modification can also be applied to other polymers. Such modified polymers could be useful for various applications in which special surface properties are required, for example, for materials used in medical practice.

scholarly journals Physico-Chemical Characterization and Antimicrobial Properties of Hybrid Film Based on Saponite and Phloxine B

Molecules ◽  
2021 ◽  
Vol 26 (2) ◽  
pp. 325
Author(s):  
Nitin Chandra teja Dadi ◽  
Matúš Dohál ◽  
Veronika Medvecká ◽  
Juraj Bujdák ◽  
Kamila Koči ◽  
...  
Keyword(s):  
Hybrid Film ◽  
Antimicrobial Properties ◽  
Chemical Characterization ◽  
Layered Silicate ◽  
Contact Angles ◽  
Exchange Capacity ◽  
Resistant Bacteria ◽  
Hybrid Films ◽  
Water Contact ◽  
Physico Chemical

This research was aimed at the preparation of a hybrid film based on a layered silicate saponite (Sap) with the immobilized photosensitizer phloxine B (PhB). Sap was selected because of its high cation exchange capacity, ability to exfoliate into nanolayers, and to modify different surfaces. The X-ray diffraction of the films confirmed the intercalation of both the surfactant and PhB molecules in the Sap film. The photosensitizer retained its photoactivity in the hybrid films, as shown by fluorescence spectra measurements. The water contact angles and the measurement of surface free energy demonstrated the hydrophilic nature of the hybrid films. Antimicrobial effectiveness, assessed by the photodynamic inactivation on hybrid films, was tested against a standard strain and against methicillin-resistant bacteria of Staphylococcus aureus (MRSA). One group of samples was irradiated (green LED light; 2.5 h) and compared to nonirradiated ones. S. aureus strains manifested a reduction in growth from 1-log10 to over 3-log10 compared to the control samples with Sap only, and defects in S. aureus cells were proven by scanning electron microscopy. The results proved the optimal photo-physical properties and anti-MRSA potential of this newly designed hybrid system that reflects recent progress in the modification of surfaces for various medical applications.

scholarly journals Conformational Changes in Wheat Gluten After using Ag-nanoparticles

2014 ◽  
Vol 28 (3) ◽  
pp. 311-317 ◽  
Author(s):  
Agnieszka Nawrocka
Keyword(s):  
Aqueous Solution ◽  
Silver Nanoparticles ◽  
Secondary Structure ◽  
Conformational Changes ◽  
Fungal Infections ◽  
Wheat Gluten ◽  
Control Sample ◽  
Antimicrobial Properties ◽  
Protective Layer ◽  
Trisodium Citrate

Abstract Silver nanoparticles have antimicrobial properties since they can be regarded as an efficient protector against pathogenic microorganisms. Fourier transform infrared spectroscopy was used to examine conformational changes in the secondary structure of wheat gluten washed out from grain treated with an aqueous solution of silver nanoparticles stabilized by tri-sodium citrate. Silver nanoparticles were used as a protective layer on the grain surface against bacterial and fungal infections (antimicrobial agent). Analysis of the amide I band revealed significant changes in the secondary structure after using silver nanoparticles. An increase in the β-sheet content (from 36.2 to 39.2%) was observed at the expense of the α-helix and β-turn content. To find factors causing these changes, the wheat grains were treated by an aqueous solution of trisodium citrate and water. The results obtained indicate that the changes in the gluten structure were connected mainly with the trisodium citrate action due to presence of a small number of free molecules of the stabilizer in the solution of silver nanoparticles. Additionally, the conformational changes in gluten pointed out that gluten flexibility increased (decrease in the αH/βS ratio from 1.40 for the control sample to 1.26 for the silver nanoparticle-treated samples) as well as the solubility of gluten decreased (decrease in the β-turn content from 13.1 to 11.4%).

scholarly journals Food Products with High Antioxidant and Antimicrobial Activities and Their Sensory Appreciation

2022 ◽  
Vol 12 (2) ◽  
pp. 790
Author(s):  
Mihaela Adriana Tița ◽  
Maria Adelina Constantinescu ◽  
Ovidiu Tița ◽  
Endre Mathe ◽  
Loreta Tamošaitienė ◽  
...  
Keyword(s):  
Dairy Product ◽  
Control Sample ◽  
Antimicrobial Properties ◽  
Antimicrobial Activities ◽  
Point Of View ◽  
Volatile Oils ◽  
Textural Characteristics ◽  
Fermented Dairy Product ◽  
Fermented Dairy ◽  
Antioxidant And Antimicrobial Activities

(1) Background: The demand for healthy and nutritious food is growing worldwide. Fermented dairy products are highly valued by consumers for their health benefits. Kefir is a fermented dairy product that brings many benefits to the consumer due to its antioxidant, anticancer, antidiabetic, antihypertensive and antimicrobial properties. Extracts from various plants in the form of volatile oils have a beneficial efct on consumer health. their antioxidant and antimicrobial activities were demonstrated. (2) Methods: In the present study, the main purpose was to obtain a fermented dairy product with a high nutritional value; therefore, kefir, enriched with three types of volatile oils, namely, volatile mint oil, volatile fennel oil and volatile lavender oil, was made. The kefir samples obtained were sensory and texturally analyzed. The beneficial effect on health must also be studied in terms of the acceptability of these products by consumers from a sensory point of view. A non-numerical method based on several multi-personal approval criteria was used to interpret the results obtained in the sensory analysis. In the textural analysis, the consistency, cohesiveness and firmness of the kefir samples were analyzed. (3) Results: The samples enriched with volatile oils obtained superior results compared to the control sample in both conducted examinations. Kefir samples with volatile oils retained their sensory and textural characteristics for a longer time during storage. (4) Conclusions: The volatile oils added to kefir positively influenced the sensory and textural characteristics of the finished product.

scholarly journals Self-repairing mechanism and surface characterization of compressor vanes lubricated with oil added with magnesium silicate hydroxide nanorods

2019 ◽  
Vol 6 ◽  
pp. 26
Author(s):  
Libo Wang ◽  
Yi Yang ◽  
Yi Qin ◽  
Gang Yang ◽  
Yuan Qin ◽  
...  
Keyword(s):  
Surface Characterization ◽  
Friction And Wear ◽  
Magnesium Silicate ◽  
Composite Membranes ◽  
Great Depth ◽  
Industrial Applications ◽  
The Self ◽  
Great Promise ◽  
Surface Modified

Using magnesium silicate hydroxide as additive of lubricating oils for reducing friction in engineering equipment/machinery has been researched intensively. However, some mechanism relating to the growth of the self-repairing layers on the won surfaces is still not clearly explained. At the same time, using magnesium silicate hydroxide (MSH) in the form of nanorods showed great promise in reducing friction and wear. In this study, surface-modified MSH in the form of nanorods was used as additive of polyolester oil (POE) which was then used for the lubrication of compressor vanes. The sample parts were studied on the morphology and the microstructure of the self-repairing layer in a great depth. The results showed that self-repairing layers with different thicknesses were generated on the worn surfaces when the POE with 1 wt.% nanorods-MSH was used. It was found that the self-repairing layers consist of organic–inorganic composite membranes, and with increase of working time of the compressor vanes, the self-repairing layers become denser and thicker, while their micro-structural form remains to be similar. The situ-repairing capability of the metal surfaces (roller-vane pair of the compressor) enforced by the MSH nanorods is very significant, indicating high potential for industrial applications where boundary and mixed lubrications are needed.

scholarly journals Preparation and Properties of Chitosan/Graphene Modified Bamboo Fiber Fabrics

Polymers ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1540 ◽  
Author(s):  
Yan Wu ◽  
Yuqing Bian ◽  
Feng Yang ◽  
Yang Ding ◽  
Kexin Chen
Keyword(s):  
Control Sample ◽  
Antimicrobial Properties ◽  
Longitudinal Direction ◽  
Bamboo Fiber ◽  
Great Promise ◽  
Detergent Solution ◽  
Optical Brightener ◽  
Elongation At Break ◽  
Finishing Agent ◽  
Impregnation Modification

Chitosan (CS) and graphene (Gr) were used to modify bamboo fiber fabrics to develop new bamboo fiber fabrics (CGBFs) with antimicrobial properties. The CGBFs were prepared by chemical crosslinking with CS as binder assistant and Gr as functional finishing agent. The method of firmly attaching the CS/Gr to bamboo fiber fabrics was explored. On the basis of the constant amount of CS, the best impregnation modification scheme was determined by changing the amount of Gr and evaluating the properties of the CS/Gr modified bamboo fiber fabrics. The results showed that the antibacterial rate of CGBFs with 0.3 wt% Gr was more than 99%, and compared with the control sample, the maximum tensile strength of CGBF increased by 1% in the longitudinal direction and 7.8% in the weft direction. The elongation at break increased by 2.2% in longitude and 57.3% in latitude. After 20 times of washing with WOB (without optical brightener) detergent solution, the antimicrobial rate can still be more than 70%. Therefore, these newly CS/Gr modified bamboo fiber fabrics hold great promise for antibacterial application in home decoration and clothing textiles.

scholarly journals Herbal Extracts for Ensuring Pork Meat Quality during Cold Storage

2017 ◽  
Vol 71 (6) ◽  
pp. 453-460 ◽  
Author(s):  
Ilze Grāmatiņa ◽  
Sanita Sazonova ◽  
Zanda Krūma ◽  
Līga Skudra ◽  
Līga Prieciņa
Keyword(s):  
Meat Quality ◽  
Control Sample ◽  
Meat Products ◽  
Antimicrobial Properties ◽  
Sensory Properties ◽  
Biologically Active ◽  
Pork Meat ◽  
Herbal Extracts ◽  
Chilled Pork

Abstract Oxidation and microbial spoilage have a negative effect on the quality of meat and meat products, causing changes in their sensory and nutritional properties. Herbs contain biologically active compounds, like phenols with antioxidative and antimicrobial properties. Phenols can be used as substitutes for commercial antioxidants to prevent lipid oxidation, thus maintaining the colour and flavour of the product. The aim of the study was to investigate the the potential use of herbal extracts in ethanol/water application for the maintenance of pork meat quality during storage. Four herbs growing in Latvia — nettle (Urtica dioica L.), lovage (Levisticum officinale L.), oregano (Origanum vulgare), and horseradish (Armoracia rusticana L.) were chosen for the study. An optimal ethanol concentration for the extraction of the phenolic compounds was obtained with ethanol 50%/water 50% concentration (v/v). Prepared herbal extracts were added to chilled pork to determine the quality of the pork during storage. Changes in meat quality and its sensory properties for chilled pork without extracts appeared on day 18 of storage. Negative changes in sensory properties of meat samples with nettle extract were observed on day 22 of storage, and with lovage, oregano, and horseradish extracts on day 32. Statistically significant differences (p ≤ 0.05) were observed for microbiological indices between pork samples with herbal extracts and the control sample.

scholarly journals Antimicrobial metal-based nanoparticles: a review on their synthesis, types and antimicrobial action

2020 ◽  
Vol 11 ◽  
pp. 1450-1469
Author(s):  
Matías Guerrero Correa ◽  
Fernanda B Martínez ◽  
Cristian Patiño Vidal ◽  
Camilo Streitt ◽  
Juan Escrig ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Food Packaging ◽  
Antimicrobial Agents ◽  
Cell Damage ◽  
Metal Oxide Nanoparticles ◽  
High Surface ◽  
Antimicrobial Properties ◽  
Antimicrobial Action ◽  
Oxide Nanoparticles ◽  
Synthesis Methods

The investigation of novel nanoparticles with antimicrobial activity has grown in recent years due to the increased incidence of nosocomial infections occurring during hospitalization and food poisoning derived from foodborne pathogens. Antimicrobial agents are necessary in various fields in which biological contamination occurs. For example, in food packaging they are used to control food contamination by microbes, in the medical field the microbial agents are important for reducing the risk of contamination in invasive and routine interventions, and in the textile industry, they can limit the growth of microorganisms due to sweat. The combination of nanotechnology with materials that have an intrinsic antimicrobial activity can result in the development of novel antimicrobial substances. Specifically, metal-based nanoparticles have attracted much interest due to their broad effectiveness against pathogenic microorganisms due to their high surface area and high reactivity. The aim of this review was to explore the state-of-the-art in metal-based nanoparticles, focusing on their synthesis methods, types, and their antimicrobial action. Different techniques used to synthesize metal-based nanoparticles were discussed, including chemical and physical methods and “green synthesis” methods that are free of chemical agents. Although the most studied nanoparticles with antimicrobial properties are metallic or metal-oxide nanoparticles, other types of nanoparticles, such as superparamagnetic iron-oxide nanoparticles and silica-releasing systems also exhibit antimicrobial properties. Finally, since the quantification and understanding of the antimicrobial action of metal-based nanoparticles are key topics, several methods for evaluating in vitro antimicrobial activity and the most common antimicrobial mechanisms (e.g., cell damage and changes in the expression of metabolic genes) were discussed in this review.

Optimization and Characterization of Bioactive Biocomposite Film Based on Orange Peel Incorporated With Gum Arabic Reinforced by Cr2O3 Nanoparticles

2021 ◽  
Author(s):  
Saba Ghasemizad ◽  
Sajad Pirsa ◽  
Saber Amiri ◽  
Parisa Abdosatri
Keyword(s):  
Water Vapor ◽  
Water Solubility ◽  
Control Sample ◽  
Antimicrobial Properties ◽  
Water Vapor Permeability ◽  
Gum Arabic ◽  
Orange Peel ◽  
Vapor Permeability ◽  
Cr2o3 Nanoparticles ◽  
Biocomposite Film

Abstract In this paper, the effect of adding gum Arabic at levels of 0-5%, and chromium oxide nanoparticles (Cr2O3 NPs) at levels of 0-3%, are investigated on orange peel-based films. The obtained results reveal a significant increase (p<0.05) in water vapor permeability, weight loss, tensile strength, and Young's modulus of film samples by increasing the percentage of both gum and nanoparticles. Moreover, the addition of gum Arabic and Cr2O3 NPs decreases the thickness, water-solubility, L*, a*, b* indexes while increasing the elongation to the breaking point. Furthermore, the moisture content of the film samples was decreased by the addition of nanoparticles, however, the addition of gum Arabic increased this parameter. The obtained results from the morphology of the samples indicated an increase in both roughness and cracks by increasing the percentage of nanoparticles as well as creating a smooth surface with the addition of gum Arabic. Besides, the results of FTIR revealed no new peak in the prepared samples, as compared to the control sample. The results of XRD indicated that the addition of gum Arabic and nanoparticles simultaneously caused the formation of new crystals and increasing the crystallinity of the films. Based on TGA results, the thermal stability of films containing the nanoparticles increased, as compared to the control sample. In the meantime, the addition of gum and nanoparticles increased the antimicrobial properties of the film samples, as compared to the control. Overall, those films created by the orange peel including gum Arabic and Cr2O3 NPs could enhance the mechanical properties and water vapor permeability of the samples.

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