Ultrasound-assisted coating of nylon 6,6 with silver nanoparticles and its antibacterial activity

The Antifungal Fibers of Polyamide 12 Containing Silver and Metal Oxides

The textile market is a vast industry that utilizes antimicrobial polymeric materials, including various types of fabrics, for medical and personal protection applications. Therefore, this study focused on examining four types of antimicrobial fillers, namely, metal oxides (zinc, titanium, copper) and nanosilver, as fillers in Polyamide 12 fibers. These fillers can be applied in the knitting or weaving processes to obtain woven polymeric fabrics for medical applications. The production of the fibers in this study involved a two-step approach: twin-screw extrusion and melt spinning. The resulting fibers were then characterized for their thermal properties (TGA, DSC), mechanical performance (tensile test, DMA), and antifungal activity. The findings of the study indicated that all of the fibers modified with fillers kill Candida albicans. However, the fibers containing a combination of metal oxides and silver showed significantly higher antifungal activity (reduction rate % R = 86) compared to the fibers with only a mixture of metal oxides (% R = 21). Furthermore, the inclusion of metal oxides and nanosilver in the Polyamide 12 matrix hindered the formation of the crystal phase and decreased slightly the thermal stability and mechanical properties, especially for the composites with nanosilver. It was attributed to their worse dispersion and the presence of agglomerates.

Functionalization and Modification of Polyethylene Terephthalate Polymer by AgCl Nanoparticles under Ultrasound Irradiation as Bactericidal

Polyethylene terephthalate polymer (PET) is widely used in diverse areas. In the current study, the surface of PET is modified in two steps in order to improve the quality. At first, the polymer was functionalized with carboxylic groups, and Fourier transform infrared spectroscopy studies were used to verify functionalization. Then, AgCl nanoparticles were synthesized on COOH functional groups on the surface of PET using a sonochemistry method by sequential dipping of the functionalized polymer in an alternating bath of potassium chloride and silver nitrate under ultrasonic irradiation. The effects of ultrasonic irradiation power, the number of dipping steps, and pH on the growth of AgCl nanoparticles as effective parameters on size and density of synthesized Ag nanoparticles were studied. The results of scanning electron microscopy studies showed that the size and density of AgCl nanoparticles under ultrasonic irradiation with a power of 100 W are better than those of AgCl nanoparticles under irradiation with a power of 30 W. Also, by 15 times dipping the polymer into the reagent solutions in pH = 9, the modified polymer with a greater number of nanoparticles with suitable size can be reached. Antibacterial properties of PET containing AgCl nanoparticles were investigated against six Gram-positive and Gram-negative bacteria species, and the results showed significant antibacterial activity, while functionalized PET did not have a significant effect on both types of bacteria.

Aerogels as promising materials for antibacterial applications: a mini-review

The increasing cases of bacterial infections originating from resistant bacteria are a serious problem globally and many approaches have been developed for different purposes to treat bacterial infections. Aerogels are a novel class of smart porous materials composed of three-dimensional networks. Recently, aerogels with the advantages of ultra-low density, high porosity, tunable particle and pore sizes, and biocompatibility have been regarded as promising carriers for the design of delivery systems. Recently, aerogels have also been provided with antibacterial activity through loading of antibacterial agents, incorporation of metal/metal oxides and via surface functionalization and coating with various functional groups. In this mini-review, the synthesis of aerogels from both conventional and low-cost precursors is reported and examples of aerogels displaying antibacterial properties are summarized. As a result, it is clear that the encouraging antibacterial performance of aerogels promotes their use in many antibacterial applications, especially in the food industry, pharmaceutics and medicine.

Incorporation of silver nanoparticles into active antimicrobial nanocomposites: Release behavior, analyzing techniques, applications and safety issues

Employing new strategies to develop novel composite systems has become a popular area of interest among researchers. Raising people's awareness and their attention to the health and safety issues are key parameters to achieve this purpose. One of the recommended strategies is the utilization of nanoparticles within the matrix of composite materials to improve their physical, mechanical, structural and antimicrobial characteristics. Silver nanoparticles (Ag NPs) have attracted much attention for nanocomposite applications mainly due to their antimicrobial characteristics. Herein, the current review will focus on the different methods for preparing antimicrobial nanocomposites loaded with Ag NPs, the release of Ag NPs from these nanostructures in different media, analyzing techniques for the evaluation of Ag release from nanocomposites, potential applications, and safety issues of nanocomposites containing Ag NPs. The applications of Ag NPs-loaded nanocomposites have been extensively established in food, biomedical, textile, environmental and pharmacological areas mainly due to their antibacterial attributes. Several precautions should be addressed before implementation of Ag NPs in nanocomposites due to the health and safety issues.

Small molecule-decorated gold nanoparticles for preparing antibiofilm fabrics

The increase in antibiotic resistance reported worldwide poses an immediate threat to human health and highlights the need to find novel approaches to inhibit bacterial growth. In this study, we present a series of gold nanoparticles (Au NPs) capped by different N-heterocyclic molecules (N_Au NPs) which can serve as broad-spectrum antibacterial agents. Neither the Au NPs nor N-heterocyclic molecules were toxic to mammalian cells. These N_Au NPs can attach to the surface of bacteria and destroy the bacterial cell wall to induce cell death. Sonochemistry was used to coat Au NPs on the surface of fabrics, which showed superb antimicrobial activity against multi-drug resistant (MDR) bacteria as well as excellent efficacy in inhibiting bacterial biofilms produced by MDR bacteria. Our study provides a novel strategy for preventing the formation of MDR bacterial biofilms in a straightforward, low-cost, and efficient way, which holds promise for broad clinical applications.

Antibacterial properties of polypyrrole-treated fabrics by ultrasound deposition

Antimicrobial textiles can contribute to the fighting against antibiotic resistance pathogenic microorganisms. Polypyrrole is a conjugated polymer that exerts a biocidal action thanks to positive charges on its backbone chain produced during it synthesis. In this work, dispersions of stable polypyrrole nanoparticles were produced by chemical oxidative polymerization at room temperature in water. An ultrasound-assisted coating process was then used to effectively treat a polyester fabric with the nanoparticles to obtain an optimal antibacterial coating which efficiently eradicates the bacteria. The results showed that the treated fabric with about 4 g/m² of polypyrrole had log bacteria reductions of 6.0 against Staphylococcus aureus and 7.5 against Escherichia coli. The combination of a polypyrrole synthesis in the form of water nanoparticles dispersions and a continuous coating of fabrics supported by ultrasound overcomes some issues of upscaling of the traditional in-situ chemical deposition used until now for the production of polypyrrole-coated textiles.

Hydrodynamically Formed Uniform Thick Coatings on Microspheres

Forming uniform thick coatings on microspheres remains a significant challenge in various surface modification and drug delivery applications. In this work, a hydrodynamic method is demonstrated for centering microspheres in droplets with sizes ranging from tens to hundreds of micrometers. The core microspheres stay at the center of the droplets due to the hydrodynamic pressure generated in the surrounding liquid shells, despite the significant density difference between the core microsphere and the liquid shell. Therefore, by using polymerizable liquids that can be solidified thermally or by illumination as the shell layer, core-shell particles with gas, liquid, or solid cores can be surrounded with uniform coatings using the present method.

Efficient removal of crystal violet and methylene blue from wastewater by ultrasound nanoparticles Cu-MOF in comparison with mechanosynthesis method

The present investigation reports the synthesis of CuBTC (BTC=1,3,5-benzenetricarboxylate) metal-organic frameworks (MOFs) under solid-state conditions and ultrasound irradiation. Herein, we study uptake and release properties of crystal violet (CV) and methylene blue (MB) from ultrasound nano-CuBTC MOF in comparison with mechanosynthesis method (bulk structure). The ultrasound-assisted methods give a decrease in the surface area as calculated from the reduced nitrogen adsorption capability. In comparison, the uptake of guest molecules on ultrasound nano-CuBTC is remarkable and clearly exceeds that of bulk structure in the aqueous solution of guests. In bulk compound the channel length is increased so that the amount of adsorption is decreased a little. The small guest enters and leaves the cavity rapidly, whereas larger guests enter slowly due to their size relative to the size of the gaps in the capsule. As a result, the uptake and release of MB from CuBTC is faster than that of CV.

Deposition of silver nanoparticles on polyester fiber under ultrasound irradiations

The polyester fiber containing Ag nanoparticles was prepared through the chemical reduction under ultrasound irradiation. Influences of reduction reagents on the morphological properties of Ag nanoparticles@polyester fiber were studied. The sizes of metallic nanoparticles vary significantly with the types of reduction reagents used in the synthesis. A strong reduction reaction promotes a fast reaction rate and favors the formation of smaller nanoparticle. A weak reduction reagent induces a slow reaction rate and favors relatively larger particles. The products were investigated by means of scanning electron microscopy (SEM) and X-ray powder diffraction (XRPD).

Ultrasound irradiation effect on morphology and size of two new potassium coordination supramolecule compounds

Two new potassium coordination supramolecular compounds (2D and 1D), [K(H₃L)(H₂L)(H₂O)]_n·H₂O (1) and [K(H₂L')(HL')(H₂O)₂]·H₂O (2), (L=1,3,5-tricarboxylic acid, L'=2,6-pyridinedicarboxylic acid), have been synthesized under different experimental conditions. Micrometric crystals (bulk) or nano-sized materials have been obtained depending on using the branch tube method or sonochemical irradiation. All materials have been characterized by field emission scanning electron microscopy (FE-SEM), scanning electron microscopy (SEM), powder X-ray diffraction (PXRD), FT-IR spectroscopy and elemental analyses. Single crystal X-ray analyses on compounds 1 and 2 show that K⁺ ions are 3- and 7-coordinated, respectively. Additionally, H-bonds incorporate the layers and chains in 1 and 2 into 3D and 2D (along (0,0,1) direction) frameworks. Topological analysis shows that the compound 1 and 2 are 3,6-coordinated kgd and 2,4-coordinated 2,4C4 net. The thermal stability of compounds 1 and 2 in bulk and nano-size has been studied by thermal gravimetric (TG) and differential thermal analyses (DTA) and compared each other. The role of different parameters like temperature, reaction time and ultrasound irradiation power on the growth and morphology of the nano-structures are studied. Results suggest that an increase of temperature, sonication power and reduction of reaction time led to a particle size decrease.

One-step surface grafting of organic nanoparticles: in situ deposition of antimicrobial agents vanillin and chitosan on polyethylene packaging films

Natural organic molecules, volatile vanillin and non-volatile chitosan, were deposited from solution onto a polyethylene surface by the ultrasonic method and demonstrate specific antimicrobial activity.

Detection of human neutrophil elastase (HNE) on wound dressings as marker of inflammation

Chronic wound fluids have elevated concentration of human neutrophil elastase (HNE) which can be used as inflammation/infection marker. Our goal is to develop functional materials for fast diagnosis of wound inflammation/infection by using HNE as a specific marker. For that, fluorogenic peptides with a HNE-specific cleavage sequence were incorporated into traditional textile dressings, to allow real-time detection of the wound status. Two different fluorogenic approaches were studied in terms of intensity of the signal generated upon HNE addition: a fluorophore 7-amino-4-trifluormethylcoumarin (AFC) conjugated to a HNE-specific peptide and two fluorophore/quencher pairs (FAM/Dabcyl and EDANS/Dabcyl) coupled to a similar peptide as a Förster resonance energy transfer (FRET) strategy. Also, two immobilization methods were tested: sonochemistry immobilization onto a cotton bandage and glutaraldehyde (GTA)-assisted chemical crosslinking onto a polyamide dressing. The immobilized fluorogenic AFC peptide showed an intense fluorescence emission in the presence of HNE. HNE also induced an enhanced fluorescent signal with the EDANS/Dabcyl FRET peptide which showed to be a more sensitive and effective strategy than the AFC peptide. However, its chemical immobilization onto the polyamide dressing greatly decreased its detection, mainly due to the more difficult access of the enzyme to the cleavage sequence of the immobilized peptide. After optimization of the in situ immobilization, it will be possible to use these fluorescence-functionalized dressings for an effective and specific monitoring of chronic wounds by simply using a portable ultraviolet (UV) light source. We envision that the development of this point-of-care medical device for wound control will have a great impact on patient's life quality and reduction of costs on health care system.

Numerical simulation of the nonlinear ultrasonic pressure wave propagation in a cavitating bubbly liquid inside a sonochemical reactor

We investigate the acoustic wave propagation in bubbly liquid inside a pilot sonochemical reactor which aims to produce antibacterial medical textile fabrics by coating the textile with ZnO or CuO nanoparticles. Computational models on acoustic propagation are developed in order to aid the design procedures. The acoustic pressure wave propagation in the sonoreactor is simulated by solving the Helmholtz equation using a meshless numerical method. The paper implements both the state-of-the-art linear model and a nonlinear wave propagation model recently introduced by Louisnard (2012), and presents a novel iterative solution procedure for the nonlinear propagation model which can be implemented using any numerical method and/or programming tool. Comparative results regarding both the linear and the nonlinear wave propagation are shown. Effects of bubble size distribution and bubble volume fraction on the acoustic wave propagation are discussed in detail. The simulations demonstrate that the nonlinear model successfully captures the realistic spatial distribution of the cavitation zones and the associated acoustic pressure amplitudes.

Sonochemistry: Science and Engineering

Sonochemistry offers a simple route to nanomaterial synthesis with the application of ultrasound. The tiny acoustic bubbles, produced by the propagating sound wave, enclose an incredible facility where matter interact among at energy as high as 13 eV to spark extraordinary chemical reactions. Within each period - formation, growth and collapse of bubbles, lies a coherent phase of material formation. This effective yet highly localized method has facilitated synthesis of various chemical and biological compounds featuring unique morphology and intrinsic property. The benign processing lends to synthesis without any discrimination towards a certain group of material, or the substrates where they are grown. As a result, new and improved applications have evolved to reach out various field of science and technology and helped engineer new and better devices. Along with the facile processing and notes on the essence of sonochemistry, in this comprehensive review, we discuss the individual and mutual effect of important input parameters on the nanomaterial synthesis process as a start to help understand the underlying mechanism. Secondly, an objective discussion of the diversely synthesized nanomaterial follows to divulge the easiness imparted by sonochemistry, which finally blends into the discussion of their applications and outreach.

Sonochemical co-deposition of antibacterial nanoparticles and dyes on textiles

The sonochemical technique has already been proven as one of the best coating methods for stable functionalization of substrates over a wide range of applications. Here, we report for the first time on the simultaneous sonochemical dyeing and coating of textiles with antibacterial metal oxide (MO) nanoparticles. In this one-step process the antibacterial nanoparticles are synthesized in situ and deposited together with dye nanoparticles on the fabric surface. It was shown that the antibacterial behavior of the metal oxides was not influenced by the presence of the dyes. Higher K/S values were achieved by sonochemical deposition of the dyes in comparison to a dip-coating (exhaustion) process. The stability of the antibacterial properties and the dye fastness was studied for 72 h in saline solution aiming at medical applications.

Silver nanomaterials as future colorants and potential antimicrobial agents for natural and synthetic textile materials

Over the past few years, antimicrobial textiles have gained considerable interest for use in different application fields.

Tannic acid NPs - synthesis and immobilization onto a solid surface in a one-step process and their antibacterial and anti-inflammatory properties

Tannic acid nanoparticles were synthesized from an aqueous solution without the use of stabilizers via a sonochemical process. In order to avoid the dissolution of the formed nanoparticles, the sonochemical reaction was performed in the presence of a cotton fabric: following their formation, the tannic acid nanoparticles were embedded into the cotton substrate in a one-step process. The bioactive properties of the tannic acid coated surface were examined towards the inhibition of myeloperoxidase and collagenase, two major enzymes related with inflammatory processes. In addition, the antibacterial activity of the tannic acid nanoparticles coated textiles was evaluated against Staphylococcus aureus and Pseudomonas aeruginosa.

Laundering durable antibacterial cotton fabrics grafted with pomegranate-shaped polymer wrapped in silver nanoparticle aggregations

To improve the laundering durability of the silver functionalized antibacterial cotton fabrics, a radiation-induced coincident reduction and graft polymerization is reported herein where a pomegranate-shaped silver nanoparticle aggregations up to 500 nm can be formed due to the coordination forces between amino group and silver and the wrapping procedure originated from the coincident growth of the silver nanoparticles and polymer graft chains. This pomegranate-shaped silver NPAs functionalized cotton fabric exhibits outstanding antibacterial activities and also excellent laundering durability, where it can inactivate higher than 90% of both E. coli and S. aureus even after 50 accelerated laundering cycles, which is equivalent to 250 commercial or domestic laundering cycles.

Release of silver and copper nanoparticles from polyethylene nanocomposites and their penetration into Listeria monocytogenes

Since infection is a major cause of death in a patient whose immune responses have been compromised (immunocompromised patient), considerable attention has been focused on developing materials for the prevention of infections. This has been directed primarily at suppressing or eliminating the host's endogenous microbial burden and decreasing the acquisition of new organisms. In this study, the antibacterial properties of two nanocomposites, polyethylene modified with silver nanoparticles (PE-AgNps) or copper nanoparticles (PE-CuNps), against Listeria monocytogenes have been investigated. In order to elucidate the antibacterial mechanism, specifically whether this mechanism corresponds to bactericidal or bacteriolytic activities, we have determined the extent of release of metal ions (Ag(+) and Cu(2+)) and, also, the morphology of the bacteria. The metal ion release from nanocomposites was followed by inductively coupled plasma spectrometry and the morphology of the bacteria was revealed through examination of ultramicrotomed sections of bacteria in a transmission electron microscope. The study of metal ion release from the nanocomposites shows that for both nanocomposites the amount of ions released varies with time, which initially displays a linear behavior until an asymptotic behavior is reached. Further, TEM images show that silver nanoparticles (AgNps) and copper nanoparticles (CuNps), which are released from the nanocomposites, can penetrate to the cell wall and the plasma membrane of bacteria. Resulting morphological changes involve separation of the cytoplasmic membrane from the cell wall, which is known to be an effect of plasmolysis. It was revealed that the antibacterial abilities of the two nanocomposites against L. monocytogenes are associated with both bactericidal and bacteriolytic effects.

Preparation of Polymer Nanocomposites with Enhanced Antimicrobial Properties

Plasma surface activation and antibacterial properties of nanocomposites of polypropylene/silver nanoparticles (PP/nAg) and nylon-6/silver nanoparticles (Ny6/nAg) were investigated. The nanocomposites were prepared by melt blending assisted by ultrasound, while surface activation was achieved by means of argon plasma. To evaluate the antimicrobial properties of the nanocomposites, pathogen microorganisms such as Pseudomonas aeruginosa and Aspergillus niger were tested. Scanning Electron Microscopy (SEM) analyses showed a uniform dispersion of nanoparticles within the polymer matrix, though the presence of some agglomerates was also appreciated. On the other hand, surface topography by Atomic Force Microscopy (AFM) suggested that ions from the argon plasma generated ion collisions with the surface of the nanocomposites removing or etching polymer from surface and improving silver nanoparticles exposure, increasing their antimicrobial properties as corroborated by antimicrobial analyses. Nanocomposites exposed to argon plasma presented higher antimicrobial properties than the ones not exposed. These results indicated that plasma treatment increased the contact area of the nanoparticles with the microorganisms and enhanced the antimicrobial properties of nanocomposites. The results also showed that PP/nAg nanocomposites presented higher bacterial inhibition than Ny6/nAg nanocomposites, indicating that the chemical structure of the polymer also plays a big role in the final performance of the composite.

Ultrasound-assisted coating of polyester fiber with silver bromide nanoparticles

The growth of silver bromide nanoparticles on polyester fiber was achieved by sequential dipping steps in alternating bath of potassium bromide and silver nitrate under ultrasound irradiation. The effects of ultrasound irradiation, concentration and sequential dipping steps in growth of the AgBr nanoparticles have been studied. Particle sizes and morphology of nanoparticle are depending on power of ultrasound irradiation, sequential dipping steps and concentration. These systems depicted a decrease in the particles size accompanying an increase in the sonication power. Results suggest that an increasing of sequential dipping steps and concentration led to an increasing of particle size. The physicochemical properties of the nanoparticles were determined by powder X-ray diffraction (XRD) and scanning electron microscopy (SEM).

Synthesis and characterization of Ag nanoparticles@Polyethylene fibers under ultrasound irradiation

The polyethylene fibers containing Ag nanoparticles were prepared through the chemical reduction under ultrasound irradiation. The effect of reducing reagent, power of ultrasound irradiation, reaction time and temperature in growth of the nanometric Ag were studied. Particle sizes and morphology of nanoparticle are depending on power of ultrasound irradiation. Results show a decrease in the particles size as increasing power of ultrasound irradiation. Also, an increase in temperature led to increase of particle size. The polyethylene fibers containing Ag nanoparticles were characterized with powder X-ray diffraction (XRD) and scanning electron microscopy (SEM).

Releasing dye encapsulated in proteinaceous microspheres on conductive fabrics by electric current

The current paper reports on the relase properties of conductive fabrics coated with proteinaceous microspheres containing a dye. The release of the dye was achieved by passing an electric current through the fabric. The conductivity of the polyester fibers resulted from nanosilver (Ag NPs) coated on the surface of these fibers. Both types of coatings (nanosilver coating and the coating of the proteinaceous microspheres) were performed using high-intensity ultrasonic waves. Two different types of dyes, hydrophilic RBBR (Remazol Brilliant Blue R) and hydrophobic ORO (Oil Red O), were encapsulated inside the microspheres (attached to the surface of polyester) and then released by applying an electric current. The Proteinaceous Microsphere (PM)-coated conductive fabrics could be used in medicine for drug release. The encapsulated dye can be replaced with a drug that could be released from the surface of fabrics by applying a low voltage.

Influence of solvents on the morphological properties of AgBr nano-structures prepared using ultrasound irradiation

Nano-structures of AgBr have been prepared by reaction between AgNO(3) and KBr under ultrasound irradiation. Particle sizes and morphology of nanoparticle are depending on temperature, power of sonicating, reaction time and concentration. The effects of these parameters in growth and morphology of the nano-structures have been studied. Results suggest that an increasing of temperature, sonication power and concentration led to a decreasing of particle size. The samples were characterized with powder X-ray diffraction (XRD) and scanning electron microscopy (SEM).

A one-step process for the antimicrobial finishing of textiles with crystalline TiO2 nanoparticles

Titanium oxide (TiO(2)) nanoparticles (NPs) in their two forms, anatase and rutile, were synthesized and deposited onto the surface of cotton fabrics by using ultrasonic irradiation. The structure and morphology of the nanoparticles were analyzed by using characterization methods such as XRD, TEM, STEM, and EDS. The antimicrobial activities of the TiO(2)-cotton composites were tested against Escherichia coli (gram-negative) and Staphylococcus aureus (gram-positive) strains, as well as against Candida albicans. Significant antimicrobial effect was observed, mainly against Staphylococcus aureus. In addition, the combination of visible light and TiO(2) NPs showed enhanced antimicrobial activity.

Silver polymeric nanocomposites as advanced antimicrobial agents: classification, synthetic paths, applications, and perspectives

Utilization of metallic nanoparticles in various biotechnological and medical applications represents one of the most extensively investigated areas of the current materials science. These advanced applications require the appropriate chemical functionalization of the nanoparticles with organic molecules or their incorporation in suitable polymer matrices. The intensified interest in polymer nanocomposites with silver nanoparticles is due to the high antimicrobial effect of nanosilver as well as the unique characteristics of polymers which include their excellent structural uniformity, multivalency, high degree of branching, miscellaneous morphologies and architectures, and highly variable chemical composition. In this review, we explore several aspects of antimicrobial polymer silver nanocomposites, giving special focus to the critical analysis of the reported synthetic routes including their advantages, drawbacks, possible improvements, and real applicability in antibacterial and antifungal therapy. A special attention is given to "green" synthetic routes exploiting the biopolymeric matrix and to the methods allowing preparing magnetically controllable antimicrobial polymers for targeting to an active place. The controversial mechanism of the action of silver against bacteria, fungi and yeasts as well as perspectives and new applications of silver polymeric nanocomposites is also briefly discussed.

Sonochemical coating of paper by microbiocidal silver nanoparticles

Colloidal silver has gained wide acceptance as an antimicrobial agent, and various substrates coated with nanosilver such as fabrics, plastics, and metal have been shown to develop antimicrobial properties. Here, a simple method to develop coating of colloidal silver on paper using ultrasonic radiation is presented, and the coatings are characterized using X-ray diffraction (XRD), high resolution scanning electron microscope (HRSEM), and thermogravimetry (TGA) measurements. Depending on the variables such as precursor concentrations and ultrasonication time, uniform coatings ranging from 90 to 150 nm in thickness have been achieved. Focused ion beam (FIB) cross section imaging measurements revealed that silver nanoparticles penetrated the paper surface to a depth of more than 1 μm, resulting in highly stable coatings. The coated paper demonstrated antibacterial activity against E. coli and S. aureus, suggesting its potential application as a food packing material for longer shelf life.

Synthesis and properties of silk yarn containing Ag nanoparticles under ultrasound irradiation

The silk yarn containing Ag nanoparticles was prepared through the chemical reduction under ultrasound irradiation. In this system, ethylene glycol served as a reduction reagent and protecting silver nanoparticles from aggregation. The effect of some parameter, such as power of ultrasound irradiation and temperature in growth of the nanometric Ag were studied. Particle sizes and morphology of nanoparticle are depending on power of ultrasound irradiation. Results show a decrease in the particles size as decreasing power of ultrasound irradiation. Also, an increasing of temperature leads to an increasing of particle size. The silk yarn containing Ag nanoparticles were characterized with powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and FT-IR spectroscopy.

A review on the application of inorganic nano-structured materials in the modification of textiles: focus on anti-microbial properties

Textiles can provide a suitable substrate to grow micro-organisms especially at appropriate humidity and temperature in contact to human body. Recently, increasing public concern about hygiene has been driving many investigations for anti-microbial modification of textiles. However, using many anti-microbial agents has been avoided because of their possible harmful or toxic effects. Application of inorganic nano-particles and their nano-composites would be a good alternative. This review paper has focused on the properties and applications of inorganic nano-structured materials with good anti-microbial activity potential for textile modification. The discussed nano-structured anti-microbial agents include TiO(2) nano-particles, metallic and non-metallic TiO(2) nano-composites, titania nanotubes (TNTs), silver nano-particles, silver-based nano-structured materials, gold nano-particles, zinc oxide nano-particles and nano-rods, copper nano-particles, carbon nanotubes (CNTs), nano-clay and its modified forms, gallium, liposomes loaded nano-particles, metallic and inorganic dendrimers nano-composite, nano-capsules and cyclodextrins containing nano-particles. This review is also concerned with the application methods for the modification of textiles using nano-structured materials.