Multifunctional Textiles with Flame Retardant and Antibacterial Properties: A Review.
Molecules (Basel, Switzerland)
It is well known that bacterial infections and fire-hazards are potentially injurious in daily life. With the increased security awareness of life and properties as well as the improvement of living standards, there has been an increasing demand for multifunctional textiles with flame retardant and antibacterial properties, especially in the fields of home furnishing and medical protection. So far, various treatment methods, including the spray method, the dip-coating method, and the pad-dry-cure method, have been used to apply functional finishing agents onto fabrics to achieve the functionalization in the past exploration stage. Moreover, in addition to the traditional finishing technology, a number of novel technologies have emerged, such as layer-by-layer (LBL) deposition, the sol-gel process, and chemical grafting modification. In addition, some natural biomasses, including chitin, chitosan (CS), and several synthetic functional compounds that possess both flame-retardant and bacteriostatic properties, have also received extensive attention. Hence, this review focuses on introducing some commonly used finishing technologies and flame retardant/antibacterial agents. At the same time, the advantages and disadvantages of different methods and materials were summarized, which will contribute to future research and promote the development and progress of the industry.
10.3390/molecules28186628
Surpassingly competitive electromagnetic field enhancement at the silica/silver interface for selective intracellular surface enhanced Raman scattering detection.
Radziuk Darya,Möhwald Helmuth
ACS nano
A thin plasmonic nanofilm is formed by preformed silver nanoparticles (30 nm) in the matrix of poly(vinyl alcohol) adsorbed on silica microparticles (1.5 μm) (SiO2@Ag-PVA). By applying finite element method (FEM) analysis the surface enhanced Raman spectroscopy (SERS) enhancement factors (EFs) can reach 10(5) with higher values from 10(9) to 10(11) in the silver layer of 5 nm thickness. Nanoparticles in the SiO2@Ag-PVA nanofilm need at least 15 nm radius to exhibit SERS EFs greater than 10(7). High values of this enhancement at the silver/silica interface of spherical geometry can be reached faster by using a 532 nm compared to 785 nm excitation wavelength. By this approach different SERS spectral features can be distinguished between live fibroblasts with spread ("healthy" state) or round ("unhealthy" state) shapes. Characteristic features of secondary protein structures, detection of different acidic conditions and cholesterol with at least a 3-fold higher sensitivity are examined. Moreover, a greater amount of glucose (glucogen) and also tyrosine can be monitored in real time. This is important in identification of higher risk of diabetes as well as in several genetic metabolic disorders (e.g., phenylketonuria, tyrosinaemia type II and tyrosinosis).
10.1021/nn506741v
Changes in the microbiological and chemical characteristics of white bread during storage in paper packages modified with Ag/TiO2-SiO2, Ag/N-TiO2 or Au/TiO2.
Peter Anca,Mihaly-Cozmuta Leonard,Mihaly-Cozmuta Anca,Nicula Camelia,Ziemkowska Wanda,Basiak Dariusz,Danciu Virginia,Vulpoi Adriana,Baia Lucian,Falup Anca,Craciun Grigore,Ciric Alexandru,Begea Mihaela,Kiss Claudia,Vatuiu Daniela
Food chemistry
Microbiological and chemical characteristics of white bread during storage in paper-packages modified with Ag/TiO2-SiO2, Ag/N-TiO2 or Au/TiO2 were investigated. The whiteness and the water retention of the modified packages were slightly superior to those exhibited by the reference sample, as the color of the composite was lighter. The water retention was very good especially for the Ag/TiO2-SiO2-paper. These improvements can be associated with the high specific surface area and with the low agglomeration tendency of Ag nanoparticles in comparison with the Au ones. The preservation activity of the composites for the bread storage is positively influenced by photoactivity and presence of nano-Ag. Packages Ag/TiO2-SiO2-paper and Ag/N-TiO2-paper can find their applicability for extending the shelf life of bread by 2 days as compared with the unmodified paper-package. No influence of the Au/TiO2 on the extending the shelf life of bread was observed.
10.1016/j.foodchem.2015.11.048
Enhanced photochemistry of ethyl chloride on Ag nanoparticles.
Toker Gil,Bespaly Alexander,Zilberberg Liat,Asscher Micha
Nano letters
Enhanced photodecomposition of ethyl chloride (EC) adsorbed on SiO2/Si (100) supported silver nanoparticles (Ag NPs) under ultrahigh vacuum (UHV) conditions has been studied in order to assess the potential contribution of plasmonic effects. The cross section for photodecomposition of EC and overall photoyield were found to increase with increasing photon energy regardless of the plasmon resonant wavelength and with Ag coverage without any noticeable particle size effect. The influence of EC-Ag NPs separation distance on the rate of EC decomposition was studied in order to examine potential local electric field influence on the photodissociation process. Long (∼5 nm) photoactivity decay distance has been observed which excludes local surface plasmon dominance in the photodecomposition event. These findings suggest that the alignment of excited electron energy and adsorbate affinity levels is central for efficient photochemical reactions, whereas short-range electric field enhancement by plasmon excitation on top and at the immediate vicinity of silver nanoparticles does not have any measurable effect.
10.1021/nl503700y
Mesoporous Silica Supported Silver-Bismuth Nanoparticles as Photothermal Agents for Skin Infection Synergistic Antibacterial Therapy.
Cao Changyu,Ge Wei,Yin Jiajia,Yang Dongliang,Wang Wenjun,Song Xuejiao,Hu Yanling,Yin Jie,Dong Xiaochen
Small (Weinheim an der Bergstrasse, Germany)
The emergence of multidrug resistant bacteria has resulted in plenty of stubborn nosocomial infections and severely threatens human health. Developing novel bactericide and therapeutic strategy is urgently needed. Herein, mesoporous silica supported silver-bismuth nanoparticles (Ag-Bi@SiO NPs) are constructed for synergistic antibacterial therapy. In vitro experiments indicate that the hyperthermia originating from Bi NPs can disrupt cell integrity and accelerate the Ag ions release, further exhibiting an excellent antibacterial performance toward methicillin-resistant Staphylococcus aureus (MRSA). Besides, under laser irradiation, Ag-Bi@SiO NPs at 100 µg mL can effectively obliterate mature MRSA biofilm and cause a 69.5% decrease in the biomass, showing a better therapeutic effect than Bi@SiO NPs with laser (26.8%) or Ag-Bi@SiO NPs without laser treatment (30.8%) groups. More importantly, in vivo results confirm that ≈95.4% of bacteria in abscess are killed and the abscess ablation is accelerated using the Ag-Bi@SiO NPs antibacterial platform. Therefore, Ag-Bi@SiO NPs with photothermal-enhanced antibacterial activity are a potential nano-antibacterial agent for the treatment of skin infections.
10.1002/smll.202000436
Shape restoration effect in Ag-SiO2 core-shell nanowires.
Vlassov Sergei,Polyakov Boris,Dorogin Leonid M,Vahtrus Mikk,Mets Magnus,Antsov Mikk,Saar Rando,Romanov Alexey E,Lõhmus Ants,Lõhmus Rünno
Nano letters
The combination of two different materials in a single composite core-shell heterostructure can lead to improved or even completely novel properties. In this work we demonstrate the enhancement of the mechanical properties of silver (Ag) nanowires (NW) achieved by coating them with a silica (SiO2) shell. In situ scanning electron microscope (SEM) nanomechanical tests of Ag-SiO2 core-shell nanowires reveal an improved fracture resistance and an electron-beam induced shape restoration effect. In addition, control experiments are conducted separately on uncoated Ag NWs and on empty SiO2 shells in order to gain deeper insight into the peculiar properties of Ag-SiO2. Test conditions are simulated using finite-element methods; possible mechanisms responsible for the shape restoration and the enhanced fracture resistance are discussed.
10.1021/nl5019063
The structures and antibacterial properties of nano-SiO2 supported silver/zinc-silver materials.
Jia Husheng,Hou Wensheng,Wei Liqiao,Xu Bingshe,Liu Xuguang
Dental materials : official publication of the Academy of Dental Materials
OBJECTIVES:The aims of this study were to investigate the structures and antibacterial properties of two kinds of sterilizing nano-SiO(2) specimens. METHODS:The specimens were synthesized by adsorption methodology. One of them was synthesized by adsorbing silver cation onto nano-SiO(2) carrier (silver-loading nano-SiO(2) specimen (SLS)), and the other one by co-adsorbing zinc and silver cations onto the same kind of carrier (zinc-silver-loading nano-SiO(2) specimen (SLZS)). Chemical compositions of these specimens were estimated. The structure and morphology of the specimens were determined by X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM). Also, the antibacterial properties of the specimens were examined. RESULTS:The amount of silver loaded in SLZS was approximate to that of SLS. Consequently, it can be proved that the amount of nano-SiO(2) adsorbed silver cation did not change with the addition of zinc cation. The obvious differences were not observed among the XRD patterns for each specimen. So it was possible to confirm no formation of new phase(s) after Ag(+)/Zn(2+) absorption. The loaded silver and zinc existed as nano-particles, as observed by HRTEM. Antibacterial properties of SLS and SLZS were excellent against Escherichia coli and S. faecalis. The antibacterial effect of the same antibacterial agent against E. coli or S. faecalis was different. In addition, the antibacterial effect of SLZS was better than that of SLS. SIGNIFICANCE:These results suggested SLS and SLZS can be effectively incorporated in dental resin-based materials to provide antibacterial activity against bacteria.
10.1016/j.dental.2007.04.015
A Gold/Silver Hybrid Nanoparticle for Treatment and Photoacoustic Imaging of Bacterial Infection.
ACS nano
Ag ions are a well-known antibacterial agent, and Ag nanoparticles act as a reservoir of these Ag ions for targeted therapy of bacterial infections. However, there are no tools to effectively trigger and monitor the release of Ag ions from Ag nanoparticles. Photoacoustic (PA) imaging is an emerging noninvasive imaging tool, and gold nanorods (AuNRs) are an excellent contrast agent for PA imaging. In this work, we developed Au/Ag hybrid nanoparticles by coating AuNRs with silver (Ag), which decreased their photoacoustic signal. The as-prepared, Ag-coated Au nanorods (Au/AgNRs) are stable under ambient conditions, but the addition of ferricyanide solution (1 mM) results in oxidative etching of the silver shell. The PA contrast is simultaneously recovered as the silver is released, and this PA signal offers noninvasive monitoring of localized release of Ag ions. The released Ag ions exhibit a strong bactericidal efficacy similar to equivalent free Ag ions (AgNO), and the nanoparticles killed >99.99% of both (Gram-positive) methicillin-resistant Staphylococcus aureus (MRSA, 32 μM Ag equivalent) and (Gram-negative) Escherichia coli (8 μM Ag equivalent). The theranostic potential of these nanoparticles was demonstrated in a pilot in vivo study. Mice were inoculated with MRSA and Au/AgNRs were subcutaneously implanted followed by silver etching. There was a 730% increase in the PA signal ( p < 0.01) pre- and post-etching, and the bacterial counts in infected tissues of the treated group were reduced by 1000-fold (log CFU/g = 4.15 vs 7.75) versus the untreated control; this treatment efficacy was confirmed with histology. We further showed that these hybrid nanoparticles could release Ag after stimulation by reactive oxygen species including hydrogen peroxide and peroxynitrite. These hybrid Au/Ag nanoparticles are a useful theranostic agent for the photoacoustic imaging and treatment of bacterial infections.
10.1021/acsnano.8b01362