Assessing bio-available silver released from silver nanoparticles embedded in silica layers using the green algae Chlamydomonas reinhardtii as bio-sensors
“…17 It is possible that some of these silver nanoparticles may migrate from these containers and into foods so that they could be ingested by humans. [17][18][19] Silver nanoparticles may also form spontaneously within biological media (such as GIT fluids or foods) when soluble silver salts interact with other components present. 20 It has been estimated that adults may consume between 20 and 80 μg/day of silver, with only a fraction of this being in the form of nanoparticles.…”
Nanotechnology offers the food industry a number of new approaches for improving the quality, shelf life, safety, and healthiness of foods. Nevertheless, there is concern from consumers, regulatory agencies, and the food industry about potential adverse effects (toxicity) associated with the application of nanotechnology in foods. In particular, there is concern about the direct incorporation of engineered nanoparticles into foods, such as those used as delivery systems for colors, flavors, preservatives, nutrients, and nutraceuticals, or those used to modify the optical, rheological, or flow properties of foods or food packaging. This review article summarizes the application of both inorganic (silver, iron oxide, titanium dioxide, silicon dioxide, and zinc oxide) and organic (lipid, protein, and carbohydrate) nanoparticles in foods, highlights the most important nanoparticle characteristics that influence their behavior, discusses the importance of food matrix and gastrointestinal tract effects on nanoparticle properties, emphasizes potential toxicity mechanisms of different food-grade nanoparticles, and stresses important areas where research is still needed. The authors note that nanoparticles are already present in many natural and processed foods, and that new kinds of nanoparticles may be utilized as functional ingredients by the food industry in the future. Many of these nanoparticles are unlikely to have adverse affects on human health, but there is evidence that some of them could have harmful effects and that future studies are required.
“…17 It is possible that some of these silver nanoparticles may migrate from these containers and into foods so that they could be ingested by humans. [17][18][19] Silver nanoparticles may also form spontaneously within biological media (such as GIT fluids or foods) when soluble silver salts interact with other components present. 20 It has been estimated that adults may consume between 20 and 80 μg/day of silver, with only a fraction of this being in the form of nanoparticles.…”
Nanotechnology offers the food industry a number of new approaches for improving the quality, shelf life, safety, and healthiness of foods. Nevertheless, there is concern from consumers, regulatory agencies, and the food industry about potential adverse effects (toxicity) associated with the application of nanotechnology in foods. In particular, there is concern about the direct incorporation of engineered nanoparticles into foods, such as those used as delivery systems for colors, flavors, preservatives, nutrients, and nutraceuticals, or those used to modify the optical, rheological, or flow properties of foods or food packaging. This review article summarizes the application of both inorganic (silver, iron oxide, titanium dioxide, silicon dioxide, and zinc oxide) and organic (lipid, protein, and carbohydrate) nanoparticles in foods, highlights the most important nanoparticle characteristics that influence their behavior, discusses the importance of food matrix and gastrointestinal tract effects on nanoparticle properties, emphasizes potential toxicity mechanisms of different food-grade nanoparticles, and stresses important areas where research is still needed. The authors note that nanoparticles are already present in many natural and processed foods, and that new kinds of nanoparticles may be utilized as functional ingredients by the food industry in the future. Many of these nanoparticles are unlikely to have adverse affects on human health, but there is evidence that some of them could have harmful effects and that future studies are required.
“…Moreover, the plasma process offers the possibility to overcome the limit imposed by their fabrication, replying in this way to the drastic requirements for controlling on a large area, and in a reproducible way, a well-defined spacing between the metallic nanoparticles and the probing molecules deposited on the surface of the plasmonic substrates [29]. A strongly original application of the nanostructured dielectrics containing AgNPs is related to their use in microbiology to modulate the activity of silver nanostructured surfaces by tuning the release of Ag + and/or AgNPs, thus the toxicity of nanocomposite materials to the exposed media [40].…”
Section: Potential Applications Of the Presented Nanostructured Lamentioning
1 -New concept concerning dielectric engineering is presented in this work aiming at a net improvement of the performance of dielectric layers in RF MEMS capacitive switches with electrostatic actuation and an increase of their reliability. Instead of synthesis of new dielectric materials we have developed a new class of dielectric layers that gain their performance from design rather than from composition. Two kinds of nanostructured dielectrics are presented. They consist of: (i) silicon oxynitride layers (SiO x N y :H) with gradual variation of their properties (discrete or continuous), and (ii) organosilicon (SiO x C y :H) and/or silica (SiO 2 ) layers with tailored interfaces; a single layer of silver nanoparticles (AgNPs) is embedded in the vicinity of the dielectric free surface. The nanostructured dielectric layers were deposited in a plasma process. They were structurally characterized and tested under electrical stress and environmental conditions typical for RF MEMS operation. The charge injection and decay dynamics were probed by Kelvin Force Microscopy (KFM). Modulation of the conductive properties of the nanostructured layers over 7 orders of magnitude is achieved. Compared to dielectric mono-layers, the nanostructured ones exhibit much shorter charge retention times. They appear to be promising candidates for implementation in RF MEMS capacitive switches with electrostatic actuation, and more generally for applications where surface charging must be avoided.
“…We demonstrated that embedding AgNPs in a silica matrix efficiently minimizes their interaction with the buffered water media, thereby preserving the AgNPs from fast oxidation. This study also reveals that the release of bioavailable silver (i.e., the one impacting algal photosynthesis) is governed by silica cover layer thickness or in other words, by the spatial position of the AgNPs under the host matrix surface (see Figure ) . In addition, the toxicity of silver released from these embedded AgNPs during the photosynthesis of green algae is similar to equivalent concentrations of Ag + released from silver nitrate salt (AgNO 3 ).…”
Section: Application To Ag+ Release and Toxicitymentioning
confidence: 67%
“…Samples (a) and (b) have been elaborated by ultra LE‐II; meanwhile, samples (c) and (d) have been fabricated by plasma deposition. Reproduced with permission . Copyright 2016, Elsevier Ltd.…”
Section: Application To Ag+ Release and Toxicitymentioning
confidence: 99%
“…In this feature article, we present our 10 years’ efforts on the safe‐by‐design synthesis of multifunctional nanocomposites consisting of 3D patterns of small AgNPs embedded in dielectrics by low‐energy ion implantation (LE‐II) and dedicated to both optical spectroscopy and controlled biocide action . Different architectures made of 3D arrays of AgNPs embedded in a dielectric matrix are designed to concomitantly take advantage of the optical interference phenomenon in the embedding multilayer and LSPR of AgNPs.…”
Many applications as optical spectroscopy, photothermal therapy, photovoltaics, or photocatalysis take advantage of the localized surface plasmon resonance of noble metal nanoparticles (NPs). Among them, AgNPs are multifunctional nano‐objects that can be used not only as efficient plasmonic antennae but also as electron reservoirs for charge transfer or ion reservoirs with strong biocide activity. Herein, the 10 years’ efforts on the safe‐by‐design synthesis of multifunctional nanocomposites consisting of 3D patterns of small AgNPs embedded in dielectrics are presented by coupling low‐energy ion implantation and stencil masking techniques. Their multifunctional coupling with different objects deposited on top of the dielectric surface is also presented through three examples. The twofold role of this single plane of AgNPs as the embedded plasmonic enhancer and charge carrier reservoir is first tested on few‐layer graphene deposited in specific areas at a controlled nanometer distance from the AgNPs. These buried AgNPs are also coupled to light emitters coimplanted in the dielectric matrix in specific regions, showing light emission enhancement. Finally, these AgNPs also provide an efficient biocide activity on green algae when submerged in water, with the amount of Ag+ release simply controlled by the thickness of the silica cover layer.
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