Nanotoxicology and in vitro studies: the need of the hour.

Silver nanoparticles in the environment: Sources, detection and ecotoxicology.

Toxicological studies on silver nanoparticles: challenges and opportunities in assessment, monitoring and imaging

https://www.materialstoday.com/download/50974/

The role of the lateral dimension of graphene oxide in the regulation of cellular responses

The different behaviours of dissolved silver and silver nanoparticles under ICP-MS single particle detection conditions have been used to differentiate directly between both forms of silver in aqueous samples. Suspensions containing silver nanoparticles at number concentrations below 109 L−1 and/or dissolved Ag(I) are introduced into the ICP-MS by conventional pneumatic nebulization and measured with a time resolution of 5 ms. Each silver nanoparticle is converted in the ICP into a packet of ions, which are detected as a single pulse, whose intensity is proportional to the number of silver atoms in the nanoparticle, whereas dissolved silver produces pulses of averaged constant intensity. The frequency plots with respect to the intensity measured for each pulse show independent distributions for dissolved silver and silver nanoparticles, whose profiles are also different (Poisson and lognormal, respectively). Size limits of detection for pure Ag nanoparticles of 18 nm, equivalent to a silver mass of 32 ag, were obtained. Number concentration limits of detection of 1 × 104 L−1 can be achieved. A methodological approach for identification, characterization and determination of mass and number concentration of dissolved Ag(I) and silver nanoparticles at environmentally relevant concentrations is presented.

Selective identification, characterization and determination of dissolved silver(I) and silver nanoparticles based on single particle detection by inductively coupled plasma mass spectrometry

The discovery of fullerenes in 1985 has ushered in an explosive growth in the applications of engineered nanomaterials and consumer products. Nanotechnology and engineered nanomaterials (ENMs) are being incorporated into a range of commercial products such as consumer electronics, cosmetics, imaging and sensors. Nanomaterials offer new possibilities for the development of novel sensing and monitoring technologies. Nanosensors can be classified under two main categories: (i) Nanotechnology-enabled sensors or sensors that are themselves nanoscale or have nanoscale materials or components, and (ii) Nanoproperty-quantifiable sensors or sensors that are used to measure nanoscale properties. The first category can eventually result in lower material cost, reduced weight and energy consumption. The second category can enhance our understanding of the potential toxic effects of emerging pollutants from nanomaterials including fullerenes, dendrimers, and carbon nanotubes. Despite the enormous literatures and reviews on Category I sensors, there are few sensors to measure nanoscale properties or sensors belonging to Category II. This class of nanosensors is an area of critical interest to nanotoxicology, detection and risk assessment, as well as for monitoring of environmental and/or biological exposure. This article discusses emerging fields of nanotoxicology and nanomonitoring including the challenges of characterizing engineered nanomaterials and the potentials of combining existing analytical techniques with conventional cytotoxicity methods. Two case studies are provided for development of Category II nanosensors for fullerene nanoparticles and quantum dots. One highlights the uniqueness of a portable, dissolved oxygen electrochemical sensor arrays capable of detecting the ENMs as well as provide rapid nanotoxicological information. This review has shown that addressing the complex and critical issues surrounding the environmental transformation and toxicity of ENMs must be accompanied by the creation of new approaches or further developments of existing instrumentation.

Sensors as tools for quantitation, nanotoxicity and nanomonitoring assessment of engineered nanomaterials

A new approach for creating flexible, mechanically strong poly(amic acid) (PAA) hybrid copolymers is described. The reduction of gold salts to gold nanoparticles by PAA coupled with its copolymerization in the presence of various silanes (e.g., N-[3-(trimethoxysilyl)-propyl] aniline (TMOSPA), 3-aminopropyl-trimethoxysilane (APTMOS), dichlorodimethylsilane (DCMS), and tetramethoxysilane (TMOS)) has enabled the design of a series of polymeric films. The resulting poly(amic acid), silane, and gold (PSG) solutions were employed for the fabrication of flexible, ternary polymers with a minimum bend ratio of 3 mm using thermal desolvation and/or wet-phase inversion techniques. By controlling the composition and synthesis conditions, porous PSG films were produced that are flexible or rigid, transparent or opaque, and/or mechanically strong. 1H NMR, 13C NMR, and Fourier transform infrared spectroscopy (FTIR) characterization results showed that the carboxylic acid moieties were retained in the PSG copolymer. Ther...

Flexible poly(amic acid) conducting polymers: effect of chemical composition on structural, electrochemical, and mechanical properties.

Biofunctionalized poly (amic) acid membranes for absolute disinfection of drinking water

Application of nanotechnology to water purification is currently faced with the issue of how to design nanomaterials that are capable of collecting and preconcentrating a large number of contaminants per unit volume. Specifically, it is not clear how to interface nanoparticles with contaminants because direct addition of nanoparticles into drinking water may require extra separation steps to recover the expensive nanomaterials. Due to their large pore sizes, conventional membrane filters cannot be used for removing submicron particles, engineered nanoparticles, or biological particles within the range of 100 nm or below. To overcome these challenges, we present transformative membrane technologies that are based on the use of nanostructured conducting phase-inverted poly(amic acid) membranes to isolate and remove silver nanoparticles, quantum dots, and titanium dioxide particles in environmental samples. nPAA membranes have also been utilized to remove pathogenic bacteria in drinking water. Filtration efficiency of over 99.98% was recorded for most contaminants. The membrane pore sizes were experimentally controlled from 4 to 35 nm, and the optimized membranes were tested against three of the most common drinking water contaminants, namely Escherichia coli, Citrobacter freundii, and Staphylococcus epidermidis. Hundred percent removal of these microbial species were recorded and the results were validated with conventional plating techniques.

Nanostructured Membranes for Water Purification

Nanoscale materials offer new possibilities for the development of novel remediation and environmental monitoring technologies. Different nanoscale materials have been exploited for preventing environmental degradation and pollutant transformation. However, the rapid self-aggregation of nanoparticles or their association with suspended solids or sediments where they could bioaccumulate supports the need for polymeric coatings to improve mobility, allows faster site cleanups and reduces remediation cost. The ideal material must be able to coordinate different nanomaterials functionalities and exhibit the potential for reusability. We hereby describe two novel environmental applications of nanostructured poly (amic acid)-based (nPAA) materials. In the first application, nPAA was used as both reductant and stabilizer during the in situ chemical reduction of chromium(VI) to chromium(III). Results showed that Cr(VI) species were rapidly reduced within the concentration range of 10−1 to 102 mM with efficiency of 99.9% at 40 °C in water samples and 90% at 40 °C in soil samples respectively. Furthermore, the presence of PdNPs on the PAA-Au electrode was found to significantly enhance the rate of reduction. In the second application, nPAA membranes were tested as filters to capture, isolate and detect nanosilver. Preliminary results demonstrate the capability of the nPAA membranes to quantitatively capture nanoparticles from suspension and quantify their abundance on the membranes. Silver nanoparticles detection at concentrations near the toxic threshold of silver was also demonstrated.

Nian Du

Papers

Sensors as tools for quantitation, nanotoxicity and nanomonitoring assessment of engineered nanomaterials

Flexible poly(amic acid) conducting polymers: effect of chemical composition on structural, electrochemical, and mechanical properties.

Biofunctionalized poly (amic) acid membranes for absolute disinfection of drinking water

Nanostructured Membranes for Water Purification

Environmental applications of poly(amic acid)-based nanomaterials.