Engineered Nanomaterials and Human Health: Part 2. Applications and Nanotoxicology (IUPAC Technical Report) (Review)

Research on engineered nanomaterials (ENM) has progressed rapidly from the very early stages of studying their unique, size-dependent physicochemical properties and commercial exploration to the development of products that influence our everyday lives. We have previously reviewed various methods for synthesis, surface functionalization, and analytical characterization of ENM in a publication titled \u27Engineered Nanomaterials: Preparation, Functionalization and Characterization\u27. In this second, inter-linked document, we first provide an overview of important applications of ENM in products relevant to human healthcare and consumer goods, such as food, textiles, and cosmetics. We then highlight the challenges for the design and development of new ENM for bio-applications, particularly in the rapidly developing nanomedicine sector. The second part of this document is dedicated to nanotoxicology studies of ENM in consumer products. We describe the various biological targets where toxicity may occur, summarize the four nanotoxicology principles, and discuss the need for careful consideration of the biodistribution, degradation, and elimination routes of nanosized materials before they can be safely used. Finally, we review expert opinions on the risk, regulation, and ethical aspects of using engineered nanomaterials in applications that may have direct or indirect impact on human health or our environment

Aqueous one-pot synthesis of epoxy-functional diblock copolymer worms from a single monomer: new anisotropic scaffolds for potential charge storage applications

Nitroxide-functional polymers have garnered considerable interest in recent years and appear to hold promise for energy storage applications. However, their synthesis can be both expensive and time-consuming. Here, we propose a highly convenient method for the preparation of TEMPO-functional diblock copolymer nanoparticles directly in water. Epoxy-functional diblock copolymer worms are synthesized from a single monomer, glycidyl methacrylate (GlyMA), using a three-step, one-pot protocol in aqueous solution via polymerization-induced self-assembly (PISA). First, an initial aqueous emulsion of GlyMA was heated at 85 °C for 9 h to afford an aqueous solution of glycerol monomethacrylate (GMA). Then reversible addition-fragmentation chain transfer (RAFT) polymerization of GMA was conducted in aqueous solution using a dicarboxylic acid-based RAFT agent to produce a water-soluble PGMA homopolymer. Finally, chain extension of this pre-cursor block via RAFT aqueous emulsion polymerization of GlyMA at 50 °C produced amphiphilic diblock copolymer chains that self-assembled in situ to form a 15% w/w aqueous dispersion of diblock copolymer worms. These worms can be derivatized directly using 4-amino-TEMPO in aqueous solution, affording novel crosslinked anisotropic nanoparticles that contain a relatively high density of stable nitroxide radicals for potential charge storage applications</p

Effects of surface-active block copolymers with oxyethylene and fluoroalkyl side chains on the antifouling performance of silicone-based films

Block copolymers made from a poly(dimethyl siloxane) (Si) and a poly(meth)acrylate carrying oxyethylene (EG) or fluoroalkyl (AF) side chains were synthesized and incorporated as surface-active components into a silicone matrix to produce cross-linked films with different surface hydrophilicity/phobicity. Near-edge X-ray absorption fine structure (NEXAFS) studies showed that film surfaces containing Si-EG were largely populated by the siloxane, with the oxyethylene chains present only to a minor extent. In contrast, the fluorinated block was selectively segregated to the polymer–air interface in films containing Si-AF as probed by NEXAFS and X-ray photoelectron spectroscopy (XPS) analyses. Such differences in surface composition were reflected in the biological performance of the coatings. While the films with Si-EG showed a higher removal of both Ulva linza sporelings and Balanus amphitrite juveniles than the silicone control, those with Si-AF exhibited excellent antifouling properties, preventing the settlement of cyprids of B. amphitrite

Development of an operational high refractive index resist for 193nm immersion lithography

Generation-three (Gen-3) immersion lithography offers the promise of enabling the 32nm half-pitch node. For Gen-3 lithography to be successful, however, there must be major breakthroughs in materials development: The hope of obtaining numerical aperture imaging 1.70 is dependent on a high index lens, fluid, and resist. Assuming that a fluid and a lens will be identified, this paper focuses on a possible path to a high index resist. Simulations have shown that the index of the resist should be 1.9 with any index higher than 1.9 leading to an increased process latitude. Creation of a high index resist from conventional chemistry has been shown to be unrealistic. The answer may be to introduce a high index, polarizable material into a resist that is inert relative to the polymer behavior, but will this too degrade the performance of the overall system? The specific approach is to add very high index (~2.9) nanoparticles to an existing resist system. These nanoparticles have a low absorbance; consequently the imaging of conventional 193nm resists does not degrade. Further, the nanoparticles are on the order of 3nm in diameter, thus minimizing any impact on line edge roughness (LER)

Development and Evaluation of a 193nm Immersion Generation-Three Fluid Candidates

The need to extend 193nm immersion lithography necessitates the development of a third generation (Gen-3) of high refractive index (RI) fluids that will enable approximately 1.7 numerical aperture (NA) imaging. A multi-pronged approach was taken to develop these materials. One approach investigated the highest-index organic thus far discovered. The second approach used a very high refractive index nanoparticle to make a nanocomposite fluid. This report will describe the chemistry of the best Gen-3 fluid candidates and the systematic approach to their identification and synthesis. Images obtained with the Gen-3 fluid candidates will also be presented for a NA ≥ 1.7

Development and Evaluation of a 193nm Immersion Generation-Three Fluid Candidates

The need to extend 193nm immersion lithography necessitates the development of a third generation (Gen-3) of high refractive index (RI) fluids that will enable approximately 1.7 numerical aperture (NA) imaging. A multi-pronged approach was taken to develop these materials. One approach investigated the highest-index organic thus far discovered. The second approach used a very high refractive index nanoparticle to make a nanocomposite fluid. This report will describe the chemistry of the best Gen-3 fluid candidates and the systematic approach to their identification and synthesis. Images obtained with the Gen-3 fluid candidates will also be presented for a NA ≥ 1.7

Association of citrulline concentration at birth with lower respiratory tract infection in infancy: Findings from a multi-site birth cohort study

Assessing the association of the newborn metabolic state with severity of subsequent respiratory tract infection may provide important insights on infection pathogenesis. In this multi-site birth cohort study, we identified newborn metabolites associated with lower respiratory tract infection (LRTI) in the first year of life in a discovery cohort and assessed for replication in two independent cohorts. Increased citrulline concentration was associated with decreased odds of LRTI (discovery cohort: aOR 0.83 [95% CI 0.70-0.99], p = 0.04; replication cohorts: aOR 0.58 [95% CI 0.28-1.22], p = 0.15). While our findings require further replication and investigation of mechanisms of action, they identify a novel target for LRTI prevention and treatment

Rheo-PIV of a shear-banding wormlike micellar solution under large amplitude oscillatory shear

We explore the behavior of a wormlike micellar solution under both steady and large amplitude oscillatory shear (LAOS) in a cone–plate geometry through simultaneous bulk rheometry and localized velocimetric measurements. First, particle image velocimetry is used to show that the shear-banded profiles observed in steady shear are in qualitative agreement with previous results for flow in the cone–plate geometry. Then under LAOS, we observe the onset of shear-banded flow in the fluid as it is progressively deformed into the non-linear regime—this onset closely coincides with the appearance of higher harmonics in the periodic stress signal measured by the rheometer. These harmonics are quantified using the higher-order elastic and viscous Chebyshev coefficients e [subscript n] and v [subscript n] , which are shown to grow as the banding behavior becomes more pronounced. The high resolution of the velocimetric imaging system enables spatiotemporal variations in the structure of the banded flow to be observed in great detail. Specifically, we observe that at large strain amplitudes (γ [subscript 0] ≥ 1), the fluid exhibits a three-banded velocity profile with a high shear rate band located in-between two lower shear rate bands adjacent to each wall. This band persists over the full cycle of the oscillation, resulting in no phase lag being observed between the appearance of the band and the driving strain amplitude. In addition to the kinematic measurements of shear banding, the methods used to prevent wall slip and edge irregularities are discussed in detail, and these methods are shown to have a measurable effect on the stability boundaries of the shear-banded flow.Spain. Ministerio de Educación y Ciencia (MEC) (Project FIS2010-21924-C02-02