Bioavailability of engineered nanoparticles

Engineered nanomaterials (ENMs) are finding increasing applications because of their unique physicochemical properties. The increasing usage of these nanomaterials, however, raises concerns about their potential toxicity and of lack of control or even understanding over the life cycle from production, to use, and finally disposal. ENMs used in consumer products are highly likely to reach the environment during use and disposal, so it is critical to investigate their potential impact. Detailed mechanistic information about the particles and their state at the point of exposure to organisms must be developed to understand this risk. In this thesis, the possible transformation of ENMs in synthetic and realistic environments is explored, and the impact on marine organisms investigated. The work encompasses comparisons of transformations under inorganic versus organic sulfides and anaerobic digestion and correlative experiments on the effect of these particles on marine algae. Natural organic matter (NOM) is the main content of the natural system, and in particular, humic acid (HA) is an organic matter that is known to influence the transformation of silver nanoparticles (AgNPs). An in situ sulfidation process was used to follow the transformation of citrate-capped silver nanoparticles (Cit-AgNPs) in environments containing organic versus inorganic sulfide. In both cases, sulfidation was observed, with a core-shell structure being more stabilised in organic components, and humic acid capped silver sulfide nanoparticles (HA-Ag2SNPs) displayed evidence of a hollow sphere structure. Anaerobic digestion is a wastewater treatment plant process, so ENMs polluting consumer waste streams will likely be exposed to this process. Its impact on particle transformation is essential to understand, as well as any impact that the particle may have on the digestion processes. Thus, ENMs were tested within a lab-scale anaerobic digester: 10 mg/l of AgNPs, titanium oxide nanoparticles (TiO2NPs), cerium oxide nanoparticles (CeO2NPs) and silver sulfide nanoparticles (Ag2SNPs) were shown to have no significant effect on biogas production, indicating that at low concentrations, the ENMs do not interfere with the reactors. Also, there was no differences between the impacts of AgNPs and Ag2SNPs on the performance of the reactor, and both structures aggregated and became fully sulfided). The speciation of zinc oxide nanoparticles (ZnONPs) and zinc sulfide nanoparticles (ZnSNPs) were observed after 35 days: 54% of ZnONPs had absorbed iron oxyhydroxides (Zn-Fe-Ox), and the rest had a different ratio of zinc oxide (ZnO), zinc phosphate Zn3PO4, and ZnS. ZnSNPs had mostly transformed into zinc phosphate (Zn3PO4). Both ZnONPs and ZnSNPs had a ratio of ZnO, which was not less than 15%. Finally, to achieve the objective of mimicking the environmental conditions, AgNPs were aged in Economic Co-operation and Development-((3-(N-morpholino) propanesulfonic acid) medium (OECD-MOPs). The medium was prepared according to organisation guidance 201 before AgNPs incubation. An algal growth inhibition test with MOPS buffer was carried out by spiking the freshwater green algae Raphidocelis subcapitata (R. subcapitata) with the particle-containing medium. The morphology of algal cells after treatment showed extensive deformation and disorganised cell walls. Some cells had evident changes on the cell wall from a rigid structure to a ‘hairy’ exterior and, in more extreme cases, had released extracellular polymeric substances (EPS). This EPS trapped the particles outside the algae and resulted in nanoparticle aggregation. Cytotoxicity was observed when Algae were exposed to AgNPs as well as some sulfidation, which correlated with intracellular uptake, dissolution, and precipitation of secondary Ag2SNPs. For the AgNPs, the release of ions was directly linked to toxicity, and this changed in the presence of light, oxygen, and EPS.  Open Acces

Preparation and Preliminary Dielectric Characterization of Structured C\u3csub\u3e60\u3c/sub\u3e-Thiol-Ene Polymer Nanocomposites Assembled Using the Thiol-Ene Click Reaction

Fullerene-containing materials have the ability to store and release electrical energy. Therefore, fullerenes may ultimately find use in high-voltage equipment devices or as super capacitors for high electric energy storage due to this ease of manipulating their excellent dielectric properties and their high volume resistivity. A series of structured fullerene (C60) polymer nanocomposites were assembled using the thiol-ene click reaction, between alkyl thiols and allyl functionalized C60 derivatives. The resulting high-density C60-urethane-thiol-ene (C60-Thiol-Ene) networks possessed excellent mechanical properties. These novel networks were characterized using standard techniques, including infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and thermal gravimetric analysis (TGA). The dielectric spectra for the prepared samples were determined over a broad frequency range at room temperature using a broadband dielectric spectrometer and a semiconductor characterization system. The changes in thermo-mechanical and electrical properties of these novel fullerene-thiol-ene composite films were measured as a function of the C60 content, and samples characterized by high dielectric permittivity and low dielectric loss were produced. In this process, variations in chemical composition of the networks were correlated to performance characteristics

Role of Graphene Oxide in Bacterial Cellulose−Gelatin Hydrogels for Wound Dressing Applications

Biopolymer-based hydrogels have several advantages, including robust mechanical, high biocompatibility, and excellent properties. These hydrogels can be ideal wound dressing materials and advantageous to repair and regenerate skin wounds. In this work, we have reported fabricated of composite hydrogels from gelatin and graphene oxide-functionalized-bacterial cellulose (synthesized by hydrothermal method) (GO-f-BC) and crosslinked with tetraethyl orthosilicate (TEOS). The hydrogels were characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, atomic force microscopy, and water contact angle analyses to explore functional groups and their interactions, surface morphology, and wetting behavior, respectively. The swelling, biodegradation, and water retention were tested to respond to biofluid. Maximum swelling was exhibited by samle with maximum amount of GO (GBG-4) in all media (aqueous = 1902.83%, PBS = 1546.63%, and electrolyte = 1367.32%). The hemolysis of all hydrogel samples is less than 0.5%, and the blood coagulation time decreased as the hydrogel concentration increased. The composite hydrogels were found to be hemocompatible as they have less than 0.5% hemolysis for all hydrogel samples under in vitro standard conditions. These hydrogels performed unusual antimicrobial activities against Gram (positive and negative) bacterial strains. The cell viability and proliferation were increased with an increased GO amount, and maximum values were found for GBG-4 against fibroblast (3T3) cell lines. The mature and well-adhered cell morphology of 3T3 cells was found against all hydrogel samples. Hence, based on these results findings, these hydrogels would be potential wound dressing skin materials for wound healing applications.We are grateful to the European Union's Horizon to support the research project. This project has received funding from the European Union's Horizon 2020 research and innovation program under grant agreement no. 951747 and acknowledge the NPRP award [NPRP 12S -0310-190276] from the Qatar National Research Fund (a member of The Qatar Foundation). The statements made herein are solely the responsibility of the authors.Scopu

Review of Progress and Prospects in Research on Enzymatic and Non- Enzymatic Biofuel Cells; Specific Emphasis on 2D Nanomaterials

Energy generation from renewable sources and effective management are two critical challenges for sustainable development. Biofuel Cells (BFCs) provide an elegant solution by combining these two tasks. BFCs are defined by the catalyst used in the fuel cell and can directly generate electricity from biological substances. Various nontoxic chemical fuels, such as glucose, lactate, urate, alcohol, amines, starch, and fructose, can be used in BFCs and have specific components to oxide fuels. Widely available fuel sources and moderate operational conditions make them promise in renewable energy generation, remote device power sources, etc. Enzymatic biofuel cells (EBFCs) use enzymes as a catalyst to oxidize the fuel rather than precious metals. The shortcoming of the EBFCs system leads to integrated miniaturization issues, lower power density, poor operational stability, lower voltage output, lower energy density, inadequate durability, instability in the long-term application, and incomplete fuel oxidation. This necessitates the development of non-enzymatic biofuel cells (NEBFCs). The review paper extensively studies NEBFCs and its various synthetic strategies and catalytic characteristics. This paper reviews the use of nanocomposites as biocatalysts in biofuel cells and the principle of biofuel cells as well as their construction elements. This review briefly presents recent technologies developed to improve the biocatalytic properties, biocompatibility, biodegradability, implantability, and mechanical flexibility of BFCs.This work was supported by the Qatar National Research Fund (a member of Qatar Foundation) under UREP grant #UREP28-052-2-020. The statements made herein are solely the responsibility of the authors

3D Printing‐Enabled Design and Manufacturing Strategies for Batteries: A Review

Lithium-ion batteries (LIBs) have significantly impacted the daily lives, finding broad applications in various industries such as consumer electronics, electric vehicles, medical devices, aerospace, and power tools. However, they still face issues (i.e., safety due to dendrite propagation, manufacturing cost, random porosities, and basic & planar geometries) that hinder their widespread applications as the demand for LIBs rapidly increases in all sectors due to their high energy and power density values compared to other batteries. Additive manufacturing (AM) is a promising technique for creating precise and programmable structures in energy storage devices. This review first summarizes light, filament, powder, and jetting-based 3D printing methods with the status on current trends and limitations for each AM technology. The paper also delves into 3D printing-enabled electrodes (both anodes and cathodes) and solid-state electrolytes for LIBs, emphasizing the current state-of-the-art materials, manufacturing methods, and properties/performance. Additionally, the current challenges in the AM for electrochemical energy storage (EES) applications, including limited materials, low processing precision, codesign/comanufacturing concepts for complete battery printing, machine learning (ML)/artificial intelligence (AI) for processing optimization and data analysis, environmental risks, and the potential of 4D printing in advanced battery applications, are also presented

Magnetic nanoparticles draw solution for forward osmosis: Current status and future challenges in wastewater treatment

Forward osmosis is considered as the least energy intensive membrane process since it operates based on the osmotic pressure gradient. However, it is still considered as immature technology mainly due to the elevated cost for draw solution regeneration. Nevertheless, magnetic nanoparticles could be considered as a sustainable draw solute for forward osmosis due to high osmotic pressure and easy regeneration using magnetic force, but a significant development is still needed before implementing it for wastewater treatment and desalination. Herein, we analyzed the performance of the available magnetic nanoparticles draw solute and identified the challenges facing the use of magnetic nanoparticles as draw solute in the forward osmosis process. We first highlight the common synthesis methods of magnetic nanoparticles, and basics for generation of osmotic pressure using magnetic nanoparticles. Then, we analyzed the performance and limitations of available magnetic nanoparticles that were used as draw solute in the forward osmosis process. Later, we assessed the toxicity level of the magnetic nanoparticles and explored the regulations of using magnetic nanoparticles in the water treatment industry. Finally, new avenues of research were proposed to make magnetic nanoparticles draw solution more effective when applying it in desalination and wastewater treatment process.This research is made possible by graduate sponsorship research award ( GSRA6-1-0509-19021 ) from Qatar National Research Fund (QNRF). Also, the authors would like to thank Qatar University for funding this project through Collaborative Grant (CG) - Cycle 05 - ID492 . The statements made herein are solely the responsibility of the authors. Open access funding was provided by Qatar National Library .Scopu

Hierarchical Porous Carbon Nitride-Crumpled Nanosheet-Embedded Copper Single Atoms: An Efficient Catalyst for Carbon Monoxide Oxidation

Rational design of metal single-site embedded porous graphitic carbon nitride (P-g-C3N4) nanostructures exploiting maximum atom utilization is warranted to enhance the thermal CO oxidation (COOx) reaction. Herein, a facile, green, one-pot, and template-free approach is developed to fabricate the hierarchical porous P-g-C3N4-crumpled ultrathin nanosheets atomically doped with copper single atoms (Cu–P-g-C3N4). Mechanistically, the quick protonation of melamine and pyridine under acidic conditions induces deamination to form melem, which is polycondensed under heating. The interconnected pores, high surface area (240 m2g–1), and maximized exposed isolated Cu atomic active sites (1.8 wt %) coordinated with nitrogen atom P-g-C3N4 are the salient features of Cu– P-g-C3N4 that endowed complete conversion to CO2 at 184 °C. In contrast, P-g-C3N4 only converted 3.8% of CO even at 350 °C, implying the electronic effect of Cu single atoms. The abundant Cu-nitrogen moieties can drastically weaken the binding affinity of the CO-oxidation (COOx) intermediates and products, thus accelerating the reaction kinetics at a low temperature. This study may promote the fabrication of P-g-C3N4 doped with various single atoms for the oxidation of CO.This work was supported by the Qatar National Research Fund (QNRF, a member of the Qatar Foundation) through a National Priority Research Program Grant (NPRP) NPRP13S-0117-200095 and the Qatar University through an International Research Collaboration Co-Fund grant, QUHI-22/23–550. The authors also gratefully thank the Synchrotron-light for Experimental Science and Applications in the Middle East (SESAME), Allan 19252, Jordan for the XANES and EXAF measurements of Cu/P-g-C3N4 and its reference samples CuO, Cu2O, and Cu metal. Statements made herein are solely the responsibility of the authors.Scopu

Synthesis of mesoporous carbons with controlled morphology and pore diameters from SBA-15 prepared through the microwave-assisted process and their CO2 adsorption capacity

Mesoporous carbon materials (CMK-3-T-MW) with high surface area, different pore diameters and rod shaped morphology were synthesized via nanocasting technique using the SBA-15 templates prepared by ultra-fast microwave-assisted process under static condition. The combined microwave and static approach offers the highly ordered rod shaped morphology to the SBA-15 template, which was successfully replicated into the mesoporous carbon materials. By tuning the synthesis temperature of the template, it is possible to fabricate mesoporous carbons with different pore diameters and specific surface areas. These excellent materials can be utilized for various applications and here we demonstrate their use as adsorbents for CO2 molecules. A significant enhancement in the adsorption of CO2 was achieved for the mesoporous carbon with rod shaped morphology, large pore diameter and high surface area. The adsorption capacity of CMK-3-T-MW was also compared with commercially available activated carbon, multi walled carbon nanotubes (MWCNTs) and 2D and 3D highly basic mesoporous carbon nitrides (MCNs). The CO2 adsorption capacity of mesoporous carbon with controlled morphology is 24.4 mmol/g at 273 K and 30 bar pressure which is much higher than that of mesoporous carbon CMK-3-HT (20.3 mmol/g at the same conditions) prepared by the conventional hydrothermal method, activated carbons, MWCNTs, and MCNs. 2016The authors extend their sincere appreciation to the Deanship of Scientific Research at King Saud University for funding the Prolific Research group (PRG- 436-14).Scopu