Metal micronutrients get to the root of antifungal defence

Written by Richard Massey for Chemistry World

Flavoursome tomato varieties could benefit from nanoparticle fertilisers.

heirloom tomato

Tasty heirloom tomato varieties could soon see a return to our plates thanks to the promising antifungal properties of metal oxide nanoparticle fertilisers developed by US scientists.

Centuries of plant breeding mean we’ve grown accustomed to a narrow range of crops bred primarily for their disease resistance. But while we reap the benefits of greater yields and reliability, we’re missing out on a host of different flavours from less disease-hardy varieties.

Now a nanoparticle crop treatment developed by Wade Elmer and Jason White at Connecticut Agricultural Experiment Station, US, could give older tomato varieties – more susceptible to root pathogens such as wilt fungus – a helping hand. Applying copper and manganese oxide nanoparticles to the leaves of tomato plants grown in soil infected with the Verticillium wilt fungus increased fruit yields by up to 33% compared with untreated plants.

Read the full article in Chemistry World.


Wade H. Elmer and Jason C. White
Environ. Sci.: Nano, 2016, Advance Article
DOI: 10.1039/C6EN00146G, Paper
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Earth, wind and the sun = gold?

an article by Dan Mercea, PhD student at Imperial College London

Graphical Abstract

The precious element gold can exist in various forms, the most thought of probably being the shiny solid treasured for its aesthetic qualities. However, a number of other relevant forms exist not just in the chemistry laboratory but also in nature. Gold in its common oxidation states (I and III) can be found in water sources in the environment at appreciable concentrations. The coexistence of natural organic matter (NOM) and gold dissolved in surface water opens up the possibility for photoproduction of gold nanoparticles (AuNP), a form of gold which displays toxicity towards aquatic organisms and is prone to becoming distributed through the food chain upon ingestion.

In this Environmental Science: Nano paper entitled Aqueous photoproduction of Au nanoparticles by natural organic matter: effect of NaBH4 reduction the authors’ attention is focused on investigating what NOM functionality is involved in AuNP formation, and which mechanism is being facilitated by its presence. Samples of NOM from various sources were included in the study and characterised using their content of carbonyl, quinone and aliphatic functionality. Samples with a large percentage of the former two showed an enhanced ability for AuNP production under simulated sunlight conditions, whereas a large content of the latter afforded inferior performance in this respect. In order to test whether this oxygen-containing functionality was responsibile for the facile production of AuNPs a selective chemical reducing agent, sodium borohydride (NaBH4), was chosen to remove it from the NOM samples. This modification led to Au3+ reduction by NOM being observed, albeit at a much slower rate, which confirmed the importance of the carbonyl functionality and suggested that other functionality in the NOM was ultimately responsible for performing reduction.

One way in which the carbonyl functionality could accelerate the photoreduction process is by acting as a convenient electron source following the absorption of light, with the molecular oxygen/superoxide radical pair acting as an electron shuffle between the NOM and the gold cations. Formation of the superoxide radical on irradiation of NOM solutions was followed using electron paramagnetic resonance both before and after NaBH4 treatment. Elimination of the carbonyl functionality hindered formation of the superoxide radical, however a correlation between superoxide concentration and AuNP formation rate could not be established. To test whether the superoxide radical was involved in the nanoparticle formation process, the enzyme superoxide dysmutase was added. The enzyme efficiently removed the superoxide radical, which led to an expected decrease in rate. These observations helped support the operation of the indirect reduction mechanism, however not to the dismissal of alternatives. Indeed another mechanism which is believed to operate in parallel is based on the charge transfer from the NOM directly to the gold cations in complexes formed between the two (the charge transfer mechanism).

Experiments carried out with model substrates of aromatic ketones and quinones further supported the role that had been ascribed to the carbonyl functionality. Aromatic ketones proved superior over the quinoid model compounds in the generation of nanoparticles, as faster reduction was achieved even at much lower substrate concentration and indicated that NOM quinones played only a secondary role in the production of AuNPs. Noteworthy was the decrease in photoreduction rate observed upon NaBH4 treatment of quinones, which indicated that the resulting phenolic functionality was not responsible for photoreduction as had been previously believed.

Jiahai Ma and co-authors from the School of Chemistry and Chemical Engineering have shaped our understanding for the central role that the aromatic ketone functionality in natural organic matter plays in the photoproduction of gold nanoparticles in the aquatic environment.

Read the full article for free*:

Aqueous photoproduction of Au nanoparticles by natural organi matter: effect of NaBH4 reduction
Zilu Liu, Pengfei Xie and Jiahai Ma
Environ. Sci.: Nano, 2016, Advance Article
DOI: 10.1039/C6EN00126B, Paper

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About the webwriter

Dan Mercea is a PhD student in the Fuchter group at Imperial College London. He is working on developing enantioselective FLP catalysis.

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*Access is free until 24/08/2016 through a registed RSC account – register here

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25th Japan Society for Environmental Chemistry

The 25th Japan Society for Environmental Chemistry Annual Meeting was held in Niigata, Japan on 8-10 June 2016.

During the award ceremony Hiromitsu Urakami from the Royal Society of Chemistry presented several certificates to poster prize winners on behalf of our environmental science journals.

Congratulations to all of the winners!

Environmental Science: Nano winner:

Kosuke Tanaka, Tokyo University of Agriculture and Technology

Poster title: Concentration of persistent organic pollutants in microplastics from marine surface water and evaluation of the risk of ingestion by marine organisms

And the winners for the Environmental Science: Process & Impacts and Environmental Science: Water Research and Technology poster prizes were Tomohiko Nakano and Suzumi Nishimura. More details can be found on our  ES: Processes & Impacts and ES:Water blogs.

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Introducing our new Associate Editor

Iseult Lynch joins the Environmental Science: Nano team as Associate Editor

We are delighted to introduce Iseult Lynch as a new Associate Editor for Environmental Science: Nano.

Iseult joins Greg Lowry and Kristin Schirmer as Associate Editors handling submissions to the journal.

Iseult Lynch is a physical chemist specialising in understanding the interface between engineered nanomaterials and the environment (biotic and abiotic components) and how this determines their ultimate fate and behaviour.

Dr Lynch has been actively involved in research to elucidate the mechanisms involved in potential toxicity of nanomaterials, including being centrally involved in the pioneering studies regarding the nanoparticle-protein corona, for which she received the US National Academy of Sciences Cozzarelli Prize for 2007 (with her co-authors).

She is currently applying these concepts to assessing nanomaterial behaviour in more complex environments and whole organisms, looking for example at the role of secreted proteins and polysaccharides as well as dissolved organic matter in determining nanomaterials environmental fate, transformation and biouptake. Her expertise spans nanomaterials synthesis, characterisation and environmental interactions (biomolecules, cells, organisms).

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Please join us in welcoming Iseult to Environmental Science: Nano.

Iseult has recently published a review in Environmental Science: Nano, read it here.

Interested in the latest news, research and events of the Environmental Science journals? Find us on Twitter: @EnvSciRSC

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Silver nanoparticles lost in the first wash

An Environmental Science: Nano article highlighted in Chemistry World by Florence Greatrix

Scientists in Switzerland have discovered that more silver nanoparticles in clothing are released the first time they are washed than when they are sent to landfill.

Manufacturers add nanosilver to textiles to kill odour-causing bacteria © Shutterstock

Nanosilver’s antimicrobial properties often see it added to textiles, including socks and sportswear. Making, washing and disposing of the clothing can release the silver into the environment. Despite posing a low risk to humans, silver ions are toxic to many aquatic organisms and can accumulate in the food chain.

Commenting on the work, Amro El Badawy, an environmental engineer at California Polytechnic University, US, says:  ‘Deciphering the mechanisms of transformations of nanomaterials under the experimental conditions is key to our ability to predict any environmental implications – this work gets us closer to achieving this goal.’

Read the full ChemistryWorld article here.

Durability of nano-enhanced textiles through the life cycle: releases from landfilling after washing*
Denise M Mitrano, Pawena Limpiteeprakan, Sandhya Babel and Bernd Nowack
Environ. Sci.: Nano
, 2016, Accepted Manuscript
DOI:
10.1039/C6EN00023A

*Access is free through a registered RSC account until 11 May 2016 – click here to register

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Modelling in Environmental Nanotechnology

An Environmental Science: Nano themed collection

We are delighted to announce the publication of a themed collection on Modelling in Environmental Nanotechnology, guest edited by Mohammed Baalousha (University of South Carolina, US), Panos Georgopoulos (Rutgers University, US), Jamie Lead (University of South Carolina, US) and Dave Spurgeon (Centre for Ecology & Hydrology, UK).

This collection of papers presents state-of-the-art models for the fate, behaviour, exposure, uptake and toxicity of nanomaterials in the environment and in organisms, as well as a wide range of model types for environmental and biological processes affecting nanomaterial behaviour.

Read the full collection today: http://rsc.li/modelling

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International Conference on Environmental Effects of Nanoparticles and Nanomaterials

Message from the Meeting Chair, James Ranville

We are pleased to announce that registration and abstract submission for the 2016 International Conference on the Environmental Effects of Nanoparticles and Nanomaterials (ICEENN) is now open.

This marks the 11th year of the ICEENN, which  will take place August 14-18th 2016 in Golden, Colorado (USA). The abstract submission deadline is April 18th. To find out more about the meeting, register, submit an abstract, and book accommodation and social activities please visit the conference website.

This conference brings together participants from academia, industry, government agencies, and non-governmental organizations to present and discuss current research findings on environmental health and safety aspects of nanotechnology.

The conference format is that of plenary oral presentations and poster sessions.  Sessions are planned to cover topics that include:

• Advancements in nanomaterial analysis methods
• Surface chemistry of nanomaterials in complex matrices
• Release from consumer products and environmental fate
• In vivo and in vitro toxicology of nanomaterials
• Applications of nanomaterials in environment and health
• Environmental issues of production-scale nanotech
• Social and regulatory considerations of nanotechnology

A 2-day pre-conference workshop on nanoparticle characterization will precede the meeting. A number of social activities are planned. Updates to the website will be posted regularly. August is prime tourism season in Colorado so we strongly encourage you to book your accommodation early.

We look forward to welcoming you in Golden for the 2016 ICEENN!

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Insights from SNO 2014 Annual Conference

Nanotechnology and the Energy-Water-Food Nexus

In November 2014, the Sustainable Nanotechnology Organization (SNO), a non-profit, international, professional society, held its 3rd annual conference in Boston with over 220 participants in attendance. Drs. Jackie Isaacs of Northeastern University and Philp Demokritou of Harvard University co-chaired the meeting. SNO is dedicated to advancing sustainable nanotechnology around the world through education, research, and responsible growth of nanotechnology.

This themed collection is the summary of representative research papers presented at the Boston conference. Seven eminent scientists and engineers in the field of sustainable nanotechnology gave plenary lectures attended by participants from almost every U.S. state as well as many other countries. About 45% of participants were students, indicative of the recentness of the field.

Selected papers from the conference highlight how sustainable nanotechnology is leading the way to address economic development, global food supplies, as well as energy and water challenges while leaving minimal footprints that can give rise to environmental degradation.

Some of the papers represent the core aspects of sustainable nanotechnology, including biomedical applications, water treatment, green synthesis, life cycle assessments (LCA) and NanoEHS issues. Demokritou et al. present an integrated methodology for the assessment of environmental health implications during thermal decomposition of nano-enabled products.

Demokritou et al., DOI: 10.1039/C4EN00210E

An article by Vicki Grassian et al. reports an important finding that simple nanoscale materials can be complex when considering NanoEHS implications. A number of the fundamental research areas to address NanoEHS needs are suggested.

Grassian et al.

Grassian et al., DOI: 10.1039/C5EN00112A

In a review article by Gilbertson, Wender, Zimmerman, and co-workers, the authors summarize recent advances in human and aquatic ecotoxicity life cycle impact assessment for engineered nanomaterials (ENMs) and call for greater coordination between LCA modelers and experimentalists, including those who study fate and transport, environmental transformations, occupational exposure, and toxicology, to inform responsible development of nanotechnology, enabling the technology to reach its full potential.

Gilbertson et al.

Gilbertson et al., DOI: 10.1039/C5EN00097A

The development of nanomaterials and nano-enabled products in a “greener” manner will minimize any EHS implications while maximizing the societal benefits.  Companies working with engineered nanomaterials are expected to make tradeoffs on the costs associated with increased levels of occupational safety and potential environmental impacts. For example, Isaacs et al. present a paper on the economic analysis of carbon nanotube (CNT) lithium-ion battery manufacturing. These authors present a stochastic process-based cost model to investigate the cost drivers for the manufacture of multi-walled CNT nickel manganese cobalt batteries that are targeted for satellite and computer applications. Among other things their results underscore the need for safer manufacturing practices for CNT lithium-ion batteries for application in low and high production volume products such as satellites and portable computers, respectively.

Isaacs et al.

Isaacs et al., DOI: 10.1039/C5EN00078E

Greener nanotechnology can be the “role model” for industrial development in the 21st century. Sadik et al. demonstrate that a one-pot synthesis of silver and gold nanoparticles is possible using conductive, electroactive, and biodegradable polymers. In addition to modest cytotoxicity against non-cancerous, immortalized and cancerous cell lines, the synthesized nanoparticles exhibit excellent antibacterial activity against gram negative and gram positive bacteria.

Sadik et al.

Sadik et al., DOI: 10.1039/C5EN00053J

Pourzahedi et al. apply green chemistry and sustainable manufacturing to nanomaterial synthesis, with the goal of reducing life cycle energy use and environmental impacts. The authors use LCA to analyze and compare the environmental impacts of AgNPs produced through seven different synthesis routes (cradle-to-gate). LCA reveals both direct and indirect or upstream impacts associated with AgNPs. Results show that across synthesis routes, impacts associated with the upstream production of bulk silver itself are dominant for nearly every category of environmental impact, contributing to over 90% of life cycle burdens in some cases. The bio-based chemical reduction route has important tradeoffs in ozone depletion potential and ecotoxicity.

Pourzahedi et al.

Pourzahedi et al., DOI: 10.1039/C5EN00075K

The release of ENMs into the environment has led to concerns about the potential risks to food safety and human health. Ebbs et al. describe the extent of ENM uptake into plant foods. The authors focus on the accumulation of zinc, copper, or cerium in carrot exposed to metal oxide nanoparticles and metal ions. They demonstrate that ENMs are no more toxic than the ionic treatments and show a reduced accumulation in the edible tissues of carrot. The results demonstrate that the understanding of ionic metal transport in plants may not accurately predict ENM transport and that an additional comparative study is needed for this and other crop plants.

Ebbs et al.

Ebbs et al., DOI: 10.1039/C5EN00161G

Rodrigues et al. provide an assessment of the toxicity of exfoliated-MoS2 and annealed exfoliated-MoS2 towards planktonic cells, biofilms, and mammalian cells in the presence of electron donor.

Rodrigues et al.

Rodrigues et al., DOI: 10.1039/C5EN00031A

Lee et al. report the development of precisely engineered manganese oxide nanoscale particles for the sorption of uranium as uranyl in water. They synthesize nanoparticles via thermal decomposition of manganese oleate and then phase-transfer the particles into water using ligand exchange and bilayer stabilization methods. The resulting monodisperse suspensions demonstrate significantly enhanced uranyl adsorption as a function of size, surface coating chemistries, and solution pH.

Lee et al.

Lee et al., DOI: 10.1039/C5EN00010F

The fate of dysprosium oxide nanoparticles (Dy2O3) and their effects on natural biological systems are a growing concern. Oyanedel-Craver et al. have assessed the toxicity of nDy2O3 on Escherichia coli for concentrations between 0.02 and 2 mg/L exposed to three concentrations of NaCl and three glucose concentrations. Toxicity measurement of Dysprosium ion Dy(+3) suggest that it is the main contributor to the overall toxicity.

Oyanedel-Craver et al.

Oyanedel-Craver et al., DOI: 10.1039/C5EN00074B

Among other applications, engineered superparamagnetic nanoparticles have broad potential in biotechnologies, high contrast magnetic resonance imaging, and advanced environmental sensing and remediation technologies. Fortner et al. present the flexible surface design strategies for a variety of superparamagnetic iron oxide nanoparticles for applications in aqueous systems.

Fortner et al.

Fortner et al., DOI: 10.1039/C5EN00089K

Chen et al. describe the aggregation and interactions of chemical mechanical planarization nanoparticles with model biological membranes, focusing on the role of phosphate adsorption.

Loon Chen et al.

Chen et al., DOI: 10.1039/C5EN00176E

The difficulty of meeting the world’s energy demand is compounded by the growing need to protect human health and the environment. Nanotechnology will play a major role in the development of clean, affordable, and renewable energy sources. Soroush et al. demonstrate that silver nanoparticle (AgNPs)-decorated graphene oxide (GO) functionalized membranes exhibit super-hydrophilic properties with contact angles below 25°. The membranes also exhibit significant E. coli inactivation without adversely affecting the membrane transport properties. Such membrane could be employed as composites of forward osmosis and seawater desalination because of its energy efficiency.

Soroush et al.

Soroush et al., DOI: 10.1039/C5EN00086F

We hope you enjoy this issue which represents a snapshot of the wider conversation on the topic of sustainable nanotechnology. We also invite you to visit us at www.susnano.org as we develop a framework for using nanotechnology to address grand global challenges in the energy, water, and food sectors while maintaining a balance between the economic, environmental, and societal issues.

Enjoy this issue!

Wunmi Sadik, President & Co-founder
Barbara Karn, Executive Director & Co-founder
Jacqueline Isaacs and Philip Demokritou, SNO 2014 Co-Chairs

Read the full collection online today: http://rsc.li/sno

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Green-er gold nanoparticles

Green chemistry is hard to do. Here is another great step towards environmentally-conscious synthesis processes.

gold nano synthesis

Working in a university research laboratory, I am made aware, almost on a daily basis, of the amount of energy and chemicals we use and the amounts of—sometimes hazardous—waste we produce. Working in an environmental engineering research lab that has the word “sustainable” as part of its name, I am also well aware of how ironic that may seem.

As scientists, we want to be able to create the best, most precisely controlled, most reproducible nanoparticles and nanoparticle-containing experiments. Sometimes the cost for those conditions is high temperatures and large amounts of (sometimes harsh) chemicals (e.g., excess precursors and stabilizers). So even though the core motivation for our research is to benefit the environment, sometimes the methods we have to use in the lab are not completely environmentally friendly.

Researchers are becoming increasingly conscious that their research should also incorporate sustainability principles. It may not be possible to do research that is completely void of environmental impacts, but it’s very possible to make an effort into minimizing those impacts. This led to the establishment of the Twelve Principles of Green Chemistry, established in 1998 by Paul Anastas and John Warner.

Of these 12 principles, number six refers to energy efficiency. This work done by my colleagues Leng, Pati, and Vikesland addresses that principle by demonstrating the growth of gold nanoparticles at room temperature, resulting in significant energy savings.

By using gold seeds of about 18 nm in diameter as a starting point, they were able to produce gold nanoparticles of different sizes, ranging from 20 – 110 nm, at room temperature. The fact that nanoparticle growth happens slower at room temperature can be viewed simultaneously as a negative point (it takes longer to manufacture them) and a positive point (with a slower reaction rate, it may be possible to better understand the complicated mechanisms behind nanoparticle growth).

This work shows that we need to continue incorporating the principles of green chemistry and engineering into nanomaterial design to improve our current energy-intensive nanomaterial production practices.

To access the full article, download a copy for free by clicking the link below:

Room temperature seed mediated growth of gold nanoparticles: mechanistic investigations and life cycle assessment.
Weinan Leng , Paramjeet Pati and Peter J. Vikesland
Environ. Sci.: Nano, 2015,2, 440-453
DOI: 10.1039/C5EN00026B

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About the webwriter

Marina Vance is a PhD research scientist at Virginia Tech and Associate Director of @VTSuN. She is interested in air quality and environmental nanotechnology. You can find more information about her at mevance.com and you can find more articles by Nina in her author archive.

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Vicki Grassian moves to UC San Diego

Read more about the new affiliation of our Editor-in-Chief

We are delighted to share with our community that our Editor-in-Chief Professor Vicki Grassian has joined the Departments of Chemistry and Biochemistry, Nanoengineering and Scripps Institution of Oceanography at UC San Diego, USA.

Vicki Grassian, Distinguished Professor and Distinguished Chair of Physical Chemistry, left the University of Iowa, where she held appointments in the Departments of Chemistry, Chemical and Biochemical Engineering, and Occupational and Environmental Health.

Prof Grassian’s research focuses on fundamental molecular-based laboratory studies that provide a better molecular understanding of the surface chemistry of complex environmental interfaces.

Her projects include understanding the molecular level details of the heterogeneous chemistry of trace gases with particulate matter such as mineral dust in the atmosphere, dissolution and mobilization of Fe-containing particles, optical properties of atmospheric aerosol and applications and implications of nanoscience and nanotechnology in environmental processes and human health.

In the past five years, Vicki has received several awards for her research including the American Chemical Society National Award for Creative Advances in Environmental Science and Technology (2012), the Midwest American Chemical Society Award (2014) and the Royal Society of Chemistry John Jeyes Award (2014).

Her appointment at UC San Diego began on the 1st January 2016.

Please join us in wishing Vicki all the best in her new position in UC San Diego!

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