Tag Archives: naturally occurring nanoparticles

Nanoparticles and the gut health of major living species of animals

A July 27, 2020 news item on Nanowerk announces research into gut health described as seminal (Note: A link has been removed),

An international team of scientists has completed the first ever study into the potential impact of naturally occurring and man-made nanoparticles on the health of all types of the major living species of animals.

Conceived by researchers at the University of Plymouth, as part of the EU [European Union] Nanofase project, the study assessed how the guts of species from honey bees to humans could protect against the bioaccumulation and toxicological effects of engineered nanomaterials (ENMs) found within the environment.

A July 27, 2020 University of Plymouth press release, which originated the news item, provides more detail,

It showed that the digestive systems of many species have evolved to act as a barrier guarding against the absorption of potentially damaging particles.

However, invertebrates such as earthworms also have roving cells within their guts, which can take up ENMs and transfer them to the gut wall.

This represents an additional risk for many invertebrate species where the particles can be absorbed via these roving cells, with consequent effects on internal organs having the potential to cause lasting damage.

Fortunately, this process is not replicated in humans and other vertebrate animals, however there is still the potential for nanomaterials to have a negative impact through the food chain.

The study, published in the July [2020] edition of Environmental Science: Nano, involved scientists from the UK, the Netherlands, Slovenia and Portugal and focused on particles measuring up to 100 nanometres (around 1/10 millionth of a metre).

It combined existing and new research into species including insects and other invertebrates, fish, birds, and mammals, as well as identifying knowledge gaps on reptiles and amphibians. The study provides the first comprehensive overview of how differences in gut structure can affect the impact of ENMs across the animal kingdom.

Richard Handy, Professor of Environmental Toxicology at the University of Plymouth and the study’s senior author, said:

“This is a seminal piece work that combines nearly 100 years of zoology research with our current understanding of nanotechnology.

“The threats posed by engineered nanomaterials are becoming better known, but this study provides the first comprehensive and species-level assessment of how they might pose current and future threats. It should set the foundations for understanding the dietary hazard in the animal kingdom.”

Nanomaterials come in three forms – naturally occurring, incidentally occurring from human activities, and deliberately manufactured – and their use has increased exponentially in the last decade.

They have consistently found new applications in a wide variety of industrial sectors, including electrical appliances, medicines, cleaning products and textiles.

Professor Handy, who has advised organisations including the Organisation for Economic Co-operation and Development and the United States National Nanotechnology Initiative, added:

“Nanoparticles are far too small for the human eye to see but that doesn’t mean they cannot cause harm to living species. The review element of this study has shown they have actually been written about for many decades, but it is only recently that we have begun to understand the various ways they occur and now the extent to which they can be taken up. Our new EU project, NanoHarmony, looks to build on that knowledge and we are currently working with Public Health England and others to expand our method for detecting nanomaterials in tissues for food safety and other public health matters.”

Here’s a link to and a citation for the paper,

The gut barrier and the fate of engineered nanomaterials: a view from comparative physiology by Meike van der Zande, Anita Jemec Kokalj, David J. Spurgeon, Susana Loureiro, Patrícia V. Silva, Zahra Khodaparast, Damjana Drobne, Nathaniel J. Clark, Nico W. van den Brink, Marta Baccaro, Cornelis A. M. van Gestel, Hans Bouwmeester and Richard D. Handy. Environmental Science: Nano, Issue 7 (July 2020) DOI: 10.1039/D0EN00174K First published 27 Apr 2020

This article is open access.

If you’re curious about Nanofase (Nanomaterial FAte and Speciation in the Environment), there’s more here and there’s more about NanoHarmony here.

Chinese scientists strike gold in plant tissues

I have heard of phytomining in soil remediation efforts (reclaiming nanoscale metals in plants near mining operations; you can find a more detailed definition here at Wiktionary) but, in this case, scientists have discovered plant tissues with nanoscale gold in an area which has no known deposits of gold. From a June 14, 2018 news item on Nanowwerk (Note: A link has been removed),

Plants containing the element gold are already widely known. The flowering perennial plant alfafa, for example, has been cultivated by scientists to contain pure gold in its plant tissue. Now researchers from the Sun Yat-sen University in China have identified and investigated the characteristics of gold nanoparticles in two plant species growing in their natural environments.

The study, led by Xiaoen Luo, is published in Environmental Chemistry Letters (“Discovery of nano-sized gold particles in natural plant tissues”) and has implications for the way gold nanoparticles are produced and absorbed from the environment.

A June 14, 2018 Springer Publications press release, which originated the news item, delves further and proposes a solution to the mystery,

Xiaoen Luo and her colleagues investigated the perennial shrub B. nivea and the annual or biennial weed Erigeron Canadensis. The researchers collected and prepared samples of both plants so that they could be examined using the specialist analytical tool called field-emission transmission electron microscope (TEM).

Gold-bearing nanoparticles – tiny gold particles fused with another element such as oxygen or copper – were found in both types of plant. In E. Canadensis these particles were around 20-50 nm in diameter and had an irregular form. The gold-bearing particles in B. nivea were circular, elliptical or bone-rod shaped with smooth edges and were 5-15 nm.

“The abundance of gold in the crust is very low and there was no metal deposit in the sampling area so we speculate that the source of these gold nanoparticles is a nearby electroplating plant that uses gold in its operations, “ explains Jianjin Cao who is a co-author of the study.

Most of the characteristics of the nanoparticles matched those of artificial particles rather than naturally occurring nanoparticles, which would support this theory. The researchers believe that the gold-bearing particles were absorbed through the pores of the plants directly, indicating that gold could be accumulated from the soil, water or air.

“Discovering gold-bearing nanoparticles in natural plant tissues is of great significance and allows new possibilities to clean up areas contaminated with nanoparticles, and also to enrich gold nanoparticles using plants,” says Xiaoen Luo.

The researchers plan to further study the migration mechanism, storage locations and growth patterns of gold nanoparticles in plants and also verify the absorbing capacity of different plants for gold nanoparticles in polluted areas.

For anyone who’d like to find out more about electroplating, there’s this January 25, 2018 article by Anne Marie Helmenstine for ThoughtCo.

Here’s a link to and a citation for the paper,

Discovery of nano-sized gold particles in natural plant tissues by Xiaoen Luo (Luo, X.) and Jianjin Cao (Cao, J.). Environ Chem Lett (2018) pp 1–8 https://doi.org/10.1007/s10311-018-0749-0 First published online 14 June 2018

This paper appears to be open access.

A debate about engineered nanoparticles and naturally occurring nanoparticles

Thanks to Marina Vance’s Aug. 7, 2015 posting for the Environmental Science: Nano blog I have found an article which constitutes a debate about engineered and naturally occurring nanoparticles (Note: Links have been removed),

Summer is almost over and so is a whirlwind of environmental engineering- and nanotechnology-related conferences. At a previous environmental nanotechnology-related conference, I had the great experience to participate in a lively debate on a very fundamental, albeit not often asked question in our field: is nanotechnology novel?

In this recently published paper, Hochella, Spencer, and Jones present an overview of this unexpected debate. Jones moderated a discussion in which Hochella and Spencer, two experts in their respective fields of nanogeoscience and electrical engineering/material science, brought their arguments for and against the following statement:

“The magic of nanomaterials is not new: nature has been playing these tricks for billions of years.”

The printed debate Vance is referring to was published in Dec. 2014. Here’s a link and a citation,

Nanotechnology: nature’s gift or scientists’ brainchild? by Michael F. Hochella, Jr., Michael G. Spencer, and  Kimberly L. Jones. Environ. Sci.: Nano, 2015,2, 114-119 DOI: 10.1039/C4EN00145A First published online 02 Dec 2014

It is an open access paper.

I thought a few excerpts might be in order,

In the field of environmental nanotechnology, opinions on the novelty of engineered nanomaterials vary; some scientists believe that many engineered nanomaterials are indeed unique, while others are convinced that we are simply fabricating structures already designed in nature. In this article, we present balanced, objective evidence on both sides of the debate. While the idea of novel nanomaterials opens the mind to imagine truly unique structures with architectures unparalleled in nature, the idea that these structures have related analogs in nature has environmental relevance as scientists and engineers aim to design and manufacture more sustainable and environmentally benign nanomaterials.

The ‘there’s nothing new under the sun’ part of the debate (Note: Links have been removed),

For example, the 1996 Nobel Prize in Chemistry was awarded to Robert F. Curl Jr., Sir Harold Kroto, and Richard E. Smalley for the discovery of fullerenes in 1985. Since then, naturally-occurring and “incidental” fullerenes have been found in everything from soot14 to deep space.15,16 It is arguable that fullerenes are present in unimaginable quantities, in every conceivable configuration, throughout the universe.16 And there is a lot of room in our universe (currently measured at 1024 km across) to do it with the full compliment of the periodic table spread throughout. Temperatures and pressures just within our own solar system (not including our sun) range from 3 to 7000 K and from 10−7 to 106 atmospheres pressure. And in the Milky Way alone, there are over 100 billion stars, and roughly that many planets, including a remarkable number of Earth-sized planets orbiting Sun-like stars.17 Yet our galaxy is only one of more than 100 billion galaxies, meaning the number of stars, planets, comets, asteroids, etc. truly defy comprehension. Back here at our infinitesimally small corner of the universe, just on and near Earth’s surface alone, it has been estimated that natural biogeochemical processes produce many thousands of terragrams (1 Tg = 1 million metric tons) of inorganic, organic, and “mixed” nanomaterials per year in a much wider variety than we can possibly presently know (Fig. 1).18 And the naturally-occurring nanomaterials that we have observed to date exhibit an astounding range of variety and complexity.19 In contrast, the current estimates of the annual manmade production of high-tonnage nanomaterials (nano-TiO2; nano-CeO2; carbon nanotubes; fullerenes; nano-Ag) are in the ballpark of hundredth to thousandth of Tg per year,20,21 roughly five to six orders of magnitude less than nature’s bounty, and by comparison, limited in compositional and structural variation.

And, this is the ‘of course, we’re doing something new’ side of the debate (Note: Links have been removed),

This idea can be clearly demonstrated by examining a natural meadow (Fig. 4a) and a garden (Fig. 4b). The meadow is the subject of the scientist who seeks to find out the general physical laws, which underpin the structure and function of the meadow. The engineer can be closely identified with the artist, who in the garden weaves the natural element found in the meadow with powerful effect creating something, which is an amalgamation of nature and man.29 Florman30 summarizes this close relationship between the artist and engineer “But of course we rely upon the artist! He is our cousin, our fellow creator”. Man made nanomaterials distinguish themselves from natural materials through several properties. These properties include order, purity, and scale. These are properties that natural materials often do not have. It is clear that the ability of engineers to fabricate and control nanomaterials is not rivalled by nature.

The summary and implications draws the ideas together,

When determining whether ENMs are truly novel or not, one must realize that we have only just begun to interrogate the Earth’s surface and atmosphere for evidence of these structures, and newly identified, naturally occurring structures are being discovered everyday. At the same time, creative engineers are pushing the limits of discovery to design nanostructures with novel shapes, configurations and properties. At some point, the discovery of naturally-occurring nanomaterials may converge with new ENMs, but in the meantime, scientists and engineers must work together to increase the speed of discovery on both sides of the debate. As we continue to develop nanomaterials for applications, it is important to be aware of natural analogues in order to predict potential environmental and health impacts as well as inform the design and manufacture of nanomaterials with lower likelihood of environmental risks.

I encourage you to read the whole debate if you have the time.