Tag Archives: meadow

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.