Using plausible applications to explore the responsible use of engineered nanomaterials and other advanced materials

by Andrew Maynard on July 18, 2013

How do you identify potential health risks associated with engineered nanomaterials and other advanced materials, and develop strategies to reduce or avoid them? Last week, thirteen experts participated in a workshop at the Royal Society in London to explore how speculative yet plausible case studies on advanced materials and their potential uses can provide insight on emergent risks – and approaches to managing them.



The workshop – organized by the University of Michigan Risk Science Center and supported by the think tank MATTER – set out to explore a number of questions surrounding the responsible use of advanced materials, including:

  • Whether developing highly plausible case studies around speculative future products can provide useful insight into the potential risks – and risk mitigation strategies – associated with advanced materials
  • Whether case studies along these lines could help confine the near-infinite number of “unknown unknowns” associated with the possible risks of advanced materials to a much smaller number of “plausible unknowns”; and
  • Whether taking a product-centric approach to ensuring the acceptably safe development and use of advanced materials provides greater insight than taking a materials-centric approach in some cases?

Over the past decade, considerable research has focused on the possible health risks associated with engineered nanomaterials.  These are materials designed to have specific properties by nature of how they are engineered at a very fine size scale.  As a class of material they are intellectually and commercially interesting – they demonstrate unusual behaviors, can add value to certain products because of this, and may in some cases provide new approaches to addressing social and environmental challenges. Yet from a health risk perspective, engineered nanomaterials as a category of materials present a number of unique challenges.  They do not, for instance, represent all emerging materials that have the potential to affect people’s health and safety.  And there is a danger that emphasizing them over other materials has led to an under-emphasis on or distraction from other potentially dangerous materials that don’t fit the “engineered nanomaterial” rubric.

What’s more, characteristics that typically differentiate engineered nanomaterials from other materials are only indirectly associated with health impact.  Size for instance – a key differentiator of nanomaterials – may influence exposure and hazard, but is not necessarily a key indicator of risk.  And novel physical or chemical behavior – another characteristic of engineered nanomaterials – is not necessarily a strong predictor of risk.  To compound this, an emphasis on scale and novelty rather than end-use and plausible biological behavior can sometimes encourage speculation on a near-infinite number of risk “unknown unknowns”.  These are academically interesting, but potentially obscure the “plausible unknowns” that are important for responsible development and use.

As a result, the wider domain of advanced materials – materials that are intentionally designed and engineered to have properties that lead to new or enhanced products regardless of size – is not particularly well served in terms of identifying potential risks and strategies for addressing them.  For example, searching Web of Science for “advanced material*” AND (risk OR safety) in Topic between 2000 and 2013 returns 70 publications (search date, July 16 2013).  In contrast, the search nano* AND (risk OR safety) over the same period returns 7482 publications.  The difference is in part due to nanomaterials often not being referred to as advanced materials.  But it also indicates a dearth of risk-focused research on materials identified as advanced materials that are not also identified as engineered nanomaterials.


One possible way forward to exploring the potential risks and safe use of advanced materials more generally is to approach potential impacts from a product-perspective.  Proactively looking forward to products likely to enter the market in the near future requires some speculation on the nature of emerging materials and the types of products in which they will be used – a challenge in itself, and one open to highly speculative discussions concerning their “unknown unknowns”.  But developing speculative case studies is in principle a powerful tool if the case studies are grounded in economic, social and technological plausibility.  In other words, this is an interesting approach if the product case studies are technologically feasible, if they are likely to sit comfortably with people who produce, use and are affected by them, and if they describe products that have a reasonable chance of being commercially introduced and successful.

This is the approach that this workshop set out to explore. Over two days, the thirteen participants focused on developing four such plausible, speculative case studies.  Recognizing that a different group of people would undoubtedly come up with four different case studies, the emphasis of the workshop was primarily on the process undertaken more than the applications and materials that were imagined.  That said, both the process and the specific applications proved to be illuminating.


At the heart of the process was a strict adherence to plausibility.  Each potential case study was vetted in terms of its technological feasibility and its likely commercial viability.  This meant being specific about the nature of a proposed material, and the way it would be used in a product.  A case study did not make the cut if the participants couldn’t describe the starting material and how it would be used in a specific product (and why) that aligned with a commercial opportunity.

Once the product cases were developed, the discussion turned to potential material releases, exposures and health impacts.  These discussions did not go too deep into the potential impacts, as the workshop was looking at process rather than drawing conclusions on specific materials.  Nevertheless, they were revealing.

This process was aided by having a very diverse “brains trust” around the table – the workshop included expertise on advanced materials, product development, technology innovation, commercialization, design, risk assessment, public perception and governance.


Coming out of the workshop were a number of initial insights that arose from discussions:

  • Discussing speculative yet plausible and specific applications of advanced materials helped focus the follow-on discussions over their potential risks in a useful way.  While the four case studies developed represent a very small number of potential materials and products, the exercise was useful in moving the conversation from highly speculative risks associated with materials to more specific plausible risks.  In this respect, the process was useful in helping to focus evaluation on the likely relevance of speculative or imagined risks associated with specific advanced materials.
  • In each case study developed, participants struggled to imagine scenarios where the use of the material would lead to emergent risks that were significant and difficult to address using current tools and approaches.  This will have been influenced by the people around the table and the cases developed, and is not an indication in itself that such risks will not emerge.  Yet constraining the conversation to technologically, socially and commercially plausible products made identifying disruptive emergent risks a tough challenge.
  • The plausible, speculative case study approach helped clarify distinctions between research to extend knowledge of potential risks and research to inform action on plausible risks.  The process followed was useful to help identify practical situations where an advanced material in a product may lead to health impacts if used in a certain plausible way, as well as helping identify risk management options and areas where more research would be needed.
  • The process also highlighted the dangers of becoming complacent over advanced material risks, and failing to invest sufficient effort in exploring the “unknown unknowns” – not necessarily as a way of directly guiding production, policy and purchasing decisions, but as a way of ensuring that, given significant unidentified risks, they are subsequently identified and used to inform decisions in a timely manner.

The four case studied developed included the use of:

  • graphene in conducting inks used to print inexpensive functional labels on consumer products;
  • cadmium telluride quantum dots as a component of roll-on-roll flexible photovoltaic materials used to make inexpensive solar cell balloons;
  • micrometer scale mesoporous amorphous silicon dioxide particles for local controlled-release drug delivery from implanted medical devices;
  • cultivated recombinantly engineered tobacco mosaic virus as a template for platinum shell-based nanoparticles used in a heterogeneous catalyst for splitting water to hydrogen and oxygen under sunlight.

These cases were developed from a product-based initial vision and most-plausible parameters for anticipating technological advances, regulatory environments, and commercial incentives for product development.

Outputs from the workshop will include a book chapter in the second edition of Nanotechnology Environmental Health and Safety: Risks, Regulation and Management (Micro and Nano Technologies) (eds. Matt Hull and Diana Bowman) – forthcoming; peer reviewed publications on the use of plausible speculative case studies in exploring advanced materials safety; and more widely accessible information for a broad audience on the process, the case studies and the key findings.


From left to right: Matt Hull, Andy Goodwin, Andrew Maynard, Barry Park, David Grainger, Nick Green, Vicki Stone, Diana Bowman, Steffi Friedrich, Tim Harper, Ben Trump. Not in photo: James King and Hilary Sutcliffe (behind the camera)

The workshop was organized by the University of Michigan Risk Science Center in partnership with Matter, and included:

 July 29 2013 – minor editorial updates to text

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