Transcriber: Helen Chang Reviewer: Rhonda Jacobs
Solar panels, light-weighted drones, toothpaste, self-cleaning windows,
sports socks and medicines -
what is the commonality of these products?
They're all containing nanomaterials.
Metal alloy nanomaterials are used in solar panels
to improve sunlight capturing and transformation into energy.
In sunscreens, titanium dioxide intensified nanoparticles
are used to block the sun, as well as being a whitener in toothpaste.
Various types of nanomaterials are used to make surface smoother, stronger,
light-weighted and more scratch resistant.
These are merely a few examples,
but a list of nano-embedded products is endless.
Freely quoted from Ig Nobel Prize winner Professor Wade Adams,
“Nanotechnology is making small stuff do big things and then selling them.”
And I explicitly say “and then selling them,”
because we’re now in a period
that many engineered nanomaterials found their way into products.
Nanomaterials are microscopically small particles.
And to give you an idea,
that is roughly a hundred thousand times thinner than a human hair.
As it turns out, it is around this scale
that many materials start to exhibit a [Inaudible] of new properties.
And it is these properties
that are ultimately capitalized upon in products and technologies.
As with any implementation of new materials and substances
in our day-to-day lives,
we need to ask ourselves whether their use is safe for people,
ecosystems, and ultimately for the planet.
In the last 50 years, the safety of nanomaterials has been studied,
and it is found that nanomaterials hardly induce acute toxicity
at realistic environmental doses.
That is why these nanomaterials look “green and clean.”
However, my team of eco-toxicologists found out
that the current test used to test safety overlooked various factors,
which are likely to play a role
when nanomaterials are emitted to the environment,
for instance, in water and soil.
One of these factors is exposure time.
To come to this conclusion,
my team evaluated the effects of titanium dioxide nanoparticles,
for instance found in sunscreens,
on the development of small water organisms.
Water flea are small crustacean species that can be found in all freshwaters
and are often used in laboratory tests.
Here you see a water flea giving birth.
The results of our studies showed
that measuring one generation of water flea
exposed to [Inaudible] realistic doses
did not give adverse effects.
Whereas when we extended the timeframe of the experiment
by analyzing the development
of several successive generations within the population,
we found that the observed sensitivity to the tested nanomaterial
was significantly and thus affecting reproduction.
So while we wouldn't see any effect of titanium dioxide nanoparticles,
if we would follow the current guidelines for acute tests,
our study showed that when we extended the exposure duration,
the nanoparticles did cause negative effects.
We continued our research by looking into interactions between freshwater organisms
and if their relationships were impacted by nanomaterials.
We examined to which extent
nanomaterials are affecting zebrafish larvae and their microbes.
Zebrafish larvae come from the tropics and are common test organisms,
because their development is easy to follow.
Like all larger organisms in and on their body,
the fish larvae host a variety of microbes,
and this is called the microbiome that helps organisms with vital processes
such as immune defense and metabolism.
We found that certain types of nanomaterials could disrupt interactions
between the zebrafish and their microbiome,
but also that the microbiome can serve as a defense line
against the toxicity of other nanomaterials.
While our results were clear and published,
the current guidelines for nanoparticle safety testing do not include these tests.
In a completely different setting, we observed a similar process.
When examining freshwater crustaceans like isopods,
we found that these organisms exhibit low sensitivity to nanoparticles.
However, we found that when we exposed the food of the isopods
to the same nanoparticles,
the microbial community present at the surface of the food
was altered in composition.
And through a series of subsequent experiments,
we found that this alteration of the food
resulted in a reduced growth and development of isopods.
Here again we see that organism relationships
are important to consider when evaluating nano-safety.
After all these revealing experiments,
I decided to take nano-safety testing to the next level.
We built an outdoor living lab.
We dug ditches of 10 meters long
in which we could study the effects of nanoparticles
on whole freshwater communities.
And we found that individual planktonic species
and the communities they were part of
are adversely impacted by concentrations which are orders of magnitude lower
than those at which adverse effect had been observed
in laboratory scale toxicity tests.
So we now know that certain nanoparticles can cause effects
when brought into the environment,
effects we would never have found when conventional lab testings.
I’m a technology lover, and it is amazing to witness and experience
the benefits of nanotechnology.
We are at the stage in history
where we have more tools and more funds available than ever
to estimate the impact of our actions.
And as many applications of nanotechnology are still in the developmental stages,
we have still the chance to prevent the planet to be polluted.
Many of you may work in industry
or at companies that produce goods and products.
My plea is to question now and then
if the safety testing has been done,
and if so, if it has been done accurately.
Act proactive and invest in safety testing
during the early phases of development,
thereby considering the interaction that happen in nature,
being the millions of organisms and communities living together.
In doing so, we can continue working on making small stuff do big things
while protecting the world around us,
not only for you and me,
but for the future generations.