Nanoscience in Nature
Or
“Why Don‟t Water Striders Get Wet?”
and Other Burning Questions
By Jeannie Nye and Andrew Greenberg
Lake Mills Middle School
And University of Wisconsin-Madison
So, Why Don’t Water Striders Get Wet?
Water striders are able to “walk on water” for a number
of reasons. Striders are assisted by five things:
•surface area
•gravitational forces Tell me more! (Click here.)
•surface forces (van der Waals force)
•a waxy (hydrophobic) surface on their legs
And most important - Tell me more!
•The microhairs on their feet are
„nano-groovy‟ ! Microhairs
Nanogrooves on
microhairs
http://whyfiles.org/shorties/walk_on_water.html
Sticky Spider Toes
These are the single hairs
(setae) that make up the Water strider toes
tuft of hair on the bottom help keep it dry, but
of a jumping spider‟s foot. this spider’s toes
help make him
The oval represents the sticky!
approximate size of the
foot magnified to 270x.
This picture, magnified
8750x, shows the very
dense nanosized setules on
the underside of just one of
those many seta (hairs)
shown in the picture above.
http://www.primidi.com/2004/04/26.html
Tell me more!
Lots of nano-toes!
• Beetles and flies also have nanostructures that help them stick to walls,
ceilings and what appear to be smooth surfaces. Tell me more!
• http://shasta.mpi-stuttgart.mpg.de/biomaterials.html
http://shasta.mpi-stuttgart.mpg.de/research/Bio-tribology.htm
How sticky?
As sticky as a … Gecko?
•500,000 hairs per toe
•Hundreds of nanoprojections (spatulae)
per hair
•Adhesive force in one foot = 100
newtons
•One dime-sized spot could lift a child
http://pubs.acs.org/cen/critter/gecko.html
weighing 45 pounds.
http://www.cbid.gatech.edu/resources.htm
If their feet are that sticky, how do they pick up their feet?
How Can a Gecko Lift Its Foot Off of a Surface?
These lizards uncurl their toes like a paper party favor whistle
when putting their feet down and peel the toes back up as if
removing a piece of tape when they step away.
http://pubs.acs.org/cen/critter/gecko1.html
How strong?
As Strong as… Silk?
• The nanometer-sized biodegradable
threads of spider silk are stronger, by
weight, than high-tensile steel.
• It is also elastic enough to stretch up
to 10 times its initial length.
Toucan Beaks - Strong and Light
• The exterior of the
toucan beak is made
up of overlapping
nanosized tiles of
keratin, the same
protein that makes up
hair, fingernails, and
Keratin tiles glued together
horn.
http://www.nuthatch.birdnature.com/jan1897/touc
an.html
The interior of the beak is a
rigid foam made of a network
of nanosized bony fibers
connected by membranes.
This allows the beak to absorb
high-energy impacts.
Foam-like interior made of bony http://search.eurekalert.org/e3/query.html?qt=toucan&col=ev3r
fiber and drum-like membranes el&qc=ev3rel
http://pubs.acs.org/cen/news/83/i50/8350toucan.html
Nature uses Light
on the Nanoscale
What Makes Color?
There are three possible reasons for color:
1. One reason is pigment. If
color is due to pigment,
the color never changes.
For example, a bluejay is always blue. Though
pigment isn‟t based on nanoscience, the next two
examples of ways to create color are based on
nanoscience.
http://acept.la.asu.edu/PiN/rdg/interfere/interfere.shtml
Or Could Color Be Nanoscopic?
These nanostructures
don’t just make me
2. The colors of beetle and butterfly wings pretty. They also
keep me clean by
come from the scattering of light. shedding water and
dirt!
Light hits the nanostructures on their scales.
These nanostructures are typically smaller
than the wavelengths of visible light (smaller
than 400 nanometers, for example).
Tell me more! (weblink)
http://pubs.acs.org/cen/critter/butterfly.html
Color Can Be Iridescent, Too!
3.The third reason for color is
the interference of different
wavelengths of light (like oil on
water).
Thin films are made of nanoparticles,
smaller than 400 nanometers, that
produce iridescent (rainbow-like) colors
when light strikes them.
Iridescent colors change when you look at
the object from different angles.
Tell me more! (weblink)
http://acept.la.asu.edu/PiN/rdg/interfere/interfere.shtml
http://www.ptfe.gatech.edu/faculty/mohan/MSLAB-research-nanobiooptics.htm
Squid Lights
on a Nanoscale
Would
somebody turn
on the lights,
please? The Hawaiian bobtail squid uses a two part
process to hide from predators at night.
First, it has a light-producing organ on
its underside. How does it produce
light? Why, it contains bacteria that
produce luminescent light on the
nanoscale.
• Secondly, the squid has stacks of
silvery nanoplatelets made of proteins
behind the tissue to reflect the light
downward from the squid.
• The light prevents it from casting a
shadow when seen from above or
forming a silhouette when seen from
below.
http://pubs.acs.org/cen/topstory/8202/8202notw3.html
“You Light Up My Life”
or
Bioluminescence Basics
•Bioluminescence in fireflies is nanoscale. The
glow is caused by the exciting of electrons by a
firefly’s enzyme.
What’s an
enzyme?
•When the electrons quiet down and go back to
their stable state, they give off light.
•They glow to attract mates and communicate.
•Angler fish use
bioluminescent lures
to attract fish.
http://pubs.acs.org/cen/science/84/8414biolum
.html
http://www.anglerfish.info/
A “Blue Light Special”
• Tiny crustaceans, Ostracods, also known as
"seed shrimp" or "sea fireflies," also use this
enzyme to produce bioluminescence in courtship.
The males produce blue dots in the water, which
are used to attract mates.
A close-up using a scanning
electron microscope
http://www.pisces-conservation.com/index.html?softost.html$softebookmenu.html
http://pubs.acs.org/cen/science/84/8414biolum.html
Jellyfish Lights
A jellyfish-type invertebrate,
called a siphonophore, uses red
bioluminescent lures created at
the nanoscale to attract prey.
Doesn‟t it seem odd that it
would use red light since red
isn‟t easily visible underwater?
Click here for a weblink to a video and lesson
on bioluminescent deep sea organisms.
http://www.coml.org/medres/high2005/highlightimages.htm
Hippo Sweat is Nanoscience?
Hippo sweat contains
compounds that absorb light in
the range of 200 – 600
nanometers. This compound
protects the hippo‟s skin like
sunscreen.
http://www.pbs.org/kratts/world/africa/hippo/index.html
One of the compounds in hippo sweat,
hipposudoric acid, inhibits bacterial growth and is
hydrophilic, too. Can you think of ways the hippo
benefits from these properties?
http://pubs.acs.org/cen/news/8222/8222notw9.html
Get Ready, Get Set,
Drink!
• Imagine you‟re a very thirsty tiny beetle in a
desert. How can you get a drink?
• The Namib desert beetle in the deserts of
southwest Africa has a novel idea.
• First it must collect drinking water using its
wings, which are waxed and covered with
raised unwaxed nanobumps. The bumps attract
water (hydrophilic). When enough water
collects it rolls down the waxy areas, which
repel water (hydrophobic), into the beetle‟s
mouth.
Click here for more information!
http://www.newscientist.com/article.ns?id=dn1508
A closeup of the nanobumps on a beetle’s back.
http://biomechanics.bio.uci.edu/_html/nh_biomech/namib/beetle.htm
Speaking of Water…
Let’s Look at Snowflakes!
Have you ever looked
closely at a snowflake
and wondered why
they‟re all different?
It’s Because They’re Nano-Flakes!
They build up on the nanoscale, one
molecules at a time. Their size and shape is
determined by the altitude and air pressure
where they are formed.
Use the same bottom up
construction to make your own
snowflakes by clicking on this web
link:
http://profhorn.meteor.wisc.edu/wxwise/snowflak
e/makesnow.html
For more information click on the following link:
http://www.its.caltech.edu/~atomic/snowcrystals/primer/primer.
htm
Nanoscience Is Everywhere
in Nature
• Living cells have been using their own nanoscale
devices to create structures one atom or
molecule at a time for millions of years.
• To be specific, DNA is copied, proteins are
formed, and complex hormones are
manufactured by cellular devices far more
complex than the most advanced manufacturing
processes we have today. Click here for an example!
http://dallas.bizjournals.com/dallas/stories/2001/09/10/focus2.html?page=3
Mother Nature
Mankind has always found inspiration in
Mother Nature. Today developing
technologies allow us to probe and better
understand the nanoscience of Mother Nature.