Incorporating
Nanotechnology
Concepts in a High
School Classroom
- Ritu Linhart
Oxygen-Sensing
Nanofiber Scaffolds for
Tissue Engineering
Applications
How in the world do you translate this
to a high school classroom lesson !
Why Nanofibers ?
high surface area
small pore size
high pore volume
Jan 2010
Science Editor
 Polymer nanofibers are being
investigated to harness the power of
movement.
 Now we could possibly convert energy
20 percent more efficiently than possible
until now.
 The clothes we wear will store all our
released energy, even during sleep and
we could use that energy to power up
wireless sensors or portable electronics.
Surface Area to
Volume Ratio
 The smaller something is, the
larger its surface area is compared
to its volume. This high surface-tovolume ratio is a very important
characteristic of nanoparticles.
Total Surface Area
Increases while Total
Volume Stays Constant
Melon Cubes with
Sugar !
Increased Reactivity !
 When something has more surface
area, there are more places for other
chemicals to bind or react with it.
 Catalysts, e.g.
 Think of crushed ice vs. cubed ice
 Nanoscale particles maximize surface
area, and therefore maximize possible
reactivity!
What is Nanofiber
Technology?
Used for Tissue Engineering
Applications
To design scaffolds from
biocompatible materials,
which encourage living cells to
repair and restore damaged
tissues
Nanofiber Production
Electrospinning Nanofibers
Electrospinning
Apparatus
Syringe Pump
High
voltage
power
supply
collector
The Electrospinning Process
 a high voltage power supply is used to supply the
necessary voltage to a conical metal reservoir filled with
the desired polymer solution.
 When the electrostatic repulsive forces become sufficient
to overcome the surface tension of the polymeric solution,
a “Taylor cone” is formed, and the fluid jet is ejected.
 As the polymeric solution jet travels further from the tip of
the metal reservoir, it becomes more destabilized,
creating what is known as a bending instability.
 The combination of electrostatic and mechanical forces
pulling the polymer solution from the metal reservoir to
the grounded collector result in stretching of the polymer
fiber, which leads to the collection of fibers with
submicron (<1 μm) or nanometer diameters: nanofibers.
Oh No !
What Happened to My
Nanofibers!
A
Competition Between
the Forces !
 Surface Tension forces caused the
polymer solution to form beads during
the electrospinning process
 Process parameters needed to be
optimized
 Research does not follow YOUR time
schedule!
Hydrophilic vs.
Hydrophobic
 Make your own Magic Sand !
 It’s silicon dioxide coated with
Scotchgard fabric protector.
 When Magic Sand is added to water, it
appears to bond to itself, forming
interesting shapes.
 But when the water is decanted, the
sand is dry, and the shapes
disappear.
Where Did Magic Sand
Come From?
 It was used initially to purify water
systems from oily contaminants.
 It resembles the fumed silicon dioxide
used for optical clarity in products such
as coatings, adhesives, cosmetics,
inks, plastics, and rubbers.
 It is also used as an anti-caking agent
to promote the free flow of dry
powders.
Seeing is Believing !
Optical properties of nanofibers are
different from those of macrofibers
My PCL polymer solution was clear, but the
nanofibers were white
Use food coloring and almond essence to
demonstrate the absence of color in a
solution that has been diluted down to one
billionth of the original concentration.
Discuss how particles at nanoscale are
present even though they can’t be seen!
Optical Properties of
Nanomaterials
 Sunscreen is usually white
 It has white ZnO macro-particles that
absorb ultraviolet light and protect
our skin against sunburn
 ZnO nanoparticles, however, are
clear and scatter away all visible
light, yet absorbing uv light still
http://micro.magnet.fsu.edu/primer/java/scienceopticsu/powersof10/
Our whole
solar
system is a
single dot
on this
picture
There are
200-r400
billion suns
in our
galaxy
alone
The Milky Way
 Our Milky Way is spiral and rotating
at a speed of 370 miles/second
 It takes our sun 230 million years to
make just 1 revolution
 Albert Einstein was the first person
to realize that empty space is not
nothing.
 The matter we see is only 5% of
total matter; rest is dark matter
Other Relevant Topics
Strength of polymer nanofiber
scaffolds for bone tissue
applications
Electrical conductivity and
magnetic properties of the
nanofibers
Biological compatibility of the
nanofibers
Medical Applications of
Nanofibers
detection and treatment of tumors
therapies and drug delivery to damaged
tissue
As bandage for burn victims
Negative Implications
of Nanotechnology !
nanomaterials can move with
great speeds through aquifers
and soil
nanomaterials provide a large
and active surface for absorbing
smaller contaminants, such as
cadmium and organics.
Toxicity!
 Sunscreens
 Cosmetics
 Moisturizers
 Facial Soaps/washes
 Presence of nanoparticles
produces reactive oxygen species
(ROS) when entering a punctured
skin membrane
 which are basically cancer causing
free radicals
What Did I Gain From
My RET Experience?
 Knowledge and hands-on experience
with cutting edge technology
 Valuable Research Skills
 Modern Lab Techniques &
Instrumentation use, e.g. charge gun
and SEM training
 The Reality of Actual Research (it’s not
as glitzy as it sounds!)
By-Products of my
RET Experience !
 Published abstracts, papers, and/or
posters
 Self-confidence and Excitement
 Added Respect from Students
 Pride in being a high school teacher
 Increased Morale/Motivation
 Attending various Conferences and
Presenting the Research
Personal Long-Term
Goal
Develop a nanotechnology course
to be taught at the high school
level
Introduce this course at my school
and later to the rest of the state