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Case Study in Nanotoxicology
Michael A. Trush, PhD
Johns Hopkins University
Section A
Basic Aspects of Nanotechnology and Nanoparticles
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What Is Nanotechnology ?
! Nanoscience and nanotechnology involve:
- Studying and working with matter on the nanoscale
! One nanometer is one-millionth of a millimeter
! One human hair: around 80,000 nanometers in
width
- Involves research and technology development at the
atomic, molecular, or macromolecular levels using a
length scale of approximately one to one hundred
nanometers in any dimension
- The creation and use of structures, devices, and
systems that have novel properties and functions
because of their small size
- The ability to control or manipulate matter on an
atomic scale
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The Scale of Things: Nanometers and More
Opportunities and Challenges
! The opportunities to do things differently with
nanotechnology have enormous potential to change
society
! An estimated global research and development
investment of nearly $9 billion per year is anticipated to
lead to:
- New medical treatments and tools
- More efficient energy production, storage and
transmission
- Better access to clean water
- More effective pollution reduction and prevention
- Stronger, lighter materials
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Opportunities and Challenges
! As the use of nanomaterials in society increases, it is
reasonable to assume that their presence in
environmental media will increase proportionately, with
consequences for human environmental exposure
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The Properties of Materials Change at the
Nanolevel
! Opaque substances become transparent (copper)
! Inert materials become catalysts (platinum)
! Stable materials turn combustible (aluminum)
! Solids turn into liquids at room temperature (gold)
! Insulators become conductors (silicon)
! Gold, which is chemically inert at normal scales, can
serve as a potent catalyst at the nanoscale
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Nanomaterials Come in Many Forms
! Carbon-based materials
- These nanomaterials are composed mostly of carbon,
most commonly taking the form of hollow spheres,
ellipsoids, or tubes
- Spherical and ellipsoidal carbon nanomaterials are
referred to as fullerenes; cylindrical ones are called
nanotubes
- These particles have many potential applications,
including improved films and coatings, stronger and
lighter materials, and applications in electronics
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Nanomaterials Come in Many Forms
! Metal-based materials
- These nanomaterials include quantum dots, nanogold,
nanosilver, and metal oxides, such as titanium dioxide
- A quantum dot is a closely packed semiconductor
crystal comprised of hundreds or thousands of atoms
and whose size is on the order of a few nanometers to
a few hundred nanometers
- Changing the size of quantum dots changes their
optical properties
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Nanotubes
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Nanomaterials Come in Many Forms
! Dendrimers
- These nanomaterials are nanosized polymers built
from branched units
- The surface of a dendrimer has numerous chain ends,
which can be tailored to perform specific chemical
functions
- This property could also be useful for catalysis
! Also, because three-dimensional dendrimers
contain interior cavities into which other molecules
could be placed, they may be useful for drug
delivery
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Nanomaterials Come in Many Forms
! Composites combine nanoparticles with other
nanoparticles or with larger, bulk-type materials
- Nanoparticles such as nanosized clays are already
being added to products ranging from auto parts to
packaging materials to enhance mechanical, thermal,
barrier, and flame-retardant properties
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Nanotechnology in Fibers
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Nanotechnology in Products: Clothing
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