Fighting Cancer
with Gold Nanoshells
Goals for this presentation:
• Expand concept of nanomedicine
• Provide a brief overview of nanoshells
related cancer research
• Explore science behind gold nanoshells
First, lets get the big picture…
The BIG Idea
• Gold nanoshells cover cancer cells
• Specifically target cancer cells
• Many particles per cell
• Cell becomes more “visible” for reflective imaging
• Nanoshells absorb light and become excited/heat
up, cause cell death
• Waste disposed of naturally, other cells unharmed
But how does it all work?
Nanoshells are made in a lab
• Researchers create
special nanoparticles
• Gold shell grown
onto silica core
Why are nanoshells special?
• Small (just over 100nm in diameter!)
• Gold is biologically inert
• Different from standard nanoparticles
• Dimensions of the shell can be changed
• Stronger interactions with light waves
Next, Nanoshells are
treated…
…to be more biologically
compatible…
• Targeting treatment
allow nanoshell to bind
to abundant cell
receptors on cancer cell
• Surface coatings
prevent immune system
removal of nanoshells
…and “tuned” to desired
dimensions.
• Chemical etching of
nanoshell
• Reduced shell
thickness
• Increased shell
roughness
• Core size remains
unchanged
Wait, why are nanoshells
tuned?
“Tuning”
• Tuning is the process of resizing the exterior
of a nanoshell
• Allows nanoshells to absorb Near Infrared
(NIR) light
• NIR light passes through biological tissue
harmlessly
So…
• Nanoshells now have surface coatings to…
• Prevent immune response
• Attach to cancer cells
• Nanoshells now interact with NIR light
• Specific wavelengths reflected
• Different specific wavelengths absorbed
• Nanoshells can absorb NIR light shining in
from outside body
How exactly do nanoshells
find cancer cells?
Targeting
• Cancer cells have
many more growth
receptors than
healthy cells
• Nanoshells move
from blood flow and
attach to growth
receptors
Now that the nanoshells are
attached…
Take a picture of a tumor!
• Specific wavelengths of NIR reflect off of
the nanoshells
• Nanoshells are more reflective than
cancerous cells
• Imaging attached nanoshells is the same as
imaging the cancer cell
Imaging with OCT
• The process of Optical
Coherence Tomography
(OCT)
• NIR laser shines into body
• Nanoshells reflect NIR light
back to a sensor
• Sensor detects change in
reflected light
• Picture created from sensor
data
http://en.wikipedia.org/wiki/Optical_coherence_tomography
OCT image of a finger tip
Now we’ve imaged our
tumor…
But what if we could get rid of
it?
Ablating Cancer
• Nanoshells can be used
to kill cancer cells
• Nanoshells absorb a
specific wavelength of
NIR light
• Change in energy causes
small vibrations
• Vibrations cause cell to
heat up, causing cell
death
Lets review…
Nanoshells are…
•
•
•
•
•
•
Grown in a lab
Treated to target cancer cells
Tuned to near infrared light
Attached to cancer cells
Imaged using reflection
Heated to kill cancer cells
Benefits of gold nanoshells
• Immunotargeting (binding primarily to
cancer) prevents damage to healthy tissue
• NIR light allow for non-invasive treatment
• The same nanoshells that are used to image
cancer can also be used to treat cancer
What’s next?
• Currently, nanoshells are
NOT used in humans
• Nanoshells have been
used to image and
destroy tumors in
laboratory specimen
• Awaiting FDA approval
to begin clinical trials
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