Fighting Cancerwith 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

OCT image of a finger tip

http://en.wikipedia.org/wiki/Optical_coherence_tomography

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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