Download Using Nanotube Lasers to Kill Cells

Using Nanotubes to Kill Cancer
Cells
General Idea of Experiment
► Nanotube
rods were inserted into cancerous cells in a
solution that contained both cancerous and normal
cells
► A laser in the Near Infrared Range (λ ≈ 700 to 1100
nm) was shone on the solution – the cancer cells
heated up to 70 degrees Celsius and died
► The normal cells were fine; biological tissue is
transparent to NIR light.
Carbon Nanotubes
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Cylindrical Carbon molecules
that have very useful properties.
For example, they are incredibly
strong.
Able to absorb light at near infrared wavelengths (700-1100 nm).
The name comes from the size of
the nanotubes (their width is on
the order of a few nanometers).
Thousands of nanotubes can fit in
a single cell.
Single-walled nanotubes
(SWNTs) were used in this
experiment.
Preparation of Nanotubes
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Nanotubes were mixed with
a solution of DNA. The
DNA contained a
“fluorescent label” called
Cy3
► DNA strands wrapped
around the nanotubes
► Phospholipid molecules
were added to the ends of
the DNA strand to allow
them to be accepted by the
cancer cells.
Temperature Evolution of SWNT-DNA Solution (ex-vitro)
• Control experiment: 808 nm light at 1.4 W/cm2 shone on solution of DNAwrapped Nanotubes.
• The temperature of the solution rose by about 50 oC in 2 minutes.
Transfer of Nanotubes into Living Cells
T = 37 oC
T = 4 oC
Shine a Light
Targeting Cancer Cells
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Unlike normal cells, the surfaces of the cancer cells contained numerous
receptors for a vitamin called folate.
Phospholipids that were attached to folic acid molecules were added to the
ends of the DNA strands.
This caused the nanotubes to be accepted into diseased cells with folate
receptors (FR).
There are many other possible ways to target specific cells – for example
attaching an antibody to a nanotube to go after a particular type of diseased
cell.
Summary of Results
One of the main challenges with curing cancer is the problem of
killing normal cells along with cancer cells in treatment.
► This is what causes people to lose their hair and suffer other
side-effects.
► Biological material is transparent to light in the Near Infrared
Range, but Single Walled Carbon Nanotubes absorb light in this
range and re-emit the energy as heat.
► Tagging nanotubes with specific molecules allows them to enter
only diseased cells. Light can then be shone on a mixture of
diseased and healthy cells, killing only the diseased cells.
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References
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http://news-service.stanford.edu/news/2005/august10/nanotube-081005.html
http://en.wikipedia.org/wiki/Carbon_nanotube
http://www.stanford.edu/dept/chemistry/faculty/dai/group/Reprint/96.pdf
http://www.tipmagazine.com/tip/INPHFA/vol-10/iss-1/p24.pdf
http://www.repairfaq.org/sam/laserhen.htm