Using Nanotubes to Kill Cancer Cells

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Using Nanotubes to Kill Cancer Cells
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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 (? 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.

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Carbon Nanotubes

• Cylindrical Carbon molecules that have very
  useful properties.
• For example, they are incredibly strong.
• Able to absorb light at near infra-red
  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.

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Preparation of Nanotubes

• 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.

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Temperature Evolution of SWNT-DNA Solution
(ex-vitro)

• Control experiment 808 nm light at 1.4 W/cm2
  shone on solution of DNA- wrapped Nanotubes.
• The temperature of the solution rose by about 50
  oC in 2 minutes.

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Transfer of Nanotubes into Living Cells
T 37 oC
T 4 oC
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Shine a Light
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Targeting Cancer Cells

• 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.

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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

• http//news-service.stanford.edu/news/2005/august1
  0/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