1. Using Nanotubes to Kill Cancer Cells

2. 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.

3. 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.

4. 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.

5. Temperature Evolution of SWNT-DNA Solution (ex-vitro) Control experiment: 808 nm light at 1.4 W/cm 2 shone on solution of DNA- wrapped Nanotubes. The temperature of the solution rose by about 50 o C in 2 minutes.

6. T = 37 o CT = 4 o C Transfer of Nanotubes into Living Cells

7. Shine a Light

8. 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.

10. ► 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. Summary of Results

11. References ► http://news-service.stanford.edu/news/2005/august10/nanotube-081005.html http://news-service.stanford.edu/news/2005/august10/nanotube-081005.html ► http://en.wikipedia.org/wiki/Carbon_nanotube http://en.wikipedia.org/wiki/Carbon_nanotube ► http://www.stanford.edu/dept/chemistry/faculty/dai/group/Reprint/96.pdf 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.tipmagazine.com/tip/INPHFA/vol-10/iss-1/p24.pdf ► http://www.repairfaq.org/sam/laserhen.htm http://www.repairfaq.org/sam/laserhen.htm