Using Nanotubes to Kill Using Nanotubes to Kill Cancer CellsCancer Cells

General Idea of ExperimentGeneral Idea of Experiment

► Nanotube rods were inserted into cancerous cells in a Nanotube rods were inserted into cancerous cells in a solution that contained both cancerous and normal solution that contained both cancerous and normal cellscells

► A laser in the Near Infrared Range (A laser in the Near Infrared Range (λλ ≈≈ 700 to 1100 700 to 1100 nm)nm) was shone on the solution – the cancer cells was shone on the solution – the cancer cells heated up to 70 degrees Celsius and diedheated up to 70 degrees Celsius and died

► The normal cells were fine; biological tissue is The normal cells were fine; biological tissue is transparent to NIR light.transparent to NIR light.

Carbon NanotubesCarbon Nanotubes

► Cylindrical Carbon molecules Cylindrical Carbon molecules that have very useful properties.that have very useful properties.

► For example, they are incredibly For example, they are incredibly strong.strong.

► Able to absorb light at near infra-Able to absorb light at near infra-red wavelengths (700-1100 nm).red wavelengths (700-1100 nm).

► The name comes from the size of The name comes from the size of the nanotubes (their width is on the nanotubes (their width is on the order of a few nanometers).the order of a few nanometers).

► Thousands of nanotubes can fit in Thousands of nanotubes can fit in a single cell.a single cell.

► Single-walled nanotubes Single-walled nanotubes (SWNTs) were used in this (SWNTs) were used in this experiment.experiment.

Preparation of NanotubesPreparation of Nanotubes

► Nanotubes were mixed with Nanotubes were mixed with a solution of DNA. The a solution of DNA. The DNA contained a DNA contained a “fluorescent label” called “fluorescent label” called Cy3Cy3

► DNA strands wrapped DNA strands wrapped around the nanotubesaround the nanotubes

► Phospholipid molecules Phospholipid molecules were added to the ends of were added to the ends of the DNA strand to allow the DNA strand to allow them to be accepted by the them to be accepted by the cancer cells.cancer cells.

Temperature Temperature EvolutionEvolution of SWNT-DNA Solution of SWNT-DNA Solution (ex-vitro)(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.

T = 37 oC

T = 4 oC

Transfer of Nanotubes into Living Cells

Shine a Light

Targeting Cancer CellsTargeting Cancer Cells► Unlike normal cells, the surfaces of the cancer cells contained numerous Unlike normal cells, the surfaces of the cancer cells contained numerous

receptors for a vitamin called folate.receptors for a vitamin called folate.► Phospholipids that were attached to folic acid molecules were added to the Phospholipids that were attached to folic acid molecules were added to the

ends of the DNA strands.ends of the DNA strands.► This caused the nanotubes to be accepted into diseased cells with folate This caused the nanotubes to be accepted into diseased cells with folate

receptors (FR).receptors (FR).► There are many other possible ways to target specific cells – for example 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 attaching an antibody to a nanotube to go after a particular type of diseased cell.cell.

► One of the main challenges with curing cancer is the One of the main challenges with curing cancer is the problem of killing normal cells along with cancer cells problem of killing normal cells along with cancer cells in treatment.in treatment.

► This is what causes people to lose their hair and This is what causes people to lose their hair and suffer other side-effects.suffer other side-effects.

► Biological material is transparent to light in the Near Biological material is transparent to light in the Near Infrared Range, but Single Walled Carbon Nanotubes Infrared Range, but Single Walled Carbon Nanotubes absorb light in this range and re-emit the energy as absorb light in this range and re-emit the energy as heat.heat.

► Tagging nanotubes with specific molecules allows Tagging nanotubes with specific molecules allows them to enter only diseased cells. Light can then be them to enter only diseased cells. Light can then be shone on a mixture of diseased and healthy cells, shone on a mixture of diseased and healthy cells, killing only the diseased cells.killing only the diseased cells.

Summary of ResultsSummary of Results

ReferencesReferences► http://news-service.stanford.edu/news/2005/august10/nanotube-081http://news-service.stanford.edu/news/2005/august10/nanotube-081

005.html005.html► http://en.wikipedia.org/wiki/Carbon_nanotubehttp://en.wikipedia.org/wiki/Carbon_nanotube► http://www.stanford.edu/dept/chemistry/faculty/dai/group/Reprint/9http://www.stanford.edu/dept/chemistry/faculty/dai/group/Reprint/9

6.pdf6.pdf► http://www.tipmagazine.com/tip/INPHFA/vol-10/iss-1/p24.pdfhttp://www.tipmagazine.com/tip/INPHFA/vol-10/iss-1/p24.pdf► http://www.repairfaq.org/sam/laserhen.htmhttp://www.repairfaq.org/sam/laserhen.htm