ByKasra Manoocheri and Jared Cohen

• This therapy uses a conductive nanomaterial, either gold nanoparticles, gold nanoshells, or carbon nanotubes. This version can be attached to antibodies and the gold nanoparticles are verified as nontoxic.

• However there are conflicting reports about the toxicity of the carbon nanotubes; therefore it is not yet established whether it is safe for clinical trials.

• In addition, it is very costly to make nanoparticles in large quantities. Also, the effectiveness of this treatment without a targeting molecule is yet to be determined in humans.

• Gold nanoparticles however have proven effective and with continued research along with new nanotechnology breakthroughs, this could be a potent cure for many types of cancer.

• They are proven non-toxic in lab tests even when they penetrate the cell. The liver filters them out after 2 weeks as well.

• GNPs and Nanoshells exploit their high conductivity both electrically and thermally to allow them to heat up at certain wavelengths of light depending on how they are made. GNP’s differ from nanoshells as they are pure gold spheres. These spheres are smaller and able to bond and attach to almost any biological substance including viruses, DNA, and antibodies. This allows them to be targeted toward cancer much easier. This also increases the chance only cancer cells uptake GNP’s which makes them stronger versus cancer cells and less likely to damage normal cells. However both nanomaterials display similar characteristics. It has also been tested that it takes 1/3 less energy to destroy cancer cells which leaves the normal cells perfectly fine. The cytotoxcity of these particles is very low and are flushed from the body by the liver. These particles can also be used to mark where cancer is growing. The same properties that make it perfect for destroying cancer also make cancer far easier to see by just shining a specific beam of light and seeing where the GNP’s are active.

• GNP’s are very simple to make and are prepared by mixing Sodium Borohydride with tetrachloroauric acid and stir. After 12 hours and filtering the solution, the result is GNP’s.

• Attaching GNP’s to certain antibodies especially those that target epidermal growth factor receptor, a protein expressed in many cancers, allows it to home in on cancer easily

• By creating very small GNPs, not only can these absorb more light but also reduce the amount of gold used and escape detection by the body.

• However one of the major faults is that nanomaterials of all kinds are extremely hard to make cheaply and accurately. There is not many ways to determine the size and shape of the nanoparticles easily. This drives up the cost due to a lower supply of effective GNP’s.

Start with silica particles (tiny glass particles too small to see)Add a chemical to the particles that makes them stickyAdd another chemical that allows very small gold islands to be attached to the surface of the glass particles (one large glass particle with many tiny gold islands)Add more gold to tiny gold islands so that they grow together (Forms continuous gold shell around glass core)By varying the thickness of the shell, the properties of the nanoshell can be fine tuned.

Nanoshells

Gold Nanoparticles

Sources• http://www.jnanobiotechnology.com/content/6/1/2• April 2007 Scientific American• http://www.pbs.org/wgbh/nova/sciencenow/3209/03-nanoshells.html• http://www.pbs.org/wgbh/nova/sciencenow/3209/03-canc-flash.html• http://nano.cancer.gov/news_center/nanotech_news_2005-10-17b.asp• http://www.nanotechbuzz.com/50226711/images/nanosphere.jpg• http://www.chem.utoronto.ca/staff/DHIRANI/stm-np.jpg