Breast Cancer Treatment with Gold Nanoparticles

A professor of agricultural and biological engineering, Joseph Irudayaraj, and his team of researchers from Purdue University have come up with a method that will be able to detect the presence of cancer cells in the body and even measure the amount present. The method uses very tiny gold particles (more than a thousand sizes smaller than the width of a strand of human hair) that have tails of synthetic DNA.

These gold particles bind to BRCA1 messenger RNA splice variants. These are fragments or pieces of genetic material that can show if there are any cancer cells and what stage the breast cancer is at. BRCA1 is a gene that suppresses tumors. It can however turn a cell cancerous in certain conditions. If this gene is being expressed in quantities lower than normal then it shows a possibility of breast cancer.

Irudayaraj teamed up with who was then his graduate research assistant, Kyuwan Lee, and first engineered the gold nanoparticles. They then tagged strands of DNA that correspond to BRCA1 mRNA splice variants. These nanoparticles attach themselves to both ends of mRNA splice variants when injected into a cell.

To determine the actual number of mRNA (messenger RNA) splice variants present in a cell, they use a light on the gold nanoparticles. It shines differently depending on the activity on the other. A gold nanoparticle on its own (known as a monomer) will be green when the light is shone on it but when a pair of gold nanoparticles binds to an mRNA splice variant (known as a dimer) it will appear red.

The two different particles scatter light differently. By studying these patterns the researchers were able to tell the difference between the two. Spectroscopy, a measure of how light scatters when it meets an object, was one of the methods used. Another method used was the colorimetric image that showed the different colors of the particles. The whole process can take about 30 minutes.

Current methods used for diagnosis of cancer use samples that consist of hundreds or even thousands of cells. This does not provide enough information about how the genes involved with cancer are being produced at the lowest level, in cells. Splice variants give specific details about the specific proteins being expressed.

Irudayaraj is however tweaking the process so as to make it faster, thus allowing it for use in tissue biopsies. This method will allow doctors to give treatment that is specific to each patient’s stage or level of sickness.