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Rachel Fontana

Biochemistry, '16


Capture of circulating tumor DNA through the use of biotinylated poly-lysine affixed to gold nanoparticles

Mentor: G. Mike Makrigiorgos, PhD (Dana-Farber Cancer Institute)

In order to accurately treat and stage tumors, it is necessary to identify the current molecular alterations within the tumor DNA. However, repeated biopsies to uncover tumor DNA are problematic. For this reason, the capture and analysis of circulating tumor DNA (ctDNA) in blood would serve as a better method. ctDNA comes from DNA shed by apoptotic tumor cells. The current technical problem with ctDNA stems from the fact that, until late stages of cancer, ctDNA is present at very low levels in the blood, which makes its subsequent detection and analysis difficult with standard DNA isolation methods. Using biotinylated poly-lysine affixed to streptavidin coated magnetic nanoparticles can potentially have advantages over existing methods. The positive charge of the poly-lysine will attract negatively charged circulating DNA from the blood. The magnetic nanoparticles, with the circulating DNA, could then be easily trapped and used for upstream analysis without need for purification steps. This approach may result to a novel method for the collection of ctDNA from plasma.

PCR amplification plot of magnetic beads reacted with circulating tumor DNA. Source: Dana-Farber Cancer Institute. Source: