Biomod/2013/North Carolina State University/NCSU DNAbeans/Progress
Progress and Future Work
During the Summer we attempted multiple variations of DNA functionalization on both the gold nanorods and quantum and produced inconsistent results at best. Often times the rods would look great up until we put them into a PAGE gel to confirm DNA functionalization at which point they either would not enter the gel or would aggregate before we put them into the gel. It was a similar story with the quantum dots as well. The quantum dots were quick to aggregate in water if the mercaptoethanol did not completely cover the quantum dots. The next problem was booting the mercaptoethanol off the quantum dots with a thiol terminated DNA strand. The two gels below illustrate that while it appeared that DNA was bound to the quantum dots, it was really only in solution and was not attatched to the quantum dots at all.
What appears to be a positive result for the quantum dots in the right two columns is misleading. For this experiment we tried the functionalization procedure on both quantum dots and quantum rods. The sizes were significantly different to expect different travel distances. Also putting the gel under a uUV lamp revealed the characteristic blue and orange glow of the quantum dots and rods respectively at the tops of the wells. Our conclusion was that the DNA did not displace the the mercaptoethanol and was only present in solution. This result was repeated multiple times despite experimental tweaks and changes.
We plan on going forward with this project beyond the BIOMOD competition. Our next steps will involve polymer coated gold rods and quantum dots since the DNA cannot seem to grab a hold of the particles as they are now. Polymer coated quantum dots are readily soluble in water so we will not have to worry about any aggregation when switching solvent. We will simply need a linker that can bind the outer polymer shell to our DNA strand. We will keep this project moving and continue updating this wiki page with our progress as the prject nears completion.