Project Perseus

  Analyzing DNA-mercury Nanoparticles with Scanning electron Microscopy In the last post I discussed how I used fluorometry experiments to investigate the binding dynamics of DNA and mercury ions. In this post, I'm going to talk about how we visualized the DNA - mercury samples via Scanning Electron Microscopy (SEM) to get more information on the structure and morphology of the particles formed by these interactions. As they say, a picture is worth a thousand words! Remember how I said that the DNA forms some kind of hairpin or secondary structure around the mercury ions? Well using SEM we were able to visualize these structures more closely and see how they behave! How did I Prepare the Samples for Visualization? These samples, especially samples containing biological material like DNA, cannot just be thrown into the microscope and visualized. If that happened, the DNA would actually be invisible because of its inability to conduct electrons, since the conductivity of electrons is...

Investigating DNA - Mercury Binding Interactions using a Fluorescent Dye In my last post, I demonstrated that using a fluorescent dye that can insert between DNA bases can help me learn more about the intricacies of the DNA - mercury binding system including binding stoichiometry and affinity! Let's get right into this very colorful biochemistry! What Dye did I use? I mentioned it briefly in my last post, but for these experiments, I used an intercalating fluorescent dye called Thiazole Orange. Intercalating just means that the dye is able to insert itself in between the bases of a DNA molecule. The rationale behind using this method is that as our single-stranded DNA molecules in solution encounter mercury ions, they form a hairpin structure or some kind of secondary structure around the mercury ion per our hypothesis. Thus, the ssDNA's own bases then loop around and become in close contact with each other. Close enough for this dye to attach.  But how does the insertion of th...