Final Summary of Summer Dye Fading Project

My initial goal for my summer research was to design an experiment for obtaining single molecule scans in oil environments of a special type of organic dye known as hydroxyanthraquinone. However, this experiment became very challenging and earlier in the summer my professor presented me with a side project that soon became the main focus of my summer research. This experiment involved recreating single molecule scans of the hydroxyanthraquinone dye alizarin with our new higher energy laser, in a polar solvent (ethanol). Previous research in our lab preformed single molecule scans using alizarin in ethanol on a lower energy laser, and I assumed this would be an easy project. However, recreating this experiment turned out to be difficult process that required the whole summer.

However, after weeks of control experiments (that I documented in previous blog posts) I finally managed to obtain single molecule scans of alizarin in ethanol with our 470 nm laser. These control experiments led to some interesting findings about our molecule. One, it required a much higher laser intensity to obtain a reasonable signal to noise ratio than with 532 nm laser, which was unexpected considering alizarin should absorb 470 nm light better. This could indicate the occurrence photochemistry events that lower the overall ability of the molecule to fluoresce. Another interesting observation was that the single molecules would often undergo fluorescence for as much as 5 minutes without being photobleached, which tends to be much longer than other types of dye molecules. In the future, I hope to perform more single molecule scans of alizarin and obtain more blinking traces. It is difficult to draw conclusions about the behavior of alizarin when exposed to the laser, without obtaining more blinking traces and preforming the computational analysis of at least 100 traces. Overall, this summer I was successful at designing a consistent single molecule experiment for alizarin with our new laser.