Multi Scale Fluorescence Studies: The Spinning Disk Confocal Fluorescence Lifetime Imaging Microscopy & Single Molecule Nano-Metronome & Single Molecule Study of Tetramethyrhodamine -Dna Interaction

122 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2008.The final part presents the single molecule study on a behavior of a popular fluorescent dye called Tetramethylrhodamine (TMR) attached to the end of DNA oligomer. The study reveals that in the absence of any biological activities of DNA, the fluorescence emission of TMR undergoes multiple slow transitions among at least four different fluorescence states. While the actual number of fluorescence states and therefore the actual rates of transition among them remains open for discussion and more control measurements are definitely required, we are able to show that each fluorescence state lasts on the average in a range of hundreds of milliseconds to several seconds. These long dwell times are not observable in most of the studies done on freely diffusing TMR-DNA conjugate. It is unlikely that the fluctuation originates from the non-specific interactions between the dye and the glass surface and the interaction appears to be specific to TMR-DNA system. Therefore, TMR should be used with caution when conjugated to DNA.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD