Rhodamine Synthesis Essay

Decent Essays
My work this semester involved the continued study of the rhodamine spirolactam derivative that I synthesized in the previous semester. This rhodamine derivative is a photoactivateable dye, and exposure to 405 nm light converts the closed form of the dye to a fluorescent open form (Figure 1). This open form can then be excited with green light (510-565 nm) to observe fluorescence emission in the range of 570-650 nm1. An interesting additional consideration is the effect of pH on the stability of the open form, as the open form reverts to the closed form over time and thus becomes non-fluorescent at neutral pH. Typically, the lifetime of the open state is on the order of a few milliseconds, but it is reported that the under appreciably acid conditions this lifetime is greatly (and possibly indefinitely)…show more content…
The imaging process was conducted by illuminating the sample with 561 nm laser light and periodic illumination for 1 frame (50 ms frame duration) with 405 nm laser light every 200th frame. The data shows a significant increase in intensity after exposure to 405 nm light for labelled cells by visual analysis, confirming that photoactivation occurs. For a quantitative measure of intensity, a region of interest around a single cell was picked, and a plot of the mean intensity and standard deviation of the intensity versus frame number (time) for the pixels in this region show the increase in intensity of the sample after exposure to 405 nm light (Figure 4). Work in the coming semester will investigate imaging with this dye at different pH values in order to investigate the lifetime of the open form in labelled cells in different pH environments. This information could then be used to alter the imaging protocol for this dye, provided that cells are able to survive the pH
Get Access