Research will focus on increasing utility of intracellular fluorescence measurements for control of fermentation and cell culture by correcting on-line for background fluorescene of the media. This will use the characteristics of the evanescent wave at the surface of an optic wave guide. The wave penetrates into the less dense medium only to about the depth of 1/3 to 1/2 wave length. The thickness of media swept by the evanescent wave is much less than the size of a cell, thereby essentially separating the fluorescence of the media from that of the cells.
