The fluorescent signal is captured using a digital SPOT camera. This high quality digital camera is capable of quantitatively assessing fluorescent intensity. By measuring the intensity of green light emitted by fibers containing GFP producing e. coli we can quantitatively evaluate the level of bacterial function over time. We are also exploring the use of spectrophotometry to quantify bacterial function form a large number of fibers. We have identified and acquired an e. coli strain that produces bioluminescent luciferase.
Bioluminescence is what makes fire-flies and plankton glow.
Unlike fluorescent proteins, bioluminescence does not require excitation with ultra-violet radiation in order to emit a signal. The bacteria emit light as long as they are functioning, and the strength of the emitted light is a measure of their functional level. We intend to use both GFP and luciferase producing bacteria to quantify function. The advantage of GFP is that the fluorescent signal is very strong and thus will provide sensitive assay. Once we have completed the assessment of the functioning life span of bacteria in hollow fibers we will begin to explore ways of extending the life span.