title: On-line green fluorescent protein sensor with LED excitation.
abstract: We present an intensity based sensor designed for on-line monitoring of green fluorescent protein, a revolutionary marker of protein expression. The device consisted of a blue light emitting diode as the excitation source. A band pass excitation filter cut off light longer than 490 nm. The light was directed into a bifurcated optical fiber bundle with the common end inserted into a stainless steel housing equipped with a quartz window. The fiber bundle and stainless steel housing are steam sterilizable. The emission radiation was collected through a long wave pass filter to reject the excitation light shorter than 505 nm and was detected by a photomultiplier tube. The signal was amplified and sent to a computer for recording time course data. The sensor was tested in an Escherichia coli fermentation of JM105 transformed with pBAD-GFP. The on-line signal was compared to off-line fluorescence spectrophotometer measurements. The on-line profile closely followed the off-line. Western blot data showed that with a time shift, the sensor was able to both continuously and quantitatively monitor expression of green fluorescent protein on-line in real time.
authors.affiliation: Department of Chemical and Biochemical Engineering, University of Maryland Baltimore County, Baltimore, Maryland 21250, USA.
authors.forename: L
authors.initials: L
authors.lastname: Randers-Eichhorn
authors.forename: C R
authors.initials: CR
authors.lastname: Albano
authors.forename: J
authors.initials: J
authors.lastname: Sipior
authors.forename: W E
authors.initials: WE
authors.lastname: Bentley
authors.forename: G
authors.initials: G
authors.lastname: Rao