Ultrahigh sensitivity rapid-exchange, time-gated Tb3+ detection

PHYS 401

Michelle Ferguson Homsher, mafergus@syr.edu, Syracuse University, 1-014 Center for Science and Technology, 111 College Place, Syracuse University, NY 13244-4100 and Bruce S. Hudson, bshudson@syr.edu, Department of Chemistry, Syracuse University, Syracuse, NY 13244-4100.
Many biological assays encounter sensitivity issues due to high background signal. Sensitized emission of Tb3+ uses time-gating to filter out background fluorescence signals, resulting in increased sensitivity in assays. However, the general sensor reaction involves an equilibrium between two states S <-> S* in which S* binds to the analyte, S*A. The unreacted fluorescent sensor species S* always produces a background signal that cannot be discriminated from S*A thus limiting detection sensitivity. The long lifetime of Tb3+ (ca. 1 ms) may be longer than the S<->S* interchange process. Whereas the analyte bound complex S*A will exhibit a longer lifetime than the Tb3+ emission. The S<->S* rapid exchange results in a short average lifetime that can be distinguished from the longer S*A complex emission. Time-gated detection permits suppression of the S* sensor signal relative to the long lived emission of the complex by many orders of magnitude, increasing detection sensitivity.
 

PHYS Poster Session - General Experiment
7:30 PM-10:00 PM, Wednesday, April 9, 2008 Morial Convention Center -- Hall A, Poster

Division of Physical Chemistry

The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008