Picosecond and Femtosecond Time-Resolved Instrumentation

    Time Correlated Single Photon Counting (TCSPC) techniques in conjunction with state of the art Microchannel Plate (MCP) provide for extremely high precision determination of fluorescence lifetimes.  Two Coherent laser systems provide picosecond and femtosecond tunable excitation sources. A UV excitation source provides an ability to study the intrinsic chromophores of peptides such as tyrosine and tryptophan residues.   The lab has two systems with complimentary capability to determine time-resolved fluorescence emission form intrinsic aromatic groups of proteins in addition to dye molecules covalently attached to proteins and other biomolecules of interest.

tisaph system
 Fluorescence Anisotropy systems based upon photoelastic modulation (PEM) provide highly precise determination of anisotropy and can be utilized to measure other chiro-optic phenomena such as Fluorescence detected CD (FDCD) and Time-resolved circularly polarized fluorescence or phosphorescence.
pselec

Developement of New Technologies and Instrumentation

acquisition Time-Resolved Flourescence and Anisotropy acquisition electronics developed in this laboratory (with Steve Parus,  Chemistry Electronics Shop).  Utilizing the Time Correlated Single Photon Counting procedure(TCSPC) and microchannel plate photomultiplier (MCP) technology, resolution of 10's of picosecond decay times are attainable.

Red; Time-resolved fluorescence decay of Fluorescein labeled protein.
Blue: Time-resolved fluorescence anisotropy decay of same molecule.
Entire window is approximately 50ns wide.  Anisotropy decay is 175psec after deconvolution.