Spectroscopic innovations at the Laboratory for Fluorescence Dynamics

Abstract

The emergence of time-resolved fluorescence techniques has been very important to the study of biochemical, biophysical and biomedical research areas.Many of the advances in these fields have been technology driven. The Laboratory for Fluorescence Dynamics (LFD) has been actively involved in development of frequency domain technology for a variety of applications. Our recent work on microwave super heterodyning detectors, fluorescence lifetime resolved spectroscopy, frequency domain fluorescence imaging microscopy, fluorescence lifetime resolved stopped-flow kinetics and global methods of data analysis is summarized in this report. We provide examples of how these new technologies are applied.1 . IniroductionIn 1986, the Laboratory for Fluorescence Dynamics (LFD) at the University of Illinois at Urbana-Champaign was established as a research resource in biomedical fluorescence spectroscopy. The aims of the center are two-fold: first, provide a state-ofthe-art laboratory for time resolved fluorescence measurements with technical assistance to visiting scientist/users and secondly, design, test and implement advances in the technology, especially in hardware, automation software and applications to the biomedical arts. Accomplishments in the second area are readily transferable to the service laboratory environment. This manuscript describes several technical innovations introduced at the LFD. The presentation deals with both hardware, software and discusses applications to biomedical science.The appeal of fluorescence spectroscopy lies in its high sensitivity, which translates into low detection limits in analytical applications, and in its varied response to environmental factors, such as ionic strength, solvent polarity, proximity of charged or quenching groups and others. In research applications, especially for the biological sciences, the nanosecond time window of fluorescence spectroscopy correlates well with the temporal resolution necessary to observe events such as macromolecular conformational changes, receptor recognition, membrane dynamics and many others.