Sorting good data from bad is critical when analyzing microscopic structures like cells and their contents, according to researchers at Rice University. The trick is to find the right window of time through which to look.
A new paper by the Rice lab of Angel Mart, an assistant professor of chemistry and bioengineering, offers a methodology to optimize the sensitivity of photoluminescent probes using time-resolved spectroscopy. Mart and co-author Kewei Huang, a graduate student in his group, found their technique gave results nearly twice as good as standard fluorescence spectroscopy does when they probed for specific DNA sequences.
Their results were reported recently in the American Chemical Society journal Analytical Chemistry.
In spectroscopy, chemicals and materials from proteins to nanotubes can be identified and tracked by their fluorescence -- the light they return when excited by an input of energy, usually from a laser. In the kind of targeted spectroscopy practiced by Mart and his colleagues, a luminescent probe called a molecular beacon is designed to attach to a target like a DNA sequence and then light up.
Improving a probe's ability to detect ever smaller and harder-to-find targets is important to biologists, engineers and chemists who commonly work on the molecular scale to analyze cell structures, track disease or design tiny machines.
One problem, Mart said, has been that even in an experiment lasting a fraction of a second, a spectrometer can return too much information and obscure the data researchers actually want. "In standard fluorescence spectroscopy, you see noise that overlaps with the signal from your probe, the scattering from your solution or cuvettes, plus the noise from the detector," he said. The saving grace, he said, is that not all those signals last the same amount of time.
Time-resolved spectroscopy provides part of the answer, Mart said. Compared with standard spe
|Contact: David Ruth|