Apr 13 2010
Researchers studying the movement, interactions, and microenvironments of intracellular molecules often need to analyze information on the patterns and rates with which molecules diffuse within the cells.
Now, scientists have three powerful methods of measuring and analyzing intracellular molecular diffusion, thanks to the new Diffusion Measurement Package for Olympus ASW 2.1 software. The software allows researchers to do three different types of diffusion studies using Olympus FluoView® confocal microscope systems, providing flexibility for the widest variety of cell biology and biophysics requirements.
The first type of diffusion study, Point Fluorescence Correlation Spectroscopy (Point FCS), allows particle-by-particle analysis of signal fluctuation. By recording the fluctuation of fluorescence intensity, the number of particles that are moving can be calculated. With its high spatial and temporal resolution, this technique works well for fast-moving particles. It can output data based on either the diffusion constant or number of molecules, depending on the researcher’s needs. In addition, it has the capability to analyze cross correlations.
The second type of diffusion study, Raster scan Image Correlation Spectroscopy (RICS), provides measurement in regions, with diffusion measurement in any area of the cell. It is able to measure a wide range of intracellular structures, from molecules in solution to the proteins on a cell membrane. By limiting its area of calculation to a small region of interest, RICS can create a diffusion map from a set of 2-dimensional images, helping scientists understand different diffusion times in different locations within the cell. Results in terms of either diffusion constant or number of molecules are available, and this method too can analyze cross-correlations.
The third type of diffusion study that can be handled by the new software is Fluorescence Recovery After Photobleaching (FRAP), a widely used fluorescence analysis technique that allows researchers to analyze the diffusion constant in a particular region as molecules diffuse back into that area after it has been photobleached.