A complete description of the method can be found here.
Intra-nuclear Single Particle Tracking (SPT) is a method of quantifying fluorescent molecules dynamics inside the nucleus or cytoplasm of living cells.
Single particle tracking (SPT) enables the user to recover the movement of the molecules or diffusion characteristics from the tracks of the individual molecules.
Figure 1604.
Alternative experiments to SPT are Florescence recovery after photo-bleaching (FRAP) and Fluorescent correlation spectroscopy (FCS). As opposed to FRAP and FCS, SPT offers:
Direct observation of the movement: Reaching single molecule accuracy may reveal the heterogeneity of the fluorescent labeled molecule population
Single molecule resolution: By locating single molecule individually, one breaks the fundamental resolution limit of microscopy imposed by diffraction
Usually SPT is performed on membranes because of higher contrast (obtained by TIRF illumination) and slower diffusion in membrane (typically up to ~1µm² / s) compared to nucleus (typically up to ~10µm² / s). For tracking bright and slow moving objects, we recommend rather the binary tracking module in NIS-Elements.
I-SPT uses some specific detection and analysis tools to enable tracking inside the nucleus. I-SPT unravels the mechanisms by which a functional nuclear protein finds its substrate.