Spatial fluorescence cross-correlation spectroscopy by means of a spatial light modulator

摘要

Spatial fluorescence cross-correlation spectroscopy is a rarely investigated version of fluorescence correlation spectroscopy, in which the fluorescence signals from different observation volumes are cross-correlated. In the reported experiments, two observation volumes, typically shifted by a lew urn, are produced, with a spatial light modulator and two adjustable pinholes. We illustrated the feasibility and potentiality of this technique by: i) measuring molecular flows, in the range 0.2-1.5 μm/ms, of solutions seeded with fluorescent nanobeads or rhodamine molecules (simulating active transport phenomenons); ii) investigating the permeability of the phospholipids membrane of giant unilamellar vesicles versus hydrophilic or hydrophobic molecules (in that ease the laser spots were set on both sides of the membrane). Theoretical descriptions are proposed together with a discussion about fluorescence-correlation-spectroscopy-based. alternative methods.