Lipophilic porphyrin microparticles induced by AOT reverse micelles: A fluorescence lifetime imaging study

Fluorescence Lifetime Imaging Microscopy (FLIM) technique was applied to investigate the fluorescence dynamics and structural features of large colloidal aggregates of meso-tetra(N-dodecyl-4-amino sulfonyl-phenyl)porphyrin (PC12) induced by Sodium 1,4-bis(2-ethyl hexyl)sulfosuccinate (AOT) reverse micelles. The aggregate's particle sizes (down to 1 μm) obtained from the confocal fluorescence images matched with the particle sizes measured in the images obtained from Scanning Electron Microscopy (SEM). The fluorescence decays for those aggregates in the micro spatial domain show triexponential fluorescence lifetimes (τ1∼12 ns, τ2∼3 ns and τ3∼1 ns) which are independent of the aggregate's size.