Abstract
New UV-stimuli-responsive liposomes composed of two different kinds of phosphates, dipalmitoylphosphatidylcholine (DPPC) and azobenzene (Az)-containing amphiphilic phosphates were fabricated. The release behavior of calcein within the phospholipid vesicle lumen was studied by monitoring the changes of fluorescence intensity. As the results found in this paper, the instability of the lipid bilayers were caused along with the defects in the membrane regions through photoisomerization of Az, which provided a channel or increase the permeation for calcein release. The effects of Az structure and incorporation ratio were studied, with the results showing that high incorporation ratio induced high activity of release behavior. Moreover, the liposomes made by the Az with a longer hydrophobic alkyl chain gave a stable construction.
