Interaction between PEG lipid and DSPE/DSPC phospholipids: An insight of PEGylation degree and kinetics of de-PEGylation.

The degree to which liposomes are PEGylated is the feature, which most influences the length of the presence of stealth liposomes in the bloodstream. In order to thoroughly investigate the maximum amount of DSPE-PEG that can be used to stabilize stealth liposomes, these were synthesized at different concentrations of DSPE-PEG and their physicochemical properties were investigated by using differential scanning calorimetry (DSC). The kinetics of PEGylation and de-PEGylation were performed by incubating non-stealth liposomes in a DSPE-PEG suspension at different incubation times, and then analyzing the data using DSC and dynamic light scattering (DLS) techniques. The results demonstrated that DSPE-PEG was self-assembled in the phospholipid bilayers, thus forming stealth liposomes. The different amounts of DSPE-PEG in the bilayer triggered a de-PEGylation phenomenon, resulting in mixed nanoaggregates, which derived from the detergent-like properties of the PEGylated phospholipids.