Nanostructures by self-assembly of polyglycidol-derivatized lipids

In this work we report on the self-assembly of five non-phospholipid polyglycidol conjugates in aqueous solution. The polymers are composed of a linear polyglycidol chain (degrees of polymerization, DP, are in the 8-110 range) linked to a strongly hydrophobic lipid-mimetic residue. Their behavior in dilute aqueous solution is investigated by a combination of experimental techniques - UV-vis spectroscopy, static and dynamic light scattering, fluorescence measurements, conventional and cryogenic transmission electron microscopy, and small angle X-ray scattering. The polymers spontaneously self-associate above a certain critical concentration, which depends on polyglycidol DP and temperature. According to the thermodynamic data, the self-assembly is an enthalpically disfavored endothermic process, driven by positive entropy contribution. The polymers with polyglycidol DP of 23 and above form small core-corona micelles. The latter are parameterized and the experimental values are compared to those of micelles of the commercially available poly(ethylene glycol)-derivatized lipids and other related non-phospholipid poly(ethylene glycol) conjugates. The polymer of the lowest polyglycidol DP form lamellar structures of co-existing morphology - spherical vesicles and highly anisotropic, elongated bilayer flakes.