Studying the properties of polymer-lipid nanostructures: The role of the host lipid

The goal of the present investigation is to prepare polymer-grafted hybrid liposomes using phospholipids with different main transition temperature (Tm). In more detail, liposomes were prepared by the combination of three different lipids, having different transition temperatures, namely 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC) with the amphiphilic block copolymer poly(2-(dimethylamino)ethyl methacrylate)-b-poly(lauryl methacrylate) (PDMAEMA-b-PLMA). The physicochemical characteristics of the prepared hybrid liposomes were evaluated by light scattering and their morphology by cryo-TEM. Their thermotropic behavior was characterized by mDSC and high-resolution ultrasound spectroscopy, while their microenvironmental parameters were attained by fluorescence spectroscopy. Subsequently, in vitro nanotoxicity studies have taken place. The studies indicate that PDMAEMA-b-PLMA was encapsulated in the liposomal membrane, leading size, and shape characteristics, as well as biosafety profile, strictly affected by the formulation's parameters, namely the lipid type and the polymer concentration. Thermal analysis confirmed the different interactions taking place between the polymer and the different lipids. The obtained results show that the aqueous heat method can be successfully used for lipid-polymer hybrid structures, containing lipids with a wide range of transition temperatures. These systems can also load curcumin, which was used as model active substance.