Magnetocubosomes as Nanostructured Drug Delivery Systems: Encapsulation and Controlled Release of Amphiphilic and Hydrophilic Molecules Studied through Fluorescence Correlation Spectroscopy

Lipid-based assemblies are the subject of active research for the development of efficient and biocompatible nanocarriers. In particular, cubosomes are submicron lipid particles of bicontinuous cubic liquid-crystalline phase in which lipid bilayers are curved with a cubic symmetry organized to form two non-intersecting continuous water channels. They are characterized by a high surface area compared to bilayered nanoparticles, allowing a higher drug encapsulation efficiency.

 

In this study we present an investigation on the glycerylmonooleate (GMO) as bulk cubic phase and cubosomes stabilized with Pluronic F127 as nanocarriers. We loaded the bulk cubic phase and the cubosomes with magnetic Fe₃O₄ nanoparticles (NPs), which locally heat and perturb the cubic phase structure when a low frequency alternating magnetic field (LF-AMF) is applied, allowing a spatially and temporally controlled release of the drug.

 

A study on the encapsulation-release of model drugs by the characterized cubic phase carrier was carried out through Fluorescence Correlation Spectroscopy (FCS). First,  we monitored the encapsulation both of a fluorescently-labeled lipid (mimicking an amphiphilic drug) inside the bilayered lipid regions and of a hydrophilic fluorescent probe (mimicking a hydrophilic drug) inside the water channels of the GMO bulk cubic phase and cubosomes loaded with magnetic NPs. Finally, we monitored in real-time the release of the hydrophilic fluorescent probe encapsulated inside the aqueous channels of the bulk cubic phase loaded with Fe₃O₄ NPs, actuated by a LF-AMF.