Bioresorbable drug release platforms offer advanced treatment for hormone imbalances, malignant cancers, and diabetic conditions.

Exosomes, as cell-derived lipid nanoparticles, are promising drug carriers because they can traverse challenging physiological barriers such as the blood-brain barrier (BBB). However, a major obstacle in utilizing exosomes as drug carriers is loading large therapeutic molecules without compromising the structural integrity of embedded biomolecules. Here, we introduce a membrane fusion method utilizing fusogenic lipid nanoparticles, cubosomes, to load large molecules into exosomes in a non-destructive manner. When the drug-loaded cubosome and exosome solutions are simply mixed, membrane fusion is completed in just 10 min. Our method effectively loads doxorubicin and immunoglobulin G into exosomes. Moreover, even the most challenging molecule—mRNA—is loaded with nearly 100% efficiency, demonstrating the versatility of our approach. In terms of biological behavior, the resulting hybrid exosomes preserve the functional behavior of exosomes in BBB uptake and penetration. Surprisingly, controlling exosome-to-cubosome ratios allows precise control over BBB uptake and transport. Furthermore, these hybrid exosomes retain cell-specific delivery properties, preserving the targeted delivery functions dictated by their exosomal origin. This study demonstrates the feasibility of a mix-and-load method for rapid and efficient drug loading into exosomes, with significant potential for the treatment of neurological diseases.

Lipids self-assemble into diverse supramolecular structures that exhibit thermotropic and/or lyotropic behavior. Lyotropic mesophases, where membranes conform to periodic minimal surfaces dividing two nonpenetrating aqueous subspaces, are arguably one of the most intriguing phases of lipid materials. Traditional 3D bicontinuous cubic lipid materials appear as a polycrystal of varying degrees of order. When exposed to water, the properties of the molecular building blocks of the membrane determine specific swelling limits setting the lattice dimensions at about 15 nm. This limited swelling severely impairs their application as delivery vehicles of large drugs or as matrices for guiding protein crystallization. We report the discovery of self-assembly strategies leading to the emergence of lipid bicontinuous single crystals with unprecedented swelling capacity. The conventional strategy to increase unit cell size is tweaking membrane composition to include charged building blocks, a process to achieve electrostatic-driven swelling. In this paper, we demonstrate that controlling self-assembly external conditions when coupled to membrane composition yields 3D bicontinuous cubic phases that swell up to lattice dimensions of 68 nm. Importantly, and contrary to what is perceived for soft lyotropic materials in general, the self-assembly methodology enables the development of large super-swelled monocrystals. Utilizing small-angle X-ray scattering and cryoelectron microscopy, we underpin three crucial factors dictating the stabilization of super-swelled lipid bicontinuous cubic single crystals: (i) organic solvent drying speed, (ii) membrane charge density, and (iii) polyethylene glycol-conjugated lipids amount.