How liposomal capsules work is best understood by starting with their core architecture. Liposomal capsules are nanoscale vesicles formed when phospholipids spontaneously assemble into a bilayer, creating a spherical shell with an aqueous interior. The lipid envelope provides a defined boundary and a distinct interior environment that can accommodate a range of payloads, while the outer surface can be tuned for stability and compatibility with different media. In this science-backed guide, we explore the structural elements that underpin the behavior of these carriers as they navigate varying environments. Encapsulation properties are central to how liposomal capsules work. Payloads can reside in the aqueous core if they are hydrophilic, or be embedded within the lipid bilayer if they are hydrophobic. The composition of the lipid layer, often including cholesterol, influences membrane fluidity and stability. Surface characteristics, such as surface charge or the addition of polymers like polyethylene glycol (PEG), can alter interactions with surrounding media and help shape the vesicle’s behavior under different conditions. When liposomal capsules interact with biological contexts, several general mechanisms come into play. The most common uptake route for vesicles is endocytosis, a process by which cells internalize external materials within vesicles. Inside endosomes, pH changes or enzymatic activity can affect the integrity of the liposome and may promote release of the encapsulated content. Some lipid formulations are designed to undergo fusion with membranes or to respond to environmental cues, enabling controlled release within a given compartment. Throughout these processes, the inherent properties of the liposome—size, lamellarity, and lipid composition—play a central role in determining how the system behaves. From a design and research perspective, key factors include particle size, surface charge, and the lipid makeup of the bilayer. Researchers characterize liposomal capsules using techniques such as dynamic light scattering to assess size distribution, electron or cryo-electron microscopy for morphology, and zeta potential measurements for surface charge. Stability under storage and in various media, along with reproducibility of encapsulation and release properties, are important considerations in any study of these vesicular systems. By examining these elements, scientists build a practical understanding of how liposomal capsules work and how formulation choices influence behavior in different experimental contexts.
