Structural characteristics of phospholipid multilamellar liposomes

Area of Science:

• Lipid bilayer self-assembly
• Vesicle characterization
• Nanoparticle formulation

Background:

• Multilamellar vesicles (liposomes) are crucial in drug delivery and biomimetic studies.
• Understanding the relationship between lipid composition and internal aqueous volume is key for liposome design.

Purpose of the Study:

• To compute the lipid proportion and internal aqueous volume of spherical multilamellar vesicles.
• To correlate these volumes with vesicle dimensions and lamellarity.

Main Methods:

• Mathematical modeling based on liposome outer radius, interlamellar spacing, and bilayer number.
• Integration of experimental data into computational models.

Main Results:

• Calculations indicate spontaneously formed liposomes average 10 lamellae (0.1 micron thickness).
• These liposomes trap an average aqueous core radius of approximately 0.5 micron.
• The majority of entrapped aqueous volume resides in the internal core.

Conclusions:

• Liposome lamellarity and dimensions dictate lipid and aqueous volume proportions.
• Computational models provide insights into liposome internal structure.
• Current models may overestimate trapped volumes when using surface exposure data.