Mechanical property of lipid-coated polyelectrolyte microcapsules

Area of Science:

• Materials Science
• Physical Chemistry
• Biophysics

Background:

• Polyelectrolyte capsules are versatile structures with potential applications in drug delivery and nanotechnology.
• Understanding their mechanical properties, especially when coated with lipids, is crucial for optimizing their performance.
• Osmotic pressure is a key factor influencing capsule deformation and stability.

Purpose of the Study:

• To investigate the deformation behavior of lipid-coated polyelectrolyte capsules under osmotic pressure.
• To determine the wall thickness and elasticity of these composite capsules.
• To elucidate the structure of the lipid layer on the polyelectrolyte core.

Main Methods:

• Utilizing poly(styrene sulfonate, sodium salt) (PSS) solution to induce osmotic pressure.
• Employing single particle light scattering to measure capsule wall thickness.
• Analyzing capsule deformation at critical osmotic pressures.

Main Results:

• Spherical capsules transitioned to invaginated shapes at a critical osmotic pressure.
• Lipid-coated capsules exhibited a wall thickness of 25.6 nm, with a 4 nm lipid layer.
• The elasticity coefficient of the lipid-coated capsules was determined to be approximately 426 MPa.
• The lipid layer was identified as a bilayer structure.

Conclusions:

• Lipid coating significantly enhances the mechanical properties of polyelectrolyte capsules.
• The observed deformation and thickness measurements provide insights into the structural integrity of lipid-coated capsules.
• These findings contribute to the development of advanced functional materials based on composite capsules.