Direct measurement of interaction forces between charged multilamellar vesicles†

Area of Science:

• Soft Matter Physics
• Biophysics
• Colloid Science

Background:

• Giant multilamellar vesicles exhibit complex adhesion behaviors.
• Understanding vesicle dynamics is crucial for cell mechanics and drug delivery.

Purpose of the Study:

• To investigate the role of dynamics in vesicle adhesion and de-adhesion.
• To quantify the influence of velocity and membrane tension on vesicle separation.

Main Methods:

• Utilized a novel Cantilevered-Capillary Force Apparatus.
• Studied depletion-attraction induced adhesion of charged giant vesicles (∼ 40 μm).
• Analyzed adhesion and de-adhesion at constant separation velocities.

Main Results:

• Observed hydrodynamically controlled drainage of the thin film between vesicles prior to adhesion.
• Separation force increases with increasing separation velocity and membrane tension.
• Work done to separate vesicles increases with velocity, showing a maximum with varying membrane tension.

Conclusions:

• Hydrodynamic effects are critical in vesicle adhesion and separation dynamics.
• Vesicle separation force and work are tunable parameters influenced by velocity and tension.
• The findings provide insights into the mechanics of soft matter interactions.