Flow-Induced Vesicle Translocation through a Narrow Slit─Transit Time Scaling Relations

Area of Science:

• Soft matter physics
• Biophysics
• Nanotechnology

Background:

• Vesicle and transferosome translocation through splenic interendothelial slits is vital for transdermal drug delivery and microfluidic separations.
• Understanding these translocation dynamics is key for optimizing drug permeation and disease progression monitoring.

Purpose of the Study:

• To investigate the pressure-driven flow-induced translocation of loaded vesicles through narrow rectangular slits.
• To analyze the influence of vesicle size, applied force, and slit geometry on translocation dynamics.

Main Methods:

• Extensive Molecular Dynamics (MD) simulations were employed.
• Multiparticle Collision Dynamics (MPCD) was used to incorporate hydrodynamic interactions.
• Vesicles of varying size (M) were subjected to a constant body force (F) in slits of half-width (H).

Main Results:

• Transit time (τ) scales as τ ∝ MF⁻¹H⁻², confirming theoretical predictions.
• A critical jamming force (Fminjam ∝ H⁻¹) was identified, below which vesicles get stuck.
• At high forces, transit time becomes independent of slit width.
• Increased internal filler concentration or filler attraction increases vesicle surface area and tension, significantly prolonging transit time.

Conclusions:

• The study provides a quantitative understanding of vesicle translocation dynamics in confined geometries.
• Findings are relevant for designing efficient vesicular transdermal delivery systems and advanced microfluidic devices.
• Vesicle internal properties and surface tension significantly impact translocation efficiency.