Rhythmic pore dynamics in a shrinking lipid vesicle
Tsutomu Hamada1, Yuichi Hirabayashi, Takao Ohta
1School of Materials Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923-1292, Japan. t-hamada@jaist.ac.jp
Summary
Lipid vesicles exhibit distinct pore dynamics when treated with Triton X-100 (TX-100). The study reveals two shrinking behaviors—rhythmic and continuous pore generation—dependent on vesicle size and TX-100 concentration.
Area of Science:
- Membrane biophysics
- Soft matter physics
- Chemical physics
Background:
- Understanding nonequilibrium membrane dynamics is crucial for cellular processes.
- Lipid vesicles serve as model systems for cell membranes.
- Surfactants like Triton X-100 (TX-100) can induce significant changes in membrane structure and behavior.
Purpose of the Study:
- To investigate the distinct pore generation and shrinking dynamics of lipid vesicles under nonequilibrium conditions.
- To determine the influence of vesicle size and surfactant concentration on membrane pore behavior.
- To elucidate the underlying mechanisms governing these dynamic processes.
Main Methods:
- Utilized lipid vesicles of varying sizes.
- Applied controlled concentrations of the surfactant Triton X-100 (TX-100).
- Observed and analyzed vesicle shrinking dynamics and pore generation using microscopy and biophysical techniques.
Main Results:
- Two primary dynamics were identified: rhythmic-pore dynamics (small vesicles, low TX-100) and continuous-pore dynamics (large vesicles, high TX-100).
- Rhythmic dynamics involved repetitive, transient pore generation.
- Continuous dynamics featured sustained pore opening during vesicle shrinkage.
- Long-cycle oscillations were observed in rhythmic-pore dynamics, with cycle periods influenced by vesicle size and TX-100 concentration.
Conclusions:
- Vesicle size and TX-100 concentration are critical factors controlling membrane pore dynamics.
- The observed phenomena can be explained by considering the elastic free energy of the lipid membrane.
- This study provides insights into the fundamental physics of membrane deformation and pore formation.
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