Coarsening Dynamics of Domains in Lipid Membranes

• Published in: Biophysical journal Vol. 105; no. 2; pp. 444 - 454
• Main Authors: Stanich, Cynthia A., Honerkamp-Smith, Aurelia R., Putzel, Gregory Garbès, Warth, Christopher S., Lamprecht, Andrea K., Mandal, Pritam, Mann, Elizabeth, Hua, Thien-An D., Keller, Sarah L.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 16.07.2013; Biophysical Society; The Biophysical Society
• Subjects: Cellular biology; Coalescence; Diffusion; Kinetics; Lipids; Lipids - chemistry; Membrane; Membranes; Morphology; Ostwald ripening; phase transition; Temperature; Unilamellar Liposomes - chemistry
• ISSN: 0006-3495; 1542-0086; 1542-0086
• DOI: 10.1016/j.bpj.2013.06.013

We investigate isothermal diffusion and growth of micron-scale liquid domains within membranes of free-floating giant unilamellar vesicles with diameters between 80 and 250 μm. Domains appear after a rapid temperature quench, when the membrane is cooled through a miscibility phase transition such that coexisting liquid phases form. In membranes quenched far from a miscibility critical point, circular domains nucleate and then progress within seconds to late stage coarsening in which domains grow via two mechanisms 1), collision and coalescence of liquid domains, and 2), Ostwald ripening. Both mechanisms are expected to yield the same growth exponent, α = 1/3, where domain radius grows as timeα. We measure α = 0.28 ± 0.05, in excellent agreement. In membranes close to a miscibility critical point, the two liquid phases in the membrane are bicontinuous. A quench near the critical composition results in rapid changes in morphology of elongated domains. In this case, we measure α = 0.50 ± 0.16, consistent with theory and simulation.