Critical shear rate for thread-like vesicle division

Value 15 1/sec Range: corresponding to a shear stress of 0.35 dynes/cm^2 1/sec
Organism Generic
Reference Zhu TF, Szostak JW. Coupled growth and division of model protocell membranes. J Am Chem Soc. 2009 Apr 22 131(15):5705-13. doi: 10.1021/ja900919c. p.5709 left column top paragraph & supporting text page S5 bottom paragraph & page S6PubMed ID19323552
Method Abstract: "Here [investigators] describe a simple and efficient pathway for model protocell membrane growth and division."
Comments Abstract: "The growth of large multilamellar fatty acid vesicles fed with fatty acid micelles, in a solution where solute permeation across the membranes is slow, results in the transformation of initially spherical vesicles into long thread-like vesicles, a process driven by the transient imbalance between surface area and volume growth. Modest shear forces are then sufficient to cause the thread-like vesicles to divide into multiple daughter vesicles without loss of internal contents." P.5709 left column top paragraph: "The daughter vesicles were brightly fluorescent, showing that most of the encapsulated contents were retained during division. To quantify the fluid shear required for the division of thread-like vesicles, [investigators] used a cone−plate viscometer to measure the critical shear rate under controlled fluid shear. The critical shear rate for thread-like vesicle division was 15/sec, corresponding to a shear stress of 0.35 dynes/cm^2 (fluid viscosity measured 2.3 cP). Higher shear rates, up to 1500/sec, also led to division without disrupting the vesicles."
Entered by Uri M
ID 113226