Fission of Lipid-Vesicles by Membrane Phase Transitions in Thermal Convection
Fission of Lipid-Vesicles by Membrane Phase Transitions in Thermal Convection
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DOI：
10.1038/s41598-019-55110-0
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发表时间：
2019-12-11
影响因子：
4.6
通讯作者：
Westerhausen, Christoph
中科院分区：
文献类型：
--
作者：
Kudella, Patrick W.;Preissinger, Katharina;Westerhausen, Christoph
单层脂质囊泡可以作为原始细胞的模型。我们提出了一种热梯度下对流室的囊泡裂变机制，其中囊泡周期性地循环冷热区。在这种情况下，获得囊泡裂变的关键是温度诱导的膜相变，囊泡经历多次。我们用毛细管模拟了腔室的温度梯度，以研究单个囊泡在外力场中通过温度梯度的过程。从凝胶状阶段开始，球形囊泡被加热到其主要熔化温度以上，导致哑铃形变形。再往下游，温度降至低于转变温度就会导致囊泡分裂，而无需进一步的物理或化学干预。这种机制也适用于不太合作的系统，如图所示，脂质合金具有8 K宽的转变温度宽度。我们找到了一个临界系绳长度，可以从过渡宽度和局部施加的温度梯度来理解。这种温度诱导的膜相变和实际流动场景的结合，例如在白色烟雾中，使裂变机制能够有助于理解更高级的原始细胞周期。
Unilamellar lipid vesicles can serve as model for protocells. We present a vesicle fission mechanism in a thermal gradient under flow in a convection chamber, where vesicles cycle cold and hot regions periodically. Crucial to obtain fission of the vesicles in this scenario is a temperature-induced membrane phase transition that vesicles experience multiple times. We model the temperature gradient of the chamber with a capillary to study single vesicles on their way through the temperature gradient in an external field of shear forces. Starting in the gel-like phase the spherical vesicles are heated above their main melting temperature resulting in a dumbbell-deformation. Further downstream a temperature drop below the transition temperature induces splitting of the vesicles without further physical or chemical intervention. This mechanism also holds for less cooperative systems, as shown here for a lipid alloy with a broad transition temperature width of 8 K. We find a critical tether length that can be understood from the transition width and the locally applied temperature gradient. This combination of a temperature-induced membrane phase transition and realistic flow scenarios as given e.g. in a white smoker enable a fission mechanism that can contribute to the understanding of more advanced protocell cycles.