Dynamic and reversible shape response of red blood cells in synthetic liquid crystals
Dynamic and reversible shape response of red blood cells in synthetic liquid crystals
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DOI：
10.1073/pnas.2007753117
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发表时间：
2020-10-20
影响因子：
11.1
通讯作者：
Abbott, Nicholas L.
中科院分区：
文献类型：
--
作者：
Nayani, Karthik;Evans, Arthur A.;Abbott, Nicholas L.
哺乳动物细胞是柔软的，正常的功能需要细胞在体内经历动态的形状变化。尽管一系列疾病与红细胞（RBC;例如，镰状细胞性贫血或疟疾），但对细胞的机械性质以及因此对复杂粘弹性环境的形状响应知之甚少。我们使用蒸汽压测量来识别与RBC处于渗透平衡的水性液晶（LC），并探索RBC和LC之间的机械耦合。当从各向同性水相转移到LC中时，RBC表现出复杂但可逆的形状转变，从最初的双凹面盘到具有非圆形横截面的细长和折叠的几何形状。重要的是，尽管RBC的形状在各向同性流体中是相似的，但当通过LC应变时，测量到形状响应的大的变化，从而揭示了机械性质的细胞间变化。LC和细胞力学的数值模拟显示，RBC形状响应发生在恒定的细胞膜面积，但膜剪切模量在细胞之间变化，从2到16 × 10（-6）N/m。温度依赖性LC弹性允许RBC应变的连续调谐，并且RBC（患病细胞的模型）的化学交联导致RBC的形状响应的显著变化。总的来说，这些结果提供了深入了解软哺乳动物细胞和合成LC之间的应变耦合，并提示新的方法，用于快速表征人口中的单个哺乳动物细胞的机械性能，从而细胞间的差异。
Mammalian cells are soft, and correct functioning requires that cells undergo dynamic shape changes in vivo. Although a range of diseases are associated with stiffening of red blood cells (RBCs; e.g., sickle cell anemia or malaria), the mechanical properties and thus shape responses of cells to complex viscoelastic environments are poorly understood. We use vapor pressure measurements to identify aqueous liquid crystals (LCs) that are in osmotic equilibrium with RBCs and explore mechanical coupling between RBCs and LCs. When transferred from an isotropic aqueous phase into a LC, RBCs exhibit complex yet reversible shape transformations, from initially biconcave disks to elongated and folded geometries with noncircular cross-sections. Importantly, whereas the shapes of RBCs are similar in isotropic fluids, when strained by LC, a large variance in shape response is measured, thus unmasking cell-to-cell variation in mechanical properties. Numerical modeling of LC and cell mechanics reveals that RBC shape responses occur at constant cell membrane area but with membrane shear moduli that vary between cells from 2 to 16 x 10(-6) N/m. Temperature-dependent LC elasticity permits continuous tuning of RBC strains, and chemical cross-linking of RBCs, a model for diseased cells, leads to striking changes in shape responses of the RBCs. Overall, these results provide insight into the coupling of strain between soft mammalian cells and synthetic LCs, and hint at new methods for rapidly characterizing mechanical properties of single mammalian cells in a population and thus cell-to-cell variance.