Cell membranes are composed of a hydrated lipid bilayer that is molecularly complex and diverse, and the link between molecular hydration structure and membrane macroscopic properties is not well understood, due to a lack of technology that can probe and relate molecular level hydration information to micro- and macroscopic properties. Here, we demonstrate a direct link between lipid hydration structure and macroscopic dynamic curvature fluctuations. Using high-throughput wide-field second harmonic (SH) microscopy, we observe the formation of transient domains of ordered water at the interface of freestanding lipid membranes. These domains are induced by the binding of divalent ions and their structure is ion specific. Using nonlinear optical theory, we convert the spatiotemporal SH intensity into maps of membrane potential, surface charge density, and binding free energy. Using an electromechanical theory of membrane bending, we show that transient electric field gradients across the membrane induce spatiotemporal membrane curvature fluctuations.

细胞膜由分子复杂多样的水合脂质双层组成，分子水合结构与膜宏观特性之间的联系尚不清楚，因为缺乏可以探测分子水平水合信息并将其与微观结构联系起来的技术。和宏观性质。在这里，我们展示了脂质水化结构与宏观动态曲率波动之间的直接联系。使用高通量广域二次谐波 (SH) 显微镜，我们观察到独立脂质膜界面处有序水瞬态域的形成。这些域是由二价离子的结合诱导的，它们的结构是离子特异性的。使用非线性光学理论，我们将时空 SH 强度转换为膜电位图、表面电荷密度图、和结合自由能。使用膜弯曲的机电理论，我们表明跨膜的瞬态电场梯度会引起时空膜曲率波动。