Chakraborty Dipayan, Ma Wenchuan, Wang Xiqu, Chu Zheting, Yang Taimin, Warzecha Monika, Vekilov Peter G, Rimer Jeffrey D
William A. Brookshire Department of Chemical and Biomolecular Engineering, University of Houston, Houston, TX 77204-4004.
Department of Chemistry, University of Houston, Houston, TX 77204-5003.
Proc Natl Acad Sci U S A. 2025 Mar 11;122(10):e2415719122. doi: 10.1073/pnas.2415719122. Epub 2025 Mar 3.
Cholesterol crystallization is integral to the pathology of diseases such as atherosclerosis and gallstones, yet the relevant mechanisms of crystal growth have remained elusive. Here, we use a variety of in situ techniques to examine cholesterol monohydrate crystallization over multiple length scales. In this study, we first identified a biomimetic solvent to generate triclinic monohydrate crystals, while avoiding the formation of nonphysiological solvates and enabling crystallization at rates where the dynamics of surface growth could be captured in real time. Using a binary mixture of water and isopropanol, with the latter serving as a surrogate for lipids in physiological environments, we show that cholesterol monohydrate crystals grow classically by the nucleation and spreading of crystal layers. Time-resolved imaging confirms that layers are generated by dislocations and monomers incorporate into advancing steps after diffusion along the crystal surface and not directly from the solution. In situ atomic force microscopy (AFM) and microfluidics measurements concertedly reveal abundant macrosteps, which engender a self-inhibition mechanism that reduces the rate of crystal growth. This finding stands in contrast to numerous other systems, in which classical mechanisms lead to unhindered growth by spreading of single layers.
胆固醇结晶是动脉粥样硬化和胆结石等疾病病理过程的重要组成部分，然而晶体生长的相关机制一直难以捉摸。在这里，我们使用多种原位技术在多个长度尺度上研究胆固醇一水合物的结晶过程。在本研究中，我们首先确定了一种仿生溶剂来生成三斜一水合物晶体，同时避免形成非生理性溶剂化物，并能够以实时捕捉表面生长动力学的速率进行结晶。使用水和异丙醇的二元混合物，其中后者作为生理环境中脂质的替代物，我们表明胆固醇一水合物晶体通过晶层的成核和扩展以经典方式生长。时间分辨成像证实，晶层是由位错产生的，单体在沿晶体表面扩散后并入前进台阶，而不是直接从溶液中并入。原位原子力显微镜（AFM）和微流体测量共同揭示了大量的宏观台阶，这产生了一种自我抑制机制，降低了晶体生长速率。这一发现与许多其他系统形成对比，在那些系统中，经典机制通过单层扩展导致不受阻碍的生长。
