Cui Kiara W, Myung David J, Fuller Gerald G
Department of Chemical Engineering, Stanford University, Stanford, California 94305, United States.
Byers Eye Institute at the School of Medicine, Stanford, California 94305, United States.
J Phys Chem B. 2022 Aug 25;126(33):6338-6344. doi: 10.1021/acs.jpcb.2c04154. Epub 2022 Aug 16.
In this work, we describe the development of a tunable, acellular model of the mucin layer of the human tear film. First, supported lipid bilayers (SLBs) comprised of the phospholipid DOPC (1,2-dioleoyl--glycero-3-phosphocholine) and biotinyl cap PE (1,2-dioleoyl--glycero-3-phosphoethanolamine-N-(cap biotinyl)) are created on the surface of a glass dome with radius of curvature comparable to the human eye. Next, biotinylated bovine submaxillary mucins (BSM) are tethered onto the SLB using streptavidin protein. The mucin presentation can be tuned by altering the concentration of biotinylated BSM, which we confirm using fluorescence microscopy. Due to the optically smooth surface that results, this model is compatible with interferometry for monitoring film thickness. Below a certain level of mucin coverage, we observe short model tear film breakup times, mimicking a deficiency in membrane-associated mucins. In contrast, the breakup time is significantly delayed for SLBs with high mucin coverage. Because no differences in mobility or wettability were observed, we hypothesize that higher mucin coverage provides a thicker hydrated layer that can protect against external disturbances to thin film stability. This advance paves the way for a more physiological, interferometry-based model for investigating tear film breakup.
在这项工作中，我们描述了一种可调节的人泪膜粘蛋白层无细胞模型的开发。首先，在曲率半径与人眼相当的玻璃穹顶表面创建由磷脂DOPC（1,2 - 二油酰 - sn - 甘油 - 3 - 磷酸胆碱）和生物素化帽PE（1,2 - 二油酰 - sn - 甘油 - 3 - 磷酸乙醇胺 - N - （帽生物素））组成的支撑脂质双层（SLB）。接下来，使用链霉亲和素蛋白将生物素化的牛颌下粘蛋白（BSM）拴系到SLB上。可以通过改变生物素化BSM的浓度来调节粘蛋白的呈现，我们使用荧光显微镜对此进行了确认。由于由此产生的光学光滑表面，该模型与用于监测膜厚度的干涉测量兼容。在一定水平的粘蛋白覆盖以下，我们观察到模型泪膜破裂时间短，模拟了膜相关粘蛋白的缺乏。相比之下，粘蛋白覆盖率高的SLB的破裂时间明显延迟。因为未观察到流动性或润湿性的差异，我们推测较高的粘蛋白覆盖率提供了更厚的水合层，可以防止对薄膜稳定性的外部干扰。这一进展为基于干涉测量的更具生理性的泪膜破裂研究模型铺平了道路。
