Instability and Breakup of Model Tear Films
Instability and Breakup of Model Tear Films
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DOI：
10.1167/iovs.15-18064
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发表时间：
2016-03-01
影响因子：
4.4
通讯作者：
Fuller, Gerald G.
中科院分区：
文献类型：
--
作者：
Bhamla, M. Saad;Chai, Chew;Fuller, Gerald G.
目的。提出了一个在隐形眼镜上复制人泪膜的实验平台。使用此仪器研究，研究了界面粘弹性在体外模型撕裂膜上稳定分解和脱水的影响。创建了由牛Meibomian脂质（meibum）组成的模型撕裂膜，分布在PBS或人工撕裂溶液（ATS）上。这些薄膜的界面剪切流变性是根据温度的函数测量的。然后，使用23和35度的硅胶水凝胶（SIHY）隐形眼镜上的界面露水和排水光学平台（i-ddrop）研究这些薄膜的易碎动力学。胶片分解，厚膜的T-发作（类似于100 mu M）和撕裂时间，用于薄膜的T-BU（类似于1 MU M）。还计算出薄膜变薄速率。 ATS/Meibum膜具有最大的表面流变学，相应地显示了23和35度的T-发作时间最大。与ATS/Meibum相比，ATS/Meibum的参数T-BU也明显更大。在室温下，使用ATS和PBS/Meibum膜（T-BU相似）。但是，在35度C下，所有三个模型撕裂膜表现出类似的T-BU，类似于17秒，平均稀疏速率与4 Lm/分钟相似。泪膜稳定性受表面流变学和蒸发的影响。 35度C的体外泪液破裂时间和模型撕裂膜的变化速率与先前报道的体内测量非常吻合，这突出了I-DDROP在体外泪液膜分裂研究中的效用。
PURPOSE. An experimental platform to replicate the human tear film on a contact lens is presented. The influence of interfacial viscoelasticity in stabilizing in vitro model tear films against breakup and dewetting is investigated using this instrument.METHODS. Model tear films consisting of bovine meibomian lipids (meibum) spread on either PBS or artificial tear solution (ATS) are created. The interfacial shear rheology of these films is measured as a function of temperature. The dewetting dynamics of these films is then investigated using the Interfacial Dewetting and Drainage Optical Platform (i-DDrOP) on top of silicone hydrogel (SiHy) contact lenses at 23 and 35 degrees C. The film breakup times are evaluated using two parameters: onset of film breakup, T-onset for thick films (similar to 100 mu m), and tear breakup times, T-BU for thin films (similar to 1 mu m). Thin film thinning rates as a result of evaporation are also calculated.RESULTS. The ATS/meibum films have the largest surface rheology and correspondingly show the largest T-onset times at both 23 and 35 degrees C. The parameter T-BU is also significantly larger for ATS/meibum (T-BU similar to 40 seconds) compared with that of ATS and PBS/meibum films (T-BU similar to 30 seconds) at room temperature. However, at 35 degrees C, all three model tear films exhibit similar T-BU similar to 17 seconds and average rate of thinning of similar to 4 lm/minute.CONCLUSIONS. Tear film stability is influenced by both surface rheology and evaporation. The in vitro tear breakup times and thinning rates of model tear films at 35 degrees C are in good agreement with in vivo measurements previously reported, highlighting the utility of the i-DDrOP for in vitro tear film breakup research.