Racial variations in interfacial behavior of lipids extracted from worn soft contact lenses.
Racial variations in interfacial behavior of lipids extracted from worn soft contact lenses.
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DOI：
10.1097/opx.0000000000000098
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发表时间：
2013-12
期刊：
影响因子：
--
通讯作者：
Lin MC
中科院分区：
文献类型：
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作者：
Svitova TF;Lin MC
探索界面行为以及温度和扩张对从无症状亚洲和白人受试者佩戴的硅水凝胶 (SiH) 镜片中提取的多层人泪脂动态特性的影响。研究了从 14 名受试者连续佩戴 1 个月的 Focus® N&D 镜片中提取的脂质的界面特性。将脂质沉积在浸入模型泪液电解质 (MTE) 溶液中的气泡上，形成 100 ± 20 nm 厚的薄膜。在缓慢的膨胀/收缩循环期间记录表面压力，以评估脂质膜的可压缩性和滞后性。薄膜还在 22°–45°C 的温度下进行快速阶跃应变膨胀，以评估其粘弹性。亚洲和高加索脂质的等循环在低表面压力下相似，但在超过 30 mN/m 的动态压力下具有明显不同的压缩性和滞后性。亚洲人和白种人之间重构脂质的流变参数也不同。白种人脂质的弹性模量 E∞ 比亚洲人脂质高 1.5 倍，而松弛时间 (t) 平均比亚洲人高 1.3 倍。当温度从 22.0°C 升高到 36.5°C 时，亚洲和高加索脂质的流变特性没有观察到显着变化。然而，对于高加索脂质，E∞ 在温度高于 42.0°C 时显着降低，而 t 保持不变。对于亚洲脂质，随着温度升高至 38° C 或更高，E∞ 和 t 都开始下降。与更粘稠的亚洲脂质相比，高加索脂质的较高弹性模量和某些变形下的弹性阈值表明更强的结构和分子间相互作用。亚洲人和高加索人脂质之间界面行为的差异可能与其化学成分的差异有关。
To explore interfacial behaviors and effect of temperature and dilatation on dynamic properties of multilayered human tear lipids extracted from silicone hydrogel (SiH) lenses worn by asymptomatic Asian and Caucasian subjects. Interfacial properties of lipids extracted from Focus® N&D lenses worn by 14 subjects continuously for 1 month were studied. The lipids were deposited on an air bubble immersed in a model tear electrolytes (MTE) solution to form 100 ± 20 nm-thick films. Surface pressure was recorded during slow expansion/contraction cycles to evaluate compressibility and hysteresis of lipid films. Films were also subjected to fast step-strain dilatations at temperatures 22°–45° C for their visco-elastic properties assessment. Iso-cycles for Asian and Caucasian lipids were similar at low surface pressures, but had distinctly different compressibility and hysteresis at dynamic pressures exceeding 30 mN/m. Rheological parameters of reconstituted lipids were also dissimilar between Asian and Caucasian. The elastic modulusE∞ for Caucasian lipids was 1.5 times higher than that for Asian lipids, whereas relaxation time (t) was on average 1.3 times higher for Asian. No significant changes were observed in rheological properties of both Asian and Caucasian lipids when temperature increased from 22.0° to 36.5° C. However, for Caucasian lipids, E∞ reduced considerably at temperatures above 42.0° C, while t remained unchanged. For Asian lipids, both E∞ and t started to decline as temperature increased to 38° C and higher. Higher elastic modulus of Caucasian lipids and elasticity threshold at certain deformations indicate stronger structure and intermolecular interactions as compared with more viscous Asian lipids. The differences in interfacial behaviors between Asian and Caucasian lipids may be associated with the differences in their chemical compositions.