The Directorate of Research, Development and Innovation Management (DMCDI), Technical University of Cluj-Napoca, Cluj-Napoca, Romania.
Microsc Res Tech. 2021 Nov;84(11):2702-2715. doi: 10.1002/jemt.23833. Epub 2021 May 25.
The purpose of this work is to provide a better understanding of three-dimensional (3-D) surface texture of siloxane-hydrogel contact lenses (CLs) using atomic force microscopy (AFM) and stereometric analysis. The 3-D surface texture characterization of unworn/worn siloxane-hydrogel CLs made of Filcon V (I FDA group) was performed with stereometric analysis. The atomic force microscopy (AFM) measurements of surface roughness and micromorphology of CLs were made using a Nanoscope V MultiMode (Bruker) in intermittent-contact mode, in air, on square areas of 5 × 5 μm. Stereometric study of 3-D surface texture was made according with ISO 25178-2:2012 for CL (taken from the blister and rinsed with deionized water); CL (preserved for 12 hr in saline solution and rinsed with deionized water); CL (worn for 8 hr and presenting the smooth type morphology), and CL (worn for 8 hr and presenting the sharp-type morphology). The 3-D surface texture of siloxane-hydrogel CLs was found to have specific morphological characteristics. Statistical parameters revealed local geometrical and morphological spatial structures at nanometer scale attributed to the specific interactions at the CLs surface. Before wear, the surface micromorphology of Filcon V CLs is regular with uniformly distributed microasperities and relatively small heights (Sq = 0.6 nm). After 12 hr in saline, it is found that the micromorphology changes relatively easily, but retaining the main morphological characteristics (Sq = 1.2 nm). After 8 hr of wear, there are two typical micromorphologies: smooth type, characterized by gutter structures and isolated microasperities (Sq = 2.5 nm), while the sharp type has an appearance with compactly arranged microasperities of hill type flanked by compactly arranged microregions of valley type (Sq = 2.2 nm). Surface statistical parameters allow manufacturers in developing the next generation of CLs with improved surface texture while improving biocompatibility and minimizing the impact of the material on corneal physiology. Furthermore, the micro-elastohydrodynamic lubrication due to surface texture at a nanometer scale between the back surface of the CL with the corneal surface and the front surface of the CL with the under-surface of the eyelid can be deeper and more nuanced to understand in light of modern tribological theories.
本工作旨在使用原子力显微镜（AFM）和立体几何分析，更好地了解硅氧烷水凝胶隐形眼镜（CL）的三维（3-D）表面纹理。使用立体几何分析对未磨损/磨损的 Filcon V（I FDA 组）硅氧烷水凝胶 CL 的 3-D 表面纹理进行了表征。使用 Bruker Nanoscope V MultiMode 在间歇接触模式下，在空气中对 5×5μm 的正方形区域进行 CL 表面粗糙度和微观形貌的原子力显微镜（AFM）测量。根据 ISO 25178-2:2012 对 3-D 表面纹理进行了立体几何研究，其中 CL 取自泡罩（用去离子水冲洗）；CL（保存在盐溶液中 12 小时，并用去离子水冲洗）；CL（佩戴 8 小时，呈现光滑型形态）；CL（佩戴 8 小时，呈现尖锐型形态）。硅氧烷水凝胶 CL 的 3-D 表面纹理具有特定的形态特征。统计参数揭示了纳米尺度的局部几何和形态空间结构，这归因于 CL 表面的特定相互作用。在磨损之前，Filcon V CL 的表面微观形貌规则，具有均匀分布的微凸起和相对较小的高度（Sq=0.6nm）。在盐水中放置 12 小时后，发现微观形貌相对容易发生变化，但仍保留主要的形态特征（Sq=1.2nm）。佩戴 8 小时后，有两种典型的微观形貌：光滑型，特征是槽状结构和孤立的微凸起（Sq=2.5nm），而尖锐型具有紧密排列的山型微凸起和紧密排列的谷型微区外观（Sq=2.2nm）。表面统计参数允许制造商在开发下一代 CL 时，改善表面纹理，提高生物相容性，并将材料对角膜生理学的影响降至最低。此外，根据现代摩擦学理论，由于 CL 背面与角膜表面以及 CL 正面与眼睑底面之间的纳米级表面纹理，可以更深入、更细致地了解微弹性流体动力润滑。
