Tribological Properties of Micropored Poly(2-hydroxyethyl methacrylate) Hydrogels in a Biomimetic Aqueous Environment
Tribological Properties of Micropored Poly(2-hydroxyethyl methacrylate) Hydrogels in a Biomimetic Aqueous Environment
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DOI：
10.1021/acsami.1c13718
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发表时间：
2021-08-27
影响因子：
9.5
通讯作者：
Choi, Chang-Hwan
中科院分区：
文献类型：
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作者：
Xi, Yiwen;Sharma, Prashant Kumar;Choi, Chang-Hwan
近十年来，水凝胶在组织工程中的应用迅速发展。然而，由于水凝胶的机械和化学性质的复杂性，水凝胶在生理相关条件下的摩擦学特性，特别是有织构的水凝胶的摩擦学特性在很大程度上仍然未知。在这项研究中，我们实验研究了微孔聚（2-羟乙基甲基丙烯酸酯）（pHEMA）在生理相关条件下的摩擦学性能，与无孔pHEMA相比，微孔聚（2-羟乙基甲基丙烯酸酯）（pHEMA）是眼科中最常用的水凝胶。在33℃的磷酸盐缓冲盐水（pH 7.4）中，在不同载荷（6-60 mN，导致平均接触压力为10-21 kPa）和滑动速度（1-10 mm/s）下，pHEMA标本在光滑的玻璃曲线上滑动，以模拟人眼的生理条件。在相对较低的载荷和滑动速度（例如6 mN和1 mm/s）下，微孔pHEMA并没有显著降低耗散的摩擦能。然而，在相对较高的负载和滑动速度（例如60 mN和100 mm/s）下，微孔pHEMA的摩擦能耗散明显低于无纹理pHEMA（减少高达68%）。微孔尺寸越小，效果越明显。这是由于在较高的载荷和滑动速度下，由较小尺寸的微孔挤出的自由水支撑的界面流体的数量和保持性更大。这些结果表明，在实践中，例如在眼部应用中，可以利用水凝胶上的微孔纹理来减少生理条件下的摩擦和磨损，从而降低眼部植入物或角膜假体附近炎症的机会。
The applications of hydrogels in tissue engineering as implants have rapidly grown in the last decade. However, the tribological properties of hydrogels under physiologically relevant conditions, especially those of textured hydrogels, have remained largely unknown due to the complexity of their mechanical and chemical properties. In this study, we experimentally investigated the tribological properties of micopored poly(2-hydroxyethyl methacrylate) (pHEMA) with the lateral pore dimensions varied compared to untextured pHEMA, the most commonly used hydrogel in ophthalmology, under physiologically relevant conditions. The pHEMA specimens were slid against a smooth glass curve under varying loads (6-60 mN, leading to an average contact pressure of 10-21 kPa) and sliding speeds (1-10 mm/s) in phosphate-buffered saline (pH 7.4) at 33 degrees C to mimic the physiological conditions in human eyes. At relatively low loads and sliding speeds (e.g., 6 mN and 1 mm/s), the micopored pHEMA did not reduce the dissipated frictional energy significantly. However, at relatively high loads and sliding speeds (e.g., 60 mN and 100 mm/s), the micopored pHEMA resulted in significantly lower frictional energy (reduced by up to 68%) dissipation than the untextured pHEMA. The effect was more pronounced with the micropores with smaller dimensions. These are attributed to the greater amount and retentivity of the interfacial fluid supported by the free water squeezed out of the micropores with the smaller dimensions under the higher load and sliding speed. These results suggest that the use of micropore texturing on hydrogels in practice, such as for ocular applications, can be leveraged to reduce friction and wear under physiological conditions and hence lower the chance of inflammation near eye implants or keratoprosthesis.