W.M. Keck Center for 3D Innovation, The University of Texas at El Paso, 500 West University Avenue, El Paso, TX 79968, USA.
Biomed Microdevices. 2010 Oct;12(5):875-86. doi: 10.1007/s10544-010-9442-1.
Microstereolithography (microSL) technology can fabricate complex, three-dimensional (3D) microstructures, although microSL has difficulty producing macrostructures with micro-scale features. There are potentially many applications where 3D micro-features can benefit the overall function of the macrostructure. One such application involves a medical device called a coaxial phacoemulsifier where the tip of the phacoemulsifier is inserted into the eye through a relatively small incision and used to break the lens apart while removing the lens pieces and associated fluid from the eye through a small tube. In order to maintain the eye at a constant pressure, the phacoemulsifier also includes an irrigation solution that is injected into the eye during the procedure through a coaxial sleeve. It has been reported, however, that the impinging flow from the irrigation solution on the corneal endothelial cells in the inner eye can damage these cells during the procedure. As a result, a method for reducing the impinging flow velocities and the resulting shear stresses on the endothelial cells during this procedure was explored, including the design and development of a complex, 3D micro-vane within the sleeve. The micro-vane introduces swirl into the irrigation solution, producing a flow with rapidly dissipating flow velocities. Fabrication of the sleeve and fitting could not be accomplished using microSL alone, and thus, a two-part design was accomplished where a sleeve with the micro-vane was fabricated with microSL and a threaded fitting used to attach the sleeve to the phacoemulsifier was fabricated using an Objet Eden 333 rapid prototyping machine. The new combined device was tested within a water container using particle image velocimetry, and the results showed successful swirling flow with an ejection of the irrigation fluid through the micro-vane in three different radial directions corresponding to the three micro-vanes. As expected, the sleeve produced a swirling flow with rapidly dissipating streamwise flow velocities where the maximum measured streamwise flow velocities using the micro-vane were lower than those without the micro-vane by 2 mm from the tip where they remained at approximately 70% of those produced by the conventional sleeve as the flow continued to develop. It is believed that this new device will reduce damage to endothelial cells during cataract surgery and significantly improve patient outcomes from this procedure. This unique application demonstrates the utility of combining microSL with a macro rapid prototyping technology for fabricating a real macro-scale device with functional, 3D micro-scale features that would be difficult and costly to fabricate using alternative manufacturing methods.
微立体光刻（microSL）技术可以制造复杂的三维（3D）微结构，尽管 microSL 难以制造具有微尺度特征的宏观结构。在许多潜在的应用中，3D 微特征可以有益于宏观结构的整体功能。一种这样的应用涉及一种称为同轴白内障乳化器的医疗器械，其中白内障乳化器的尖端通过相对较小的切口插入眼睛，并用于在通过小管道从眼睛中去除晶状体碎片和相关流体的同时将晶状体分开。为了保持眼睛的恒定压力，白内障乳化器还包括在手术过程中通过同轴套管注入眼睛的冲洗液。然而，据报道，冲洗液对眼睛内部角膜内皮细胞的冲击流在手术过程中会损坏这些细胞。因此，探索了一种在手术过程中降低冲击流速度和对内皮细胞的剪切力的方法，包括在套管内设计和开发复杂的 3D 微叶片。微叶片将涡流引入冲洗液中，产生流速迅速耗散的流动。仅使用 microSL 无法完成套管的制造和装配，因此，完成了一个两部分的设计，其中带有微叶片的套管使用 microSL 制造，用于将套管连接到白内障乳化器的螺纹配件使用 Objet Eden 333 快速成型机制造。新的组合装置在水容器内使用粒子图像测速法进行了测试，结果表明在三个不同的径向方向上成功地产生了涡流流动，并通过微叶片喷射冲洗液，这三个方向对应于三个微叶片。不出所料，套管产生了具有快速耗散流向速度的涡流流动，其中使用微叶片测量的最大流向速度比没有微叶片时在距尖端 2 毫米处低 2 毫米，并且在流动继续发展时，它们保持在传统套管产生的速度的约 70%。人们相信，这种新装置将减少白内障手术过程中对内皮细胞的损伤，并显著改善患者的手术效果。这种独特的应用展示了将 microSL 与宏观快速原型制造技术相结合的实用性，用于制造具有功能 3D 微尺度特征的真实宏观装置，这些特征用替代制造方法制造既困难又昂贵。
