Insect eyes have an anti-reflective coating, owing to nanostructures on the corneal surface creating a gradient of refractive index between that of air and that of the lens material1,2. These nanocoatings have also been shown to provide anti-adhesive functionality3. The morphology of corneal nanocoatings are very diverse in arthropods, with nipple-like structures that can be organized into arrays or fused into ridge-like structures4. This diversity can be attributed to a reaction-diffusion mechanism4 and patterning principles developed by Alan Turing5, which have applications in numerous biological settings6. The nanocoatings on insect corneas are one example of such Turing patterns, and the first known example of nanoscale Turing patterns4. Here we demonstrate a clear link between the morphology and function of the nanocoatings on Drosophila corneas. We find that nanocoatings that consist of individual protrusions have better anti-reflective properties, whereas partially merged structures have better anti-adhesion properties. We use biochemical analysis and genetic modification techniques to reverse engineer the protein Retinin and corneal waxes as the building blocks of the nanostructures. In the context of Turing patterns, these building blocks fulfil the roles of activator and inhibitor, respectively. We then establish low-cost production of Retinin, and mix this synthetic protein with waxes to forward engineer various artificial nanocoatings with insect-like morphology and anti-adhesive or anti-reflective function. Our combined reverse- and forward-engineering approach thus provides a way to economically produce functional nanostructured coatings from biodegradable materials.

中文翻译：

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果蝇角膜纳米涂层的逆向和正向工程

昆虫的眼睛具有抗反射涂层，这是由于角膜表面上的纳米结构在空气和镜片材料之间产生折射率梯度1,2。这些纳米涂层也已被证明具有抗粘连功能3。角膜纳米涂层的形态在节肢动物中非常多样化，具有可以组织成阵列或融合成脊状结构的乳头状结构。这种多样性可归因于 Alan Turing5 开发的反应扩散机制 4 和模式化原理，它们在许多生物环境中都有应用 6。昆虫角膜上的纳米涂层是这种图灵图案的一个例子，也是纳米级图灵图案的第一个已知例子。在这里，我们展示了果蝇角膜上纳米涂层的形态和功能之间的明确联系。我们发现由单个突起组成的纳米涂层具有更好的抗反射性能，而部分合并的结构具有更好的抗粘附性能。我们使用生化分析和基因改造技术对蛋白质视黄素和角膜蜡作为纳米结构的构建块进行逆向工程。在图灵模式的背景下，这些构建块分别扮演激活器和抑制剂的角色。然后，我们建立了维甲酸的低成本生产，并将这种合成蛋白质与蜡混合，以正向工程设计各种具有昆虫状形态和抗粘连或抗反射功能的人造纳米涂层。