Department of Animal Physiology, University of Rostock, Albert-Einstein Str. 3, 18059, Rostock, Germany.
Department Functional Morphology and Biomechanics, Zoological Institute of the University of Kiel, Am Botanischen Garten 1-9, 24118, Kiel, Germany.
Sci Rep. 2024 Aug 6;14(1):18267. doi: 10.1038/s41598-024-69059-2.
In many insects the surface of the eye is nanostructured by arrays of protuberances termed ommatidial gratings which provide the cuticle with anti-reflective, anti-wetting and self-cleaning properties. The hypothesised anti-contamination role of the gratings against dust and pollen results from theoretical predictions on grating geometry and experiments on synthetic replicas of ommatidia surfaces but has not yet been proven in an animal. Whiteflies are biological test beds for anti-contamination surfaces because they deliberately distribute wax particles extruded from abdominal plates over their entire bodies. The numerous particles protect the animal against water evaporation and radiation, but may severely impair vision. Using scanning electron microscopy (SEM) and CryoSEM, we here show that the cornea of whiteflies exhibits ~ 220 nm wide mesh-like structures forming hexagonal gratings with thin ~ 40 nm connecting walls. Quantitative measurements of wax particles on the eye show that the nanostructures reduce particle contamination by more than ~ 96% compared to other areas of the cuticle. Altogether, our study is the first description of a predicted optimized grating geometry for anti-contamination in an arthropod. The findings serve as evidence of the high effectiveness of nanostructured surfaces for reducing contact area and thus adhesion forces between biological surfaces and contaminating particles.
在许多昆虫的眼睛表面，由称为小眼光栅的突起阵列构成了纳米结构，这些结构为外骨骼提供了抗反射、抗湿和自清洁的特性。光栅对灰尘和花粉的抗污染作用的假设源于对光栅几何形状的理论预测和小眼表面的合成复制品的实验，但尚未在动物身上得到证明。粉虱是抗污染表面的生物测试床，因为它们故意将从腹部板挤出的蜡颗粒分布在整个身体上。这些颗粒为数众多，能保护动物免受水分蒸发和辐射的影响，但可能会严重损害视力。使用扫描电子显微镜（SEM）和 CryoSEM，我们在这里表明，粉虱的角膜呈现出约 220nm 宽的网状结构，形成具有薄约 40nm 连接壁的六边形光栅。对眼睛上的蜡颗粒进行定量测量表明，与外骨骼的其他区域相比，纳米结构将颗粒污染减少了超过约 96%。总的来说，我们的研究首次描述了节肢动物中抗污染的预测优化光栅几何形状。这些发现证明了纳米结构表面在减少生物表面和污染颗粒之间的接触面积和粘附力方面的高度有效性。
