Nanoscale Pattern Formation in Biological Surfaces

Abstract

In the present chapter, three problems of nanoscale pattern formation will be discussed. (1) The particular symmetry violation in the dimple-like nano-pattern on the belly scales of the pythonid snake Morelia viridis is analyzed using correlation analysis of the distances between individual nanostructures. (2) Pattern formation in the multi-component colloidal secretion of whip-spiders (cerotegument) is numerically simulated and discussed. (3) Pattern formation of the springtail cuticle nanostructures.

Dimple-like nano-pattern on the belly scales of the snake skin is supposed to reduce both friction and abrasion. On the real snake skin surface, the pattern analysis revealed non-random, but very specific symmetry violation. The results of the analysis, performed on the snake were compared with nano-nipple pattern on the eye of the sphingid moth being well known reference of highly-ordered biological nanopatterns. In the case of the moth eye, the nano-nipple arrangement forms a set of domains, while, in the case of the snake skin, the nano-dimples arrangement resembles an ordering of molecules in amorphous state, which might provide friction isotropy to the skin. A simple model of such pattern formation is suggested, which almost perfectly reproduces the experimental results. Some other biological surfaces gain their super-hydrophobic properties by nano-structures on the surface. Some arachnids, such as the cryptic, large whip-spiders and some mites, exhibit a crust of dried secretion containing globular micro-structures covered with regularly arranged nano-particles built from a multi-phasic secretion. In order to gain a better understanding of the process of self-assembly of nanostructures on spherical microstructures, in the present chapter, we studied it from a theoretical point of view. It is demonstrated that slight changes of simple parameters lead to a variety of morphologies highly similar to the ones observed in the species specific cerotegument structures. Also springtails have a complex hierarchically structured cuticle surface with even stronger repelling properties against water, low-surface-tension liquids, and sticky secrets of predatory insects. Non-wetting property of the collembolan cuticle is mainly based on the cuticle topography rather than on the surface chemistry. In material science, analogous surface coatings have been produced by colloidal lithography utilizing the self-assembly of nanoparticles on a substrate. We introduce here a numerical model to study the effect of different interactions between the substances on the morphology of the desired structure. In general the study of biological self-organising nanopatterns and their evolution seems to be a promising approach for generating new solutions for future industrial applications.

8.1 Supplementary Electronic Material(s)

(MP4 15675 kb)

(MP4 4511 kb)

(MP4 3482 kb)

(MP4 5535 kb)

(MP4 4940 kb)

(MP4 4226 kb)

(MP4 4201 kb)

(MP4 4085 kb)

(MP4 4320 kb)

(MP4 5543 kb)

(MP4 6220 kb)

(MP4 1719 kb)

(MP4 1721 kb)