From cuticle biomechanics to bio-inspired composite materials

More than 80% of all animals in the world are arthropods, and amongst them insects are the most diverse and abundant group. Insects inhabit almost all of the world’s ecosystems and show an astonishing variety of different evolutionary adaptations. Hence, insects are often considered to be one of the evolutionary most successful groups of animals.

The insects' secret of success

Part of the insects’ secrets of evolutionary success is their cuticle exoskeleton. After wood, arthropod cuticle is the second most common biological composite material in the world. Cuticle not only exhibits unique biomechanical properties; it is also one of the most versatile biological materials. This makes cuticle an extremely interesting candidate for the design of new bio-inspired composite materials. Surprisingly, despite many decades of research, the fundamental biomechanical properties and principles found in arthropod cuticle are still mostly unknown and the biomimetic potential of cuticle is almost untapped.

To fully understand the relationship between the structure and the biomechanical properties of a hierarchical material, it is important to look at all of the material’s length-scales. In our group we work on several projects focusing on comprehensive and interdisciplinary studies on the biomechanics of cuticle on all length scales: starting from the biological functionality of the exoskeleton, down to microscopic mechanisms determining the biomechanical properties of the cuticle and nanotechnology methods to manufacture "cuticle-inspired" materials.

Some of the main questions we are currently addressing include:

• Fundamental principles of cuticle growth, healing and chitin orientation on a molecular level (DFG project in collaboration with MPI Potsdam, University of Dresden and University of Tübingen).
• Functional correlation of material properties, morphology and histology in arthropod exoskeletons. Are there fundamental common principles found in both endo- and exoskeletons? Can some principles be transferred into bio-inspired light-weight composite materials for bioengineering applications? 

• Experimental analysis and numerical simulation of exoskeleton biomechanics, in particular the role of cuticle building blocks (chitin and protein) in determining the cuticle's biomechanical properties.