Biological composites—complex structures for functional diversity

Abstract

The bulk of Earth’s biological materials consist of few base substances—essentially proteins, polysaccharides, and minerals—that assemble into large varieties of structures. Multifunctionality arises naturally from this structural complexity: An example is the combination of rigidity and flexibility in protein-based teeth of the squid sucker ring. Other examples are time-delayed actuation in plant seed pods triggered by environmental signals, such as fire and water, and surface nanostructures that combine light manipulation with mechanical protection or water repellency. Bioinspired engineering transfers some of these structural principles into technically more relevant base materials to obtain new, often unexpected combinations of material properties. Less appreciated is the huge potential of using bioinspired structural complexity to avoid unnecessary chemical diversity, enabling easier recycling and, thus, a more sustainable materials economy.

Water: How Does It Influence the CaCO3 Formation?

“…[1] This wide range of properties that can be accessed by nature is enabled by its tight control over the structure and local composition of biominerals. [1] This wide range of properties that can be accessed by nature is enabled by its tight control over the structure and local composition of biominerals.…”

Structural Orientation and Anisotropy in Biological Materials: Functional Designs and Mechanics

“…Nevertheless, many of them can be seen as similar among biological materials from the perspective of fundamental mechanics as they usually exhibit common characteristics, especially when compared to the building constituents. The structure and mechanics of interfaces in biological materials, as represented by the nanoscale interfibrillar matrices of wood and bone, and their roles in optimizing material performance have been elucidated in recent reviews …”

“…The means by which materials derive their properties and functionalities differs markedly in nature and engineering. The majority of engineering materials have been developed based on significant chemical complexity, which is not accessible to natural organisms; in contrast, the large varieties of biological materials are created from a highly limited palette of substances . By contrast, it is mainly through the perfection of their architectures that the materials in nature evolve to fulfill specific demands .…”

“…This is well represented, for example, by wood and bone; both materials feature a fibrous structure at the nanoscale with fibers of varying orientations arranged in a lamellar fashion despite their distinctly different chemical compositions . Natural materials have long been recognized as a source of inspiration for new engineering materials with their architectures being increasingly replicated in man‐made systems to obtain improved performance . To this end, it is of significance to extract the common principles of architectural designs among diverse biological materials from the viewpoint of materials science and mechanics—it is essentially these principles that need to be reproduced and that we should learn from nature.…”

“…The majority of engineering materials have been developed based on significant chemical complexity, which is not accessible to natural organisms; in contrast, the large varieties of biological materials are created from a highly limited palette of substances. [1][2][3][4] By contrast, it is mainly through the perfection of their architectures that the materials in nature evolve to fulfill specific demands. [4][5][6][7][8][9] Such architectural design presents an exceptional efficiency in property optimization as biological materials often significantly surpass their constituents and sometimes even outperform engineering materials.…”