Bioinspired Chitinous Material Solutions for Environmental Sustainability and Medicine

Abstract

Chitin—the second most abundant organic material on earth—is a polysaccharide that combines with proteinaceous materials to form composites that provide the structural backbone of insect cuticles, crustacean exoskeletons, cephalopod shells and covering surfaces of many other living organisms. Although chitin and its related chitosan materials have been used in various industrial and medical applications based on their chemical properties, their unique mechanical functions have not date been leveraged for commercial applications. The use of chitinous materials for structural applications has been limited by our inability to reproduce, or even fully understand, the complex hierarchical designs behind naturally occurring chitin composites. In this article, an example of engineered chitinous materials is used to introduce the reader to the potential value that bioinspired materials offer for engineering of synthetic and biological materials. The nature of chitin and its general characteristics are first reviewed, and examples of chitinous structures are presented that are designed to perform very different functions, such as nacre and the insect cuticle. Investigation of the structural organization of these materials leads to understanding of the principles of natural materials design that are beginning to be harnessed to fabricate biologically‐inspired composites for materials engineering with tunable properties that mimic living materials, which might provide useful for environmental challenges, as well as medical applications.

Poriferan Chitin as a Versatile Template for Extreme Biomimetics

“…Chitin plays a major role in biological structural materials with significant physical attributes, such as lobster shells [44], the mineralized dactyl club of the stomatopods [97,112], diatoms cell [20], glass sponges [52], copepod teeth's [115], spider fangs [116] and nacre [117]. Surprisingly, the industrial uses of chitinous materials have been largely based on its chemical characteristics (e.g., high nitrogen content) and unique biological properties, rather than on its ability to form structural composites with novel mechanical properties [117].…”

“…Surprisingly, the industrial uses of chitinous materials have been largely based on its chemical characteristics (e.g., high nitrogen content) and unique biological properties, rather than on its ability to form structural composites with novel mechanical properties [117]. However, in order for these unique properties of chitin to be exploited in specific fields like contact lens fabrication, bone substitutes, tubes for nerve regeneration or membranes for soft tissue engineering-the chitin-based materials need to have specific mechanical properties.…”

Biomimetic Chitin–Silk Hybrids: An Optically Transparent Structural Platform for Wearable Devices and Advanced Electronics

“…Among frequently discussed models are crustacean exoskeletons, insect cuticles, and mollusk shells (e.g., nacre) . Although most insect cuticles are free of biominerals, all of these biological structures have in common chitinous complexes (i.e., chitin nanofibers (ChNF) embedded in a proteinous matrix) as a major structural component; for example, in the “brick‐and‐mortar” structure of nacre the chitinous complex is found as the organic “mortar.” Chitin, a structural polysaccharide, is the second most abundant biopolymer only after cellulose, which is mechanically robust, lightweight, nontoxic, and biodegradable . Chitin naturally occurs as a supramolecular crystalline nanofiber (assemblage of ≈20 chitin molecules), but which is not found on its own.…”

Parametric chemistry reverse engineering biomaterial composites for additive manufacturing of bio-cement structures across scales

“…Natural biopolymers-such as chitosan and cellulose-are widely abundant in Nature and exhibit extraordinary mechanical properties, especially when combined with organic and inorganic substances ( Fernandez & Ingber, 2013;Mogas-Soldevila et al, 2014;Vincent, 2012). However, architects, designers and engineers have yet to establish the methods by which to reconfigure these biopolymers into useful composites across functional length-scales that match-and even transcend-the properties of traditional building materials (Fernandez & Ingber, 2012).…”