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Contributed by Mark Dorfman, Biomimicry Chemist, Biomimicry 3.8
Nature, the oldest and wisest chemist, is by necessity, a green chemist. By “nature”, I’m referring to the living natural world. Unlike inanimate rocks and minerals, organisms are constrained by the need to survive, thrive and nurture their young in the same place they make, use and manage chemistry. For example, minerals achieve brilliant colors using lead, mercury or cadmium, but over billions of years of R&D, organisms have figured out how to achieve a dazzling array of show-stopping displays without relying on the incorporation of heavy metals.
Color is only the tip of the iceberg. We would be hard-pressed to find a functional challenge faced by commercial chemicals and materials that organisms haven’t faced in varied environments. The list includes functions such as lubrication, self-cleaning, oxygen management, coatings, surface slipperiness, adhesion, water/ice resistance, conductance, fragrance, flavor, structural strength and flexibility, impact resistance, protection from predators, responsiveness to environmental cues, biodegradability, and signal sending/receiving.
Not only do organisms not pollute their environment or themselves, in the course of meeting these functional challenges through chemistry, they create conditions conducive to life. For example, oxygen is a by-product of the energy-generating and chemical-synthesizing photosynthetic system; mollusks filter their watery surroundings; and falling leaves decompose into nutrients that feed the host tree and nourish the surrounding soil.
A set of deep patterns common to the chemistries across species and environmental contexts make the living world a rich storehouse of strategies that could inspire innovative, green chemistry approaches to new commercial chemistries and materials. Perhaps the two most important deep patterns in nature’s chemistry are self-assembly and shape complementarity. In biology, chemical transformations occur when reactants fit together hand-in-glove at ambient temperatures and pressures. The 3D shape self-assembles as a result of the strategically placed functional groups that attract or repel each other in a watery environment, thereby pulling the complex structure into the required shape. Shape complementarity and self-assembly relate to multiple green chemistry principles including: waste prevention, atom economy, less hazardous chemical syntheses, safer solvents and auxiliaries, reduced derivatives, catalysis, and inherently safer chemistry for accident prevention.
Another important deep pattern in nature’s chemistry is maximizing the use of non-covalent bonds. This includes: hydrogen bonds, van der Waals forces, and hydrophobic, electrostatic and pi interactions relating to the green chemistry principles of reduced derivatization and designing for degradation down to reusable building blocks. Nature’s chemistry meets its functional challenges using just over two dozen elements in the periodic table in relative positions and proportions that result in effective yet safer chemicals and materials. Nature introduces toxicity only when toxicity is the desired functional challenge, such as for protection or predation.
Biomimicry is a methodology that systematically taps into the living natural world’s rich vein of innovative biological knowledge, including nature’s chemical intelligenceto tease out the deep patterns and principles at work across divergent species. It then uses these deep patterns and principles to inform the design of new high-performing, high-quality, and effective solutions for solving specific industrial chemical and materials challenges in a way that is, by nature, green.
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