Biological and Biomimetic Materials: Nature’s Inspirations
David Wright, Associate Professor, Department of Chemistry, Vanderbilt University
Animals, plants, and microbes are the consummate material scientists. They have found what works, what is appropriate, and most importantly, what lasts here on Earth. Their constructs often represent unique forms extending over several size domains that are synthesized in aqueous solutions at room temperature and standard pressure. Additionally, many biological materials, and their associated properties, cannot be readily produced in the laboratory. Evolutionary pressures drive the chemical constitution of many biological materials, producing a stunning variety of compositions. Examples include teeth made of iron or copper, directional sensors made of single domain magnets, and a variety of nanoparticle shapes only now being produced in research labs. Nature also employs a hierarchical approach to the design of biological materials. For example, in biomineralization (biology’s ability to nucleate and grow inorganic materials) processes, complex architectures are readily achieved through the utilization of smaller building blocks that are spatially patterned resulting in the stunning glass shells of the diatoms. An examination of functional biological structures, highlighted by the optical structures found in butterfly wings or cephalopods or the dry adhesive used by Geckos to scale vertical surfaces, demonstrate how the combination of chemical composition and control incorporated within hierarchical structures is more than just the some of its parts. It is very clear why these materials serve as such a rich source of inspiration for biomimetic approaches to material science.