Biomimetics: Learning from Nature

Arguably, many of the problems that an engineer wants to solve now and in the near future may already have been solved by nature, although in a different context.

It is thought that living organisms have been on planet Earth for approximately 3.8 billion years. This represents nearly 4 billion years of evolution, where nature not only has been hosting life in a sustainable, yet dynamic manner, but often using minimum resources to attain maximum performance.

From ancient days, the wonders of nature have been an inspiration for humankind. For example, more than 3,000 years ago, Chinese people were trying to mimic the remarkable strength of the spider web to produce hard synthetic silk.

One of the most illustrative recent examples is the invention of Velcro by the Swiss inventor George de Mestral (1907–1990). In the early 1940s, as he walked in the woods with his dog, he noticed that seeds were firmly stuck to his pants and also to his dog’s fur. What for de Mestral and other people who walk with dogs was a problem, from the point of view of nature, is a way of transporting seeds (and consequently new plants) to new locations. de Mestral asked himself why this happened. By performing careful microscopic observations, de Mestral understood the mechanism by which the seeds adhere so strongly. His work led to the development of a commercial product called Velcro.

Biomimetics refers to the art of adapting, for our own benefit, processes, substances, devices, or systems that resemble what nature has devised. While the main motivation is economic benefit, more importantly, we will be to learn from nature how to develop a sustainable way of living.

It is only relatively recently that scientists and engineers as a community have focused methodically on nature to improve the design of materials, devices, structures, and processes. It is now easier to look deep into nature because today we have microscopes and tools that allow us to better observe nature and improve our understanding of the micro and nano worlds.

Some examples from nature that may have relevance to food processing include:

• The lotus effect. The leaf of this plant is unique in that it highly repels water. When a water droplet is deposited on its surface, it practically forms a sphere, with very little contact angle between the water and the leaf. This super-hydrophobic surface allows water droplets to roll off the leaf, taking on its way dirt particles and self-cleaning the leaf. Water repellent characteristics go beyond plant leaves and, for example, help some insects to self-clean their large wings and facilitate flying.

• Edible films. In recent years, the use of edible films for transportation of active substances in foods has attracted much attention because of their holding capacity and/or controlled release of active compounds. Nature offers a great variety of edible coatings/peels. For example, banana peels not only extend shelf life but also control gas transfer, retard maturation, and have antibacterial activity and UV protection. The skins and peels of foods can be a source of inspiration for the design and structure of new edible films, but also should be studied for their composition, where we might extract many compounds of interest. Then, we can view processing in an integral way and design future processes like nature does, transforming and processing without waste. Furthermore, nature does not separate package and product, producing just one harmonious thing altogether.

• Can dolphins teach us heat transfer? Dolphins live in tropical waters (10–32° C) and are highly adaptable in regulating temperature. For example, in the flukes, flippers, and dorsal fin, arteries are surrounded by veins to increase heat transfer and maintain body temperature. Heat transfer is highly efficient because it is countercurrent. The dorsal fin provides stability, but also plays an important role in its body thermoregulation.

• Regulation of rates of reaction. As an example of how nature manages chemical reactions, we need look no further than at enzymes, which significantly accelerate the rates of chemical reactions. Virtually all reactions occurring within cells are catalyzed by enzymes. An essential feature is that the reactions within the cell occur at moderate temperatures (0–50° C) and typically around atmospheric pressure.

One of our most significant challenges is to significantly increase the efficiency of energy and water utilization. It may help us in this regard to look at, appreciate, and understand how nature manages these critical resources. Chemical and bioprocesses inspired by nature may help achieve harmonious and sustainable development with our environment.

Ricardo Simpson ([email protected]), a Professional member of IFT, is Professor, Dept. of Chemical and Environmental Engineering, Universidad Técnica Federico Santa María, Valparaiso, Chile.

Sudhir Sastry ([email protected]), a Professional member of IFT, is Professor, Dept. of Food, Agricultural, and Biological Engineering, Ohio State Univ.