Engineering Evolving September 1, 1997 Volume 27 Issue 3 The Bridge, Volume 27, Number 3 - Fall 1997 Biomimesis: The Road Less Traveled Monday, September 1, 1997 Author: George Bugliarello This issue of The Bridge contains an article by Joseph Coates that includes a projection of the future of biotechnology. The next issue of the magazine will look at several other facets of the integration of engineering and biology, a topic that will be the focus of the October NAE Annual Meeting technical symposium. To examine the interaction of engineering and biology is natural, indeed inevitable, if we consider engineering for what it truly is: a continuation of biology by other means. Engineering achieves this through the creation of artifacts - that is, machines - that extend and complement our biological faculties. In the process, modern engineering has created knowledge and techniques that make it possible to intervene with increasing success in living systems - to quantify aspects of their physiology; to diagnose and treat with electromagnetic or acoustic waves and with elementary particles; to create devices for doing genetic engineering; and to replace diseased tissues and organs. But this has not been and should not be a one-way street from engineering to biology. In the process of bringing to bear their skills on medicine and on the understanding of living systems, engineers have also looked for inspiration to biological designs. There have been some important results from this reverse direction, exemplified by the concept of neural networks, of DNA computing, and by the use of genetic engineering for creating new materials. But it is fair to say that the attempt to imitate features of living systems - biomimesis - is truly a road less traveled. A consciousness of the rich source of inspiration produced by almost 4 billion years of biological evolution has not permeated engineering. Yet, biology supplies examples of immense sophistication, starting with the cell with its thousands of chemical reactions that enable it to sense, compute, reach, move, and reproduce, and extending to the complexity of organs and organisms. There is also a long list of durable "inventions," like proteins, enzymes, DNA, fibers, membranes, blood, bones, teeth, neurons, fluid and heat transfer mechanisms, and all sorts of sensors, that are a marvel of what we would call design. There has been no systematic attempt to assess the engineering implications of that rich potential in all of its key domains. One of the reasons may be the fact that among the over 300 engineering programs in existence in the United States, we can count on the fingers of just one hand those that require at least one course in the biological sciences. For a long time, in some cases from the beginning of our emergence as a separate species, we humans have made use of biological materials (from leather to bone to fibers), of biological energy (from wood to draft animals), and of biological sensors (like watchdogs, or like birds and fish that alert us to environmental conditions). But by and large, we have shied away from the systematic pursuit of the ability to emulate some of the feats of living organisms. This is so even if, where biology has manifestly fueled our dreams and challenged us - as in the ability to fly or to navigate under the seas - we have been stupendously successful. The variety of challenges that living systems offer us as models for engineering design is enormous. We would like, for instance, to imitate characteristics of living materials that range from multifunctionality to self-repair, self-assembly, and almost complete recyclability. In the energy domain, the mitochondria, the power plants of the cell, offer a model of how to transform matter into energy at normal temperatures and pressures. In the information domain, the challenges range from imitating the role and capabilities of the gene to emulating the functional features of the brain and its elements. The design of the brain, with its plasticity, its ability to connect, to synthesize information, to cope with injuries and ambiguity, all on the base of the low-speed neuron, is a frontier of endless horizons that can inspire the engineer far beyond today's neural networks. Insects, in their great variety of designs, capabilities and sizes, are another potential source of engineering inspiration for the design of micromachines capable of autonomous movement and flight. This could revolutionize our ability to work in extremely small or inaccessible spaces. Of course, all cellular biological organisms have the intrinsic limitation of being fluid systems. However, organisms that we are now discovering at the bottom of the oceans and in hot springs show us designs of complex, fluidbased systems capable of performing under more extreme. environmental conditions than we ever thought possible, The ultimate challenge in drawing inspiration from biological organisms is the creation of systems that can reproduce themselves. This, of course, is what makes a system a living system. Thus far, we have attained that ability only in a very limited sense in computer viruses and have just begun to think of how simple machines may reproduce themselves. High on the wish list for emulating what a living system can do would be the attempt to provide a machine with some elements of consciousness. We know how to design a machine endowed with error-correcting feedback and, within limits, with something analogous to a reasoned error-correction ability. But to provide a machine with some elements of true consciousness (something that we cannot even define with certainty) is a far more ambitious enterprise. Yet, one could see the advantages that engineering even rudimentary levels of consciousness could give to robots and other devices. The inevitable question, if we succeed in imitating with our engineering systems these capabilities of biological organisms, is: Will this make machines indistinguishable from humans or other living organisms? The answer is clearly no. Not even the most sophisticated and imaginative engineering design can, in the foreseeable future, achieve what the long evolutionary process has produced. But the ability to engineer biomimetic machines with some of the capabilities of living systems will add new dimensions to our technological prowess and improve the quality and possibilities of the ever-expanding interfaces between humans and machines - from artificial organs to automation to ergonomics. More fundamentally, it will enhance our understanding of what life is - of what is exclusively human or biological - bringing the engineer squarely into the dialogue on the future of our species. About the Author:George Bugliarello is chancellor, Polytechnic University, and interim editor-in-chief of The Bridge.