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14

Biological Materials in Engineering Mechanisms

Justin Carlson, Shail Ghaey, Sean Moran,
Cam Anh Tran, and David L. Kaplan

CONTENTS
14.1 Introduction ........................................................................................................................................ 365
14.2 Comparisons: Biological Materials and Synthetic Materials: Synthesis and Assembly................... 366
14.2.1 Silk Processing and Assembly by Insects and Spiders — High
Performance Fibers from Nature......................................................................................... 367
14.2.2 Seashells — High Performance Organic–Inorganic
Composites from Nature ..................................................................................................... 369
14.2.3 Shark Skin — Biological Approaches to Efficient Swimming
Via Control of Fluid Dynamics........................................................................................... 371
14.2.4 Gecko and Burrs — Biological Solutions to Sticking to Surfaces..................................... 372
14.2.5 Muscles — Efficient Biological Conversion of Chemical Energy
into Mechanical Energy ...................................................................................................... 373
14.3 Conclusions ........................................................................................................................................ 377
Acknowledgments .......................................................................................................................................... 377
References....................................................................................................................................................... 377

14.1 INTRODUCTION

The biological world utilizes an amazing range of materials that provide function and survival to
organisms faced with a wide range of environmental threats. The biosynthesis, processing, and
assembly of these materials provide insight into design rules and strategies that can serve as useful
templates for broader materials science and engineering needs. High strength fibers, toughened
organic–inorganic composites, designs for efficient fluid flow, adhesion mechanisms, and actuators
are examples reviewed herein. The knowledge gained from the study of these types of complex high
performance materials systems should continue to stimulate new directions in materials science,
including new hybrid systems to exploit the strengths and utility of both biological and synthetic
versions of future materials designs.
The field of biomimetics encompasses a broad range of topics, generally based on the concept
of ‘‘learning from Nature’’ in areas of materials science and engineering. This ‘‘learning’’ may be
through inspiration in design, function, or a combination of both. Usually, this inspiration derives
from a novel attribute of a biological system that suggests new and important insights into structure
and function for materials science applications. Examples used in this chapter illustrate features of
unique materials from Nature to inspire designs and functions for new materials: (a) silk proteins
used by spiders and silkworms to construct composite encasements (cocoons) or strong and

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