Imagination has this peculiarity that it produces the greatest things with as little time and trouble as little things.

Pascal, Concerning the Vacuum

We began this journey with a goal – to understand the principles and techniques used by nature to self-assemble structures and to learn how to use these principles and techniques to design our own engineered self-assembling systems. In Part I: The Natural World, we saw examples of nature’s technique and extracted key principles that reoccur throughout her design. In Part II: Engineered Systems, we saw how scientists and engineers use these principles and we learned a bit about the obstacles they face along the way. And, in this part of the book, Part III: The Future, we’ve surveyed theoretical approaches to self-assembly and learned how mathematical models are being used to push self-assembly technology forward. Along the way, we’ve examined dozens of natural and man-made self-assembling systems. We’ve chosen to highlight these systems for one of two reasons. Either, their simplicity helped us to easily understand the principles and problems of self-assembly, or they were landmark systems that have moved the science of self-assembly ahead significantly. But to paraphrase Hamlet, there are many more self-assembling systems under the sun than are written of in this book.1 In this, the final chapter of Self Assembly: The Science of Things that Put Themselves Together, we briefly survey a collection of the most recent of these efforts. This time, we’ve chosen a mixture of examples to both illustrate broadly what is possible and examples that promise to quickly become technologically important. It’s my hope, that having made it this far, you’re ready to delve into the primary literature of self-assembly, grasp the essentials of each new development, and become an active participant in the field. The entry points into the literature provided in this chapter should help you figure out where to get started. The first system we examine relates pineapples to self-assembly. The nat-

ural world often exhibits remarkable symmetries and patterns related to the

integer sequence known as the Fibonacci numbers. In the system of Section 10.2, Li et al. [85] show that a stress-mediated self-assembly process in growing microspheres can lead to the same patterns. Our second system opens the door to technological advances in micro-and nanoelectromechanical systems (MEMS and NEMS). MEMS and NEMS technology has been hindered by the inherent planar nature of lithographic fabrication technology. In Section 10.3, we see that self-assembly may help MEMS and NEMS technology break free of the two dimensional world and start using three dimensional components. In Section 10.4, we return to biology, this time at the organism level. While nature clearly uses self-assembly to build from the cellular level on down, she also uses self-assembly to organize much larger organic systems. In a system consisting of thousands of sperm cells, we’ll witness a self-assembly process strikingly similar to the dynamic self-assembling systems of Chapter 7. In Section 10.5, we’ll look at even larger organisms, namely, humans. We’ll see how the language and science of self-assembly is being used to describe and understand the emergence of social structures – from teams of Broadway producers to teams of scientists studying self-assembly. In the final example of this book, we return to where we began and examine the question of how biological molecules first made their appearance on earth. We see that self-assembly not only promises us a remarkable future, but may help us understand our own origins in the far distant past.