Tromp also points out the benefits of nanostructural inks, which represent a generalization of the previous two applications. Manufactured in bulk, nanostructural inks can be applied to a wide variety of substrates using a wide variety of application methods, including inkjet printing, screen printing, spray application, spinning, and immersion. Inks can be mixed, layered, and patterned as applications require. Nanostructural inks might present the largest opportunity for the practical application of quantum dots and nanocrystals in the next two decades.
Dickinson writes that organisms experimented with form and function for at least 3 billion years before the first human manipulations of stone, bone, and antler.13 When pressed with an engineering problem, humans often draw guidance and inspiration from the natural world, using natural architectures as inspiration for so-called biomimetic, or bionic, design. Just as biologists are discovering the structural and physiological mechanisms that underlie the functional properties of plants and animals, engineers are beginning to develop means of fabrication that rely on nature for inspiration. As the performance gap between biological structures and mechanical analogs shortens, engineers may feel increasingly encouraged to seek and adopt such design concepts.
Dickinson points out that birds and bats, for instance, played a central role in one of the more triumphant feats of human engineering, that of airplane construction. In the 16th century, Leonardo da Vinci sketched designs for gliding and flapping machines based on anatomical study of birds. More than 300 years later, Otto Lilienthal built and flew gliding machines that were also patterned after birds. The wing-warping mechanism that enabled Orville and Wilbur Wright to steer their airplane past the cameras and into the history books is said to have been inspired by watching buzzards soar near their Ohio home.
Innovations in materials science, electrical engineering, chemistry and molecular genetics are enabling designers, Dickinson explains, to plan and construct complicated structures at the molecular or near-molecular level. Examples include buckyballs, nanotubes, and the myriad of microelectromechanical devices (MEMs) constructed with technology derived from the silicon chip industry. Integrated circuits themselves play a role in bionics projects aimed at constructing smart materials or mimicking the movement, behavior, and cognition of animals. Biological structures are complicated; only recently have engineers developed a sophisticated enough toolkit to mimic the salient features of that complexity. For
Frontiers of Science/1999. Michael H. Dickinson, at <http://www.pnas.org/cgi/content/full/96/25/14208>.