tion has devised schemes that allow the design of macromolecular building blocks that can self-assemble into functionally interesting structures. This does not mean that researchers should precisely copy the detailed chemistries of nature. Rather, they are exploring underlying universality in the schemes that natural systems employ to carry out a class of functions and are determining whether these adaptations affect biomimetic behavior.
According to Chakraborty, many biological processes, such as transmembrane signaling and pathogen-host interactions, are initiated by a protein when it recognizes a specific pattern of binding sites on part of a membrane or cell surface. Recognition means that the polymer quickly finds and then adsorbs strongly on the pattern-matched region and not on others. He writes that the development of synthetic systems that can mimic such recognition between polymers and surfaces could have a significant impact on such advanced applications as the development of sensors, molecular-scale separation processes, and synthetic viral-inhibition agents. Chakraborty believes the ability of certain classes of molecules to form organized assemblies in solution has important commercial and biological consequences. A variety of products, such as detergents, emulsifiers, catalysts, and vehicles for drug delivery, already rely on this ability.
The field of smart materials and structures combines the knowledge of physics, mathematics, chemistry, computer science, and material, electrical, and mechanical engineering in order to accomplish such tasks as making a safer car, a more comfortable airplane, and structures capable of self-repair, assert Cao et al.15 The trio write that, in the future, with the help of miniaturized electromechanical devices, structures may be “intelligent” enough to communicate directly with the human brain. The development of supersensitive noses, ears, and eyes would enable humans to smell more scents, hear beyond a certain frequency range, and see what normally cannot be seen naturally, such as the infrared spectrum.
A smart structure, explain the three scientists, is a system containing multifunctional parts that can perform sensing, control, and actuation; it is a primitive analogue of a biological body. Smart materials are used to construct these smart structures, which can perform both sensing and actuation functions. The “I.Q.” of smart materials is measured in terms of their responsiveness to environmental stimuli and their agility. The first criterion requires a large amplitude change, whereas the second assigns faster response materials a higher I.Q.
Frontiers of Science/1998. Wenwu Cao, Harley H. Cudney, and Rainer Waser, at <http://www.pnas.org/cgi/content/full/96/15/8330>.