and maintain biological functionality (Brott et al., 2004). Many polymer systems, such as poly(vinyl alcohol), qualify as hydrogels because they incorporate and maintain an enormous amount of water. While the biological side of this equation can be satisfied via the incorporation of water, polymer systems can be spin-coated, lithographically patterned, made conductive, and undergo a host of other treatments that electrical engineers routinely use. Thus, polymers represent a truly bridging material system in making biological macromolecules mesh with synthetic technology.

Another recent example highlights the potential of biological materials that have been integrated into a common electrical construct, such as a light-emitting diode (LED). To accomplish this, however, there must be a paradigm shift in materials thinking—namely, what would happen if DNA were processed in gram and kilogram quantities, instead of the traditional microgram quantities.

The fishing industry in Japan, which processes tons of seafood yearly, also throws away tons of DNA from fish gametes. Researchers at the Chitose Institute of Science and Technology in Japan, in partnership with our laboratory, have processed this discarded DNA into a surfactant complex and scaled the process up to a multigram scale (Wang et al., 2001). In this form and at this scale, DNA can be spin-coated into traditional electronics architectures. Recently, a DNA electron-blocking layer spin-deposited on the hole-injection side of the electron-hole recombination layer greatly enhanced LED efficiency and performance (Hagen et al., 2006) (Figure 1).

In another approach, we have attempted to use biology indirectly in advanced material synthesis and devices. Similar to the refrain from a commercial for a popular chemical company, biology isn’t in the final material, but it makes the final material better. Researchers around the world racing to harness the incredible electronic, thermal, and mechanical properties inherent in single-

FIGURE 1 Photographs of Alq3 green emitting bio-LED and baseline OLED devices in operation.



The National Academies | 500 Fifth St. N.W. | Washington, D.C. 20001
Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement