Contributed editorial appearing in
Scientific Computing & Instrumentation 22:3, February 2005, pg. 8.
The Holroyd Science Center here at La Salle was designed in the 1950s according to the adage "Form Follows Function." The venerable structure has educated generations of successful scientists, doctors and teachers in the natural sciences, but it is slowly losing its efficacy. Like myriad other university science buildings, the disciplines of geology, physics, biology and chemistry are separated by floor, each having its own department office, equipment room, lecture halls, laboratories and student lounge. Mathematics and computer science are housed in a separate building altogether. This form reflects the analytical thinking prevalent in the last century at a time when the word "interdisciplinary" was scarce, and it perpetuates the soft bigotry between the disciplines. Our integrated science, business and technology (ISBT) degree program does not acknowledge any differentiation among the sciences and is currently skirmishing to dissolve the barricades between the schools of Arts & Science, Business, and Engineering.Medical research benefits widely from amalgamated programs such as bioinformatics and computational chemistry. Informatics allows researchers to scour vaults of experimental data for broad trends and correlations while predictive computation of intermolecular forces and energy configurations permit the rapid screening of innumerable candidate drug compounds in silico. The symbiosis among disciplines also advantages computer science. Several optimization methods, including genetic algorithms (GA) and particle swarm optimization (PSO), are patterned after biological processes. Even though integrated electronic circuits can perform calculations a million times faster than their physiochemical counterparts found in biology, nature has developed elegant solutions permitting the tiniest organisms to perform tasks far beyond the capabilities of our best technology.
Patterning the design of processes and structures after biological solutions is known as "biomimetics" - literally, "mimicking life." In addition to computer algorithms, engineers are using biomimetics to design next-generation materials and sensors. Entomologists continue to marvel at the ability of the jewel beetle (Melanophila acuminate) to sense forest fires from miles away. The beetles are attracted to the smoldering wood in swarms to mate and lay their eggs in the newly deceased trees. The recently burned wood has no natural defenses against the beetle larvae that feed on the layer of plant tissue just under the protective bark. Zoologist Helmut Schmitz of the University of Bonn has determined the beetle is not attracted by smell or sound, but is able to detect infrared (IR) radiation in the range of 3 - 5 µm produced by a 100,000-square meter forest fire from a distance of 12 km. Distances of up to 80 km have been reported in the literature; eclipsing the capability of currently-available environmental IR detectors.
Instead of exploiting the band gap of a cooled semiconductor or the amplification of an avalanche photodiode, Melanophila uses an array of photomechanical sensors called "sensilla." Each sensillium is comprised of a wax-filled spherical cavity that is connected to the input of a single nerve cell. IR radiation is absorbed by the wax of this biological transducer causing its temperature to increase. This produces an increase in cavity pressure and volume that ultimately triggers an impulse in the nerve cell. With the goal of developing sensitive forest fire detectors, researchers in Dr. Schmitz's lab are measuring the expansion of a layer of simple polyethylene film when exposed to IR radiation with the use of a piezoelectric crystal. Initial prototypes are not as sensitive as commercially available cryogenically-cooled IR detectors. However, they operate at room temperature, making wide deployment feasible.
Researchers at the Materials and Manufacturing Directorate of the Air Force Research Laboratory have used the structure of Melanophila's IR sensilla to create a synthetic IR detector for military applications. They have chosen to base their sensor on bacterial thermoproteins, biological macromolecules that expand when excited by IR radiation, which can be genetically engineered and produced in the laboratory via fermentation. Without a synthetic nerve to sense the thermoprotein expansion, the researchers are investigating the use of circular dichroic (CD) spectroscopy, a technique that measures changes in protein secondary structure. They are also sandwiching a thin film of thermoprotein between an IR-transparent substrate and vapor-deposited thin gold film. Thermoprotein expansion alters the angle of a laser beam reflected by the gold film and this change is used to quantitate the amount of IR radiation.
La Salle will break ground for its new Science & Technology Center this autumn. The layout will reflect current trends in collaborative, interdisciplinary research and include multiple-use laboratories, configurable research space, shared analytical equipment and brainstorming conference rooms. Now, I must find a way to biomimetically justify the incorporation of a Dunkin' Donuts and Starbucks.
