Chapter 2: Building Blocks
37 - Strutting (Part One)
In the early 1970s a small company named Dome East was formed on the North Shore of Long Island, New York. The Port Jefferson start-up made geodesic domes and was, in a larger sense, an outgrowth of the enthusiasm of that time for the ideas of R. Buckminster Fuller. The company’s design was one of the more elegant materializations of his concept; it featured a soft white-plastic internal membrane suspended from a silver lattice of geodesic aluminum struts. Dome East and the genial longhairs who ran it disbanded long ago, but a picture of one of their domes turned up in 1998 in Scientific American. The article was authored by Donald Ingber, and listed him as president of Molecular Geodesics, Inc.
Ingber has a notable background. He holds five separate degrees from Yale, ranging from a master’s in philosophy to an M.D. He is a pathologist at Harvard Medical School, an associate at Children’s Hospital in Boston, and a member of the MIT Center for Bioengineering. What’s more, his zeal for Fuller’s work may exceed that of its earlier allies. Ingber brings all these perspectives to bear on his central interest, the cytoskeleton—the loosely geodesic structure that serves as a flexible, multifunctional scaffold inside our cells.
In describing geodesics, he can’t talk for long without mentioning their fractal nature. Whether one speaks of the elegant Dome East structures or the grouping of sixty carbon atoms in a microscopic Buckyball—the molecule named for Fuller—Ingber sees the same pattern. “Viruses, enzymes, organelles, cells, and even small organisms,” he explains, all exhibit geodesic properties.
Intrinsic to that is a related fractal that Fuller called tensegrity. By way of explanation he notes how the structural dynamics of most buildings come from stacking one part on top of another. “They’re stabilized mainly by gravity,” Ingber says. “If you hit them from the side, they fall apart like dominoes.” But natural structures, he adds, get their stability by a “continuous tension” between the parts, by a tendency to contract like rubber bands. If there were nothing but that, of course, they would just pull themselves into tight balls. So in nature that tendency is opposed by a countervailing force. The contracting elements—what he calls “cables”—are attached to parts that resist contraction, the “struts.” That balance of forces is self-stabilizing, a constant push matched against a constant pull, which is what Fuller meant by tensegrity.
It’s a “pre-stressed system,” Ingber explains. “A bow used to shoot an arrow is one example, as are Fuller’s own geodesic domes.” The constant tension between push and pull is how natural structures keep their shape and their strength. Toward the large end of the scale, for example, the skeletal bones in our bodies are the struts, while our muscles are the cables that keep those struts under tension. At the microscopic level, he says, proteins and other key molecules are stabilized by tensegrity, too.
Turning to the cytoskeleton, he points out that it has another function beyond supporting organelles and providing rails for protein cargo carriers. It’s also a flexible tensegrity structure. This allows the cell and its many internal parts to adjust as the cell is pushed or pulled or flattened, in response to the various movements and pressures from our bodies. In fact, looking outward to the next level of integration, the cell itself resides in a tangle of fine support fibers called the extracellular matrix. Here again, it all links together, in this case to form our tissues.
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