It sounds like science fiction, but it is not. On planet Earth, sophisticated manufacturing processes with full-fledged assembly lines have been running in many different kinds of factories for hundreds of millions of years. Nature evolved biological techniques for large-scale production and manufacturing of a huge variety of specialized materials long before human beings ever existed. Homo sapiens, in turn, have historically exploited many such natural factories to obtain a long list of essential commodities simply because comparable materials could not otherwise be efficiently produced. Even today, biologically assisted methods of production are often put to use with relatively little understanding of the underlying chemical and molecular operations.
In recent decades, science has revealed details about some of these operations. Since nature is almost always much more efficient than human industry, researchers are focusing on various biological processes that can be put to work for humanity. The promise of this research is that microbial machinery will eventually carry out many operations now carried out by heavy industry, but with fewer resources and without environmental pollution. Biological Radio addresses this interface of biology and technology.
A crystal radio is a basic resonant circuit requiring only induction, capacitance and a radio “crystal,” a mineral semiconductor used to convert received radio signals into DC electrical signals that can be resolved with headphones as sound. These simple circuits require no batteries, tubes or transistors and operate with only the difference in voltage between the antenna and the ground.
The invention of “wireless” coincided with the maturing industrial revolution of the late 19th century. Crystal radio technology rapidly gained popularity in the decades following its introduction and thousands of amateur radio enthusiasts contributed to the development of improved radio circuits. It was a cost-free, almost mystical conversion of invisible signals into music, voice and content about distant places and events in the unfolding march of history. Crystal sets can still be created with common off-the-shelf, natural and found materials, though the content of AM radio broadcasts has obviously changed. The story of crystal radio contains both a sense of wonderful innocence and a kind of tragic irony. On one hand, crystal radio seemed to characterize the optimistic spirit of its age: the promise of unending technological progress and the onset of an industrial era that would relieve humanity of labor and tedium and open up unprecedented opportunities for leisure and learning. On the other hand, many social, environmental and economic impacts of that same industrial revolution have tended to interfere with those dreams.
At no point in history has humanity been more technologically advanced. Whole populations are probably far more educated now than at any point in the past. Yet, owing to parts of knowledge gone missing, the average person has never been more clueless about the technology that makes “quality of life” possible.
In a world of propriety and non-disclosure, methods and materials made inscrutable, potted circuits and secret formulae, advancement of knowledge has become largely subsidiary to business. Students of physics and chemistry learn by repeating classical experiments that inform them about how science and our understanding of the world have progressed step by step. Advancement of knowledge depends on these “in-between” steps of understanding. As a consequence of entrepreneurship and enterprise, many of these steps are effectively removed from the public domain, creating holes in the structure of knowledge. With the ongoing merger of academic research and the corporate world, we explicitly place our faith in corporations to solve many the world’s problems. But in doing so, we can expect only those problems to be solved that can be solved at a profit. No one wants to sell you a radio that you can take apart and modify, much less tell you about one you can build yourself or one that will never require batteries.
Art is about opening up windows on the world, but you can’t open a window on something you remain clueless about. The Vitruvian ideal, that artists must seek broad knowledge, is one of the layers of meaning embedded in the Bacterial Radio project.
In spring 2011, I created a flat circuit design that could be constructed in a Petri dish. This circuit was then cast in negative relief in PDMS (polydimethylsiloxane) gel. Cells and growth media were then applied to circuit impressions in the gel. The cells used were E coli modified with a gene for silicatein,1 a ubiquitous protein native to many different marine organisms. These organisms use silicatein to polymerize silica from seawater in order to create glass endoskeletons and exoskeletons in a fantastic variety of forms. The silicatein gene used in the Bacterial Radio experiments was isolated from the marine sponge Tethya aurantia.
Silicatein is a promiscuous protein, so that if growth media is starved of silica and instead provided with metal salts or semiconductors, then the protein will try to polymerize those materials instead. In this way, electrical characteristics were imparted to the two respective cultures of bacteria used with Bacterial Radio. Bacteria were fixed and immobilized in the PDMS gel. Pins and wires were used to connect elements of the gel-embedded circuit to each other and to external components such as the antenna, the ground and headphones.
Bacterial Radio molecular biology was carried out with Tara Gianoulis and Ido Bachelet at the Wyss Institute for Biologically Inspired Engineering and George Church’s lab in the Department of Genetics at Harvard Medical School.
1 _Bioencapsulation of living bacteria (Escherichia coli) with poly(silicate) after transformation with silicatein-a gene _W. E.G. Muller, S. Engel, X. Wang, S. E. Wolf, W. Tremel, N. L. Thakur, A. Krasko, M. Divekar, H. C. Schroder Biomaterials 29 (2008) 771–779