The signal itself would have to be small to activate the nanotube, and be set at a specific wavelength (or combination of wavelengths) so the radio would recognize it—in effect, the radio would have its own channel. Once perfected, the cellular radio could be a new interface of genetic and electronic components—a bionic, biotic thing. A six-million-dollar cell.
A radio tuned to heat up the cell uncontrollably serves just one purpose: to destroy the cell, potentially handy for eliminating undesirable cells like cancer. Nanotube radio can also initiate electrolysis in surrounding water, producing protons which acidify the area around the nanotube. Though lethal in high doses, local acidification in specific organelles of the cell can potentially instruct the cell to perform other functions than just self-destruction. Cells change the pH of their organelles in many occasions. So, why not do it remotely via the radio?
A more complex action is to channel the action of the nanotube to influence just one biomolecule in the cell and to perform a specific function, such as stimulating production of calcium ions. Calcium has different functions at different times in different cells based on the function of the cell, so this one strategy represents many possibilities in regulating cell behavior, from neurotransmitter activation to muscular contraction. Activating the nanotube in leukocytes would excite the calcium ions to stimulate an immune response; and in some stem cells and progenitor cells, triggering the calcium burst by nanotube could activate cell division. Tissue homeostasis, then, could also be controlled remotely: Push a button, and the radio triggers cell division, leaving the radio in the original stem cell while the newly produced cell goes on to replicate over and over and become some kind of tissue. Need a new piece of pancreas? Tune in to cellular radio.
As the IDR team discussions proved, genetic engineering is a staple of synthetic biology. Drawing up new genetic blueprints presents possibilities for new cells. But to make changes in existing cells, a subtler approach is sometimes required—something chemical or physical that can be controlled remotely. It’s a whole different approach to synthetic biology, not intended to replace genetic manipulation, but to augment its possibilities without getting into the tricky wiring of the DNA. Because while genetic engineering presents better and better models for manipulating life, there is always the noise of evolution acting on the creation, the static of mutation threatening to change the engineered thing. At times like this, sometimes it’s best to turn up the radio.