Radio frequency waves (RF) are electromagnetic waves between the frequencies of 3 kilohertz to 300 gigahertz, used in radio, cellphones, wi-fi, radar, GPS, and many other systems. While humans have used RF technology to communicate for over 100 years, no living organism has ever been observed using RF to communicate without technology.
Scientists have known for a long time that “certain biological organisms ranging from bacteria to birds possess the faculty of magnetoreception, i.e., the ability to sense the earth’s magnetic field.” Scientists have also wondered whether electromagnetic waves might play a role in intra- and inter-cell signaling.
Researchers have suggested since the 1960s, for example, that terahertz frequencies emanate from cell membranes, but they’ve lacked the technology and tools to conduct reproducible experiments that could prove whether electromagnetic waves constitute purposeful signals for biological function—or if they’re merely background noise. With recent advances in technology and modeling, experiments may now be possible to test signaling hypotheses.
DARPA has launched a new program to explore whether electromagnetic waves are purposefully transmitted and received within or between cells and, if so, to leverage those insights not just for biosystems but also for communicating in cluttered electromagnetic environments
Our interest is first to determine whether there is any purposeful EM signaling between biosystems that we can model in terms of a transmit-receiver communication channel of some kind. DARPA is looking for low power and possibly resonant interactions between structures in those biosystems. If this proves successful and we find such signaling occurs, we should be able to model it and reproduce experimental results with confidence. Following this, the next step could be to try to make use of EM waves for, example, medical purposes.
DARPA funds projects that are high risk, but with high potential. The risk is that no one has ever observed RF activity from a live animal and the concept might prove unobservable. But if Deheyn and his collaborators can detect biologically active RF, the rewards for biology would be huge. In the future, it’s possible humans could build a cell phone antenna using just molecular units or a soft, biological material such as tissue, researchers said.
“There are many complex interactions within and between cells, so determining if electromagnetic waves, which could be low or high frequencies, somehow play a role in transmitting and receiving meaningful signals through what might be an ion-rich, aqueous solution is a significant challenge,” said Mike Fiddy, DARPA program manager.
“If we can prove that purposeful signaling is happening, the next step would be to discover how the process works. This insight could eventually lead to a broad range of technologies important in biology as well as new small antenna designs, and other innovative concepts for communication systems in ever increasing cluttered electromagnetic environments.”
“This project is the first step to open the door towards a very new field. It would be a scientific first if we can find situations where the radio frequencies alter behavior of some organisms, or if we can measure RF from them,” Deheyn said.
DARPA awards a team of UC San Diego researchers grant under RadioBio program
Researchers in Europe were able to demonstrate that biological cells produce RF in the gigahertz range, which is what your radio or your cellphone works at,” said UC San Diego’s Scripps Institution of Oceanography marine biologist Dimitri Deheyn, the project’s lead investigator. “Those discoveries were made in cells that are cultured in petri dishes, and so the big question that the RadioBio program wants to assess and that we will try to answer through this grant is: Are such frequencies biologically relevant? Can we measure them from organisms?”
Deheyn has been awarded a $3.3 million grant from the federal Defense Advanced Research Projects Agency (DARPA). Team scientists include Scripps researcher Adrianus Kalmijn, UC San Diego electrical engineering Professor Daniel Sievenpiper, and professors Jeffrey Rinehart, an expert in nano- and molecular magnetism, and synthetic biologist Neal Devaraj, both from the Department of Chemistry and Biochemistry within UC San Diego’s Division of Physical Sciences.
“It’s a difficult problem from both modeling and measurement perspectives, but the biggest challenge will be determining if the electromagnetic effects that we find are purposeful, as opposed to just a side effect of something else,” Sievenpiper said. But, he added, “if we find that animals, cells, or even smaller structures within cells can interact through electromagnetic waves, that would open up a whole new field of research.”
There are a number of unexplained “cold cases” in biology where organisms show behaviors, morphological changes or coordinations of cellular features that seem inexplicable if one considers only using known forms of communication – sight, sound, touch, smell, and ultimately electrical transduction. For example, squids are able to change the texture of their skin to match their environment and thus camouflage their body. But squids are still able to do this even if they have been blinded. So how do they do this? If they’re not using sight, how do they sense the 3-D shape of their surroundings?
Members of Deheyn’s lab studying bioluminescence in brittle stars have similarly discovered that a brittle star’s photocytes (the cells that make them produce light) have cilia – hair-like structures all along their cell membrane.
“Cilia are good for helping a cell to swim and for helping a cell to react to the dynamism of the surrounding environment,” Deheyn said. “It doesn’t make sense for a cell that is embedded in deep tissue to be ciliated but the photocytes in the brittle star have cilia. Why?”
Deheyn thinks it’s possible that microtubules – molecular units that control cilia to make them extend, shrink, or bend – form an electromagnetic dipole that is emitting or receiving electromagnetic signals. Essentially, the cells inside brittle stars might be covered in tiny radio antennae.
Investigating this idea will be one of several experiments Deheyn and his collaborators will undertake under the umbrella of the DARPA RadioBio program. They will test organisms into electromagnetically isolated facilities and measure whether they can detect biological RF emissions, and expose them to RF to see if it affects their behavior.
“For example, we will be working on exposing brittle stars to electromagnetic fields to see if we can trigger light from those cells just by exposing them to a range of electromagnetic fields,” Deheyn said. “This would demonstrate that these cells can actually respond to the signal and would be the first evidence that these signals could be biologically relevant, if they respond to a specific frequency.”
The experiments will take place in the Electro-Magnetic Research Facility at Scripps, which was developed by co-principal investigator Kalmijn in 1990, with funds from the Keck Foundation and the Office of Naval Research. The facility operates like an underground aquarium in which the electromagnetic field can be precisely controlled. Some measurements will also be done in the laboratory of Sievenpiper, where electromagnetically isolated chambers are used to investigate cell phone antenna technology.
“Our research spans a wide range of topics, and this project takes us in yet another new and interesting direction,” Sievenpiper said. “This is an exciting project because it’s a chance to tackle a very hard problem that could have profound implications for our understanding of the interaction between organisms and electromagnetic waves. It’s particularly interesting because it lies at the intersection of two very different fields – biology and electromagnetics – which is where many of new discoveries are often found.”
If the experiments discover positive results, they will not only uncover and unveil a new mode of communication among organisms, but could also open up new avenues for innovation in RF technology.
“Organisms might be able to sense RF using biological material, using molecular units, whereas right now as human beings we can only capture, sense, or record electromagnetic frequencies using these cell phone antennae,” Deheyn said. “This would be an incredible step towards applications that we can’t even foresee right now because this would be so new, and so disruptive in terms of the possibilities that we have. Stay tuned,” said Deheyn.
DARPA’s RadioBio program, seeks to establish whether functional signaling via electromagnetic wave signaling between biological cells exists—and if evidence supports that it does, to determine what mechanisms are involved and what information is being transferred. It wants to understand how the structure and function of these natural “antennas” are capable of generating and receiving information in a noisy, cluttered electromagnetic environment.
“One of the greatest challenges of the program will be to develop theoretical and numerical models that can describe the properties of near-field, time-varying, sub-wavelength-size biological structures that function as antennas,” Fiddy said. “To overcome such difficulties, RadioBio seeks expertise in antenna design, theoretical and structural biology, biochemistry and other related disciplines.”
DARPA wants a predictive, quantitative, parametric, theoretical model” to be considered under the program. So what will be admissible under the DARPA program? Here are the key criteria:
■ Predictive: Specific, quantitative, theoretical predictions must be made and then tested (which will require modeling/simulating biosystems as transmit/receive antennas, modeling/ simulating the surrounding electromagnetic environment, and so on).
■ Quantitative: The models must predict absolute, numeric measures of field strengths, ranges, bandwidths, channel capacities, etc.
■ Parametric: As key parameters are varied, the models must predict and the experiments must test a continuum of responses to reveal and understand underlying mechanisms.
■ Controlled: The experiments must carefully control for a wide range of systematic effects related to both biological sample preparation and antenna measurements. In addition, adequate verification of the results requires a particular model of electromagnetic communication to be tested in different environments, with different biological systems and at different length and time scales.
The program envisions two, 24-month phases. During Phase 1, performers will be asked to theoretically model and simulate hypothesized electromagnetic signaling pathways and then experimentally test those theoretical predictions. In Phase 2, the goal would be to independently develop test beds to replicate, confirm and demonstrate the pathways modeled in Phase 1 and reveal design principles potentially relevant to biological or other applications.
Nanoprobes might well be a necessary part of measurement methods as well as being required for active interventions that validate and verify that the processes under investigation are involved with purposeful signaling. Also, deliberate engineering of biosystems, such as cells to enhance antenna-like properties might be necessary to help develop measurement techniques in Phase 1 or for Phase 2 applications.
We are more interested in evidence of, and models for, natural signaling phenomena in Phase 1 and then, in Phase 2, the refinement of these models through reproducible experiments to gain a deeper understanding and develop applications.
Fiddy is quick to note that RadioBio is a fundamental research effort. Even if the program proves that electromagnetic signaling occurs between cells, applications would likely be many years away.