The appearance of synthetic biology will be a defining moment, ushering in the direct design and control of evolution at the protein level of life. Its integration with programmable matter and swarm robotics has the potential to be disruptive in barely imaginable ways. Right now, one may be thinking of some classic science fiction cyborgs: T-1000 from Terminator, Data from Star Trek, replicants from Blade Runner, or androids from Aliens. Although these cybernetic organisms might come to exist some day, most inventions within the next decade will not resemble these humanoid cyborgs. Programmable living matter (PLM) instead resembles small- (or even micro- or nano-) scale components of the larger entities.
Consider teeth. Through a process called biomineralization, DNA-controlled cells produce proteins to create organic structures on which minerals or salts are deposited. This process creates the hard enamel on teeth in distinct shapes and sizes based on the cells’ self-determined organization. The teeth cells then protect and maintain the enamel over their lifetime. PLM will mirror this by taking control of the three main parts of the system: the cells, their organization, and their DNA programming. These parts can be used in different ways to create not only new living materials, but also power systems, communication systems, processors, sensors, and anything else that living cells can create today.
Physicist Richard Feynman described much of this nano/microrobotic field in his 1959 talk, “Plenty of Room at the Bottom.”1 But today, with considerable advances in the nanorobotics and biological fields, humanity is finally catching up to his ideas and surpassing them. For instance, in 2006 the Defense Advanced Research Projects Agency (DARPA) defined programmable matter as “an intelligent, or programmable, material that contains the actuation and sensing mechanisms to ‘morph’ into desirable/useful shapes under software control, or in reaction to external stimuli.”2 DARPA was speculating about “InfoChemistry,” or building information directly into materials, but now the concept has advanced from merely creating shapes to creating effects.3 DARPA’s Engineered Living Materials (ELM) program, for example, seeks to create living materials that will construct and maintain buildings.4
ELM and InfoChemistry have mostly been limited to technology that impregnates biological life with inorganic materials, such as the bionic leaf or self-healing concrete, adding capabilities in response to external stimuli. The bionic leaf, as depicted in Figure 1, uses a biologic catalyst to split water into hydrogen and oxygen, then uses the hydrogen with bacteria to create a multitude of other materials.5 Self-healing concrete involves a slightly different approach, impregnating the concrete mix with long-lasting capsules of bacteria and nutrients.6 When the finished concrete cracks, it breaks the capsules, and, when water is added, the bacteria produce a hard filler, fixing the concrete. The past few years have seen rapid advancement in this field, including cement that mixes living nondormant bacteria and minerals to form self-replicating cement.7 Damage to this type of cement can be repaired by adding some sand and nutrients. The living bacteria throughout the material will grow and mineralize, similar to the teeth example. Adding more will go beyond repair to expansion.
Research over the past 40 years has led to nanomachines for DNA-targeted drug treatment and nanorobotic production. New control methods have advanced rapidly, and potential breakthrough technology could arrive within a decade. Engineers and researchers have developed prototypes that include artificial DNA-based motors controlled by light, DNA-based robotic arms controlled by an electric field, and DNA tethered with metal nanoparticles controlled by electromagnetic signals.8 These control methods have all been done in the lab under ideal conditions, and given time and resources, this research will build into complex programmable dynamic controls capable of macroscale effects.
Controlling individual cells or a few bacteria is not the same as controlling billions of cells in a large muscle. Thus, the final piece in the puzzle to a fully realized PLM is organizing large swarms of this material. Here, too, recent advances in fluid dynamics, cells, and nanoparticles are promising. A combination of algorithms and physical techniques will drive swarms to accomplish missions. For example, MIT’s Self-Assembly Laboratory has created some striking effects with swarms, such as its replicating circles and a self-assembled chair.9 Most research so far has focused on algorithms, which direct swarms toward or away from pheromones within the environment.10 But many chemical or other signals could do this, controlling even individuals within the swarm. Thus, a tuned algorithm eventually will be the mass control needed for a pseudo-hive mind.
It is not difficult to speculate about the effects PLM could achieve in the next decade. For example, living buildings connected through a root or moss system might be resistant to disastrous weather. Self-healing roads could repair themselves using nearby materials. Quantum optical networks could grow themselves; self-driving cars might navigate by pheromones; and so on. The economy will see an everything-as-a-service industry revolution.
While the effects of this technology will be enormous across human endeavors, they will have the most disruptive impact on the military. For instance, how will the military target PLM runways, bridges, or buildings that repair themselves? How will the Navy’s plans be affected when PLM creates static living seabed communication and power lines? What happens when PLM can heal a solider’s wounds on the battlefield? How will logistic supply chains change when any military can create oil from water and bacteria? How does a SEAL team protect itself when any tree or plant with infused PLM can sense and track movement? Perhaps scariest of all: What happens when the enemy uses PLM in humans to control and enhance them?
The answers to these questions could fundamentally change the character of warfare, much as cyber and space have done. The promise of additive manufacturing will be met and exceeded by PLM, bringing a truly decentralized, zero-length supply chain for many systems and vast possibilities in materiel.
The U.S. military will need to start small to implement effective new strategies as a result of PLM. The first phase could be to replace general construction materials for buildings, runways, bridges, and dams—anything requiring concrete. Next, replace infrastructure such as pipes, ducts, conduit, fiberoptics, lights, wires, and antennas—anything stationary but flexible. Such things often are damaged or destroyed in combat, and replacing them with PLM would shorten or eliminate supply chains.
The next phase would come with a jump in functionality, to PLM systems that can replace computing, communications, memory, and other silica-based devices. Shape shifting input/output devices could be difficult to reverse engineer; programmed DNA could be used as an embedded firewall soft/hardware system to thwart potential hackers. Further progress could bring new functionalities—entire platforms made of PLM and, one day perhaps, new worlds built with PLM.
PLM eventually could lead to autonomous or optionally manned platforms that perform the same missions as manned ships—except instead of carrying fixed-size and -shape payloads, the PLM ship would create the payloads it needs in the moment. Any chemical reaction can be recreated with the correct base chemicals on board. Against an adversary’s PLM platform, a kinetic hit might not be the best response. Instead, these types of ships might manufacture PLM-focused biological weapons, ones that can tell the difference between synthetic and nonsynthetic biology, a hard but not impossible task.
To achieve these things will require sustained growth in research and development. The Department of Defense has created a triservice research program with $45 million in funding, but more must be done.11 The Sea Services should increase partnerships with academic and commercial industries, specifically in the medical field, where much of this research is taking place. Programmable living matter is coming, and it is not a race the United States wants to lose.
1. Richard P. Feynman, “Plenty of Room at the Bottom,” lecture to American Physical Society, December 1959.
2. Seth Copen Goldstein and Peter Lee, “Realizing Programmable Matter,” Defense Advanced Research Projects Agency ISAT Study, 2009.
3. Gill A. Pratt, “Programmable Matter,” Defense Sciences Office, December 2010.
4. Blake Bextine, “Engineered Living Materials,” Defense Advanced Research Projects Agency.
5. Anna Asvolinsky, “Make Like a Leaf: How Copying Photosynthesis Can Change Society,” NewScientist, 11 April 2017.
6. Alexander McNamara, “Environmentally Friendly Living Concrete Capable of Self Healing,” Science Focus, 15 January 2020; Jiaguang Zhang et al., “Immobilizing Bacteria in Expanded Perlite for the Crack Self Healing in Concrete,” Construction and Building Materials 148 (1 September 2017): 610–17.
7. Chelsea M. Heveran et al., “Biomineralization and Successive Regeneration of Engineered Living Building Materials,” Matter 2, no. 2 (5 February 2020): 481–94.
8. Mingxu You et al., “An Autonomous and Controllable Light-Driven DNA Walking Device,” Angewandte Chemie, 1 February 2012; Enzo Kopperger et al., “A Self-Assembled Nanoscale Robotic Arm Controlled by Electric Fields,” Science 359, no. 6373 (19 January 2018): 296–301; Shachar Arnon et al., “Thought-Controlled Nanoscale Robots in a Living Host,” Plos One (15 August 2016).
9. Dimitris Mairopoulos and Skylar Tibbits, “Self-Replicating Spheres,” MIT Self-Assembly Lab; Skylar Tibbits et al., “Fluid-Assembly Chair,” MIT Self-Assembly Lab.
10. Yong Song et al., “A Novel Foraging Algorithm for Swarm Robotics Based on Virtual Pheromones and Neural Network,” Applied Soft Computing 90, no. 106156 (May 2020).
11. Marisa Alia-Novobilski, “Tri-Service Effort Leverages Synthetic Biology Expertise to Address Future Warfighter Needs,” Air Force Research Laboratory, 27 September 2017.