Biohybrid robotics (Bio-syncretic robotics)

Proposed applications for biohybrid actuators include miniaturized therapeutic robots and biohybrid medical devices, in vitro muscle models for drug testing and platforms for investigating muscle contractions. In the longer term biohybrid actuators have applications in the interaction of soft robotic artifacts with humans, microscale devices that perform medical procedures, biobased surveillance systems, manufacturing systems that self-assemble and self-repair and environmental monitoring with swarm biorobots.

Biobots that could be injected into a patient’s bloodstream and destroy a blood clot or cancer would require sensing, computation and actuation. Living cells have an advantage over synthetic microswimmers in their ability to detect and respond to environmental stimuli without additional components. Bacteria and algae can be steered using their attraction to light, which is not possible in deep tissues of the body. Magnetic control is one possibility for medical applications since magnetic fields can safely penetrate the body. Magnetotactic bacteria naturally have magnetic nanocrystals and other living cells could be artificially magnetized if embedded with iron oxide nanoparticles or by attaching them to magnetic substrates. Chemicals can also control cell behavior. Biohybrid devices could respond to biochemical signals released from tumor cells. Thermotaxis and aerotaxis are also possible ways to steer microorganism-based biohybrid robots.

Researchers at Polytechnique Montréal demonstrated magnetic guiding of a magnetotactic bacteria bound to drug-containing nanoliposomes. These Magentococcus marinus bacteria also use aerotaxis, to migrate towards low oxygen in their natural environment. Since tumors are also low oxygen environments, the researchers demonstrated in mice that this aerotaxis can be exploited for delivering drugs to tumors.