The beating of heart cells powers the tiny bio-hybrid machines.
A team of engineers has developed self-propelled bio-hybrid machines that swim using the same mechanism as sperm. Sperm, and many other single-celled organisms, use long tails called flagella to swim. The tails move like a propeller to push the cell forward. The tiny bio-bots look a lot like sperm, with a plastic head and long, flexible plastic tail. Heart cells are cultured where the tail meets the head. The heart cells synchronize and beat together, sending a wave down the tail and allowing it to swim. A video of the bot” swimming shows the motion. The bots could be used to navigate to a target or sense a particular chemical in medical or environmental applications.
Taher Saif, University of Illinois Gutgsell Professor of mechanical science and engineering, led the team behind the tiny machines. “Micro-organisms have a whole world that we only glimpse through the microscope,” says Saif. “This is the first time that an engineered system has reached this underworld.” The synchronized beating of the heart cells is key to the operation of the machines, but how the heart cells communicate is not fully understood. “It’s the minimal amount of engineering – just a head and a wire,” says Saif. “Then the cells come in, interact with the structure, and make it functional.”
The tiny bio-hybrid machines are about 2 millimeters in length, a bit longer than a dime is wide. The team also built bots with multiple tails, which were able swim faster. Multiple tails also added the possibility of navigation. Saif envisions several possibilities for using the bots in biological environments in the future. “Could we make elementary structures and seed them with stem cells that would differentiate into smart structures to deliver drugs, perform minimally invasive surgery or target cancer?”