Robotics: Small living robots made from human cells surprised scientists

The research was published on Thursday in Advanced Science Journal.

The scientists used adult human cells from the trachea, or windpipe, from anonymous donors of different ages and sex. Gizem, co-author of the study, said researchers focused on this type of cell because it is relatively easy to access due to work on coronavirus and lung disease, and, more importantly, because of the feature that scientists believe makes the cells motile. Gumoskaya, a doctoral student at Tufts University.

Tracheal cells are covered with hair-like protrusions called cilia, which wave back and forth. They normally help bronchial cells push out small particles that find their way into the airways in the lungs. Previous studies have also shown that cells can form organoids, clumps of cells widely used in research.

Gomoskaya experimented with the chemical composition and growth conditions of tracheal cells, and found a way to encourage cilia to point outward on organoids. Once they found the right matrix, the organelles became mobile after a few days, with the cilia acting somewhat like paddles.

“Nothing happened on day one or day two or day four or five, but as biology usually does, around day seven, there was a rapid turnaround,” she said. “It was like a blooming flower. By the seventh day, the cilia had flipped over and were on the outside.

“In our method, each robot grows from a single cell.”

This self-assembly is what makes it unique. The biological robots were made by other scientists, but they were handcrafted by making a mold and seed cells to live on top of, Levine said.

Different shapes and sizes

The robots the team created were not identical.

Some were spherical and completely covered with cilia, while others were football-shaped and irregularly covered with cilia. They also moved in different ways — some in straight lines, others in tight circles, while others sat and rocked, according to a press release about the study. They have survived up to 60 days in laboratory conditions.

Levine and Gomoskaya said the experiments described in this latest study are still at an early stage, but the goal is to see if the robots could have medical applications. To see if such applications were possible, the researchers examined whether robots were able to move over human neurons grown in a laboratory dish that had been “scratched” to mimic damage.

They were surprised to see the robots encourage growth in the damaged area of ​​neurons, although researchers do not yet understand why this is the case. The study indicated a healing mechanism.

Falk Tauber, group leader at the Freiburg Center for Interactive Materials and Biotechnologies at the University of Freiburg in Germany, said the study provided a basis for future efforts to use biorobots for different jobs and make them into different shapes.

Tauber, who was not involved in the research, said the robots showed “surprising behavior,” especially when they moved through scratches in human neurons and eventually shut them down.

The ability to create these structures from a patient’s own cells suggests diverse applications both in the laboratory and perhaps eventually within humans, he said.