14 Jan. 2020. A team of biologists and computer scientists created tiny robotic devices designed by computer models and made from frog embryo cells. Researchers at University of Vermont in Burlington and Tufts University in Medford, Massachusetts describe their process and devices in yesterday’s Proceedings of the National Academy of Sciences.
The team led by Vermont computer scientist Joshua Bongard and systems biologist Michael Levin at Tufts are seeking a way to design and build robotic systems from living matter that are bio-compatible and can self-renew, unlike steel and plastics that degrade over time or may have harmful adverse effects. In addition, the authors aim to design these new life forms from scratch, rather than altering properties of existing organisms, or with limited functions like organoids.
Bongard, Levin, and colleagues developed an automated tool kit for designing these new types of life forms with a computer model that simulates evolutionary processes. Their algorithm connects behaviors and functions desired by the system to cells as biological building blocks, then constructs a pathway to assemble collections of cells that deliver those system functions. The authors note that the collections of cells put together by the computer model often have little resemblance to existing organisms.
Tests of the algorithm using Vermont’s supercomputer system enabled the researchers to identify the most scalable and better-performing cell combinations for live development. The team employed stem cells from embryos of Xenopus laevis frogs, also known as African clawed frogs, as raw material for their biological robots. These embryonic stem cells, say the authors, naturally develop into cardiomyocytes, heart muscle progenitor cells that exhibit contractions similar to heart cells. The team then assembled the cells into life forms with electrodes and microsurgery tools to match designs from the algorithm.
The Vermont-Tufts team produced new types of bio-robots they call xenobots, from the species of frog embryos used, about one millimeter across, designed to perform four types of functions:
– Locomotion, using the cells’ contractions
– Collecting and clearing objects
– Transporting objects, with a pouch for storage
– Collective behavior, cooperating in groups
“These are novel living machines,” says Bongard in a University of Vermont statement. “They’re neither a traditional robot nor a known species of animal. It’s a new class of artifact: a living, programmable organism.”
“What actually determines the anatomy towards which cells cooperate?” notes Levin. “You look at the cells we’ve been building our xenobots with, and, genomically, they’re frogs. It’s 100% frog DNA, but these are not frogs.” He adds, “As we’ve shown, these frog cells can be coaxed to make interesting living forms that are completely different from what their default anatomy would be.”
The researchers believe that combining their cell-design model with deep machine learning and synthetic biology, xenobots could be constructed to perform valuable medical functions, such as diagnostics, drug delivery, and internal surgery, as well as environmental tasks like detecting and cleaning up toxic waste deposits. And because they have a naturally limited life span and are bio-degradable, they would have limited environmental impact.
A time-lapse video made by co-author Douglas Blackiston at Tufts University, shows cells being manipulated and assembled into xenobots.
More from Science & Enterprise:
- Robotic Device Navigates Brain Blood Vessels
- Engineered Microbe Bio-Sensors Added to Robotic Arm
- Microrobot Swarm Breaks Up Bacterial Biofilms
- Spider Silk Property Discovered with Robotics Uses
- Micro Robots Made to Climb in Curved, Inverted Spaces
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