Imagine Lego bricks that are made out of living cells. You could put them together, however you wanted, and make them carry out whatever task you desired.

That is what scientists in the USA have achieved.

Researchers worked together to prototypeOriginal or test version of something. a whole new species, the xenobot.

First, the scientists decide on the simple action they want their biological robot to do. This could be reaching a destination, moving a smaller object, or grouping together.

The researchers use a computer to figure out the perfect arrangement of cells to fulfil that function. An algorithmAny set of rules followed by a computer. In the context of social media, "the algorithm" refers to the intelligent AI that learns the interests of the user and presents them with posts that it thinks will interest them. will run through hundreds and thousands of possible shapes.

Once they have the ideal design, the scientists use tiny forcepsLike tweezers with curved ends. to piece together dozens of cells taken from a frog. They build the creature as best they can in a petri dishCircular case used to conduct cellular experiments and grow cell cultures..

Some of the cells, grown like those from a frog's heart, then contract allowing the new creature to move through liquid.

Researchers hope that similar creations will be able to carry out medical tasks such as delivering drugs to infected cells or targeting viruses. We could program miniature doctors that could propel themselves around our veins.

The xenobots are given enough food in their cells to survive for a week before they degradeWaste away. naturally. This means they could carry out tasks inside a human body without causing any damage or leaving any waste.

The scientists have made discoveries they did not expect. When you cut a xenobot in half, it grows back together again.

It is very difficult to say with any certainty whether the xenobots are alive or if they are machines. They are built entirely from organic matter, not from wires and steel. But they cannot eat, grow or reproduce.

The shape they take and the functions they carry out are determined with the help of a machine, but they are still limited by the boundaries of biology.

Why not? A xenobot is fundamentally no stranger than a muleA cross between a horse and a donkey. or a genetically modified crop. Existing parts of nature are simply being recombined. We are not creating anything radically new. If it can help us make breakthroughs in healthcare, then we should not hold back just because it 'feels' wrong. Novelty is always frightening. But it is also something to marvel at and enjoy.

Then again, many say, by using computers to design new life forms, we might accidentally create something unstoppable. A disaster situation is always unlikely but unless we put limits on what scientists can do, the worst is always possible. Life has a tendency to do whatever it can to survive. And while today we want to use xenobots to fight diseases, tomorrow they could be turned into weapons or worse.