There are two stories I would like to tell with this edition of Business Unusual, the first is about the Darpa funded research to build robots out of living cells, the second is the incredible history of the animal that was used to build the first biological robots - Platannas.

The Defense Advanced Research Projects Agency (DARPA) is an agency of the American Department of Defense. It has funded many projects for military projects that in time have come to be used for civilian applications. The best-known example is the predecessor of the internet.

Why a military agency would fund research into creating living robots might be concerning but the stated objectives include managing environmental clean-ups or improving drug delivery which certainly are worthy pursuits. Of greater concern, are the ethical questions that are raised by creating new forms of a living organism. At the moment the designs dont attempt to make them self-replicating but that is part of the future plans.

Robots typically are designed and programmed to perform a specific task. Until now they would have been constructed out of non-living materials. These robots are also designed for a specific task but created from living cells. The choice of cell and the specific construction determines what action or function the living robot can perform.

One function that was attempted was movement. Starting from scratch researchers used stem cells from a frog to create skin cells and heart cells. The heart cells are muscles and so can contract while heart cells are able to do so rhythmically. Using those properties a machine learning program was tasked with testing thousands of configurations to determine which design would use the least cells to achieve the motion required. Once the best designs were determined, the living robots were constructed by researchers manipulating individual cells under a microscope.

The tiny constructed robots demonstrated that living robots designed by computer could offer an alternative to traditionally constructed machines. Future versions would look to make the constructions more complex and eventually able to self replicate.

One intended function was using a swarm of living robots with the ability to decompose plastic to be used to remove microplastics in the ocean. That may be a long way off, but if it is to become a reality the best time to start working on it is now.

Another application might be to not find plastic in the sea, but cancers in your body. Your body is already very good at doing so, but as we age and at certain times of our lives it becomes more challenging to correctly identify and kill cancer cells when they are still only tiny tumours.

This would require building robots consisting of your own body cells arranged in a way to allow them to move through the body and specifically find the corrupted cells. Adding them in numbers as we age may reduce the chance of developing tumours or even help the body recover after exposure to damaging external factors like sun damage to your skin.

This too is a long way off, but if successful and added to the many other options for extending and improving our lives then the research is most welcome.

_Image credit: Wikipedia African clawed frog_

Setting the other issues relating to building living robots aside, you might wonder why a frog from South Africa was chosen to build the first living robots.

It was not a random choice but points to a fascinating history that makes this particular frog one that has helped humanity overcome medical issues on a number of occasions.

A pregnancy test these days simply requires peeing on a stick. The reaction to a specific hormone in the urine can be isolated in minutes and let you know if you are pregnant within days of it occurring. It was not always this easy, the first method we are aware of would see a potentially pregnant woman urinate on ungerminated wheat and barley and wait a week or so to see if it germinated. Incredibly it works and was first mentioned over 3 000 years ago by the Egyptians. It was scientifically tested in the 1960s and found to be 70% accurate.

There were a variety of other methods used most on the expectation that something in the urine of females could be used to confirm pregnancy. In the 1920s it was injecting urine into female rabbits that after a day would require the examination of the rabbit ovaries. If swollen the woman was pregnant. In order to do the examination the rabbit was always killed and so the search continued for a better option.

Enter Lancelot Hogben, an English researcher lecturing in Cape Town in the early 1930s. He advised a student to consider using the local platanna as a potential for use as a model organism for biological tests. His hunch proved correct with Hillel Shapiro and Harry Zwarenstein creating the test to use the frog to indicate pregnancy.

The frog would be injected and in hours if the woman was pregnant would produce eggs. Not only was it accurate, but it also would not harm the frog which was easy to keep in a lab and would live for over a decade. As a result, the remarkable frog was exported around the globe and provided the answer to the question, am I pregnant, to the largest population explosion in our history. Most baby boomers parents and indeed many baby boomers would have found out if they were pregnant thanks to this strange-footed frog.

Xenopus literally means strange foot, frogs typically dont have claws which is why the African clawed frog got the name and as for Platanna, that may be a reference to the frog being very flat - plat in Afrikaans.

Given its widespread use for pregnancy and acceptance as a good species for embryonic development when researchers attempted to clone an organism, this frog was once again a key in understanding the process. In 1958, Xenopus was cloned not from splitting an embryonic cell which was the original method, but by using the DNA from an adult specialised cell which replaced the original DNA in a frog egg. The method proved successful and paved the way to allow Dolly the sheep to be cloned from an adult sheep cell in 1996.

We owe a huge debt of gratitude to six species that for a variety of reasons have helped us understand biological processes and how best to deal with disease and the efficacy of drugs. There are nematode worms, fruit flies, zebrafish, chickens, mice and the African clawed toad.

These six animals are our real guinea pigs.

Image credit: Xenobot - Tuft University & University of Vermont

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Biological robots, that is a thing now - 702