It looks like a tiny, penny-sized ray but it is not what it seems to be. Scientist at Harvard University have created a small cyborg in their biotech laboratories. It’s a biohybrid robot made of abiotic materials and living cells.
Bio-robots as a Blueprint
A golden skeleton builds the basic structure while a silicone layer forms the ray body shape. The quirky detail are about 200.000 rat heart muscle cells which are incorporated into this construct. The genetically modified muscle cells contract in reaction to light flashes and facilitate rhythmical movement through an isotonic salt solution. Actually, the way the cyborg swims looks similar to what we know from living ray. A light-induced contraction of the muscle cells curves down the silicone fins and cyborg body, which bend back when the contraction ease. With this movement, the little ray bio-robot achieves up to 3,2 millimeters per second. This is even faster than its cyborg jellyfish companion, which was first develop in the Harvard laboratories.
However, the very meaning and purpose of the scientist’s work was not to create an artificial organism but in fact they wanted to move forward in tissue engineering. Coupling living heart cells to structures which show movement that is comparable to the mammalian heart muscle contraction, gives them a deeper insight into the requirements and possibilities for bio-engineering of hearts.
Living Heartbeats: Future Dreams or Realistic Hope?
Scientists all over the world are actively working to find ways of efficient tissue engineering. It is a future hope, once to be able to produce sufficient amounts of artificial organs to provide all people who are waiting for transplants with new lifesaving hearts, lungs, livers or kidneys. However, the science is getting closer to its goal.
TECHNOBEAT, a multinational European consortium of tissue engineering experts for example, is currently establishing methods to efficiently produce high quality human heart muscle cells in bioreactors. These cells are gained from reprogrammed stem cells which are obtained from umbilical cord blood. In their project the researchers grow small spherical aggregates of a few thousand cells each. Prospectively, such small pieces of tissue might be used to replace dead heart tissue after a heart attack or in other cardiac diseases. By investigating diverse aggregate combinations of heart muscle cells with different other cell types like connecting tissue or heart vessel tissue they will find out about their potential for curing heart tissue damages and the bioengineering of artificial hearts.
Complexity is the Biggest Challenge
When thinking about the development of complex tissues from living cells, such as whole artificial hearts, special attention must be paid on the supply of the cells with nutrients and especially oxygen. Blood vessels need to be incorporated to imitate arteries which transport oxygen through the living organism. Very recently, scientist of the Chinese biotech company Sichuan Revotek first reported the construction of cell-based 3D-printed synthetic blood vessels and successful transplantation into rhesus monkey as well. This might be a groundbreaking work that can further accelerate developments in regenerative medicine.
In any case, beside our heart we have more than six hundred individual muscles including the smooth and skeletal muscles in our body. Every single one has a specific function which in turn means that each damage results in functional limitation. Therefore, the cultivation of non-heart muscle cells in the laboratory is of vital medical importance as well. Scientist at Rome University for example successfully grew a fully functional mice leg muscle from genetically engineered stem cells and transplanted it into injured mice. However, a direct transfer of this method to humans is not possible now. The bigger size and a missing circulatory system makes it impossible at present.
On Another Issue
Not all researchers who cultivate muscle cells in bioreactors have medical applications in mind. A group at Maastricht University in the Netherlands created the first animal-free meat. They cultivated bovine muscle cells from stem cells to produce beef mince.
In 2013 they presented the first artificial burger media-effective at a live-stream press conference. However, it will take another while till we can buy meat from the laboratory in our supermarket just around the block. The price of the first burger was 250.000 €. The people who were chosen to test this first burger were all of the same opinion: The texture and taste needs to be improved. Instead of growing pure muscle cells the scientists now mean to include fat cells to give the meat a more typical beef character. They plan to have it ready for the market by 2020 – tasty, with a delicious appearance and at an affordable price.