A primary goal in medicine is to one day be able to restore the function of damaged or missing sensory structures through the use of biological or artificial replacement components.
While the vast majority of developments in limb replacements focus on artificial components – prosthetics – one doctor in Massachusetts is experimenting on frogs and other animals to develop biological restorations and believes he’s not far from doing the same for humans. Is he a genius or a Dr. Frankenstein?
That’s a six-legged frog we made, showing you can trigger ectopic limb formation by appropriate voltage gradients.
Dr. Michael Levin is a researcher at Tufts University in Massachusetts. In an interview in Popular Science, he opens the doors of his laboratory and reveals his latest developments and discoveries in biological organ replacements. Levin’s primary lab subjects – for now – are frogs, tadpoles and flatworms. An early experiment involved tadpoles whose eyes had been removed having donor eyes implanted on their backs and connected directly to their spinal cords, resulting in the tadpoles being able to see with a lower version of eyes in the back of their heads.
Levin accomplished this at a cellular level by manipulating hollow proteins called ion channels which reside on cell surfaces and act as gates controlling the flow of electrical charges that define the growth and development of the cells. Levin took over control of the ion channels using neurotoxins and forced the cells to develop the way he wanted them to develop and eventually into the organs he wanted to create. He likens the process to Photoshop.
The endgame of this field is complete specification of shape. You’d be able to sit down on a computer, like in Photoshop, and draw what you want, and out it comes. If you said, ‘I want a triangular frog with seven legs, and the eyes should be over here,’ I don’t see any reason you couldn’t do that.
In fact, he’s already very close to doing that. The six-legged frog he made had two legs, one left arm and three arm-like protrusions on the right side of its body. He's also created two-headed flatworms.
This seems creepy and sounds like his Photoshop needs to be upgraded to the latest version, but Levin now has set his sights on working with humans. In May of this year, he was able to manipulate cancer cells and render them harmless. What’s next?
Worst-case scenario: If you get your arm blown off at 25, by 35 you will have a teenager's hand, which is very functional.
Levin admits it’s a big jump from changing cancer cells and manipulating frog legs to human limb regeneration. Other researchers, including Levin’s former mentor Cliff Tabin, are disturbed about where this is heading.
How do you control it? 'If you are designing the logic of the system, how do you decide where to make a head as opposed to where you make a tail? You might need channel proteins to make these decisions, but that might not be the linchpin of the decision itself.
Is Levin a genius or a Dr. Frankenstein? Who will decide? Should his research continue? Would you allow it?