One of the most burning and perplexing questions in biology today is: just what is life? While on the surface it seems obvious, the line between life and non-life is much blurrier than it seems. At the microscopic level, it becomes nearly impossible to distinguish the processes of life from other chemical reactions that are going on around us all the time.
The mascot for this debate is the humble virus. There is a large degree of disagreement about what exactly viruses are. They seem to be alive; they exist on the same scale as single-celled organisms and interact with them (often in very negative ways). However, they are unable to reproduce on their own, and require host cells to infect. They inject their own genetic structure into the nucleus of the victim cell, and force the cell to make more copies of the virus. While this is a form of reproduction, it is not self-replication, which many biologists believe is required to earn the status of “life.”
Now, the debate is about to get even more complicated. Professor Lee Cronin from Glasgow University has begun research on creating self-replicating molecules out of inorganic compounds. They have already created inorganic-chemical-cells, or “iCHELLS,” with membranes that separate different chemical reactions from each other, just like in living cells. The difference between these inorganic iCHELLs and organic, natural cells is their compositions. Cells that evolved naturally, and make up all of the life we see around us today, are made of carbon-based organic compounds – amino acids, nucleotides and sugars. ICHELLS, on the other hand, are made of compounds that are considered inorganic and not necessarily carbon based at all.
The applications of these iCHELLS are wide-ranged. Once they begin replicating and evolving, they can teach us a lot about the evolution of life on Earth. The purpose of Professor Cronin’s project in his own words is: “…to construct complex chemical cells with life-like properties that could help us understand how life emerged and also to use this approach to define a new technology based upon evolution in the material world – a kind of inorganic living technology.” Essentially, it will be technology that evolves and adapts without our guidance.
Many people are familiar with the concept of nanobots, tiny molecular machines that can perform tasks on tiny scales. Professor Cronin’s work is similar, but allowing these iCHELLS to reproduce themselves takes the project another step further. Professor Cronin is essentially freeing life and the evolutionary process from the constraints of organic matter; you can only do so much with carbon. If he succeeds in creating organisms based on different compounds, the potential abilities of these creations are nearly limitless.
Below is a link to a TED talk by Professor Cronin regarding iCHELLS and his ideas: