The notion of the “replicator” is rooted in our collective imagination, and takes us straight into a Star Trek-inspired future. Do you need a meal? Press a button on the replicator. Do you need a wrench? Press the same button. Anything you want can be made on site, science fiction is freedom.
But is it just science fiction?
The concept of building things “atom by atom” was first proposed by Richard Feynman in a great speech of 1959, which perhaps contributed to giving impetus and fascination to research on nanotechnology. The idea then gained traction in the 80s and 90s, fueled by the scientific and popular work of K. Eric Drexler, the engineer and theorist known as the father of nanotechnology.
What chance do we have of building a replicator?
According to Feynman, there is no physical law that prohibits assembling molecules and atoms in this way. Not only is it plausible, but we ourselves are a living example of “nanofabrication”. Cells possess the necessary equipment to use blueprints (DNA) and to encode messages (RNA) that provide instructions to molecular “foundries” (ribosomes).
But nature is no longer the only "replicator" (the more correct term would be "nanomanufacturer", but I will continue to use the 'popular' one too. Because I'm a Trekkie, that's why). Human creativity has already devised synthetic tools to operate on even infinitesimal scales, but there is clearly something to fine-tune.
What's the problem?
The obstacles to practical design of a replicator could fill a book. And they certainly filled up a famous debate between Drexler himself and the Nobel prize-winning chemist Richard Smalley. Smalley highlighted the problem of “sticky fingers” and “fat fingers” problems. Behind simple names, these problems clearly represent the difficulties inherent in the mechanical manipulation of molecules and atoms. Our body is an example of how things can be created, but it is not easy to “touch” them when they are so small.
Smalley suggested that nanomakers could operate through chemical processes, such as those that occur inside cells. However, this perspective also has significant shortcomings, such as a limited variety of molecules that can be produced and the need to develop a vast field of chemistry that is simply still unknown.
Replicator, does distrust prevail?
To make a long story short: scientific thought in recent years has consolidated on Smalley's positions, slowing down the impulse for research on the replicator. Nonetheless, the confidence of some scientists in the possibility that nanobots (nano-sized robots) today and nanomakers tomorrow would revolutionize society remains unchanged. Today, the closest thing to a practical nanofabrication is the polymerase chain reaction (PCR), a seminal invention behind the spread of DNA sequencing, infectious disease testing, and forensic investigations.
How does it work? Think of it a bit like the Photoshop “clone stamp”. With a specific mixture of chemicals, called “reagents,” and a special machine, called a “thermal cycler,” PCR duplicates a given strand of genetic material hundreds of millions of times.
In short (Italian only)
Nanomanufacturing is certainly possible, although the obstacles are enormous. But the revolution it could bring about for human civilization means that the idea of having a replicator is too tempting to give up. The prize is worth the patience, and humans will continue to chase it. Frontier science, in short, but science. And that's enough.
