From a synthetic biologists perspective: Very cool work! It doesn't get us that much closer to fully synthetic life (ie, self replicating), but can likely be used for interesting devices.
Paul Chaikin, Ned Seeman and other folks at NYU have made some interesting experiments towards self-replicating artificial building blocks, if you're interested...
As a huge fan STEM fields and biology, I have to ask if this type of thing should even be allowed. We dont know - but what if the current pandemic is a result of "gain of function" research? Never mind weather it is or not, its plausible and that should raise concern. Anyone making self replicating anything IMHO should think twice, or thrice. Dont get me wrong, that stuff is really interesting - to the point where a lot of people won't be willing to seriously consider the question "should we?"
Do you think China and Russia are going to stop working on these technologies just because the west buries its head in the sand? Technical innovation is a race and unfortunately such technologies that gets us closer to artificial cells that have a huge weaponizing potential will be worked on by someone at some corner in the world. So it's better to be done first by people who believe in rule of law and individual rights.
The question, I think, is not whether we should or should not. That is irrelevant. Someone eventually will whether that someone is us or not and the end result is still a possible release of grey goo. The question is how we prepare for someone having it who will do things with it we might find irresponsible or dangerous. It seems like historically the answer to that question is 'we should make it first'.
Given "green goo", there's no guarantee that grey goo will be more troublesome to control than green goo.
Indeed, green goo is already completely out of control, with viruses for pretty much every life form on earth, and yet almost all viruses are not harmful to us, ditto for biological lifeforms.
But that's just it. We are all made from green goo. Viruses, bacteria, plant cells, human cells - they're all just a variation of this. Fluctuations that exist because the green goo isn't too stable over time.
Now, if you introduce a completely different type of goo, that happens to outcompete the green goo, the effect might just be total replacement of the green with grey. And who knows, maybe in a million years, that grey goo will evolve into a rich ecology, eventually giving rise to a sentient species. But from where I sit, I don't like the part where green is eaten by grey.
From a synthetic biologists perspective: Very cool work! It doesn't get us that much closer to fully synthetic life (ie, self replicating), but can likely be used for interesting devices.