It’s my opinion that Drexler simply underestimated the basic scientific problems that yet needed to be solved. The discrete nature of atoms and the limited range of geometries that can be utilised for structures at the nanoscale alone make complex molecular machine design extraordinarily challenging. Drug design is challenging enough and all we usually need to do there is create the right shaped static block to fit the working part of the target protein and stop it functioning (OK, I over-simplify, but a drug is a very long way from a molecular machine). Additionally the simulation tools needed to design molecular machines are only now becoming accurate enough, largely because it is only now that we have cheap enough and fast enough compute power to run them in reasonable real time.
It will happen, in time, but there is still a large amount of basic science to be done first IMO. My best guess is that self-assembling biomimetic molecular machines, based on polypeptides, will be the first off the blocks. New tools such as AlphaFold will play an important role in their design.
It’s my opinion that Drexler simply underestimated the basic scientific problems that yet needed to be solved. The discrete nature of atoms and the limited range of geometries that can be utilised for structures at the nanoscale alone make complex molecular machine design extraordinarily challenging. Drug design is challenging enough and all we usually need to do there is create the right shaped static block to fit the working part of the target protein and stop it functioning (OK, I over-simplify, but a drug is a very long way from a molecular machine). Additionally the simulation tools needed to design molecular machines are only now becoming accurate enough, largely because it is only now that we have cheap enough and fast enough compute power to run them in reasonable real time.
It will happen, in time, but there is still a large amount of basic science to be done first IMO. My best guess is that self-assembling biomimetic molecular machines, based on polypeptides, will be the first off the blocks. New tools such as AlphaFold will play an important role in their design.