 He then agreed that something like an enzyme or ribosome would be capable of precise chemistry, but asked how the nanorobot would be able to obtain, control, and repair such an enzyme, and noted the incompatibility of many reactions with water-based biological systems, stating that "biology is wonderous in the vast diversity of what it can build, but it can 't make a crystal of silicon, or steel, or copper, or aluminum, or titanium, or virtually any of the key materials on which modern technology is built." Smalley asked what kind of "nonaqueous enzymelike chemistry" Drexler would envision for his molecular assemblers to operate upon, calling this "a vast area of chemistry that has eluded us for centuries."
