Great challenge for nanoscopic machines to control atoms

The nanoscale world is almost unimaginably small. A nanometre is just one-billionth of a meter. Engineers and scientists have been working with material on this scale for a few years. For example, some of the most powerful microprocessors have millions of
transistors just a few dozen nanometres wide.

But the real problem for nanoscopic machines is the assembler. An assembler is a hypothetical nanoscopic machine that can build things molecule by molecule. Millions of these assemblers could build practically anything given the right raw materials. We call
this type of engineering molecular nanotechnology.

In medicine, doctors and engineers are working together to create nanoscopic drug delivery systems to fight diseases like cancer. The goal is to build a virus like module that can seek out cancerous cells. The module will contain a payload of cancer-killing
drugs. Proteins on the module will act as a guidance system, turning the module into the equivalent of a smart bomb. By targeting specific cancer cells, doctors hope to minimize the negative effects of cancer treatments.

That’s not to say we can’t manipulate individual atoms using other tools. In 1990, IBM engineers manipulated atoms using a scanning tunnelling microscope. They arranged atoms on a metal surface to spell IBM. While the microscope itself wasn’t nanoscopic,
it has a very fine stylus with a point that is just one atom in size.

We’re not there yet. Most of the devices we’ve built are on the micro scale. A micrometer is one-millionth of a meter — significantly larger than a nanometre. These devices are far too large to manipulate individual atoms, because the atomic scale is even
smaller than the nanoscale. Atoms vary in size, but in general a single nanometre is a few atoms wide. We measure the size of atoms in angstroms. One angstrom is one-tenth the length of a nanometre.

Will we ever build nanoscopic devices that can move atoms around? The answer is uncertain. Some scientists and engineers say the molecular nanotechnology concept isn’t plausible. Many turn to manipulating atoms through chemistry rather than building a nanoscopic
machine to build molecular chains. Even if we never build molecular assemblers, the knowledge we’ll gain from trying may change the world.