First off, what the heck is a ‘Catom’ you ask? Well, a catom is short for “claytronic atoms”. That would be atom sized robots that could assemble themselves into all sorts of handy devices with the aid of a computer. Think a bucket of smart micron sized LEGO bricks. You order up some way cool germ seeing micro glasses off the Internet and your computer commands your bucket of smart LEGOs to take the shape and functionality of it. Once finished you pull your micro glasses out of the bucket and start to freak out about how unclean your house is.
Right now researchers are trying to build centimeter sized robots that will do this so don’t look for your catom based replicator just yet, give them about 20 years for that.