Microscopic robots, sometimes called nano-droids, represented a technological advancement that allowed for target tracking or the creation of explosive devices.
In 3653 BBY, Vrath Xizor employed a tracking solution comprised of nano-droids to monitor Zeerid Korr; these tiny machines stuck to the sole of Korr's footwear.
During the Clone Wars, around 20 BBY, Letta Turmond administered nano-droids to Jackar Bowmani, her husband and an Abyssin employee at the Jedi Temple; she then manipulated him to orchestrate the bombing of the Temple hangar.