Nanolysins are nano-machines designed to attack the cell membranes of organic materials.
Operation
Each individual machine has a net charge which, when exposed to electrical current, causes them to align with each other so quickly that they behave like flechettes, shredding anything in their path.
General usage
Although they would have to be produced by the hundreds of trillions to create a pandemic effect, nanolysins are banned by numerous international arms treaties and are classified as a WMD. They are extremely expensive to produce and lethal to handle unprotected.