The human immune system offers no effective protection against synthetic, non-biological nanos. Artiphages are an augmentation of the immune system to handle these invasions. An artiphage is a warship of molecular machinery the size of a white blood cell, bristling with weaponry. Each artiphage is totally specialised for its hunter-killer role, with no capacity for self-replication. Instead they are produced by dedicated artiphage factories scattered across the circulatory system. Most of the artiphages are non-specific, but the factories also contain templates for countermeasures to specific threats.
The augmentation also includes a dedicated communications system linking ports set in the walls of arteries and veins with each other and with the factories, or a patch into a pre-existing comm system. The comm-net is also used to communicate details of friendly nanosystems to prevent disassembly of benign structures.
The artiphages usually cruise the bloodstream in a low state of alert, with offensive systems powered down. Some specialised artiphages patrol the other tissues of the body, but the blood-travelling ones provide the first line of defence. Chemical, acoustic, laser and contact sensors maintain vigilance against nanotech incursion, but only at a low intensity.
When it is in an artery or vein, the artiphage intermittently docks with a comm-port and communicates its state to a local controller. The artiphage carries a map of major bloodvessels in its onboard memory, and constucts a local map as it travels through lesser vessels or tissues.
When a hostile nanosystem is detected the artiphage rapidly changes to a high state of alert. The artiphage docks with a comm-port and requests reinforcements. The artiphage factories step up production of the devices, and other units switch on their weapons and make their way to engage invaders. Their primary weapons are disassembler arms and 'missiles' tipped with killer enzyme or free-radical bombs. If possible, isolated enemy nanos are captured and transported to analysis stations, where they are studied to aid in the construction of specific countermeasures. Larger structures are usually attacked with free-radical bombs, and the debris cleaned up by support artiphages.
All aspects of the artiphage system are constructed from and powered by nutrients carried in the bloodstream, and their efficiency is limited by the supply of these chemicals. The system is usually able to handle nanotech infections, making use of numerical superiority and rapid, flexible response. In some cases, especially when under attack by modern nanoweapons, this victory may be phyrric, laying waste to large regions of the body. In such cases the only resort is prompt treatment at a well-equiped hosptial.
The future of Ad Astra