Being a big fan of the Japanese animation "Ghost in a Shell", I have seen cyborgs with the fiercest fighting spirits have whole limbs or parts of limbs cut off. It broke my heart every time I saw it. Yes, I know it's just a cartoon, but what if it was in real life? What if the most talented fighter, with the best of heart and the strongest will, in the middle of combat - gets wounded and can not resume fighting to change the world? What if he was the only one that had the best chance against the evil?
My replication structure is designed for such a fighter. Upon swallowing this hypersensitive artificial organism, named Hatchi (after one of my nicknames), the fighter can resume combat in less than a second after receiving a wound: Hatchi would go to wounded area, plug up the bursted blood vessels, and spit out spider silk (perhaps, with other materials as well) to replace the exterior. If the fighter receives another wound, Hatchi would split in half to assist the other wound. In a sense, the fighter is a habitat for Hatchi, and Hatchi replicates to benefit its habitat.
Hatchi looks like a puffer fish, and has a size good enough to travel through the smallest blood vessels. It would have the following qualities:
1) Waterproof in a way that it is almost like a fish swimming in blood. We do not want Hatchi to drown in blood.
2) Hypersensitive to pressure. If there is a wound, the pressure flow of blood would change, and the sensors in Hatchi would detect this change.
3) Hatchi would have a vein reconstruction or blood clot mechanism.
4) To prevent infections, Hatchi would secrete advanced antibiotics.
5) Spider silk production
Hatchi replenishes with food and nutrition, and a certain amount of exercise (stimulate blood flow). Side effects have not been discovered yet. Hatchi would hold the wounds in place until physicians remove it.
Spider silk is a type of fiber secreted by spiders used for preying and making spiderwebs, and is one of the strongest naturally-ocurring fiber known with a tensile strength of approximately 1.3GPa. Although spider silk is not as strong as steel, its ratio of strength to density is almost five times greater than steel. It is also very ductile and tough (easy to stretch and hard to break). The spider can recycle the silk by eating it.
Artificial spider silk synthesis has been of great interest to industrial companies. However, it is extremely difficult to nourish enough small spiders and keep them under control for industrial purposes (spiders tend to eat each other). Some research effort has been made to extract the spider silk gene from the spider and insert it into a bigger, less aggressive organisms to produce the spider silk instead. Nexia (a Canadian biotechnology company) proved this to be possible in 2000 having transgenic goats produce the spider silk protein. (The goat milk contained the proteins.) However, the artificial spinning of spider silk protein into spider silk failed, and Nexia abandoned the project.
Citation: Wikipedia, http://www.xs4all.nl/~ednieuw/Spiders/Info/spindraad.htm