It's first use was to combat Hemophilia, ViriiSoma's Nanosurgons accelerate the coagulation of blood, preventing excessive blood loss from the illness. What was once a cure for a rare disease now is a default implant on troops around the world and even some law-enforcement groups.
This injection of nanomachines stays suspended in your blood, only activating on blood loss. They have the effect of stopping you from bleeding. Unfortunately, they do not replenish themselves, so when you bleed too much, they'll run out and you'll have to get an injection again. Takes 24 hours to take effect and lasts until you bleed them out of your system.