Battlefield medics and paramedics rely on chemical-infused bandages to help stem blood loss and treat wounds. However, the blood itself is frequently their worst enemy -- it takes those chemicals away from where they're needed. Those first responders may soon have a much smarter solution, though. Researchers have developed bandages with a combination of powdered marble, acid and enzymes that fizzes on contact with blood, using the resulting bubbles to transport microparticles toward deeper vessels that need clotting. The particles currently travel in all directions, but scientists envision using an endoscope to send the fizz to where it's most useful.