Instant repairs to the human body has been a science-fiction dream for nanotech since the idea was first put forward.  Researchers at MIT have taken the first step towards that amazing goal with a material that can stop bleeding in seconds.

The clear liquid acts almost like a "healing potion", instantly staunching blood flow and thereby stabilizing potentially fatally wounded patients.  The material is a cunningly constructed peptide (a short polymer chain made of alpha-amino acids) consisting of a comb-like structure with a central spine (which hates water) and a large number of projecting teeth (which love water).  On contact with the wet, salty kind of environment you get inside the human body these schizophrenic peptides instantly twist themselves into a bunched, compact ribbons.

No removing stitches, no after-op care.