Graphene re-knits its holes
  Nano-holes, etched under an electron beam at room temperature in singlelayer graphene sheets as a result of their interaction with metalimpurities, are shown to heal spontaneously by filling up with either non-hexagon, graphene-like, or perfect hexagon 2D structures. Scanning transmission electron microscopy was employed to capture the healing process and study atom-by-atom the re-grown structure. A combination of these nano-scale etching and re-knitting processes could lead to new graphene tailoring approaches. 
Recep Zan, Quentin M. Ramasse, Ursel Bangert and Konstantin S.   Novoselov
cond-mat.mes-hall cond-mat.mtrl-sci