Small graphene spikes can slice open and kill bacteria. This creates a protective surface against infection.
I have seen conflicting results about anti bacterial properties of graphene so I personally find it satisfying that the group at Chalmers University of Technology discovered what kills the bacteria is not graphene itself but the vertical orientation of the flakes that act as tiny knives.
These small vertical flakes can damage and slice open the bacteria but because human cells are so much larger ( 25 micrometer vs 1 um) it doesn’t damage the human cells. Another cool thing is that they used PECVD (Plasma-Enhanced Chemical Vapor Deposition) to create these flakes which makes the layer of carbon grows vertically instead of horizontally.