Due to its unique physicochemical properties, graphene has received increasing attention. This article selectively
reviews the application of graphene for direct electrochemistry of enzymes, small biomolecules, DNA sensing, and
environmental analysis. Graphene oxide (GO) and reduced graphene oxide (RGO) have been used as sensors for gases
and heavy metal ions. In all cases, the sensors performed well, proving to be highly sensitive, selective, and stable.