which is composed of a two-dimensional, mono-layered nanosheet that is constituted of sp2-hybridized carbon atoms densely packed in a honeycomb crystal-lattice, is a rising star owing to its superior performance, like mechanical strength , excellently high conductivity and superior mobility of charge carriers . Therefore, GRA has been widely used in electrochemical biosensing, such as glucose determination and single nucleotide polymorphisms detection for DNA, early disease diagnose and other fields.