342 Biosensors Based on Nanomaterials and Nanodevices
even totally lost advantages. Moreover, due to insufcient binding sites, it is difcult to
deposit or grow ultrasmall and uniformly distributed active components/materials on the
graphene surface. Surface functionalization can provide rich surface chemistries for gra-
phene to overcome the challenge. A suitable functional agent should be carefully chosen to
modify graphene with required functionalization for its specic electrochemical biosen-
sor application. Nevertheless, functionalization of graphene with designed components at
a molecular level to control location and distribution of electroactive sites on the surface
is still an arduous task. Doping graphene with heteroatoms such as ...