Covalent Immobilization of Enzymes to Graphitic Particles

The use of carbon as a support material for enzymes is receiving increasing attention, particularly in the field of enzyme electrodes, in which use is made both of the conducting nature of carbon and the degree of surface chemical reactivity associated with the material. This final consideration makes it possible to attach enzymes directly to the surface of carbon by using suitable bidentate linking reagents. Although there are a large number of carbon materials available that differ in their chemical and physical properties, the basis of almost all carbonaceous material is the layer plane of carbon atoms that forms the hexagonal graphite crystal where each carbon atom in the basal plane is a trigonally bonded to three adjacent coplanar atoms in sp 2 hybridization ( see Fig. 1 ).   Fig. 1.  Schematic representation of the layer plane of carbon atoms in graphite showing various surface functional groups.