Enzymes on conducting surfaces

Second, sensors are often intended for a single use, or for usage over periods of one week or less, and enzymes are capable of excellent performance over these time scales, provided that they are maintained in a nfild environment at moderate temperature and with minimal physical stress. Stabilization of enzymes on conducting surfaces over longer periods of time presents a considerable challenge, since enzymes may be subject to denaturation or inactivation. In addition, the need to feed reactants to the biofuel cell means that convection and therefore viscous shear are often present in working fuel cells. Application of shear to a soft material such as a protein-based film can lead to accelerated degradation due to shear stress [Binyamin and Heller, 1999]. However, enzymes on surfaces have been demonstrated to be stable for several months (see below). 

When working with enzymes on conducting surface, for example, during characterization of amperometric biosensors, overlap of different feedback mechanisms must be expected as exemplified in the work by Kranz et al. who used A-(a)-aminoalkyl)pyrrole to form derivatized PPy that provides amino groups for binding periodate-oxidized GOx to the outer polymer surface [11]. 

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