Mediation in Cross-Linked Redox Polymers

When in contact with a fluid under convection, enzyme and mediator must be confined to the electrode surface to avoid being lost to the bulk fluid. Although semipermeable membranes are appropriate in some cases, in other cases they introduce unwanted complexity or block convection of fuel, oxidant, or analytes to the electrode surface. As a result, many other methods have been devised to attach both enzyme and mediator to the electrode surface  

Enzymes embedded in a cross-linked redox hydrogel film. 

Enzymes and small mediator molecules co-immobilized in a cross-linked film such as polypyrrole or Nafion. 

Multiple cross-linked layers in contact, that is, the first containing enzymes and a cofactor, and the second containing mediator species. 

Any of the above incorporated in a high surface area matrix such as carbon paper or fabric. 

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