PHYSICOCHEMICAL PROPERTIES OF CRYSTALLINE NANOSCALE ENZYME-PROTEIN-METAL LAYER COMPOSITES IN BIOSENSORS

Crystalline bacterial cell surface proteins (S-layers) are introduced as immobilization matrices for binding biologically functional molecul es in the development of amperometric biosensors. Due to the crystalli ne character of S-layers, functional groups are located in well define d position and orientation on the protein meshwork and thus allow to b ind molecules in densely packed monolayers. One of the most critical p rocedures in the development of amperometric biosensors is the deposit ion of an electrical contact onto the sensing layer. Conventional sput tering techniques using platinum or gold, or, more recently, pulsed la ser deposition of precious metals under inert gas conditions allow to establish electrically conductive contacts on S-layer-based enzyme ele ctrodes.