The authors describe the plating of polypyrrole utilizing STM tips as the plating probe. Pyrrole is oxidized in electrolyte solution to form a polymer that can switch between conducting and insulating states. The combination of small effective tip surface area, small tunneling gap and a short applied-pulse duration results in nanoscale size features of polypyrrole plated on highly oriented pyrolytic graphite. It is shown that tip-induced deposition can proceed only above a certain threshold pulse potential value. Polypyrrole was deposited from two types of electrolyte solution: one containing supporting electrolyte and the monomer and the other containing, in addition, 1000 units ml-1of the enzyme glucose oxidase. The reason for studying the deposition in the solution containing the enzyme is to simulate the conditions of fabricating an enzyme-immobilized biosensor. The results presented for pyrrole/glucose oxidase deposit agree with earlier macroscale data for this biosensor.
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