Redox state control of a metalloprotein to generate multi-level signals for applications to bioelectronic devices

Abstract

In this research, we investigate the redox state control of metalloprotein immobilized on a metal surface for the generation of different output signals. Ferredoxin, as a type of metalloprotein, is immobilized on an Au substrate by a chemical linking method using organic materials for the fabrication of a stable protein thin film. To control ionic state of the immobilized ferredoxin, the external electrochemical potentials for oxidation and reduction are applied selectively to the ferredoxin layer. The initial output signal is enhanced or suppressed by the reverse potential, which can inhibit electron transfer by restricting the number of redoxreactive molecules. Consequently, multi-level signals are achieved using a single protein film, and this proposed concept can be used widely to fabricate biosensors for multi-target detection and bioelectronic devices with new functionalities.