In this work, electrochemical maltose biosensors based on mutants of the maltose binding
protein (MBP) are developed. A rutheniumII complex (RuII), which is covalently attached to MBP,
serves as an electrochemical reporter of MBP conformational changes. Biosensors were made
through direct attachment of RuII complex modified MBP to gold electrode surfaces. The responses
of some individual mutants were evaluated using square wave voltammetry. A maltose-dependent
change in Faradic current and capacitance was observed. It is therefore demonstrated that
biosensors using generically this family of bacterial periplasmic binding proteins (bPBP) can be
made lending themselves to facile biorecognition element preparation and low cost electrochemical
transduction.