Development of a peroxide biosensor made of a thiolated-viologen and hemoglobin-modified gold electrode

A gold electrode modified with thiolated-viologen is used to design a biosensor in corporate with hemoglobin (Hb). A highly stable self-assembled monolayer (SAM) of thiol-based viologen is immobilized onto the gold electrode. Hb is then immobilized onto the viologen-modified electrode. The modified electrode is very stable. By incorporating with SAMs of viologen and Hb, viologen can act as an electron transfer mediator for Hb to the gold electrode. The potential of Hb was found to be about − 135 mV versus Ag/AgCl for ferro and ferri active centers. The electrochemistry of Hb provides an opportunity to manufacture a third generation of biosensors. Experimental conditions influencing the biosensor performances such as pH, and potential are optimized and assessed. This sensor offered an excellent electrochemical response for H₂O₂ concentration below the μmol level with high sensitivity and selectivity with a short time response.