Surface plasmon resonance sensors that incorporate graphene as one of the layers in the sensor structure have been proven to provide higher sensitivity in the detection of biomolecules, compared to sensors without graphene. Graphene an allotrope of carbon facilitates better adsorption to biomolecule samples due to the carbon-hydrocarbon affinity to biomolecules, thereby resulting in higher sensitive biosensors. Recently, a revolutionary method has been presented, at least in theory for now, that there is still a possibility to increase the sensitivity of the SPR sensors by the application of electric bias across the metal-graphene sensor system. A mathematical treatment to understand the physics of how the electrical bias contributes to an increase in sensitivity is presented in this chapter, using a sensor surface structure comprising of Au-MoS2-Gr. The results indicate that the application of electrical bias across the sensor surface consisting of Gr and other materials provides a method to increase the sensitivity of these biosensors. The scope and impact of this research can be felt in many industries that need sensors either in the food industry for food contamination check, harmful gas detection for environmental monitoring or safety measures, medical diagnostics etc.

The effect of electrical bias across the SPR sensor surface to dynamically tune its refractive index is investigated. This technique provides a dynamic sensor surface and a handle to enhance and tune the sensor sensitivity.