Most current techniques for Biomolecular interaction analysis (BIA) are optical. They measure changes in the transmission of light waves at the sensor surface during the binding events.
In contrast, the HexagonFab Bolt sensor measures changes in the electronic properties at the sensor-analyte interface. The sensor surface uses graphene, a two-dimensional conductive carbon nanomaterial. In the sensor, a layer of graphene is positioned between electrodes. As graphene is a nanomaterial (each graphene sheet is one atom thick), its electrical properties are strongly affected by the surrounding environment, particularly by charged particles or molecules at the interface. This is known as the Field Effect. This ability of the sensor is particularly useful for sensing charged biological molecules in solution, for example proteins or small molecules like DNA/RNA. The changes in electrical properties are translated into response units. The magnitude of the response units depends on the number of charges at the analyte/sensor interface, thus different responses can be measured for varying concentration – the higher the concentration, the higher the response change.