Sensor Technology

Carbon nanomembranes can be used as nanointerposer to functionalise sensor surfaces by immobilisation of capture molecules. Since CNMs are thin enough, it is possible to detect interactions of the capture molecules on the top side by the underlying sensor.

Detection systems using this strategy can be label free, e. g. based on refractory index (surface plasmon resonance, ring resonators, ellipsometry), charge (field effect transistors, electrochemical impedance), mass change (quartz crystal microbalance, microelectromechanical systems), surface stress (cantilever biosensors) or based on optical readout (fluorescence, absorption and luminescence) when used with labelled competitors.

We developed this concept in the European funded PoC-ID project, where we immobilised aptamers via the CNM-nanointerposer to the surface of a newly developed graphene field effect transistor, solving two demanding problems:

• chemically functionalising a graphene surface without impeding the unique electronic structure of graphene
• immobilisation of aptamers to a surface while keeping their unique three-dimensional structure and therefore their specific binding properties to the target molecules (see application note).