Graphene veils: A versatile surface chemistry for sensors.

Thin spun-coat films (~4 nm thick) of graphene oxide (GO) constitute a versatile surface chemistry compatible with a broad range of technologically important sensor materials. Countless publications are dedicated to the nuances of surface chemistries that have been developed for sensors, with almost every material having unique characteristics. There would be enormous value in a surface chemistry that could be applied generally with functionalization and passivation already optimized regardless of the sensor material it covered. Such a film would need to be thin, conformal, and allow for multiple routes toward covalent linkages. It is also vital that the film permit the underlying sensor to transduce. Here we show that GO films can be applied over a diverse set of sensor surfaces, can link biomolecules through multiple reaction pathways, and can support cell growth. Application of a graphene veil atop a magnetic sensor array is demonstrated with an immunoassay. We also present biosensing and material characterization data for these graphene veils.