One-step exfoliation and functionalization of graphene by hydrophobin for high performance water molecular sensing

Abstract

A novel one-step strategy to exfoliate and functionalize two dimensional layered materials (2DLM) is described to promote the production and performance of the 2DLM for bio-related and molecule adsorption based practical applications. This method applies sonication to the 2DLM dissolved in the aqueous solution of hydrophobin protein, during which process the hydrophobins penetrate into the interlayer and automatically bind onto the surface of 2DLM to peel off the mono-/few-layer from the bulk material. The exfoliated 2DLM is spontaneously wrapped with a dense and ordered hydrophobin monolayer, forming unique bio-nanocomposites with greatly enhanced biocompatibility and molecule adsorption capability. The product exfoliated and functionalized by this method from reduced graphite oxide is successfully applied for an exemplary application of water molecular sensing, which, to the best of our knowledge, is the first time that a protein layer is used as an active sensing layer for water molecules. The device shows exceptional improved performance in harsh environments with complicated background interferents as compared to a bare reduced graphene oxide sensor and a commercial sensor.