Tetrazine Functionalized Graphene Enables Capture of Ultra‐Low Concentrations of Biomacromolecules

Monolayer graphene has great potential for a range of technological and biomedical applications. To achieve this potential, however, selective functionalization of the surface using mild chemical methods that yield spatially and chemically well‐defined functional groups is needed. Here, we describe a method to densely and uniformly modify the surface of graphene using a diazonium salt containing a tetrazine moiety, a functional group amenable to bioorthogonal chemistry. The resulting functionalized graphene efficiently undergoes inverse electron demand Diels‐Alder reactions with trans ‐cyclooctene (TCO) coupled compounds, including a small organic molecule and an anti‐GFP nanobody. The nanobody decorated graphene readily captures EGFP tagged apoferritin (EGFP apo‐Ftn) and by following the binding by total internal fluorescence microscopy, we demonstrate that the functionalized graphene can robustly capture EGFP apo‐Ftn molecules at a concentration of 2 p m .