Surface modifications in graphene by DNA aptamers for Staphylococcus aureus detection

Surface modifications with organic molecules comprise a versatile tool to enable applications of graphene in the field of biotechnology. In this context, interfacing graphene with ligands such as antibodies and aptamers constitutes a prevalent methodology for the realization of bioselective graphene surfaces. Following this concept, in this work, we describe two novel routes for surface modifications of graphene devices with Staphylococcus aureus aptamers (SA20), which render graphene surfaces specific for this bacterium. The first method makes use of amino-modified SA20 and the second approach involves SA20 aptamers featuring a pyrene moiety. Significantly, while the resulting aptamer-modified graphene devices exhibit an evident discrimination between the target ( Staphylococcus aureus ) and control ( Escherichia coli ) bacteria, bare graphene transistors respond similarly to the addition of these distinct biological compounds. This reveals that both functionalization strategies successfully result in selective graphene surfaces, providing robust alternatives for construction of tailored graphene-based biosensors.