Here, we describe a novel type of graphene oxide linking layer for highly sensitive biosensing based on surface plasmon resonance (SPR), which has become an indispesible tool for scientific research and drug development [1]. During the last three decades, researchers have used only two technologies of linking layers for SPR biosensors, which are based on self-assembled monolayers of thiol molecules and on hydrogel layers. Using graphene and its derivatives, we developed biosensor chips for existing commercial biosensors, whose sensitivity is higher than for commercial sensor chips available on the market [2] (Fig. 1). Modification of carboxyl groups to N-hydroxysuccinimide esters in the flow cell of SPR biosensor demonstrated that the num-ber of carboxyl groups, which can be used for molecule immobilization, is more than 20 times higher in the graphene oxide linking layer than in the linking layer of commercial hydrogel-based sensor chip. In addition, the graphene oxide sensor chip was demonstrated to be 3 times more sensitive comparing to the commercial hydrogel chips when using in the standard biosensing protocol based on streptavidin-biotin interaction with streptavi-din immobilized on the GO surface via pi-stacking. This will enable us to investigate interactions of protein targets with small ligands and will broaden and accelerate academic and pharmaceutical research.