Metallic atoms are known to play a vital role in several cellular environments through interacting with nucleobases.However,it still remains a great challenge in delicately controlling the balance between the interactions of nucleobases and metallic atoms within the biological system.Thus,a fundamental insight to understand the interactions between metal and nucleobases and further to rationally design ligands for novel biomedical applications is necessarily needed.Here,from the interplay of high-resolution STM imaging and state-of-the-art DFT calculations we have systematically studied the interactions between nucleobases(G,C,U)and transition metallic atoms on solid surfaces.Different nucleobases coordinating with Ni atoms have been investigated on 2D surfaces under ultrahigh vacuum(UHV)conditions.These results would provide new insights into the basic physicochemical nature of biologically relevant systems and shine light on the ultimate design of man-made ligands that would be promising for novel anticancer drugs.