Electronic transport through short dsDNA measured with mechanically controlled break junctions: New thiol–gold binding protocol improves conductance

It is shown that double-stranded DNA which is directly coupled to gold via a modified thymidine base exhibits a higher conductance than reported for DNA coupled to metal electrodes using different binding schemes. The measurements of electrical conductance are performed in a mechanically controlled break junction setup in aqueous solution and in high vacuum at room temperature. The current–voltage characteristics obtained in vacuum can be understood if a single molecular energy level determines the transport.