Nucleic acid fragment-fixed electrode and its use

A method for producing a nucleic acid fragment-fixed electrode wherein a nucleic acid fragment is fixed on the surface of a multi-component self-assembled monolayer of two or more different components which is formed on the electrode, by a covalent bond via a bifunctional linking molecule, the method comprising at least the steps of:

• (a) forming a multi-component self-assembled monolayer on an electrode by contacting the electrode with at least two components represented by the following formula (1) with the type of Jn being different:
• qn-Rn-Jn (1)
• wherein qn represents a group which is chemically bound to or adsorbed on the electrode, Rn represents s a linking group, Jn represents different functional groups of n types, and n represents an integer of 2 or more, and in the components of formula (1) of n types, qn and Rn may be identical or different from each other, and Jn are different from each other;
• and then removing the components which were not chemically bound to or adsorbed on the electrode;
• (b) introducing a reactive group X2 onto the surface of the multi-component self-assembled monolayer by contacting the electrode obtained in step (a) on which the multi-component self-assembled monolayer is formed with a bifunctional linking molecule represented by the following formula (2):
• X1-L1-X2 (2)
• wherein X1 represents a reactive group which forms a covalent bond with at least one type of functional group Jn in the above formula (1), X2 represents a reactive group which forms a covalent bond with a functional group Z in the following formula (3), and L1 represents a linking group;
• and then removing the components which did not form a covalent bond with the reactive group Jn on the multi-component self-assembled monolayer;
• and
• (c) binding a nucleic acid fragment partially to the surface of the multi-component self-assembled monolayer by contacting the electrode obtained in step (b) having a multi-component self-assembled monolayer on which the reactive group X2 is introduced with a nucleic acid fragment represented by the following formula (3):
• Z-L2-Nc (3)
• wherein Z represents a reactive group which forms a covalent bond with the reactive group X2 in the above formula (2), Nc represents a nucleic acid fragment, and L2 represents a linking group;
• and then removing the unwanted components which did not form a covalent bond with the reactive group X2 introduced onto the multi-component self-assembled monolayer.