It is an object of the present invention to provide a biosensor, which is not significantly affected by the baseline fluctuation and suppresses nonspecific adsorption. The present invention provides a biosensor, which comprises a metal surface or metal film coated with a hydrophobic polymer, and has two or more types of different surfaces in a region coated with a hydrophobic polymer.
1. A biosensor comprising a substrate which is coated with a hydrophobic polymer, to the surface of which a hydrophilic compound binds, and wherein the hydrophobic polymer is formed with a hydrophobic monomer selected from the group consisting of vinyl esters, acrylic esters, methacrylic esters, olefins, styrenes, crotonic esters, itaconic diesters, maleic diesters, fumaric diesters, allyl compounds, vinyl ethers and vinyl ketones.
2. The biosensor according to claim 1 , wherein the molecular weight of the hydrophilic compound is between 50 and 20,000.
3. The biosensor according to claim 1 , wherein one group capable of binding to one molecule of a physiologically active substance exists in one molecule of the hydrophilic compound.
4. The biosensor according to claim 1 , wherein 2 to 1,000 groups binding to a physiologically active substance exist in one molecule of the hydrophilic compound.
5. The biosensor according to claim 1 , wherein the hydrophilic compound is gelatin, alginic acid, chitosan, dextran, polyvinyl alcohol, polyethylene glycol or a derivative thereof, carrageenan, agarose, polyacrylic acid, or polyacrylamide.
6. A method for producing the biosensor according to claim 1 , which comprises steps of coating the substrate with the hydrophobic polymer, and allowing a hydrophilic compound to bind to the hydrophobic polymer coated on the substrate.
7. The biosensor according to claim 1 , wherein a physiologically active substance is bound to the surface by covalent bonding.
8. A method for immobilizing a physiologically active substance on a biosensor, which comprises a step of allowing a physiologically active substance to come into contact with the biosensor according to claim 1 , so as to allow said physiologically active substance to bind to the surface of said biosensor via a covalent bond.
9. A method for detecting or measuring a substance interacting with a physiologically active substance, which comprises a step of allowing a test substance to come into contact with the biosensor according to claim 1 to the surface of which the physiologically active substance binds via a covalent bond and then detecting or measuring the test substance.
10. The method according to claim 9 , wherein the substance interacting with the physiologically active substance is detected or measured by a non-electrochemical method.
11. The method according to claim 9 , wherein the substance interacting with the physiologically active substance is detected or measured by surface plasmon resonance analysis.