Fabrication process of biosensor

• US 5,445,920 A
• Filed: 02/02/1994
• Issued: 08/29/1995
• Est. Priority Date: 02/18/1993
• Status: Expired due to Term

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Saito, Atsushi
• Primary Examiner(s): Duda, Kathleen
• Application Number:
  US08/190,371
• Time in Patent Office: 573 Days
• Field of Search: 430/311, 430/315, 430/319, 430/320, 430/324, 430/329
• US Class Current: 430/311
• CPC Class Codes: C12Q 1/002 Electrode membranes

Abstract

A process is provided for the mass-fabrication of biosensors having a permeation-restricted membrane of uniform quality. A photoresist is coated over an entire surface of a wafer on which at least two pairs of electrochemical transducer devices are arranged together with electrode(s) as many as needed. The photoresist is removed at predetermined areas by photolithography. The entire surface of the wafer is next coated with a liquid coating formulation of a crosslinkable polymer and a crosslinking agent, followed by the gelation of the coating formulation. Further, a liquid coating formulation of a crosslinkable polymer and a crosslinking agent, the coating formulation preferably containing a silicone, is coated over the entire surface of the wafer and is then caused to gel. The wafer is next treated in an organic solvent to dissolve the photoresist, so that an enzyme-free, crosslinked membrane and a permeation-restricted membrane are formed. Using an enzyme-containing liquid coating formulation of a crosslinkable polymer and a crosslinking agent, an enzyme-immobilized membrane and a permeation-restricted membrane are next formed likewise. The resulting wafer is finally cut functional unit by functional unit into chips.

Claims

1. A process for the fabrication of plural biosensors having uniform response characteristics and a wide response range, each of said biosensors having at least two pairs of electrochemical transducer devices and a pseudo-reference electrode located substantially at a midpoint between said at least two pairs of electrochemical transducer devices, said devices and said electrode being both formed on one side of a wafer, and also an enzyme-immobilized membrane and a permeation-restricted membrane, both arranged over said devices and said electrode, which comprises:

1) covering said wafer with a first photoresist coating film except for surfaces of one of said devices and of said electrode;

2) spin-coating said surfaces with an enzyme-free liquid coating formulation of an enzyme-immobilizing crosslinkable polymer;

3) spin-coating the resulting structure further with a first permeation-restricted-membrane-forming liquid coating formulation of a crosslinkable polymer;

4) causing said enzyme-free liquid coating formulation and said first permeation-restricted-membrane-forming liquid coating formulation to gel, whereby first and second gelled membranes are formed in a stacked form;

5) dissolving said first photoresist coating film with portions of said first and second gelled membranes which have been formed on said first photoresist coating film, whereby said first and second gelled membranes remain in the stacked form only on said surfaces of said one device and said electrode and a partly coated wafer is obtained;

6) covering a surface of the partly-coated wafer with a second photoresist coating film except for a surface of the other device;

7) spin-coating said surface of said other device with an enzyme-containing liquid coating formulation of an enzyme-immobilizing crosslinkable polymer;

8) spin-coating the spin-coated surface of said other device further with a second permeation-restricted-membrane-forming liquid coating formulation of a crosslinkable polymer;

9) causing said enzyme-containing liquid coating formulation and said second permeation-restricted-membrane-forming liquid coating formulation to gel, whereby third and fourth gelled membranes are formed in a stacked form;

10) dissolving said second photoresist coating film with said third and fourth gelled membranes which have been formed on said second photoresist coating into solvent, whereby a structure is obtained wherein said third and fourth gelled membranes remain only on said surface of said other device; and

then

11) cutting the structure into pieces so that each piece includes parts of said paired electrochemical transducer devices and a part of said pseudo-reference electrode, with said electrode being located substantially at the midpoint between the parts.

2. A process according to claim 1, wherein each of said first and second permeation-restricted-membrane-forming liquid coating formulations is a silicone-containing liquid coating formulation of a protein and a crosslinking agent.

3. A process according to claim 2, wherein said protein is albumin.

4. A process according to claim 1, wherein each of said first and second permeation-restricted-membrane-forming liquid coating formulations is a liquid coating formulation of an amino-modified silicone and a crosslinking agent.

5. A process according to claim 1, wherein each of said devices is an ion-sensitive field effect transistor.

6. A process according to claim 1, wherein each of said devices is an amperometric electrode.

7. A process according to claim 1, wherein the enzyme in said enzyme-containing liquid coating formulation is glucose oxidase.

8. A process according to claim 1, wherein each enzyme-free liquid coating formulation of the enzyme-immobilizing crosslinkable polymer is a liquid coating formulation containing a protein and a crosslinking agent.

9. A process for the fabrication of plural biosensors having uniform response characteristics and a wide response range, each of said biosensors having at least two pairs of electrochemical transducer devices and a pseudo-reference electrode located substantially at a midpoint between said at least two pairs of electrochemical transducer devices, said devices and said electrode being both formed on one side of a wafer, and also an enzyme-immobilized membrane and a permeation-restricted membrane, both arranged over said devices and said electrode, which comprises:

1) covering said wafer with a first photoresist coating film except for surfaces of one of said devices and of said electrode;

2) spin-coating said surfaces with an enzyme-free liquid coating formulation of an enzyme-immobilizing cross-linkable polymer and then causing said enzyme-free liquid coating formulation to gel, whereby a first gelled membrane is formed;

3) dissolving said first photoresist coating film with a portion of said first gelled membrane which has been formed on said first photoresist coating film, whereby said first gelled membrane remains only on said surfaces of said one device and said electrode and a partly coated wafer is obtained;

4) covering a surface of the partly-coated wafer with a second photoresist coating film by a lithographic technique except for a surface of the other device;

5) spin-coating said surface of said other device with an enzyme-containing liquid coating formulation of an enzyme-immobilizing crosslinkable polymer;

6) dissolving said second photoresist coating film with said enzyme-containing liquid coating formulation of an enzyme-immobilizing crosslinkable polymer, whereby a first structure is obtained wherein said enzyme-immobilizing crosslinkable polymer remains only on said surface of said other device;

7) spin-coating the first structure further with a permeation-restricted-membrane-forming liquid coating formulation of a photocrosslinkable polymer;

8) photopolymerizing the coated permeation-restricted-membrane-forming liquid coating formulation by a photolithographic technique followed by dissolving unpolymerized coating formulation, whereby a second structure is obtained wherein a gelled membrane is formed only on said remaining first gelled membrane and enzyme-immobilizing photocrosslinkable polymer in a stacked form; and

9) cutting the second structure into pieces so that each piece includes parts of said paired electrochemical transducer devices and a part of said pseudo-reference electrode, with said electrode being located substantially at the midpoint between the parts.

10. A process according to claim 9, wherein said permeation-restricted-membrane-forming liquid coating formulation is a silicone emulsion containing a protein and a crosslinking agent.

11. A process according to claim 10, wherein said protein is albumin.

12. A process according to claim 9, wherein said liquid coating formulation of said permeation-restricted-membrane-forming crosslinkable polymer further comprises a reaction initiator and a sensitizer.

13. A process according to claim 9, wherein each of said devices is an ion-sensitive field effect transistor.

14. A process according to claim 9, wherein each of said devices is an amperometric electrode.

15. A process according to claim 9, wherein the enzyme in said enzyme-containing liquid coating formulation is glucose oxidase.

16. A process according to claim 9, wherein each enzyme-free liquid coating formulation of the enzyme-immobilizing crosslinkable polymer is a protein solution containing a crosslinking agent.