Biosensor and its use to indicate the status of a product

• US 6,642,016 B1
• Filed: 03/27/2002
• Issued: 11/04/2003
• Est. Priority Date: 10/05/1999
• Status: Expired due to Fees

• Current Assignee: Bioett AB
• Original Assignee: Bioett AB
• Inventors: Sjöholm, Johan, Erlandsson, Per-Olof
• Primary Examiner(s): Leary, Louise N.
• Application Number:
  US10/089,181
• Time in Patent Office: 587 Days
• Field of Search: 435/15, 435/18, 435/12, 435/283.1, 435/287.1, 435/289.1
• US Class Current: 435/15
• CPC Class Codes: C12Q 1/005 involving specific analytes or enzymes including groups of enzymes, e.g. oxydases; C12Q1/004 takes precedence
• CPC Class Codes: G01K 1/024 for remote indication
• CPC Class Codes: G01K 2207/04 for conservation purposes
• CPC Class Codes: G01K 3/04 in respect of time
• CPC Class Codes: G01N 33/02 Food
• CPC Class Codes: G06K 19/0717 the sensor being capable of sensing environmental conditions such as temperature history or pressure

Abstract

A biosensor comprises a unit, comprising a substrate and an enzyme, which when brought into contact with the substrate is adapted to affect the substrate so that its conductivity changes as a function of time and temperature, and an electric circuit. The unit is included as a component in said electric circuit and the electric circuit is activable by applying an electric field and/or a magnetic field over the same to generate a measurable signal which is dependent on the total resistance of the circuit. The invention also relates to the use of a biosensor, a label with such a biosensor and a method of indicating the status of a product with such a biosensor.

Claims

1. A biosensor for indicating the status of a product, that comprises

unit (1), comprising a substrate (1b) and an enzyme (1a) selected from one of the enzyme classes Transferases, Hydrolases and Lyases, which when brought into contact with the substrate (1b) is adapted to affect the substrate (1b) so that conductivity changes as a function of time and temperature, and

an electric circuit (2),

said unit (1) being included as a component in said electric circuit (2), and

said electric circuit (2) being activated by applying an electric field and/or a magnetic field (M) over the product to generate a measurable signal, which is dependent on the total resistance of the circuit (2) and indicates enzyme activity in the product.

2. A biosensor as claimed in claim 1, in which the enzyme (1a) is adapted to affect the substrate (1b) so that its conductivity increases as a function of time and temperature.

3. A biosensor as claimed in claim 1, in which the enzyme (1a) is Urease.

4. A biosensor as claimed in claim 3, in which the substrate (1b) comprises Urea.

5. A biosensor as claimed in claim 1, wherein said signal is a measurable current, which is generated in the circuit (2).

6. A biosensor as claimed in claim 1, wherein said circuit (2) is an oscillation circuit (2).

7. A label (7) for application to a product container (6), comprising a biosensor as claimed in claim 1.

8. A method of indicating the status of a product which is located in a container (6), characterised by the steps of

(i) determining the status of the product as a function of time and temperature,

(ii) adapting the enzyme (1a) of a biosensor as claimed in claim 1 to affect the conductivity of the substrate (1b) according to the same function of time and temperature,

(iii) arranging the biosensor on said container (6),

(iv) activating the unit (1) of the biosensor by bringing the enzyme (1a) into contact with the substrate (1b) when placing the product in the container (6),

(v) applying an electric field and/or a magnetic field (M) over the electric circuit (2) when the status of the product is to be checked,

(vi) measuring the signal which in this context is generated by the electric circuit (2) of the biosensor and which is dependent on the present conductivity of the substrate (1b), and

(vii) indicating on the basis of said signal the present status of the product.

9. A method as claimed in claim 8, further comprising the step of storing in a memory unit the measured signal together with data identifying the container (6) on which the biosensor is arranged.

10. A biosensor as claimed in claim 2, in which the enzyme (1a) is Urease.

11. A biosensor as claimed in claim 10, in which the substrate (1b) comprises urea.

12. A biosensor as claimed in claim 2, wherein said signal is a measurable current, which is generated in the circuit (2).

13. A biosensor as claimed in claim 3, wherein said signal is a measurable current, which is generated in the circuit (2).

14. A biosensor as claimed in claim 4, wherein said signal is a measurable current, which is generated in the circuit (2).

15. A biosensor as claimed in claim 2, wherein said circuit (2) is an oscillation circuit (2).

16. A biosensor as claimed in claim 3, wherein said circuit (2) is an oscillation circuit (2).

17. A biosensor as claimed in claim 4, wherein said circuit (2) is an oscillation circuit (2).

18. A biosensor as claimed in claim 5, wherein said circuit (2) is an oscillation circuit (2).

19. A method according to claim 8, wherein the product is a food product.

20. A method of indicating the status of a product which is located in a container (6), comprising the steps of

(i) determining the status of the product as a function of time and temperature,

(ii) adapting the enzyme (1a) of a biosensor as claimed in claim 2 to affect the conductivity of the substrate (1b) according to the same function of time and temperature,

(iii) arranging the biosensor on said container (6),

(iv) activating the unit (1) of the biosensor by bringing the enzyme (1a) into contact with the substrate (1b) when placing the product in the container (6),

(v) applying an electric field and/or a magnetic field (M) over the electric circuit (2) when the status of the product is to be checked,

(vi) measuring the signal which in this context is generated by the electric circuit (2) of the biosensor and which is dependent on the present conductivity of the substrate (1b), and

(vii) indicating on the basis of said signal the present status of the product.