Integrated circuit hydrated sensor apparatus

• US 5,338,435 A
• Filed: 06/26/1992
• Issued: 08/16/1994
• Est. Priority Date: 06/26/1991
• Status: Expired due to Term

• Current Assignee: Radiometer California, Inc.
• Original Assignee: PPG Industries Incorporated (Nouryon BV)
• Inventors: Graves, Jeffrey A., Savage, Douglas R., Betts, Ronald E., Koerner, Richard J., Sherman, Marshall L., Leader, Matthew J., Sin, Kee V.
• Primary Examiner(s): Niebling, John
• Assistant Examiner(s): Bell, Bruce F.
• Application Number:
  US07/905,255
• Time in Patent Office: 781 Days
• Field of Search: 204/406, 204/408, 204/409, 204/412, 204/416, 204/422, 204/433, 204/435, 204/400, 204/415, 204/153.1, 204/153.17, 338/22 R, 128/635, 219/209, 219/121.6
• US Class Current: 204/406
• CPC Class Codes: A61B 2562/08 Sensors provided with means for identification, e.g. barcodes or memory chips
• CPC Class Codes: A61B 5/14539 for measuring pH
• CPC Class Codes: A61B 5/14542 for measuring blood gases A61B5/14551 takes precedence
• CPC Class Codes: A61B 5/1468 using chemical or electrochemical methods, e.g. by polarographic means A61B5/1486 takes precedence
• CPC Class Codes: A61B 5/1473 invasive, e.g. introduced into the body by a catheter A61B5/1482 takes precedence
• CPC Class Codes: A61B 5/15003 for venous or arterial blood
• CPC Class Codes: A61B 5/150251 Collection chamber divided into at least two compartments, e.g. for division of samples injection syringes having more than one chamber A61M5/19; syringes for injection of two or more media A61M5/2448, A61M5/284; sample preparation for further analysis A61B5/150755
• CPC Class Codes: A61B 5/150305 Packages specially adapted for piercing devices or blood sampling devices kits for diabetes A61M5/003; packaging in general B65D
• CPC Class Codes: A61B 5/150786 Optical identification systems, e.g. bar codes, colour codes
• CPC Class Codes: A61B 5/153 Devices specially adapted for taking samples of venous or arterial blood, e.g. with syringes
• CPC Class Codes: A61B 5/157 Devices characterised by integrated means for measuring characteristics of blood
• CPC Class Codes: B01L 3/502 with fluid transport, e.g. in multi-compartment structures centrifugal-type cuvettes G01N21/07; analysis by separation into components G01N30/00; automatic analysers G01N35/00
• CPC Class Codes: G01N 33/4925 measuring blood gas content, e.g. O2, CO2 , HCO3

Abstract

A plastic covered nonconducting substrate with an electrical circuit means is secured to the extent to withstand the presence of liquids in contact with the substrate. The covered substrate can have the substrate with one or more fluid preconditionable electrical components, a housing secured to the substrate to maintain contact of the preconditioning fluid with the electrical component like a sensor, and moisture impervious seals to cover openings in the housing for the disposition of the preconditioning fluid in the housing for contact with the electrical component on the substrate. The housing can have one or more parts and have one or more channels for containing the preconditioning fluid.

The electrical component can be an improved electronic wiring board having a thermistor and at least one blood gas sensor supported, in close relation, one to the other, on one side of the board and a heater supported on the other side of the board to provide heat in response to temperature sensed by the thermistor, to at least the region where the thermistor and the blood gas sensor are positioned on the board to control the temperature of the region of the board within a narrow distribution of temperatures.

Claims

1. An apparatus having a preconditioned sensor and electronic circuit, comprising:

nonconducting substrate with at least one electrochemical sensor and with electrical circuitry in electrical contact with the sensor to convey electrical impulses from the sensor,

housing having at least one part enclosing the nonconducting substrate and forming a channel in fluid contact with the at least one sensor on the substrate, wherein the channel has two openings form the housing for fluid flow through the channel and that is in fluid contact with the at least one sensor on the substrate to allow fluid in the channel to be in fluid contact with the sensor where one opening is adapted for receipt of a fluid sample for measurement of a component by the sensor, and another opening is positioned in the channel after the at least one sensor,

fluid occupying a substantial portion of the channel to precondition the membrane of the one or more sensors,

seals that are substantially impervious to at least moisture associated with the channel to maintain the hydrating fluid in contact with one or more sensors and to minimize the transport of hydrating fluid away from contact with the one or more sensors,

electrical attachment means electrically associated with the circuit means of the substrate to convey the sensor signals from the apparatus for interpretation,

wherein the hydrating fluid is electrically isolated from the electric circuitry of the substrate and the electrical attachment means.

2. Apparatus of claim 1 wherein the at least one electrochemical sensor on the substrate is an analyte sensor to detect one or more analytes in fluid.

3. Apparatus of claim 2 wherein the at least one electrochemical sensor is a gas sensor to measure blood gas analytes in blood.

4. Apparatus of claim 1 wherein the substrate is ceramic and has three sensors, one for measuring the partial pressure of oxygen, another for measuring the partial pressure of carbon dioxide and another of measuring the pH of a fluid like blood.

5. Apparatus of claim 1 wherein substrate has the electrical circuitry designed to enhance electrical isolation from the hydrating fluid.

6. Apparatus of claim 1 wherein housing has at least two sections and both sections have at least one set of attachment means for suitable attachment of the two sections to enclose the substrate in the internal space.

7. Apparatus of claim 6 wherein the housing has a channel formed by one section of the housing and the substrate within the internal space between the sections of the housing.

8. Apparatus of claim 7 wherein the housing has the channel extending along a longitudinal axis in a near linear orientation from one end of the housing to the other.

9. Apparatus of claim 8 wherein the housing has the channel emerging from each end of the housing in tips for attachment to a sample collection device at one end and a sample disposal device at the other end.

10. Apparatus of claim 8 wherein the housing includes one or more adhesive ports filled with cured adhesive.

11. Apparatus of claim 1 wherein the housing has one or more side channels fluidly connected to the channel that has openings from the housing that where the side channels have fluid selected from the group consisting of preconditioning fluid and hydrating fluid and mixtures thereof.

12. Apparatus of claim 11, wherein the housing and the substrate are associated with each other so that the side channels have one or more reference electrodes that are present on the substrate.

13. Apparatus of claim 12, wherein the polymers are selected from the group consisting of:

methyl methacrylate styrene butadiene terpolymer, polyesters and polycarbonate.

14. Apparatus of claim 1 wherein the housing has a slot for the ingress and egress of the electronic attachment means.

15. Apparatus of claim 1 wherein the preconditioning fluid is a hydrating fluid that is isotonic with the hydrated state of the submembrane of the sensor.

16. Apparatus of claim 1 wherein the seals are located one at each opening of the channel from the housing.

17. Apparatus of claim 1 wherein the seals are substantially impervious to oxygen and carbon dioxide.

18. Apparatus of claim 1 wherein the seals have inner surface attached to the housing covering the opening of the channel and outer surface, where the outer surface is metal and the inner surface is an adhesive type polymer, where said seal covers the opening of the channel by the inner adhesive surface being stuck to at least a portion of the housing surrounding opening of the channel.

19. Apparatus of claim 18, wherein seals are multilayer seals with the exterior surface is a metal foil and the interior surface is a polymeric layer selected from the group consisting of:

polyethylene, polypropylene, polyvinylidene chloride and nylon and where the thickness of the seals is in the range from around 1 to around 10 mils.

20. Apparatus of claim 19, wherein the multilayer seals are a three layer laminate having an exterior surface selected from the group consisting of nylon, polyester, polyethylene and polypropylene, and an intermediate layer of aluminum foil and an inner heat sealable polymeric layer selected from the group consisting of:

polyethylene, polypropylene, polyvinylidene chloride and nylon.

21. Apparatus of claim 1 wherein the seals are induction sealed to the housing over the channel openings.

22. Apparatus of claim 1 wherein the seals are heat sealed to the housing over the channel openings.

23. Apparatus of claim 1 wherein the seals are flexible generally circular disc having a generally circular periphery and a diameter such as to circumferentially seal the openings of the channel.

24. Apparatus of claim 1, which includes an electrically isolating means to isolate the electric circuit means on the substrate and the hydrating fluid, where the electrically isolating means occupies the internal space not already occupied by other components, and wherein the electrically isolating means is placed in the housing through a hole in the housing.

25. Apparatus of claim 1 wherein the apparatus is gamma-sterilized.

26. Apparatus of claim 1 wherein the nonconducting substrate with at least one preconditioned electrochemical sensor and with electrical circuitry in electrical contact with the sensor is comprised of:

the nonconducting substrate, thermistor and at least one analyte sensor supported, in close relation, one to the other, on the substrate and a heater, also supported on the substrate, to provide heat in response to temperature sensed by said thermistor to at least the region where said thermistor and said blood gas sensor are positioned on said board to thereby control the temperature of said region of said board within a said board for connecting said board to an external electrical source.

27. Apparatus of claim 26 wherein said board is manufactured using thick film layered circuit technique.

28. Apparatus of claim 26 wherein said thermistor and said blood gas sensors are supported in the same plane on said board.

29. Apparatus of claim 26 wherein said blood gas sensors includes at least an oxygen sensor.

30. Apparatus of claim 26 wherein said blood gas sensors includes at least a carbon dioxide sensor.

31. Apparatus of claim 26 wherein said blood gas sensors includes at least a pH sensor.

32. Apparatus of claim 26 wherein said blood gas sensors include an oxygen sensor, a carbon dioxide sensor and a pH sensor.

33. Apparatus of claim 26 wherein said connecting means includes plurality of external leads, a resistor is supported on said board on the same side as said heater and commonly connected to one of said external leads with said thermistor, dividing the voltage therebetween.

34. Apparatus of claim 26 wherein the temperature coefficient of said thermistor is negative or positive and the temperature coefficient of said resistor is around zero, and where the divided voltage is proportional or inversely proportional to temperature, the this output is used to measure temperature.

35. Apparatus of claim 26 wherein said connecting means further includes a plurality electronic conducting pathways individually and electrically connecting each of said sensors and said thermistor with external leads provided on said board at the end of said pathways.

36. Apparatus of claim 26 wherein said resistor and said heater are each electrically connected to external leads.

37. Apparatus of claim 26 wherein said heater is powered by pulsed DC whereby said heater is continually turned on and off thereby avoiding said heater from overshooting or undershooting a predetermined temperature.

38. Apparatus of claim 26 wherein said external leads are positioned on the same side of said board as said resistor and said heater.

39. Apparatus of claim 26 wherein said electronic conducting pathways individually and electrically connecting each of said sensors and said thermistor on one side of said board with external leads provided on the other side of said board through a plurality of holes in said board.

40. Apparatus of claim 26 wherein said resistor is a laser trimmed resistor.

41. Apparatus of claim 26 wherein said oxygen sensor is an electrochemical cell and includes a anode and a cathode, each connected to an external lead.

42. Apparatus of claim 26 wherein said oxygen sensor includes an oxygen permeable membrane covering, in a fluid tight manner, an opening in said board containing an electrolyte, said anode being grounded on said board to thereby assure that potential of said electrolyte is the same as the anode potential.

43. Apparatus of claim 26 wherein there is at least one reference electrode, to provide an accurate reference potential, supported on said board and is electrically connected to a electronic conducting pathway.

44. Apparatus of claim 26 wherein there is one reference electrode supported on said board and is electrically connected to a electronic conducting pathway extending from said anode.

45. Apparatus of claim 26 wherein said board includes a patterned metallic layer provided on said ceramic substrate layer.

46. Apparatus of claim 26 wherein said metallic layer is a deposited metallic printing paste on said substrate forming electronic conducting pathways and the electrodes of said sensors and the electrode of a reference electrode, and wherein said metallic layer has at least one encapsulating layer of a chemically stable and moisture resistant encapsulant, and wherein said board includes a thermistor provided on ceramic substrate layer, said thermistor is encapsulated with at least one thin layer of a chemically stable and moisture resistant encapsulant.

47. Apparatus of claim 1 wherein the one or more sensors are prepared by the thick film process.

48. Apparatus of claim 47 wherein both the one or more sensors and the electrical circuitry are prepared by the thick film process.

49. Apparatus of claim 1, wherein the housing around the channel is a rigid molded polymer selected from the group consisting of:

thermoplastic polymers and thermosetting polymers.

50. A preconditioned electrochemical sensor assembly, comprising:

1) a housing having a first and second exterior surface mated for attachment to each other to form an interior space that has an opening from the housing and to form a channel that communicates with the interior space and that has two openings from the housing for fluid flow through the channel where at least one opening is adapted for contact with a fluid sample gathering means,

2) nonconducting substrate with a plurality of hydratable electrochemical sensors and with electrically isolated electrical circuitry means in electrical contact with the sensors to convey electrical impulses from the sensors and adapted for location within the interior space of the housing to communicate with the channel to have the sensors arranged for fluid contact with any fluid in the channel,

3) hydrating fluid occupying a substantial portion of the channel to hydrate the membrane of the sensor,

4) seals that are substantially impervious to at least moisture placed in the channel to maintain the hydrating fluid in contact with one or more sensors and to minimize the transport of moisture away from contact with the one or more sensors to hydrate the membrane of the sensor, gas adhering to the housing to cover each opening,

5) electrical isolating means occupying the interior space of the housing around the nonconducting substrate to isolate the electrical circuitry connected to the sensor from the channel and the hydrating fluid contained in the channel.

51. Apparatus of claim 50 wherein the electrical isolating means is a hardened epoxy polymer.