Fiber-optic physiological probes

• US 5,127,077 A
• Filed: 12/18/1990
• Issued: 06/30/1992
• Est. Priority Date: 07/25/1988
• Status: Expired due to Term

• Current Assignee: Hospira Incorporated (Pfizer Inc.)
• Original Assignee: Abbott Laboratories Incorporated
• Inventors: Iyer, Lokanathan M., Lyon, Kenneth S., Yim, Jeffrey B.
• Primary Examiner(s): Ullah, Akm E.
• Application Number:
  US07/629,988
• Time in Patent Office: 560 Days
• Field of Search: 350/96.29, 350/96.15, 350/96.30, 350/96.31, 350/96.34, 128/634
• US Class Current: 385/116
• CPC Class Codes: A61B 5/14539 for measuring pH
• CPC Class Codes: A61B 5/1459 invasive, e.g. introduced into the body by a catheter A61B5/1464 takes precedence
• CPC Class Codes: G01N 2021/0385 Diffusing membrane; Semipermeable membrane
• CPC Class Codes: G01N 2021/6434 Optrodes
• CPC Class Codes: G01N 2021/772 Tip coated light guide
• CPC Class Codes: G01N 21/6428 Measuring fluorescence of fluorescent products of reactions or of fluorochrome labelled reactive substances, e.g. measuring quenching effects, using measuring "optrodes" in vivo A61B5/00; immunoassay G01N33/53
• CPC Class Codes: G01N 21/77 by observing the effect on a chemical indicator
• CPC Class Codes: G01N 21/783 for analysing gases
• CPC Class Codes: G01N 21/80 Indicating pH value
• CPC Class Codes: G01N 21/8507 Probe photometers, i.e. with optical measuring part dipped into fluid sample

Abstract

Fiber optic sensors suitable for monitoring physiological analyte concentrations are described. The sensors include analyte permeable matrices disposed in a light path defined by the axial core at one end of an optical fiber segment. The matrix contains an indicator molecule covalently linked to a polymer or admixed with the polymer. The indicator molecule may be an absorptive molecule or a luminescent molecule. pH, PCO₂, and PO₂ sensors are described and may be disposed together in substantially coterminal arrangement to make a multivariable probe.

Claims

1. A fiber optic sensor suitable for monitoring physiological analyte concentration, comprising a preformed film of an analyte permeable matrix disposed in a light path defined by an axial core at one end of an optical fiber segment, the analyte permeable matrix comprising an indicator molecule covalently linked to or admixed with a polymer, the indicator molecule capable of responding to the analyte in an optically-detectable manner.

2. The fiber-optic sensor of claim 1, wherein the polymer is selected from the group consisting of methyl methacrylate/methacrylamidopropyl trimethylammonium chloride, N-vinylpyrrolidone/p-aminostyrene, methyl methacrylate/hydroxymethyl methacrylate, methyl methacrylate/N-vinylpyrrolidone, and methyl methacrylate/acrylic acid.

3. The fiber-optic sensor of claim 1, wherein the pre-formed film is supported on a reflective film.

4. The fiber-optic sensor of claim 3, wherein the preformed film is a preformed pellet.

5. The fiber-optic sensor of claim 2, wherein the polymers formulated in the range are from about 60:

40 to about 80;

20 weight/weight percent.

6. The fiber-optic sensor of claim 1, wherein the polymer comprises approximately 94:

6 mole/mole percent of either methyl methacrylate/methylacrylamidopropyltrimethylammonium chloride or N-vinylpyrrolidone/p-aminostyrene copolymer.

7. The fiber-optic sensor of claim 1, wherein the indicator molecule is covalently linked to the polymer through an aminoarylalkylamine.

8. The fiber-optic sensor of claim 7, wherein the aminoarylalkylamine is selected from the group consisting of 4-(aminophenyl)-ethylamine and 4-(aminophenyl)-propylamine.

9. The fiber-optic sensor of claim 1, wherein the indicator molecule is an absorptive molecule.

10. The fiber-optic sensor of claim 9, wherein the analyte is hydrogen ion.

11. The fiber-optic sensor of claim 10, wherein the indicator molecule is selected from the group consisting of phenol red and carboxynaphthophthalein.

12. The fiber-optic sensor of claim 1, wherein the indicator molecule is a luminescent molecule.

13. The fiber-optic sensor of claim 12, wherein the analyte is hydrogen ion.

14. The fiber-optic sensor of claim 12, wherein the analyte is oxygen.

15. The fiber-optic sensor of claim 1, further comprising a gas permeable but ionimpermeable membrane encapsulating the analyte-permeable matrix, the analyte-permeable matrix comprising a base having a pKa ranging from about 6.0 to about 7.8.

16. The fiber-optic sensor of claim 15, wherein the base has a pKa ranging from about 7.0 to 7.4.

17. The fiber-optic sensor of claim 15, wherein the gas-permeable but ion-impermeable membrane comprises a resin selected from the group consisting of silicones polycarbonates, and urethanes.

18. The fiber-optic sensor of claim 15, wherein the base comprises an inorganic salt and wherein the analyte-permeable matrix further comprises an antioxidant.

19. The fiber-optic sensor of claim 15, wherein the analyte-permeable matrix comprises one or more of the group consisting of poly-N-vinylpyrrolidone, polyethylene glycol, and polyethylene oxide.

20. The fiber-optic sensor of claim 15, wherein the analyte-permeable matrix comprises approximately 80:

20 weight/weight percent.