# US 5,326,585 A · Method and compositions for manufacture of chemical sensors > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,326,585 A - Document ID: US5326585A - Status: Granted - Kind: A - Application number: 08/108,108 - Filed: 1993-08-17 - Granted: 1994-07-05 - Earliest claimed: 1992-04-27 - Assignees: Puritan-Bennett Corporation - Inventors: Alan M. Nelson; Carmen L. Soikowski - Web page: https://patentgrep.com/patent/US5326585A ## CPC - G01N 21/7703: {using reagent-clad optical fibres or optical waveguides (using measurement of total internal reflection or attenuated total reflection G01N21/552; optical fibres or waveguides per se G02B)} - G01N 2021/773: {Porous polymer jacket; Polymer matrix with indicator} - G01N 2021/7786: {Fluorescence} - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) ## Abstract The method for making an optical fiber microsensor involves applying an uncured analyte sensing matrix to an optical fiber and crosslinking the sensing matrix in situ on the optical fiber to yield an ion permeable microsensor which can be used intravascularly to monitor pH, or partial pressures of oxygen or carbon dioxide in blood. The liquid form of the sensing matrix contains a crosslinking agent and a crosslinking inhibitor which can be removed by exposure to elevated temperatures to allow the sensing matrix to crosslink and cure as desired, in situ, on the surface of the optical fiber. A liquid crosslinking overcoat layer containing a crosslinking agent and a crosslinking inhibitor which can be removed by exposure to heat can also be applied over the cured sensing matrix. ## Claims ### Claim 1 A method of making an analyte sensor including an optical fiber having a surface portion covered with a polymeric analyte sensing matrix including a dye indicator material, comprising the steps of: preparing an analyte permeable polymer with an analyte sensitive indicator dye covalently bonded to the analyte permeable polymer to form a liquid polymeric analyte sensing matrix; forming a liquid mixture of said liquid polymeric analyte sensing matrix with a crosslinking agent and a crosslinking inhibitor which can be removed by exposure to heat; coating said optical fiber surface portion with said liquid mixture; and heating said liquid mixture on said optical fiber surface portion for a sufficient period of time to remove said crosslinking inhibitor from said liquid mixture, whereby said crosslinking agent crosslinks said liquid polymeric analyte sensing matrix in situ on said optical fiber surface portion thereby producing a cured sensing matrix. ### Claim 2 (depends on 1) The method of claim 1, wherein said crosslinking agent comprises a blocked polyether isocyanate incorporating said crosslinking inhibitor selected from the group consisting of ethanol, o-nitrophenol, resorcinol, benzenethiol, acetyl acetone, 2-methyl-2-propanol, p-chlorophenol, phloroglucinol, ethyl acetoacetate, acetone oxime, methyl ethyl ketone oxime, m-cresol, guaiacol, 1-dodecanthiol, diethyl malonate, diphenyl amine, phenol caprolactam, 2, 4-diisobutylphenol, monomethylaniline, and isoocytylphenol. ### Claim 3 (depends on 2) The method of claim 2, wherein said crosslinking inhibitor is acetone oxime. ### Claim 4 (depends on 2) The method of claim 2, wherein said liquid polymeric analyte sensing matrix comprises a copolymer of hydroxyethyl methacrylate and N-(3-aminopropyl) methacrylate hydrochloride. ### Claim 5 (depends on 4) The method of claim 4, wherein said dye indicator material comprises 8-hydroxy-1, 3, 6 pyrenetrisulfonic acid. ### Claim 6 (depends on 1) The method of claim 1, wherein said liquid polymeric analyte sensing matrix comprises a crosslinkable vinyl terminated organosiloxane, said crosslinking agent comprises a catalyst and said crosslinking inhibitor comprises a vinyl terminated dimethylsiloxane. ### Claim 7 (depends on 6) The method of claim 6, wherein said crosslinking inhibitor has the chemical structure ##STR4## ### Claim 8 (depends on 6) The method of claim 6, wherein said crosslinking inhibitor is divinyl tetramethyldisiloxane. ### Claim 9 (depends on 6) The method of claim 6, wherein said dye indicator material is selected from the group consisting of fluorescein and 8-hydroxy-1, 3, 6 pyrenetrisulfonic acid. ### Claim 10 (depends on 9) The method of claim 9, wherein said dye indicator material is covalently bonded with a copolymer selected from the group consisting of acrylamide, hydroxyethyl methacrylate, and a copolymer of hydroxyethyl methacrylate and N-(3-aminopropyl) methacrylate hydrochloride. ### Claim 11 (depends on 6) The method of claim 6, wherein said dye indicator material is selected from the group consisting of coronene and decacyclene, and a combination thereof. ### Claim 12 (depends on 9) The method of claim 9, wherein said liquid polymeric analyte sensing matrix comprises methylhydrodimethylsiloxane copolymer. ### Claim 13 (depends on 6) The method of claim 6, wherein said dye indicator material comprises a polynuclear aromatic dye covalently linked to the organosiloxane copolymer. ### Claim 14 (depends on 1) The method of claim 1, wherein said liquid mixture on said optical fiber surface portion is heated to a temperature exceeding the boiling point or temperature of decomposition of said crosslinking inhibitor. ### Claim 15 (depends on 1) The method of claim 1, wherein said liquid mixture on said optical fiber surface portion is exposed to a temperature of from about 140.degree. to about 240.degree. C. for approximately 10-60 seconds. ### Claim 16 (depends on 1) The method of claim 1, wherein said liquid mixture on said optical fiber surface portion is exposed to a temperature of about 220.degree. C. for approximately 15 seconds. ### Claim 17 (depends on 1) The method of claim 1, wherein said liquid mixture on said optical fiber surface portion is exposed to a temperature of about 175.degree. for approximately 20 seconds. ### Claim 18 (depends on 1) The method of claim 1, further including the step of applying a layer of an uncured overcoat mixture comprising a second crosslinking agent and a second crosslinking inhibitor which can be removed by exposure to elevated temperature over said liquid polymeric analyte sensing matrix following said step of heating said liquid mixture; and heating said uncured overcoat mixture on said optical fiber surface portion for a sufficient period of time to remove said second crosslinking inhibitor from said uncured overcoat mixture, whereby said second crosslinking agent crosslinks said overcoat mixture in situ over said cured sensing matrix. ### Claim 19 (depends on 18) The method of claim 18, wherein said overcoat mixture includes titanium dioxide. ### Claim 20 (depends on 18) The method of claim 18, wherein said overcoat second crosslinking agent comprises a blocked form of a polyether isocyanate incorporating said second crosslinking inhibitor, and said second crosslinking inhibitor is selected from the group consisting of ethanol, o-nitrophenol, resorcinol, benzenethiol, acetyl acetone, 2-methyl-2-propanol, p-chlorophenol, phloroglucinol, ethyl acetoacetate, acetone oxime, m-cresol, guaiacol, 1-dodecanthiol, diethyl malonate, diphenyl amine, phenol caprolactam, 2,4-diisobutylphenol, monomethylaniline, and isooctylphenol. ### Claim 21 (depends on 18) The method of claim 18, wherein said overcoat second crosslinking inhibitor comprises acetone oxime. ### Claim 22 (depends on 18) The method of claim 18, wherein said overcoat second crosslinking agent comprises a crosslinkable vinyl terminated organosiloxane and a catalyst, and said second crosslinking inhibitor comprises a vinyl terminated dimethylsiloxane. ### Claim 23 (depends on 22) The method of claim 22, wherein said second crosslinking inhibitor has the chemical structure ##STR5## ### Claim 24 (depends on 22) The method of claim 22, wherein said second crosslinking inhibitor is divinyl tetramethyldisiloxane. ### Claim 25 (depends on 22) The method of claim 22, wherein said overcoat mixture comprises methylhydrodimethylsiloxane copolymer. ### Claim 26 (depends on 18) The method of claim 18, wherein said uncured overcoat mixture on said cured sensing matrix is heated to a temperature exceeding the boiling point or temperature of decomposition of said second crosslinking inhibitor. ### Claim 27 (depends on 18) The method of claim 18, wherein said uncured overcoat mixture on said cured sensing matrix is exposed to a temperature of from about 140.degree. to about 220.degree. C. ### Claim 28 (depends on 18) The method of claim 18, wherein said uncured overcoat mixture on said cured sensing matrix is exposed to a temperature of from about 140.degree. to about 220.degree. C. for approximately 10 to 60 seconds. ### Claim 29 (depends on 18) The method of claim 18, wherein said uncured overcoat mixture on said cured sensing matrix is exposed to a temperature of about 175.degree. for approximately 30 seconds. ### Claim 30 (depends on 1) The method of claim 1, further including the step of priming said optical fiber surface portion by applying a silanizing agent selected from the group consisting of isocyanatopropyltriethoxysilane and vinyltriethoxysilane to said optical fiber surface portion prior to said step of coating said optical fiber surface portion with said liquid mixture.