DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Continued Examination Under 37 CFR 1.114
A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on July 28, 2026 has been entered.
Status of Objections and Rejections
The rejection of claim(s) 4 is/are obviated by Applicant’s cancellation.
All other rejections from the previous office action are maintained.
Claim Rejections - 35 USC § 103
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
Claim(s) 1, 5-6, 8-9, 21-22, and 24 is/are rejected under 35 U.S.C. 103 as being unpatentable over Surridge (U.S. Patent Pub. 2003/0116447) in view of Steinman (DE 3614470A1, a machine translation used for citation), and further in view of Wang (U.S. 2013/0065257), and further in view of Berry (U.S. 6,068,971), and further in view of Charter (U.S. 7,410,755), supported by Hoenes (U.S. 5,286,362) as an evidence for claim 6.
Regarding claim 1, Surridge teaches a test strip (claim 1, line 1: a disposable electrochemical sensor; ¶9: test strips), comprising:
a working electrode (claim 1, line 2: a working electrode; Fig. 1; ¶35: working electrode 2);
a reference electrode (claim 1, line 3: a reference electrode; Fig. 1; ¶35: counter electrode 4 that is deemed to be the reference electrode);
a testing area (claim 1, lines 3-4: a sample-receiving cavity; Fig. 3, 5; ¶62: capillary chamber 34), including the working electrode and the reference electrode (Fig. 3, 5: indicating the capillary chamber 34 includes the interdigitated electrodes 22 that includes the working electrode and the reference electrode);
a reagent mixture (claim 1, line 4: a reagent layer; Fig. 5-6; ¶63: a chemical coating 40), the reagent mixture deposited in association with one of the working electrode, the reference electrode, and the testing area (claim 1, lines 4-5: the reagent layer disposed within the sample-receiving cavity over at least the working electrode; Fig. 5: indicating the chemical coating 40 deposited on the array of interdigitated electrodes 22 inside the capillary chamber 34), the reagent mixture including a mediator (claim 2, lines 1-2: the reagent layer further comprises an electron transfer mediator) and an oxidase (claim 1, lines 5-6: the reagent layer comprising an enzyme; e.g., claim 12, lines 1-2: the enzyme is glucose oxidase), wherein the mediator is nitrosoaniline (claim 4, line 2; ¶45), the reference electrode and the working electrode configured to provide a signal indicating a level of analyte in the blood sample (¶41: when the sample containing the analyte is contacted with the coating, the analyte, enzyme, and the mediator participate in a reaction, in which the analyte is oxidized and the mediator is reduced, producing a constant or “steady state” current between the electrodes that is measured and correlated to the amount of analyte in the sample; ¶3: examples of substances that may be analyzed include bodily fluids such as blood).
Surridge further discloses different enzymes that are reactive to different analytes, such as glucose oxidase to glucose, pyruvate oxidase to pyruvate (page 4-5, Table 1). Surridge does not explicitly disclose detecting potassium in a blood sample or the reagent mixture including Adenosine diphosphate (ADP), Phosphoenolpyruvate, Pyruvate Kinase, Mg2+, Phosphate, and the Oxidase is Pyruvate Oxidase.
However, Steinman teaches a method for measuring potassium levels in biological fluids, such as blood (¶2). The underlying enzyme reaction is (Original document, page 1):
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Steinman teaches that pyruvate kinase requires the presence of potassium as a cofactor which much be activated and required for maximum function, and by using predetermined amounts of phosphoenolpyruvate (PEP), ADP, pyruvate kinase and magnesium and measuring the rate at which the products appear, one can determine the level of enzyme activity that is directly proportional to the potassium concentration (¶11). Thus, Steinman teaches the reagent mixture in example 2 includes phosphate, ADP, PEP (i.e., Phosphoenolpyruvate), pyruvate kinase, Mg2+, and pyruvate oxidase (¶32).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified Surridge by substituting the components of the reagent mixture with one having ADP, PEP, pyruvate kinase, Mg2+, phosphate, and pyruvate oxidase as taught by Steinman because use of these reagents for enzyme reactions to detect potassium concentration (Steinman, ¶11) is one of applications of Surridge’s electrochemical sensor to detect the presence or concentration of a selected analyte (Surridge, ¶4). Simple substitution of one known element, i.e., the reagent mixture, for another, i.e., the reagent components for detecting the potassium level, to obtain predictable results, i.e., to provide a signal indicating a level of potassium in the blood sample, is prima facie obvious. MPEP 2141(III)(B).
Further, the designation “derived from Bacillus stearothermophilus” for the Pyruvate Kinase is a product-by-process limitation. There is no apparent difference between the claimed test strip and the prior art as taught by Surridge in view of Steinman. Even though product-by-process claims are limited by and defined by the process, determination of patentability is based on the product itself. The patentability of a product does not depend on its method of production. If the product in the product-by-process claim is the same as or obvious from a product of the prior art, the claim is unpatentable even though the prior product was made by a different process.” In re Thorpe, 777 F.2d 695, 698, 227 USPQ 964, 966 (Fed. Cir. 1985). MPEP 2113(I).
Steinman further discloses magnesium acetate is used (¶23). Surridge and Steinman do not explicitly disclose using a phosphate buffer or Mg2+ is in the form of magnesium sulfate.
However, Wang teaches an electrochemical measurement of the NADH concentrations using square wave voltammetry in phosphate buffer solution (pH 7.2) (¶163). For TBI mode, the phosphate buffer contains magnesium sulfate, while for STI mode, the buffer contains magnesium acetate (¶258). Thus, Wang teaches Mg2+ in the buffer is selected from either magnesium sulfate or magnesium acetate.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified Surridge and Steinman by substituting the Tris-HCl buffer of Steinman with a phosphate buffer with magnesium sulfate as taught by Wang. The suggestion for doing so would have been that the phosphate buffer is a suitable buffer and magnesium sulfate is a suitable reagent for providing Mg2+ for electrochemical measurements by a biosensor and the selection of a known material, which is based upon its suitability for the intended use, is within the ambit of one of ordinary skill in the art. MPEP § 2144.07.
Surridge, Steinman, and Wang do not explicitly disclose the phosphate buffer is lithium phosphate buffer to eliminate sodium interference while potassium is measured.
However, Berry teaches methods and reagents for the determination of ions (Col. 1, lines 10-11), for example, using an enzyme-mediated assay for measuring potassium ions employing pyruvate kinase (Col. 3, lines 2-4). Berry teaches, for determination of potassium ions, a buffered mixture containing ADP, PEP, reduced NADH, pyruvate kinase (PK), and LDH (Col. 7, ll. 49-53). Any buffer having a pK in the required pH range with negligible binding capacity for the measured ions or a negligible chloride concentration may be used (col. 12, ll. 33-35; col. 13, ll. 9-10). The use of pyruvate kinase to potassium ions is the overcoming of the interference by sodium and ammonium ions (Col. 6, lines 5-7). Inclusion of ions which are competitive inhibitors of the sensitive indicator enzyme in the assay, for example, the use of lithium ions to compete with sodium ions and potassium ions (Col. 6, lines 17-20). Since lithium ions are less effective as a competitor against potassium ions, the net effect is to increase the relative sensitivity of pyruvate kinase towards potassium ions a further (Col. 6, lines 22-25). This allows the possibility of measurement of the concentration of either potassium or sodium ions, provided that the concentration of the other ions is known (Col. 6, lines 28-30).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified Surridge, Steinman, and Wang by substitute the phosphate buffer with a lithium phosphate buffer including lithium ions for measurement of potassium ions as taught by Berry because lithium ions are less effective as a competitor against potassium ions for the net effect of further increasing the relative sensitivity of pyruvate kinase towards potassium ions (Col. 6, lines 22-25). Further, the designation “as a buffer to eliminate sodium interference while potassium is measured” is deemed to be functional limitation in apparatus claims. MPEP 2114 (II). "[A]pparatus claims cover what a device is, not what a device does." Hewlett-Packard Co. v. Bausch & Lomb Inc., 909 F.2d 1464, 1469, 15 USPQ2d 1525, 1528 (Fed. Cir. 1990) (emphasis in original). A claim containing a "recitation with respect to the manner in which a claimed apparatus is intended to be employed does not differentiate the claimed apparatus from a prior art apparatus" if the prior art apparatus teaches all the structural limitations of the claim. Ex parte Masham, 2 USPQ2d 1647 (Bd. Pat. App. & Inter. 1987). Here, Surridge in view of Steinman, Wang, and Berry teaches all structural limitations of the presently claimed test strip including all recited reagent components, which would necessarily result in lithium phosphate buffer that is capable of eliminating sodium interference while potassium is measured.
Surridge, Steinman, Wang, and Berry do not explicitly disclose wherein the reagent mixture includes LiOH and the pH of the reagent mixture is 6.5 and having trace amounts of LiOH in the reagent mixture.
However, Charter teaches assays for detecting ADP presence and formation (Col. 1, lines 24-25), and the ADP enzyme reagent includes PEP (Phosphoenolpyruvate), Pyruvate Kinase, Pyruvate Oxidase in sodium phosphate buffer at pH 7.0 (Col. 8, lines 26-38). The pH is conveniently about 7, but can be varied from 5-9 (Col. 7, lines 21-22). Thus, the pH value of the reagent is deemed to be a result-effective variable.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified Surridge, Steinman, Wang, and Berry by adjusting the pH value of the reagent mixture at the claimed value as suggested by Charter because the pH value of the reagent mixture is a result-effective variable and can be optimized through routine experimentation. MPEP 2144.05 (II)(B). Further, in the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists. In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990). MPEP 2144.05(I). Since the combined Surridge, Steinman, Wang, and Berry has a reagent mixture using lithium phosphate as its buffer, the reagent mixture would necessarily have Li+ and OH- in the acidic solution at a pH of 6.5, i.e., having trace amount of LiOH in the reagent mixture.
The designation “wherein LiOH is added to adjust the pH of the reagent mixture” is a product-by-process limitation. There is no apparent difference between the claimed test strip and the prior art as taught by Surridge in view of Steinman, Wang, Berry, and Charter. Even though product-by-process claims are limited by and defined by the process, determination of patentability is based on the product itself. The patentability of a product does not depend on its method of production. If the product in the product-by-process claim is the same as or obvious from a product of the prior art, the claim is unpatentable even though the prior product was made by a different process.” In re Thorpe, 777 F.2d 695, 698, 227 USPQ 964, 966 (Fed. Cir. 1985). MPEP 2113(I)
The preamble “for detecting potassium in a blood sample” is deemed to be a statement with regard to the intended use and are not further limiting in so far as the structure of the product is concerned. In article claims, a claimed intended use must result in a structural difference between the claimed invention and the prior art in order to patentably distinguish the claimed invention from the prior art. MPEP § 2111.02(II). The combined apparatus as taught by Surridge, Steinman, Wang, Berry, and Charter is identical to the presently claimed structure and would therefore would have the ability to perform the use recited in the claim.
The designation “configured to provide a signal indicating a level of potassium in the blood sample” for the reference electrode and the working electrode is deemed to be functional limitation in apparatus claims. MPEP 2114 (II). "[A]pparatus claims cover what a device is, not what a device does." Hewlett-Packard Co. v. Bausch & Lomb Inc., 909 F.2d 1464, 1469, 15 USPQ2d 1525, 1528 (Fed. Cir. 1990) (emphasis in original). A claim containing a "recitation with respect to the manner in which a claimed apparatus is intended to be employed does not differentiate the claimed apparatus from a prior art apparatus" if the prior art apparatus teaches all the structural limitations of the claim. Ex parte Masham, 2 USPQ2d 1647 (Bd. Pat. App. & Inter. 1987). Here, Surridge in view of Steinman, Wang, Berry, and Charter teaches all structural limitations of the presently claimed test strip (Surridge, claims 1-2, Fig. 1, 3, 5) and all components of the reagent mixture for measuring potassium levels in biological fluids (Steinman, ¶¶11, 32; Berry, Col. 7, lines 3-5) at an appropriate pH (Charter, Col. 7, lines 21-22), and thus the combined test strip having the reference electrode and the working electrode is capable of providing a signal indicating a level of potassium in the blood sample.
Regarding claim 5, Surridge in view of Steinman, Wang, Berry, and Charter discloses all limitations of claim 1, including that the analyte is pyruvate (Surridge, claim 6, line 4), and for detecting pyruvate, the enzyme is pyruvate oxidase (page 5, Table 1-continued). When the sample containing the analyte is contacted with the coating, the analyte, enzyme, and the mediator participate in a reaction, in which the analyte is oxidized and the mediator is reduced, producing a constant or “steady state” current between the electrodes that is measured and correlated to the amount of analyte in the sample (¶41). Thus, the combined Surridge and Steinman teaches the test strip detects potassium according to the equation:
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(Steinman, reaction I), and
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(Steinman, reaction II; Surridge, ¶41), wherein the reduced mediator represents a charge detectable by a meter (Surridge, page 4-5, Table 1; ¶41).
Further, the designation “wherein the test strip detects potassium according to the equation:
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wherein, the reduced mediator represents a charge detectable by a meter” is inherent to the claimed apparatus. The combined apparatus of Surridge, Steinman, Wang, Berry, and Charter teaches all structural limitations of the claimed test strip and all components of the reagent mixture for measuring potassium level, and thus is capable of detecting potassium according to the claimed reactions as disclosed by Steinman which result in a current, i.e., a charge detectable by a meter, due to the reduced mediator.
Regarding claim 6, Surridge teaches the mediator is 4-nitrosoaniline (page 4-5, Table 1: nitrosoanaline derivatives; ¶45: nitrosoanaline; as evidenced by Hoenes that the mediator is 4-nitrosoaniline (Hoenes, Col. 17, Table I, last line)).
Regarding claim 8, Surridge teaches the reagent mixture further includes polyethylene oxide (¶55: the binder can provide integrity of the coating, for example, polyethylene oxide) and Triton X-100 (¶104: the chemical coating was formulated from several sub-mixtures of components; e.g., Triton X-100).
Regarding claim 9, Surridge teaches the working electrode and the reference electrode are interdigitated (¶29: the micro-electrode can be arranged into an interdigitated array; Fig. 1: indicating the electrode structure, including the working electrode and the reference electrode, is interdigitated).
Regarding claim 21, Surridge teaches a test strip (claim 1, line 1: a disposable electrochemical sensor; ¶9: test strips), comprising:
a working electrode (claim 1, line 2: a working electrode; Fig. 1; ¶35: working electrode 2);
a reference electrode (claim 1, line 3: a reference electrode; Fig. 1; ¶35: counter electrode 4 that is deemed to be the reference electrode);
a testing area (claim 1, lines 3-4: a sample-receiving cavity; Fig. 3, 5; ¶62: capillary chamber 34), including the working electrode and the reference electrode (Fig. 3, 5: indicating the capillary chamber 34 includes the interdigitated electrodes 22 that includes the working electrode and the reference electrode);
a reagent mixture (claim 1, line 4: a reagent layer; Fig. 5; ¶63: a chemical coating 40), the reagent mixture deposited in association with one of the working electrode, the reference electrode, and the testing area (claim 1, lines 4-5: the reagent layer disposed within the sample-receiving cavity over at least the working electrode; Fig. 5: indicating the chemical coating 40 deposited on the array of interdigitated electrodes 22 inside the capillary chamber 34), the reagent mixture including a Mediator (claim 2, lines 1-2: the reagent layer further comprises an electron transfer mediator) and an oxidase (claim 1, lines 5-6: the reagent layer comprising an enzyme; claim 12, lines 1-2: the enzyme is glucose oxidase), wherein the mediator is nitrosoaniline (claim 4, line 2; ¶45), the reference electrode and the working electrode configured to provide a signal indicating a level of analyte in the blood sample (¶41: when the sample containing the analyte is contacted with the coating, the analyte, enzyme, and the mediator participate in a reaction, in which the analyte is oxidized and the mediator is reduced, producing a constant or “steady state” current between the electrodes that is measured and correlated to the amount of analyte in the sample; ¶3: examples of substances that may be analyzed include bodily fluids such as blood).
Surridge further discloses different enzymes that are reactive to different analytes, such as glucose oxidase to glucose, pyruvate oxidase to pyruvate (page 4-8, Table 1). Surridge does not explicitly disclose detecting potassium in a blood sample or the reagent mixture including Adenosine diphosphate (ADP), Phosphoenolpyruvate, Pyruvate Kinase, and the Oxidase is Pyruvate Oxidase.
However, Steinman teaches a method for measuring potassium levels in biological fluids, such as blood ([0001] line 1). The underlying enzyme reaction (Original document, page 1) is:
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Steinman teaches that pyruvate kinase requires the presence of potassium as a cofactor which much be activated and required for maximum function, and by using predetermined amounts of phosphoenolpyruvate (PEP), ADP, pyruvate kinase and magnesium and measuring the rate at which the products appear, one can determine the level of enzyme activity that is directly proportional to the potassium concentration (¶11). Thus, Steinman teaches the reagent mixture in example 2 includes ADP, PEP (i.e., Phosphoenolpyruvate), pyruvate kinase, and pyruvate oxidase (¶32).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified Surridge by substituting the components of the reagent mixture with one having ADP, PEP, pyruvate kinase, and pyruvate oxidase as taught by Steinman because use of these reagents for enzyme reactions to detect potassium concentration (Steinman, ¶11) is one of applications of Surridge’s electrochemical sensor to detect the presence or concentration of a selected analyte (Surridge, ¶4). Simple substitution of one known element, i.e., the reagent mixture, for another, i.e., the reagent components for detecting the potassium level, to obtain predictable results, i.e., to provide a signal indicating a level of potassium in the blood sample, is prima facie obvious. MPEP 2141(III)(B).
Further, the designation “derived from Bacillus stearothermophilus” for the Pyruvate Kinase is a product-by-process limitation. There is no apparent difference between the claimed test strip and the prior art as taught by Surridge in view of Steinman. Even though product-by-process claims are limited by and defined by the process, determination of patentability is based on the product itself. The patentability of a product does not depend on its method of production. If the product in the product-by-process claim is the same as or obvious from a product of the prior art, the claim is unpatentable even though the prior product was made by a different process.” In re Thorpe, 777 F.2d 695, 698, 227 USPQ 964, 966 (Fed. Cir. 1985). MPEP 2113(I).
Steinman further discloses magnesium acetate is used (¶23). Surridge and Steinman do not explicitly disclose using a phosphate buffer or Mg2+ is in the form of magnesium sulfate.
However, Wang teaches an electrochemical measurement of the NADH concentrations using square wave voltammetry in phosphate buffer solution (pH 7.2) (¶163). For TBI mode, the phosphate buffer contains magnesium sulfate, while for STI mode, the buffer contains magnesium acetate (¶258). Thus, Wang teaches Mg2+ in the buffer is selected from either magnesium sulfate or magnesium acetate.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified Surridge and Steinman by substituting the Tris-HCl buffer of Steinman with a phosphate buffer with magnesium sulfate as taught by Wang. The suggestion for doing so would have been that the phosphate buffer is a suitable buffer and magnesium sulfate is a suitable reagent for providing Mg2+ for electrochemical measurements by a biosensor and the selection of a known material, which is based upon its suitability for the intended use, is within the ambit of one of ordinary skill in the art. MPEP § 2144.07.
Surridge, Steinman, and Wang do not explicitly disclose the phosphate buffer is lithium phosphate to eliminate sodium interference while potassium is measured.
However, Berry teaches methods and reagents for the determination of ions (Col. 1, lines 10-11), for example, using an enzyme-mediated assay for measuring potassium ions employing pyruvate kinase (Col. 3, lines 2-4). Berry teaches, for determination of potassium ions, a buffered mixture containing ADP, PEP, reduced NADH, pyruvate kinase (PK), and LDH (Col. 7, ll. 49-53). Any buffer having a pK in the required pH range with negligible binding capacity for the measured ions or a negligible chloride concentration may be used (col. 12, ll. 33-35; col. 13, ll. 9-10). The use of pyruvate kinase to potassium ions is the overcoming of the interference by sodium and ammonium ions (Col. 6, lines 5-7). Inclusion of ions which are competitive inhibitors of the sensitive indicator enzyme in the assay, for example, the use of lithium ions to compete with sodium ions and potassium ions (Col. 6, lines 17-20). Since lithium ions are less effective as a competitor against potassium ions, the net effect is to increase the relative sensitivity of pyruvate kinase towards potassium ions a further (Col. 67, lines 22-25). This allows the possibility of measurement of the concentration of either potassium or sodium ions, provided that the concentration of the other ions is known (Col. 6, lines 28-30).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified Surridge, Steinman, and Wang by substitute the phosphate buffer with a lithium phosphate buffer including lithium ions for measurement of potassium ions as taught by Berry because lithium ions are less effective as a competitor against potassium ions for the net effect of further increasing the relative sensitivity of pyruvate kinase towards potassium ions (Col. 6, lines 22-25). Further, the designation “as a buffer to eliminate sodium interference while potassium is measured” is deemed to be functional limitation in apparatus claims. MPEP 2114 (II). "[A]pparatus claims cover what a device is, not what a device does." Hewlett-Packard Co. v. Bausch & Lomb Inc., 909 F.2d 1464, 1469, 15 USPQ2d 1525, 1528 (Fed. Cir. 1990) (emphasis in original). A claim containing a "recitation with respect to the manner in which a claimed apparatus is intended to be employed does not differentiate the claimed apparatus from a prior art apparatus" if the prior art apparatus teaches all the structural limitations of the claim. Ex parte Masham, 2 USPQ2d 1647 (Bd. Pat. App. & Inter. 1987). Here, Surridge in view of Steinman, Wang, and Berry teaches all structural limitations of the presently claimed test strip including all recited reagent components, which would necessarily result in lithium phosphate buffer that is capable of eliminating sodium interference while potassium is measured.
Surridge, Steinman, Wang, and Berry does not explicitly do not explicitly disclose wherein the pH of the reagent mixture is 6.5 and having trace amounts of LiOH in the reagent mixture.
However, Charter teaches assays for detecting ADP presence and formation (Col. 1, lines 24-25), and the ADP enzyme reagent includes PEP (Phosphoenolpyruvate), Pyruvate Kinase, Pyruvate Oxidase in sodium phosphate buffer at pH 7.0 (Col. 8, lines 26-38). The pH is conveniently about 7, but can be varied from 5-9 (Col. 7, lines 21-22). Thus, the pH value of the reagent is deemed to be a result-effective variable.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified Surridge, Steinman, Wang, and Berry by adjusting the pH value of the reagent mixture at the claimed value as suggested by Charter because the pH value of the reagent mixture is a result-effective variable and can be optimized through routine experimentation. MPEP 2144.05 (II)(B). Further, in the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists. In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990). MPEP 2144.05(I). Since the combined Surridge, Steinman, Wang, and Berry has a reagent mixture using lithium phosphate as its buffer, the reagent mixture would necessarily have Li+ and OH- in the acidic solution at a pH of 6.5, i.e., having trace amount of LiOH in the reagent mixture.
The designation “wherein LiOH is added to adjust the pH of the reagent mixture” is a product-by-process limitation. There is no apparent difference between the claimed test strip and the prior art as taught by Surridge in view of Steinman, Wang, Berry, and Charter. Even though product-by-process claims are limited by and defined by the process, determination of patentability is based on the product itself. The patentability of a product does not depend on its method of production. If the product in the product-by-process claim is the same as or obvious from a product of the prior art, the claim is unpatentable even though the prior product was made by a different process.” In re Thorpe, 777 F.2d 695, 698, 227 USPQ 964, 966 (Fed. Cir. 1985). MPEP 2113(I).
The preamble “for detecting potassium in a blood sample” is deemed to be a statement with regard to the intended use and are not further limiting in so far as the structure of the product is concerned. In article claims, a claimed intended use must result in a structural difference between the claimed invention and the prior art in order to patentably distinguish the claimed invention from the prior art. MPEP § 2111.02(II). The combined apparatus as taught by Surridge, Steinman, Wang, Berry, and Charter is identical to the presently claimed structure and would therefore would have the ability to perform the use recited in the claim.
The designation “configured to provide a signal indicating a level of potassium in the blood sample” for the reference electrode and the working electrode is deemed to be functional limitation in apparatus claims. MPEP 2114 (II). "[A]pparatus claims cover what a device is, not what a device does." Hewlett-Packard Co. v. Bausch & Lomb Inc., 909 F.2d 1464, 1469, 15 USPQ2d 1525, 1528 (Fed. Cir. 1990) (emphasis in original). A claim containing a "recitation with respect to the manner in which a claimed apparatus is intended to be employed does not differentiate the claimed apparatus from a prior art apparatus" if the prior art apparatus teaches all the structural limitations of the claim. Ex parte Masham, 2 USPQ2d 1647 (Bd. Pat. App. & Inter. 1987). Here, Surridge in view of Steinman, Wang, Berry, and Charter teaches all structural limitations of the presently claimed test strip (Surridge, claims 1-2, Fig. 1, 3, 5) and all components of the reagent mixture for measuring potassium levels in biological fluids (Steinman, ¶¶11, 32; Berry, Col. 7, lines 3-5) at an appropriate pH (Charter, Col. 7, lines 21-22), and thus the combined test strip having the reference electrode and the working electrode is capable of providing a signal indicating a level of potassium in the blood sample.
Regarding claim 22, Surridge, Steinman, Wang, Berry, and Charter disclose all limitations of claim 21, in which Steinman teaches the components of the reagent mixture, including ADP, PEP, pyruvate kinase, pyruvate oxidase, and Mg2+, phosphate (¶32).
Regarding claim 24, Surridge, Steinman, Wang, Berry, and Charter discloses all limitations of claim 21, including the reagent mixture including lithium (Berry, Col. 7, lines 3-5).
Response to Arguments
Applicant’s arguments have been considered but are unpersuasive.
Applicant argues the combination does not teach or suggest the recited structural limitation, i.e., the Pyruvate Kinase is “derived from Bacillus stearothermophilus” (Response, p. 6, section I). This argument is unpersuasive. The limitation “Pyruvate Kinase” is structural limitation that limits the composition of the reagent components, but the limitation “derived from Bacillus stearothermophilus” is product-by-process limitation for defining it’s source that Pyruvate Kinase is obtained. Even though product-by-process claims are limited by and defined by the process, determination of patentability is based on the product itself. The patentability of a product does not depend on its method of production. If the product in the product-by-process claim is the same as or obvious from a product of the prior art, the claim is unpatentable even though the prior product was made by a different process.” In re Thorpe, 777 F.2d 695, 698, 227 USPQ 964, 966 (Fed. Cir. 1985). MPEP 2113(I). Further, Applicant points out that Berry teaches pyruvate kinase from Bacillus stearothermophilus (p. 7, para. 3), and does not provide any evidence that the pyruvate kinase from Bacillus stearothermophilus cannot replace pyruvate kinase as disclosed in the art. Here, Applicant’s argument that pyruvate kinase from Bacillus stearothermophilus cannot be combined with nitrosoaniline as a mediator is merely a conclusory statement.
Applicant argues the combination of nitrosoaniline and pyruvate kinase from Bacillus stearothermophilus produces unexpected results (p. 7, section II). This argument is unpersuasive. The prior art does not teach away or discourage one of ordinary in the art to combine nitrosoaniline and pyruvate kinase from Bacillus stearothermophilus. The prior art, Surridge, explicitly discloses pyruvate kinase is one of the components in the reagents for detecting pyruvate, and nitrosoaniline is a suitable mediator (pp. 4-5: Table 1; ¶45). The instant application finds that the addition of lithium and the usage of pyruvate kinase from Bacillus stearothermophilus results in improved performance by the reduction of interference from sodium (Specification, PGpub ¶50), but fails to find that the result is unexpected or merely arisen from the use of pyruvate kinase from Bacillus stearothermophilus. Instead, the prior art, Berry, discloses that the use of lithium has a net effect is to increase the relative sensitivity of pyruvate kinase towards potassium ions a further (Berry, Col. 6, lines 22-25).
Applicant argues the limitation “lithium phosphate as a buffer to eliminate sodium interference while potassium is measured” is not a functional limitation (p. 8, section III). Examiner disagrees. Here, the limitation “lithium phosphate” is structural limitation that limits the composition of the reagent components, but the limitation “as a buffer to eliminate sodium interference while potassium is measured” is functional limitation in apparatus claims. MPEP 2114 (II). Here, Surridge in view of Steinman, Wang, and Berry teaches all structural limitations of the presently claimed test strip including all recited reagent components, which would necessarily result in lithium phosphate buffer that is capable of eliminating sodium interference while potassium is measured.
In response to applicant's argument that the examiner's conclusion of obviousness is based upon improper hindsight reasoning (p. 9, section IV), it must be recognized that any judgment on obviousness is in a sense necessarily a reconstruction based upon hindsight reasoning. But so long as it takes into account only knowledge which was within the level of ordinary skill at the time the claimed invention was made, and does not include knowledge gleaned only from the applicant's disclosure, such a reconstruction is proper. See In re McLaughlin, 443 F.2d 1392, 170 USPQ 209 (CCPA 1971). Applicant argues none of the cited references teaches or suggests the combination of Surridge and Steinman while using nitrosoaniline as the mediator (p 10, para. 2). This argument is unpersuasive. First, Applicant cannot show nonobviousness by attacking references individually where the rejections are based on combinations of references. Second, one of ordinary skill in the art would be motivated to combine Surridge and Steinman because Surridge explicitly disclose an electrochemical test strip for detecting Pyruvate using nitrosoaniline as the mediator (Surridge, pp. 4-5, Table 1, ¶45), and Steinman discloses detailed reagent composition for detecting Pyruvate. Further, there is no “teaching away” or discouragement for their combination as argued by Applicant.
Conclusion
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/C. SUN/Primary Examiner, Art Unit 1795
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