DETAILED ACTION
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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 4/8/26 has been entered.
Claim Rejections - 35 USC § 112
The following is a quotation of the first paragraph of 35 U.S.C. 112(a):
(a) IN GENERAL.—The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor or joint inventor of carrying out the invention.
The following is a quotation of the first paragraph of pre-AIA 35 U.S.C. 112:
The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor of carrying out his invention.
Claim 42 is rejected under 35 U.S.C. 112(a) or 35 U.S.C. 112 (pre-AIA ), first paragraph, as failing to comply with the written description requirement. The claim(s) contains subject matter which was not described in the specification in such a way as to reasonably convey to one skilled in the relevant art that the inventor or a joint inventor, or for applications subject to pre-AIA 35 U.S.C. 112, the inventor(s), at the time the application was filed, had possession of the claimed invention.
As to claim 42, the claim recites that “the first layer consists of the copolymer”. The closed transitional phrase excludes any unrecited components from the first layer. The closest the specifications gets is a teaching that “the membranes comprises from about 1% to about 100% of a polyurethane or a copolymer thereof” ([0125]). There is no description of a first layer from which all other potential components are excluded.
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claim 41 is rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
As to claim 41, the claim recites “wherein the first layer does not require a crosslinker”. It’s not clear whether this limitation expressly and affirmatively excludes a crosslinker from the first layer or whether the presence of a crosslinker is merely optional in its formation/constitution. For purposes of examining, the limitation is treated as requiring only that the first layer be formable without a crosslinker, and a first layer that in fact contains a crosslinker would nonetheless satisfy the recitation. Applicant is advised to amend the claim to recite (e.g. “wherein the first layer is free of a crosslinker”) if the exclusion is intended but may lack written description support.
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
Claim(s) 1-4, 24-25, and 40-45 is/are rejected under 35 U.S.C. 103 as being unpatentable over Chen et al. (US 2019/0320947) in view of Tseng (“Fabrication of Implantable, Enzyme-Immobilized Glutamate Sensors for the Monitoring of Glutamate Concentration Changes in Vitro and in Vivo”) and Zhang (US 2013/0126349).
As to claim 1, Chen teaches an analyte sensor for detecting analytes in vivo (Abstract), the sensor comprising at least a first working electrode ([0044]), an analyte-responsive active area (218) disposed upon a surface of the first working electrode (214) ([0045]), wherein the active area comprises an enzyme ([0060]) and an electron transfer agent ([0066]), a multi-layered mass transport limiting membrane permeable to the analyte that overcoats at least a portion of the analyte-responsive active area, the multi-layered mass transport limiting membrane comprising first and second layers ([0071] – mass transport limiting membrane may be multi-component in a bilayer configuration), wherein the first layer is disposed over the active area and the second layer is disposed over the first layer ([0072] – “the first layer may be disposed directly upon the active area, and second layer may be disposed upon the first layer”), the second layer comprising polyvinylpyridine or a copolymer thereof; or polyvinylimidazole or a copolymer thereof ([0071] – crosslinked polyvinylpyridine copolymer), and wherein the sensor is configured to be partially inserted into a user's skin such that a distal portion of the sensor is in contact with an interstitial fluid to detect the analyte in vivo ([0039]).
Chen fails to expressly teach an analyte sensor for detecting glutamate in vivo and a glutamate-responsive active area comprising glutamate oxidase. Tseng teaches an analyte sensor for detecting glutamate in vivo comprising a glutamate responsive active area disposed upon a working electrode, the active area comprising glutamate oxidase (p7350, p7352). It would have been obvious to modify Chen with Tseng to allow the monitoring of glutamate.
The above combination fails to expressly teach that the first layer comprises a copolymer of polyurethane and a second polymer, wherein the second polymer is selected from the group consisting of a polyether, a polyester, a polyalkene, a polyamine, and a polyalkylene oxide. Zhang teaches a selectively permeable membrane for biosensors including a polyether-based thermoplastic polyurethane copolymer ([0066]), wherein the polyurethane copolymer’s hydrophilic block comprises polyalkylene oxide ([0072]), with the membrane capable of regulating flux of various molecules ([0081]). It would have been obvious to modify the above combination further with Zhang as it would be obvious to substitute for a known polymer material that’s capable of performing as a mass transport limiting membrane.
As to claim 2, Chen teaches the active area further comprises a polymer, and wherein the enzyme, the electron transfer agent, or both, are crosslinked with the polymer ([0071]).
As to claim 3, Chen teaches the active area further comprises a stabilizer ([0044]).
As to claim 4, Chen teaches the stabilizer comprises an albumin ([0044]).
As to claim 24, Chen teaches the layer comprises a crosslinker ([0271]).
As to claim 25, Chen teaches the second layer comprises polyvinylpyridine-co-styrene ([0137]).
As to claim 40, Zhang teaches the second polymer is polyether ([0066] – polyether-based polyurethane copolymer).
As to claim 41, Zhang teaches the first layer does not require a crosslinker ([0066] – using a polymer mixture to produce a solvent cast film, which is a process for forming via solvent evaporation rather than by chemical crosslinking). It would have been obvious to modify the above combination further with Zhang to utilize a solvent cast film process to produce the membrane, negating the need for a crosswalker as it would be an obvious substitution yielding equivalent results.
As to claim 42, Zhang teaches the first layer consists of the copolymer as it teaches membranes formed of the polyether-based thermoplastic polyurethane copolymers ([0066-67]). It would have been obvious to form the first layer of the modified Chen sensor from the polyurethane copolymer alone, as Zhang teaches that this is capable of performing the flux-limiting function alone, and using a single polymer in a layer is the simplest implementation possible.
As to claim 43, Zhang teaches the second polymer is polyether ([0066] – polyether-based polyurethane copolymer).
As to claim 44, Chen teaches the second layer comprises polyvinylpyridine or a copolymer thereof ([0071]).
As to claim 45, Chen teaches the second layer comprises polyvinylpyridine or polyvinylpyridine-co-styrene ([0071]).
Claim(s) 23 is/are rejected under 35 U.S.C. 103 as being unpatentable over Chen et al. (US 2019/0320947), Tseng (“Fabrication of Implantable, Enzyme-Immobilized Glutamate Sensors for the Monitoring of Glutamate Concentration Changes in Vitro and in Vivo”), and Zhang (US 2013/0126349), and further in view of Tapsak (US 2003/0217966).
As to claim 23, the above combination fails to expressly teach that the first layer is capable of absorbing from about 30% to about 70% of its weight in water. Tapsak teaches that hydrophilic polyurethanes, used as flux controlling membranes, can be synthesized with the ability to absorb up to 50% of its dry weight of water ([0006]). Accordingly it would have been obvious to modify the above combination with Tapsak to ensure that the resulting membrane is sufficiently capable of absorbing enough water to allow the passage of analytes through the system.
Claim(s) 26 is/are rejected under 35 U.S.C. 103 as being unpatentable over Chen et al. (US 2019/0320947), Tseng (“Fabrication of Implantable, Enzyme-Immobilized Glutamate Sensors for the Monitoring of Glutamate Concentration Changes in Vitro and in Vivo”), and Zhang (US 2013/0126349), and further in view of Pestice et al. (US 2009/0143658).
As to claim 26, while Chen teaches that the active area (618) may be up to about 10 µm ([0067]), along with a bilayer membrane (Fig. 14 – 621a and 621b) which appears to be roughly double the thickness of the active area, it does not necessarily teach that layers are within the recited thickness. Pestice teaches electrochemical sensors with multiple membrane layers, including an interference layer which may be around 20 microns ([0072]) as well as flux limiting membranes which can also be around 20 microns ([0084]). Accordingly, it would have been obvious to modify the above combination with Pestice to explicitly use layers of the recited thickness as it would have been obvious to try in view of what has been taught within Chen as well as explicitly disclosed within Pestice.
Response to Arguments
Applicant's arguments filed 4/8/26 have been fully considered but they are not persuasive.
Applicant has argued that the combined references fail to disclose the multi-layered membrane as recited. However, this argument is no longer applicable, in view of the reinterpretation of the Chen reference. Chen now expressly teaches the claimed arrangement: a bilayer mass transport limiting membrane in which the first layer is disposed directly upon the active area, and the second area disposed upon the first area ([0072]), second layer comprising polyvinylpyridine or a copolymer thereof; or polyvinylimidazole or a copolymer thereof ([0071] – crosslinked polyvinylpyridine copolymer). What remained was only the selection of a particular polymer for the inner layer and thus no longer rests on just the combination of polymers, but on an express prior-art teaching of the structural arrangement of the polymers.
In addition, applicant has argued that the applied references do not teach or suggest that a multi-layered membrane is suitable for a glutamate sensor. The test for obviousness is not whether the references expressly suggest the combination for glutamate, but what the combined teachings would have suggested to one of ordinary skill in the art (In re Keller, 642 F. 2d 413 (CCPA 1981)). Chen teaches that its sensor platform for broad use for detection of analytes in various interstitial settings ([0039]). Tseng teaches the monitoring of glutamate in vivo (Abstract) in which the enzyme is stabilized with albumin (p7342). There is nothing within the teachings of which would suggest the combination would fail to function in the detection of glutamate.
Similarly, applicant’s argument with respect to alleged unexpected results is not persuasive for several reasons.
First, the arguments are not commensurate in scope with the recited claims. The data of Fig. 13 is limited to a membrane of PU polymer HydroMed D1 that’s paired with 10Q5 or PVP and with a specified thickness and water absorption capacity ([0181-0184]). In contrast, claim 1 recites a first layer in which a copolymer of polyurethane is combined with ANY of a polyether, polyester, polyalkene, polyamine, and a polyalkylene oxide, and a second layer of ANY polyvinylpyridine or polyvinylmidazole or a copolymer thereof, at any thickness and any water uptake. Objective evidence of nonobviousness must be commensurate in scope with the claims which the evidence is offered to support (MPEP 716.02(d)).
Second, the applicant compares the specified membrane against a sensor having “only a polyurethane-based membrane”. The closest prior art is Chen’s bilayer membrane, and not any single-component membrane. No comparison against a Chen-type bilayer has been provided. (MPEP 716.02(e)).
Third, the asserted result is expressly taught by the closest prior art. Applicant states that they had “surprisingly found” that the composite multi-layered membrane was operationally stable with sufficient sensitivity over a range of analyte concentrations. Chen similarly notes that the use of a “bilayer construct surprisingly afforded a stable current response over time at an acceptable level of sensitivity, even though neither polymer provided acceptable performance alone” ([0136]). Similarly, Chen notes that the use of the membrane can be characterized functionally as having a response stability that varies by about 1% or less over 190 hours of measurement ([0070]), which is in range with the under 4% and 2% loss in sensitivity over a 14 day period observed by the applicant. A result that the prior art itself teaches and relies upon cannot be unexpected (MPEP 716.02(a)).
Any inquiry concerning this communication or earlier communications from the examiner should be directed to CHRISTIAN JANG whose telephone number is (571)270-3820. The examiner can normally be reached Monday-Friday (7-3:30 EST).
Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice.
If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Robert Chen can be reached at 571-272-3672. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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CHRISTIAN JANG
Primary Examiner
Art Unit 3791
/CHRISTIAN JANG/Primary Examiner, Art Unit 3791 9/19/26
