Alliance for Sustainable Energy, LLC et al.

Patent Trials and Appeals Board

Mar 1, 2022

2022000569 (P.T.A.B. Mar. 1, 2022)

UNITED STATES PATENT AND TRADEMARK OFFICE UNITED STATES DEPARTMENT OF COMMERCE United States Patent and Trademark Office Address: COMMISSIONER FOR PATENTS P.O. Box 1450 Alexandria, Virginia 22313-1450 www.uspto.gov APPLICATION NO. FILING DATE FIRST NAMED INVENTOR ATTORNEY DOCKET NO. CONFIRMATION NO. 15/818,450 11/20/2017 Paul Wayne KING NREL 15-86 6442 23712 7590 03/01/2022 Alliance for Sustainable Energy, LLC 15013 Denver West Parkway RSF-056 GOLDEN, CO 80401-3305 EXAMINER HOLLAND, PAUL J ART UNIT PAPER NUMBER 1656 NOTIFICATION DATE DELIVERY MODE 03/01/2022 ELECTRONIC Please find below and/or attached an Office communication concerning this application or proceeding. The time period for reply, if any, is set in the attached communication. Notice of the Office communication was sent electronically on above-indicated "Notification Date" to the following e-mail address(es): Nancy.Ronzone@nrel.gov Reina.Bernfeld@nrel.gov ipdocketing@nrel.gov PTOL-90A (Rev. 04/07) UNITED STATES PATENT AND TRADEMARK OFFICE ________________ BEFORE THE PATENT TRIAL AND APPEAL BOARD ________________ Ex parte PAUL WAYNE KING, KATHERINE ALICE BROWN, LANCE C. SEEFELDT, JOHN W. PETERS, and GORDANA DUKOVIC1, 2 ________________ Appeal 2022-000569 Application 15/818,450 Technology Center 1600 ________________ Before JOHN G. NEW, MICHAEL A. VALEK, and JAMIE T. WISZ, Administrative Patent Judges. NEW, Administrative Patent Judge. DECISION ON APPEAL 1 We use the term “Appellant” to refer to the “applicant” as defined in 37 C.F.R. § 1.142. Appellant identifies the Alliance for Sustainable Energy, LLC, Utah State University, Montana State University, and The Regents of the University of Colorado as the real parties-in-interest. App. Br. 2. 2 Oral argument was heard in this appeal on February 17, 2022. A transcript of the hearing will be entered into the record in due course. Appeal 2022-000569 Application 15/818,450 2 SUMMARY Appellant files this appeal under 35 U.S.C. § 134(a) from the Examiner’s Final Rejection of claims 1, 5, and 8-133 as unpatentable under 35 U.S.C. § 103 as being obvious over the combination of Maxwell (US 2015/0225742 Al, August 13, 2015) (“Maxwell”), C. Rong et al., Fabrication of Gold Nanoparticles with Different Morphologies in HEPES Buffer, 29(2) RARE METALS 180-86 (2010) (“Rong”), and I. Willner et al., Nanoparticle-Enzyme Hybrid Systems for Nanobiotechnology, 274 FEBS J. 302-09 (2007) (“Willner”). We have jurisdiction under 35 U.S.C. § 6(b). We AFFIRM. NATURE OF THE CLAIMED INVENTION Appellant’s claimed invention is directed to biohybrid protein complexes capable of using light energy to photocatalyze the reduction of N2 into NH3. Spec. Abstr. REPRESENTATIVE CLAIM Independent claim 1 is representative of the claims on appeal and recites: 3 We note that the Final Office Action, Appellant’s Brief, and the Examiner’s Answer each list claim 4 among the rejected claims. See Final Act. 3, App. Br. 5, Ans. 3. However, Appellant’s submitted Claims Appendix indicates that claim 4 is cancelled, as does the Advisory Action of December 14, 2020. See App. Br. 11, Adv. Act. 2. We consequently do not include claim 4 in our consideration of the claims on appeal. Appeal 2022-000569 Application 15/818,450 3 1. A biohybrid complex, comprising an electron donor consisting of HEPES, a photoactive CdS nanoparticle and an enzyme, wherein the photoactive nanoparticle, while being exposed to light having a wavelength of from 380 nm to 450 nm, produces electrons and the enzyme uses the electrons produced by the photoactive nanoparticle to catalyze an enzymatic reaction. App. Br. 11. ISSUE AND ANALYSIS For the reasons set forth below, we adopt the Examiner’s findings, reasoning, and conclusions that the claims are obvious over the cited prior art. We address Appellant’s arguments below. The Examiner’s Findings and Conclusions The Examiner finds that Maxwell teaches a biohybrid complex comprising a photoactive CdSe nanoparticle and an enzyme, in which the photoactive nanoparticle produces excited electrons when exposed to light and the enzyme uses the electrons produced by the photoactive nanoparticle to catalyze an enzymatic reaction. Final Act. 3 (citing Maxwell Abstr., ¶¶ 8-9, 51). The Examiner finds that Maxwell teaches the biohybrid complex further comprises an electron donor, dithionite (S2O42-). Id. (citing Maxwell ¶ 51). The Examiner also finds that Maxwell teaches exposing the nanoparticle to a halogen lamp, which emits a wavelength encompassing the claimed wavelength of light from about 380 to about 450 nm. Id. at 4 (citing Maxwell ¶¶ 78, 104, Fig. 6). With respect to Appellant’s claims 10-13, the Examiner acknowledges that Maxwell does not expressly teach the enzymatic reaction producing: (1) up to about 86 moles of NH3 per mole of MoFe protein per Appeal 2022-000569 Application 15/818,450 4 minute, as recited by claim 10; (2) up to 827 moles of H2 per mole of MoFe protein per minute, as recited by claim 11; (3) up to 12,000 moles of NH3 per mole of MoFe protein-1 per 300 minutes of exposure to light, as recited by claim 12; or up to 12,000 moles of H2 per mole of MoFe protein per 300 minutes of exposure to light, as recited by claim 13. Final Act. 4. However, the Examiner takes the position that, because Maxwell teaches an identical particle of identical structure to that recited in Appellant’s claims, the photoactive nanoparticle of Maxwell would have the capability of achieving the claimed amount of ammonia and hydrogen. Id. at 4-5 (citing, e.g., In re Best, 562 F.2d 1252, 1255 (C.C.P.A. 1977)). The Examiner finds that Rong teaches the formation of gold nanoparticles using HEPES buffer. Final Act. 5 (citing Rong Abstr.). The Examiner finds that Rong further teaches that, compared to ascorbic acid, HEPES buffer is a moderate reducing agent. Id. (citing Rong, 184). The Examiner finds that Willner teaches nanoparticle-enzyme hybrid systems comprising gold, CdSe, and CdS nanoparticles for development of photoreactive sensors for probing biocatalytic functions. Final Act. 5 (citing Willner Abstr., 306-07, Figs. 1-6). The Examiner concludes that it would have been obvious to a person of ordinary skill in the art to combine the teachings of Maxwell, Rong, and Willner to employ HEPES buffer as an electron donor, and to substitute a CdS nanoparticle for the CdSe nanoparticle taught by Maxwell. Final Act. 5. The Examiner reasons that a skilled artisan would have had a reasonable expectation of success, and would have been motivated to use HEPES buffer as an electron donor because Rong acknowledges that HEPES buffer can function as a moderate reducing agent. Id. at 5-6. The Examiner further Appeal 2022-000569 Application 15/818,450 5 concludes that a person of ordinary skill in the art would have a reasonable expectation of success in using a CdS nanoparticle in place of Maxwell’s CdSe nanoparticle, because Willner teaches that CdS nanoparticles are obvious variants of CdSe nanoparticles for photoactive biochemical sensors. Id. at 6. Issue Appellant argues that the Examiner erred because the level of unpredictability in the chemical arts is great, and that, consequently, a person of ordinary skill in the art would have had no reasonable expectation of success in combining the teachings of the cited references to arrive at Appellant’s claimed invention. App. Br. 6. Analysis Appellant argues that, generally, the level of unpredictability in the chemical arts is much greater than that in the mechanical arts, in which structures are usually interchangeable in different systems. App. Br. 6. Appellant argues that the art of its invention is in the fields of chemistry and biochemistry, and that exchanging one chemical element for another chemical element in a complex chemical reaction of substrates does not necessarily result in a predictable outcome. Id. Appellant disputes the Examiner’s finding that, because Maxwell teaches a particle of identical structure to the nanoparticle recited in Appellant’s claims, the photoactive nanoparticle of Maxwell would have the capability of achieving the claimed amount of ammonia and hydrogen. App. Br. 7. Appellant asserts that the Examiner has provided no support that the Appeal 2022-000569 Application 15/818,450 6 quantities of ammonia and hydrogen produced and claimed in Appellant’s invention in claims 10-13 are produced in any of the cited references. Id. Rather, Appellant contends, the Examiner makes a conclusory statement with no evidentiary support that the combination of the HEPES buffer, photoactive CdS nanoparticles and enzymes, as recited in the claims on appeal, would generate the ranges of ammonia and hydrogen that are generated by the Appellant’s biohybrid complex. Id. Appellant points out that CdSe, the photoactive nanoparticle taught by Maxwell, is a different chemical composition than CdS, the photoactive nanoparticle recited in Appellant’s claims. App. Br. 7. Appellant contends that the Examiner has not presented any evidence demonstrating that CdS and CdSe do not have different properties. Id. Furthermore, argues Appellant, the Examiner has not presented any evidence showing that CdSe, as taught by Maxwell, would interact with HEPES buffer in the same manner as Appellant’s CdS. Id. at 7-8. Appellant argues further that the Examiner relies upon Rong as teaching that HEPES buffer transfers electrons to HAuCl4. App. Br. 8. Appellant asserts that the Examiner is drawing a false equivalency as between CdS and HAuCl4, two different chemical compositions having different properties. Id. According to Appellant, the Examiner focuses on only a piece of Appellant’s claimed subject matter (viz., the transfer of electrons from HEPES buffer) and not on the claimed subject matter as a whole (viz., transfer of electrons from HEPES buffer to photoactive CdS nanoparticles in a biohybrid complex). Id. Appellant again emphasizes that CdS is chemically different from CdSe and from HAuCl4, all of which have different properties from one another. Id. Appeal 2022-000569 Application 15/818,450 7 Finally, Appellant argues, the Examiner relies upon Willner as teaching that CdSe and gold nanoparticles are useful in Willner’s biosensor systems. App. Br. 9. Appellant contends that the claims on appeal are directed to a biohybrid complex capable of generating amounts of ammonia and hydrogen. Id. (citing claims 10-13). Appellant argues that Willner does not disclose a biohybrid complex generating ammonia or hydrogen and, as such, does not cure the alleged deficiencies of Maxwell and Rong. Id. We are not persuaded by Appellant’s arguments. With respect to claim 1, Willner teaches CdS indirectly, via cytochrome c, transferring photaically-excited electrons to enzymes (lactose dehydrogenase or nitrogen reductase) to catalyze reactions. See Willner Figs. 6A, 6B. Willner does not teach the limitation of claim 1 reciting “an electron donor consisting of HEPES,” rather, the electron donor taught by Willner is a gold electrode linked to the CdS nanoparticle via a dithiol linker, and thiopyridine units. Id. at 306-07, Fig. 6. Willner teaches that “the transfer of electrons from the electrode to the valence-band of the [nanoparticles] restored the ground-state of the [nanoparticles].” Id. at 307. However, Rong expressly teaches that HEPES buffer is known in the art as a moderate reducing, i.e., electron-donating, agent. Rong, 184. We agree with the Examiner that a person of ordinary skill in the art would have found it obvious to use HEPES buffer as an electron donor in place of immobilizing the particles on a gold electrode via dithiol linker, and thiopyridine linkers, because HEPES buffer is known in the art, and can also be advantageously used to control the pH of the solution containing the nanoparticles. Appeal 2022-000569 Application 15/818,450 8 With respect to the dependent claims presently on appeal, claim 8 requires that the enzyme is a nitrogenase, and claim 9 requires that this nitrogenase is a MoFe protein. Appellant’s claims thus expressly define a MoFe protein as a species of nitrogenase. See also Spec. ¶ 6 (“In an embodiment, the enzyme is a nitrogenase. In an embodiment, the nitrogenase is MoFe protein”). Maxwell teaches the use of a NafY FeMo-co complex comprising a NafY protein and an iron-molybdenum cofactor (FeMo-co).4 Maxwell teaches that the iron-molybdenum cofactor is the most studied iron-sulfur cluster of its kind among the nitrogenases. Maxwell ¶ 34. FeMo-co catalyzes the energetically uphill reduction of nitrogen gas, considered inert, to form NH3 and hydrogen as a byproduct, thereby providing the major route by which nitrogen enters the biosphere. Id. Maxwell teaches: “FeMo-co … which is the catalytic cofactor found in the active site of the molybdenum- iron protein (MoFe protein) component of nitrogenase. The MoFe protein and Fe protein, also denoted as component I and component II, respectively, are the two proteins that comprise nitrogenase.” Id. at ¶ 35. Specifically, Maxwell expressly teaches that FeMo-co catalyzes the balanced reaction presented as Maxwell’s Equation 1: N2 + 8e- + 16 MgATP + 8H+ → 2NH3 + H2 + 16MgADP + 16P Id. Maxwell teaches that the NafY FeMo-co complex is associated in its invention with CdSe nanoparticles: 4 MoFe and FeMo-co are interchangeable terms. Appeal 2022-000569 Application 15/818,450 9 Toward the goal of developing a novel advanced material for photocatalytic H2 production, a complex containing FeMo-co and CdSe, a photoreductive nanoparticle is provided by the present disclosure. Such a CdSe.FeMo-co system is a passive way to produce hydrogen as an alternative fuel source. The CdSe.FeMo-co system could photocatalytically generate H2 is substantiated by the fact that CdSe nanoparticles are able to reduce methyl viologen (MV2+) by photoactivation. Maxwell ¶ 39. Maxwell thus expressly teaches the use of FeMo-co, which Appellant’s claim 9, and Appellant’s Specification, expressly define as a species of nitrogenase. Maxwell teaches the use of CdSe as its photoreductive nanoparticle, rather than the CdS nanoparticle recited in the claims. Willner, however, expressly teaches that CdSe and CdS are both photaically-excitable nanoparticles that can be used as high-energy electron donors when illuminated by appropriate wavelengths, and that such excited electrons (“excitons”) can be used to drive enzymatic catalyzation. See, e.g., Willner Figs. 5, 6. Indeed, Willner expressly teaches that “[t]he photocurrents generated by the biocatalytic cascades at various concentrations of the different substrates are depicted in Fig. 6C. These results show that the photoelectrochemical functions of semiconductor NPs [(nanoparticles, i.e., CdSe and CdS)] could be used to develop sensors for biocatalytic transformations.” Id. at 307-08. We agree with the Examiner that a person of ordinary skill in the art, upon comprehending the teachings of Willner, would have found it obvious to substitute CdS for Maxwell’s CdSe as the photoreductive nanoparticle in Maxwell’s CdSe.FeMo-co system. Appeal 2022-000569 Application 15/818,450 10 When there is a design need or market pressure to solve a problem and there are a finite number of identified, predictable solutions, a person of ordinary skill has good reason to pursue the known options within his or her technical grasp. If this leads to the anticipated success, it is likely the product not of innovation but of ordinary skill and common sense. In that instance the fact that a combination was obvious to try might show that it was obvious under § 103 KSR Int’l Co. v. Teleflex Inc., 550 U.S. 398, 421 (2007). Maxwell does not teach the limitation of claim 1 (and, by incorporation, the dependent claims) reciting “an electron donor consisting of HEPES.” Rather Maxwell teaches the use of dithionite (S2O42-) as an electron donor. Maxwell ¶ 51. Specifically, Maxwell teaches that “[t]he purpose of the dithionite in excess was twofold. It served to preserve the anaerobicity of the sample and was a sacrificial electron donor to fill the electron hole generated by exciton creation by light energy.” Id. (emphasis added). As we explained supra, HEPES buffer is well known in the art as being a moderate reducing agent, i.e., an electron donor. We agree with the Examiner that a person of ordinary skill in the art would have found it obvious to substitute HEPES buffer for the dithionite taught by Maxwell. KSR, 550 U.S. at 421. Dependent claims 10-13 recite functional limitations concerning the production of ammonia (NH3) and hydrogen gas (H2). Appellant argues that the Examiner has provided no support that the quantities of ammonia and hydrogen produced and claimed in Appellant’s invention in claims 10-13 are produced in any of the cited references. App. Br. 7. The Examiner responds that, given that the combination of Maxwell, Rong, and Willner renders the claimed invention obvious, the capability of the biohybrid Appeal 2022-000569 Application 15/818,450 11 complex to produce the claimed amount of ammonia and hydrogen would be a latent property that flows naturally from the teachings from the prior art. Ans. 8-9 (also citing In re Wiseman, 596 F.2d 1019, 1023 (C.C.P.A. 1979) (holding that an invention was obvious over the combined cited prior art even if it possesses an inherent, but hitherto unknown, function)). We are not persuaded by Appellant’s argument. Maxwell expressly teaches the production of hydrogen by its CdSe.FeMo-co system. Maxwell ¶¶ 116-20. We acknowledge that Maxwell does not expressly measure the production of ammonia, but Equation 1 of Maxwell states that the conversion of atmospheric nitrogen (N2) to hydrogen by FeMo-co also produces ammonia. Maxwell ¶ 35. Consequently, we conclude that Maxwell also teaches the production of ammonia as well as hydrogen. In sum, we find that the Examiner has met its burden to present a prima facie showing that claims 1, 5, and 8-13 are obvious over the cited combination of the references. Appellant makes no argument and adduces no evidence of secondary considerations of nonobviousness. We consequently affirm the Examiner’s rejection of claims 1, 5, and 8-13. CONCLUSION The rejection of claims 1, 5, and 8-13 as unpatentable under 35 U.S.C. § 103 is affirmed. No time period for taking any subsequent action in connection with this appeal may be extended under 37 C.F.R. § 1.136(a). See 37 C.F.R. § 1.136(a)(1)(iv) (2020). AFFIRMED Appeal 2022-000569 Application 15/818,450 12 Claim(s) Rejected 35 U.S.C. § Reference(s)/Basis Affirmed Reversed 1, 5, 8-13 103 Maxwell, Willner, Rong 1, 5, 8-13