DETAILED ACTION
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA . Applicant should note that the examiner assigned to this case has changed.
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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 9/11/2025 has been entered.
Response to Amendments
Applicant's amendments filed 9/11/2025 to claims 1, 36, 41, and 42 have been entered. Claims 2, 5, 6, 8, 11, 13-15, 18-25, 27, 29, 33-35, 38-40, 43, 44, 46, 52, 55, and 56 are canceled. Claims 1, 3, 4, 7, 9, 10, 12, 16, 17, 26, 28, 30-32, 36, 37, 41, 42, 45, 47-51, 53, 54, and 57 remain pending, and are being considered on their merits. No claims are withdrawn from consideration at this time. References not included with this Office action can be found in a prior action. Any rejections of record not particularly addressed below are withdrawn in light of the claim amendments and/or applicant’s comments.
Claim Rejections - 35 USC § 112
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 10 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.
The term “about” in claim 10 is a relative term which renders the claim indefinite. The term “about” is not defined by the claim, the specification does not provide a standard for ascertaining the requisite degree, and one of ordinary skill in the art would not be reasonably apprised of the scope of the invention. Correction is required.
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.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claims 1, 3, 4, 9, 10, 12, 28, 30-32, 36, 37, 41, 42, 45, 48-49, 50, 54, and 57 are rejected under 35 U.S.C. 103 as being unpatentable over Huemmerich et al. (Biochemistry (2004), 43, 13604-13612; provided in the IDS dated 1/30/2024) in view of Zhang et al. (Journal of Biomaterials Applications (2016), 31(3), 450-463; Reference U).
Huemmerich’s general disclosure relates to the production and purification of recombinant spider silk proteins in bacterial cells (see Abstract). Regarding claim 1s and 54, Huemmerich teaches providing a cell culture comprising host cell expressing recombinant spider silk proteins, collecting the recombinant spider silk proteins by sedimentation/precipitation, and adding the collected recombinant spider silk proteins to a solution containing a salt (guanidinium chloride) thereby solubilizing the recombinant spider silk proteins (see section titled “Experimental Procedures”, pg. 13605-13607). Regarding claim 28, Huemmerich teaches lysing the host cell by sonification (see subsection titled “Protein Purification”, pg. 13605-13606). Regarding claim 30, Huemmerich teaches the denatured silk proteins were precipitated and then harvested by centrifugation to obtain a cell lysate pellet (see subsection titled “Protein Purification”, pg. 13606). Regarding claims 31-32 and 37, Huemmerich teaches purification of the cell lysate pellets by dialysis (see subsection titled “Protein Purification”, pg. 13606-13607), thereby removing impurities and isolating the recombinant spider silk protein. Regarding claims 36, 41, and 42, Huemmerich teaches that 5/8 species of purified silk protein were not fragmented (Fig. 2A, and the paragraph spanning both columns on page 11608; with multiple bands indicative of fragmentation) Regarding claims 37 and 45, Huemmerich teaches and all of the species of purified silk protein were completely free of contaminating bacterial proteins (Fig. 2B and 2C, and the paragraph spanning both columns on page 11608). Regarding claims 48-49, Huemmerich teaches the cell culture comprises E. coli as host cells for silk protein gene expression (see subsection titled “Gene Expression”, pg. 13605). Regarding claim 50 and 57, Huemmerich teaches lyophilization or freeze drying of the silk proteins (see subsection titled “Protein Purification”, pg. 13607, left column, lines 1-2).
Regarding claims 1, 3, and 54, Huemmerich does not teach the embodiment of ethanol and 1-2M calcium chloride. Regarding claim 1 and 54, Huemmerich does not teach the claimed ranges of incubation time and temperature. Regarding claims 9 and 10, Huemmerich does not teach the insoluble portion being at least 5% or about 15% (w/v) of the solution volume. Regarding claim 12, Huemmerich does not teach wherein the ratio volume of the solution of the solution to the insoluble portion is least 3X.
Zhang teaches a method of purifying silk fibroin protein, the method comprising adding 4g degummed silk fibers to 20 ml Ajisawa’s reagent which comprises calcium chloride (CaCl2), ethanol (EtOH), and water in a 1:2:8 ratio and incubating the mixture for 80°C for two hours thus solubilizing the silk fibroin protein (page 451, “Preparation of aqueous silk solution”, and termed “silk-TS-4210”), reading on claim 1 and 3. For claims 9, 10, and 12, the combination of 4g degummed silk fibers to 20 ml Ajisawa’s reagent equates to 16.67% w/v of the insoluble silk fibers and wherein the solution volume being greater than 3X the insoluble portion, and so reads on these claims. Zhang teaches that the silk-TS-4210 product is cytocompatible as a substrate for mesenchymal stem cell culture (Abstract), reading on claims 1 and 3. Zhang teaches that reducing the incubation temperature from 80°C to 60°C reduced the right-shifted monomer peak and indicates reduced degradation of the silk protein product (Fig. 5b, and the paragraph spanning pages 458-459), reading in-part on the temperature range of claim 1.
Based on the following calculations, Zhang teaches a calcium chloride concentration that reads on claim 1:
1) 20 ml Ajisawa’s reagent = CaCl2:EtOH:water at 1:2:8 = 9.09% CaCl2 (i.e. 1 part out of 11) = 1.81 ml CaCl2;
2) 1.81 ml CaCl2 * 2.15 g/cm3 = 4.525 g CaCl2 (i.e. cm3 = ml);
3) 4.25 g CaCl2 * (1 mol ÷ 110.98) = 0.38295 mol CaCl2
4) (0.38295 mol CaCl2 ÷ 20 ml) * (1000 ml ÷ 1L) = 1.9147M CaCl2. (PubChem CID: 5284359 for density and molecular weight).
Regarding claims 1, 3, 9, 10, and 12, and 54, it would have been obvious to a person of ordinary skill in the art before the invention was filed to substitute the Ajisawa’s reagent and solubilization step at Zhang’s ratios and incubation time for the guanidinium chloride salt solubilization step of Huemmerich. A person of ordinary skill in the art would have had a reasonable expectation of success to do so because both Zhang and Huemmerich are both directed in-part towards methods of solubilizing silk proteins. The skilled artisan would have been motivated to do so because Zhang teaches that the silk-TS-4210 product (i.e. solubilized with Ajisawa’s reagent) is cytocompatible as a substrate for mesenchymal stem cell culture, and would thus predictably improve the properties of the silk protein composition of Huemmerich.
Regarding the temperature range of claim 1, optimization within prior art conditions or through routine experimentation will generally not support patentability absent a showing of criticality of the claimed range to the contrary. See M.P.E.P. § 2144.05, particularly subsections II and III. In this case, Zheng clearly teaches that a temperature of 60°C is effective to solubilize and obtain a silk protein product and teaches a known trend that reducing the incubation temperature generally reduces the degradation of and so improves the purity of the silk protein product. Thus, the burden is shifted back to establish criticality of the claimed temperature range by objective evidence.
Therefore, the invention as a whole would have been prima facie obvious to a person of ordinary skill before the invention was filed.
Claims 7, 16, 17, and 26 are rejected under 35 U.S.C. 103 as being unpatentable over Huemmerich and Zhang as applied to claims 1 and 3 above, and further in view of Dyakonov et al. (Journal of Drug Delivery (2012), Article ID 490514, 10 pages; provided in the IDS date 1/30/2024) and Osawa et al. (US 2015/0329587) .
The teachings of Huemmerich and Zhang are relied upon as set forth above. The teachings of Zhang above equating to 1.9147M CaCl2 reads in-part on the 2M CaCl2 concentration of claim 17 and 51. The teachings of Huemmerich above towards lyophilization reads on claim 53.
Regarding claim 7, Huemmerich and Zhang do not teach calcium nitrate. Regarding claims 16 and 17, Huemmerich and Zhang do not teach methanol. Regarding claim 17, Huemmerich and Zhang do not teach 2M calcium chloride. Regarding claim 26, Huemmerich and Zhang do not teach evaporating the alcohol.
Dyakonov’s general disclosure relates to spider and silk worm silk fibroin and preparation for controlled drug delivery systems (see Abstract and Introduction). Dyakonov teaches silk protein fibroin need to be dissolved for biomedical applications and teaches the use of neutral salt-alcohol systems are particularly useful since no degradation occurs (see page 3, right-hand column, para. 3). Regarding claims 7, 16, 17, Dyakonov teaches calcium nitrate as a salt and methanol as an alcohol are used together commonly or widely to dissolve silk fibroin or silk protein (see page 3, right-hand column, para. 3). Dyakonov teaches calcium chloride as a salt used in the dissolving or solubilizing solution (see Table 1), reading on claims 16 and 17. Regarding claim 17, Dyakonov teaches the silk fibroin is dissolved in a triad solvent of CaCl2:EtOH:H2O with a molar ratio 1:2:8, at a concentration of 14.4% (w/w) (see page 2, right-hand column, para. 3). Regarding claim 26, Dyakonov teaches evaporating the liquids of the solution which includes alcohol (see page 3, left-hand column, para. 1).
Regarding claim 17, Osawa is drawn to methods of extracting and solubilizing recombinant spider silk proteins, and Osawa teaches such methods utilize a solubilizing solution comprising a combination of inorganic salts and alcohol, with a preferred salt being CaCl2 at a concentration of at least 0.1 M but not more than 2.5 M, and that said amount of salt is result effective for increasing the purity of the recombinant protein (see paragraphs [0004]-[0007], [0026]-[0027] and [0030]).
Regarding claim 7, a person of ordinary skill in the art would have had a reasonable expectation of success in substituting the calcium nitrate of Dyakonov for the guanidinium chloride of Heummerich because calcium nitrate and guanidinium chloride are both explicitly taught as being useful for THE SAME PURPOSE as solubilizing agents for silk proteins. Therefore, these compositions are functional equivalents in the art, and substituting one for the other would have been obvious at the time of the invention. “When a patent ‘simply arranges old elements with each performing the same function it had been known to perform’ and yields no more than one would expect from such an arrangement, the combination is obvious.” See KSR International Co. v. Teleflex Inc., 82 USPQ2d 1385 (U.S. 2007) at 1395-1396, quoting Sakraida v. AG Pro, Inc., 425 U.S. 273 (1976) and In re Fout, 675 F.2d 297, 301 (CCPA 1982) (“Express suggestion to substitute one equivalent for another need not be present to render such substitution obvious”).
Regarding the methanol of claims 16 and 17, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to add the methanol of Dyakonov into the method for producing recombinant spider silk protein as taught Huemmerich in view of Zhang. A person of ordinary skill in the art would have had a reasonable expectation of success to do so because both Dyakonov, Zhang, and Huemmerich are both directed in-part towards methods of solubilizing silk proteins. The ordinary artisan would have been motivated to do so because Dyakonov teaches the use of neutral salt-alcohol systems such as methanol with calcium chloride are particularly useful since no degradation occurs (see page 3, right-hand column, para. 3), and so the addition would predictably improve upon the methods of Huemmerich.
Regarding the calcium chloride concentration of claim 17, It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to further substitute the 2.0 M calcium salt as taught by Osawa in the method of Huemmerich in view of Zhang and Dyakonov for producing recombinant spider silk protein. The ordinary artisan would have been motivated to do so because Dyakonov teaches the use of neutral salt-alcohol systems such as methanol and calcium chloride are particularly useful since no degradation occurs, Osawa teaches that 0.1 M to 2.5 M calcium salt is useful in such solubilizing solution for spider silk protein to increase purity, and that the amount within that range is result effective for increasing the purity of the recombinant protein and thus would predictably improve upon the methods of Huemmerich.
Therefore, the invention as a whole would have been prima facie obvious to a person of ordinary skill before the invention was filed.
Claim 47 is rejected under 35 U.S.C. 103 as being unpatentable over Huemmerich and Zhang as applied to claims 1 and 37 above, and further in view of Turner (WO 2015/042164 A2).
The teachings of Huemmerich and Zhang are relied upon as set forth above.
Regarding claim 47, Huemmerich and Zhang do not the embodiment of SEQ ID NO: 1.
Turner’s general disclosure relates to methods and compositions for synthesizing improved silk fibers from recombinant microorganisms (see Abstract). Regarding claim 47, Turner teaches SEQ ID NO: 1077 as the repetitive polypeptide sequence in a spider’s silk polypeptide (see para. [0098]). SEQ ID NO: 1077 has 100% identity to SEQ ID NO: 1; therefore, Turner teaches the recombinant spider silk protein of this application. See appendix below for alignment.
Regarding claim 47, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to substitute the recombinant spider silk protein taught by Turner as SEQ ID NO: 1 for one or any of the recombinant silk protein the method of Huemmerich. A person of ordinary skill in the art would have had a reasonable expectation of success to do so because both Turner and Huemmerich are both directed in-part towards methods of recombinantly expressing silk proteins. The ordinary artisan would have been motivated to do so because Turner teaches SEQ ID NO: 1077 as a repetitive polypeptide sequence which contains the crystalline and amorphous regions that confer strength and flexibility to the silk fiber (see para. [0004] and [0098]), and so the substitution would be predictably advantageous in the methods of Huemmerich. Therefore, selection of the sequence for the method of Huemmerich, Dyakonov and Osawa would be considered advantageous as provided by the teachings of Turner.
Therefore, the invention as a whole would have been prima facie obvious to a person of ordinary skill before the invention was filed.
Claims 51 and 53 are rejected under 35 U.S.C. 103 as being unpatentable over Huemmerich et al. (Biochemistry (2004), 43, 13604-13612; provided in the IDS dated 1/30/2024)in view of Osawa et al (US 20150329587).
Huemmerich’s general disclosure relates to the production and purification of recombinant spider silk proteins in bacterial cells (see Abstract). Regarding claim 51, Huemmerich teaches providing a cell culture comprising host cell expressing recombinant spider silk proteins, collecting the recombinant spider silk proteins by sedimentation/precipitation, and adding the collected recombinant spider silk proteins to a solution containing a salt thereby solubilizing the recombinant spider silk proteins (see section titled “Experimental Procedures”, pg. 13605-13607). Huemmerich teaches purification of the cell lysate pellets by dialysis (see subsection titled “Protein Purification”, pg. 13606-13607), thereby removing impurities and isolating the recombinant spider silk protein. Regarding claims 53, Huemmerich teaches lyophilization or freeze drying of the silk proteins (see subsection titled “Protein Purification”, pg. 13607, left column, lines 1-2).
Regarding claim 51, Huemmerich does not teach: the solution containing calcium chloride and methanol.
Regarding claim 51, Osawa is drawn to methods of extracting and solubilizing recombinant spider silk proteins, and Osawa teaches such methods utilize a solubilizing solution comprising a combination of inorganic salts and alcohol, with a preferred alcohol being methanol and a preferred salt being CaCl2 at a concentration of at least 0.1 M but not more than 2.5 M, and that said amount of salt is result effective for increasing the purity of the recombinant protein (see paragraphs [0004]-[0007], [0026]-[0027], [0030], and [0032]-[0033]).
Regarding the methanol of claim 51, "It is prima facie obvious to combine two compositions each of which is taught by the prior art to be useful for the same purpose, in order to form a third composition to be used for the very same purpose.... [T]he idea of combining them flows logically from their having been individually taught in the prior art." In re Kerkhoven, 626 F.2d 846, 850, 205 USPQ 1069, 1072 (CCPA 1980) (citations omitted). See M.P.E.P. § 2144.06. In this case, both guanidinium chloride and methanol are taught as useful in methods of obtaining recombinant silk proteins by Huemmerich and Osawa, respectively, and so their combination must be held as prima facie obvious absent any persuasive showing of nonobviousness to the contrary.
Regarding the calcium chloride of claim 51, a person of ordinary skill in the art would have had a reasonable expectation of success to further substitute the 1-2M calcium chloride of Osawa for the guanidinium chloride of Huemmerich because guanidinium chloride and calcium chloride are both explicitly taught as being useful for THE SAME PURPOSE of solubilizing recombinant silk proteins. Therefore, these compositions are functional equivalents in the art, and substituting one for the other would have been obvious at the time of the invention and in the absence of any persuasive showing of nonobviousness to the contrary. “When a patent ‘simply arranges old elements with each performing the same function it had been known to perform’ and yields no more than one would expect from such an arrangement, the combination is obvious.” See KSR International Co. v. Teleflex Inc., 82 USPQ2d 1385 (U.S. 2007) at 1395-1396, quoting Sakraida v. AG Pro, Inc., 425 U.S. 273 (1976) and In re Fout, 675 F.2d 297, 301 (CCPA 1982) (“Express suggestion to substitute one equivalent for another need not be present to render such substitution obvious”).
Therefore, the invention as a whole would have been prima facie obvious to a person of ordinary skill before the invention was filed.
Claims 54 and 57 are rejected under 35 U.S.C. 102(a)(a) as anticipated by or, in the alternative, under 35 U.S.C. 103 as obvious over Huemmerich et al. (Biochemistry (2004), 43, 13604-13612; provided in the IDS dated 1/30/2024)
Huemmerich’s general disclosure relates to the production and purification of recombinant spider silk proteins in bacterial cells (see Abstract). Huemmerich teaches providing a cell culture comprising host cell expressing recombinant spider silk proteins, collecting the recombinant spider silk proteins by sedimentation/precipitation, and adding the collected recombinant spider silk proteins to a solution containing a salt (guanidinium chloride) thereby solubilizing the recombinant spider silk proteins (see section titled “Experimental Procedures”, pg. 13605-13607), anticipating or reading on claim 54. Huemmerich teaches lyophilization or freeze drying of the silk proteins (see subsection titled “Protein Purification”, pg. 13607, left column, lines 1-2), anticipating or reading on claim 57..
Claims 54 and 57 are product-by-process claims. See M.P.E.P. § 2113; product-by-process claims are not limited to the manipulations of the recited steps, only the structure implied by the steps. Furthermore, alternate grounds of rejection under both 102 and 103 is permissible given the lack of physical description of product-by-process claims and the inability of the USPTO to manufacture and compare products. See M.P.E.P. § 2113 (III). Once a product appearing to be substantially identical is found and an art rejection made, the burden shifts to the applicant to show an unobvious difference. In this case, Huemmerich teaches a substantial identical recombinant spider silk proteins but produced by a different of method of solubilization with guanidinium chloride. Therefore, the burden is shifted to Applicant to show that the manufacturing process steps of the product-by-process claims impart any novel and/or non-obvious structural characteristics to the claimed product as compared to the composition taught by Huemmerich Particularly, if the product-by process limitations of claims 54 and 57 impart no structural difference then the claims are anticipated. If the product-by process limitations of claim 13 impart a structural difference, then Applicant must clearly set forth why any structural difference between the claimed composition and the composition of Huemmerich is non-obvious.
Therefore, the invention as a whole would have been prima facie obvious to a person of ordinary skill before the invention was filed.
Response to Arguments
Applicant's arguments on pages 6-12 of the reply have been fully considered, but not found persuasive of error. Applicant’s arguments regarding Dyakonov and Osawa on pages 8-10 of the reply regarding claim 1 are moot as Zhang has replaced these references with respect to the 35 U.S.C. § 103 rejection of independent claim 1. Similarly, Applicant’s arguments regarding Kotaka on pages 10-11 of the reply are moot as Kotaka was not applied against independent claim 1 in the last Office Action and is no longer applied against any of the claims at this time. Additional teachings of Huemmerich are cited above to fully address dependent claims 36, 37, 41, 42, and 45.
Applicants rely on arguments traversing the above rejection of claim 1 to traverse the rejection of claim 47 further in view of Turner on page 11 of the reply. Therefore, the response set forth above to arguments also applies to this rejection.
Applicant’s argument regarding the rejection of claims 51 and 53 over Heummerich and Osawa are not found persuasive over the modified grounds of rejection set forth above. Applicant’s allegation that Osawa is “unsuitable” for extracting recombinant protein from a host is not persuasive of error as Applicant has not cited any portion of Osawa substantiating the allegation, and is directly contradicted by Osawa at [0032]-[0033] in that methanol removes contaminating host cell proteins from the cell lysate.
Conclusion
No claims are allowed. No claims are free of the art.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to SEAN C BARRON whose telephone number is (571)270-5111. The examiner can normally be reached 7:30am-3:30pm EDT/EST (M-F).
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/Sean C. Barron/Primary Examiner, Art Unit 1653
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