DETAILED ACTION
Status of Application
The amendments and response filed 23 June 2026 are acknowledged and have been considered in their entireties. Claim 17 is new, thus, claims 1-17 are pending and subject to examination on the merits.
Withdrawal of Previous Objections/Rejections
The objection to claims 12-13 for minor typographical errors (repeating “that” twice) is withdrawn in view of the amendments to the claims.
The rejection of claim 8 under 35 U.S.C. 112(b) as being indefinite for recitation of percentage with out a clear value as to what the percentage is directed is withdrawn in view of the amendments to recite percentage by mass.
Maintained Rejection
Claim Rejections - 35 USC § 102
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention.
(a)(2) the claimed invention was described in a patent issued under section 151, or in an application for patent published or deemed published under section 122(b), in which the patent or application, as the case may be, names another inventor and was effectively filed before the effective filing date of the claimed invention.
Claim(s) 1-5, 9-16 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Kim et al. (BMB Reports, 2009 – cited on IDS 04/26/2024).
Kim et al. teach:
Regarding claims 1-5, 9-16, a method of generating a silk fibroin solution comprising (See Materials and Methods, Silk Powder, p. 54):
providing a raw silk;
degumming twice by adding Marseilles soap (0.5% of weight of fiber) and sodium carbonate (0.3% of weight of fibroin), at a temperature of 100oC for 1 hour, to separate fibroin from the secondary constituent of sericin;
washing the sericin-free solution with distilled water;
lowering the pH by adding 6M HCl and incubating for 5 hours;
raising the pH by adding NaOH;
desalting by electrodialysis.
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) 6-8 are rejected under 35 U.S.C. 103 as being unpatentable over Kim et al. (BMB Reports, 2009 – cited on IDS 04/26/2024) as applied to claims 1-6, 9-16 above, and further in view of Bressner & Tilburey (US 20160215030 – cited herein).
The teachings of Kim et al. are discussed above and incorporated into the instant rejection its entirety.
Kim et al., however, do not teach a conductivity value (e.g. measure of salt) of a salt value of at most 1000, 750, 500 or 250 μS/cm in the fibroin solution (claim 6), nor a concentration step that employs an “overpressure” of the silk fibroin solution, resulting in a concentration of at least 3%, 10%, 20% or 30% is achieved (claims 7-8).
Bressner & Tilburey teach methods of degumming silk fibroin solution to remove sericin from the fibroin, followed by solubilization and a concentration/desalting step which employs diafiltration e.g. a procedure that utilizes pressure rather than passive dialysis – See paragraph 0007. It is specifically taught:
[0028] The silk fibroin solution is isolated from the solubilization agent via the final step of the process, purification. This step may be referred to as desalination, in consideration that the vast majority of practitioners employ a salt to solubilize silk fibroin. However, the same procedure is equally applicable when alternate non-salt molecules are utilized.
[0029] In the present invention, diafiltration, desalting columns or any combination thereof serve as purification techniques through which a solubilization agent can be removed from the solubilized silk fibroin solution. Tangential flow filtration (TFF) is one technique that applies diafiltration in the removal of the solubilization agent; said agent is eliminated in the filtrate, which is known equivalently as the permeate. In the TFF process, the presence of a concentrating step requires that the original input solution, containing both solubilization agent and solubilized silk fibroin, first be diluted to an acceptable viscosity for suitable input into the TFF system. Passing through the system, the resulting permeate contains water as well as the solubilization agent; the retentate contains an increasingly purified regenerated silk fibroin solution which has been both concentrated and desalted within a single technique.
The resultant concentration of the step is that the fibroin possesses a concentration of 5, 10, 15 or 20 wt % (See claims 13-16) and a salt concentration of less than 1 Siemen or less than 100 microSiemen (See claims 17-18).
Therefore, it would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to substitute the electrodialysis last step of Kim et al. with the diafiltration step/TFF step of Bressner & Tilburey because Bressner & Tilburey teach the advantages diafiltration step/TFF step in silk fibroin degumming and purification, e.g. “the retentate contains an increasingly purified regenerated silk fibroin solution which has been both concentrated and desalted within a single technique” – paragraph 0029. Furthermore, the concentration step results in concentrations of at least 5, 10, 15 or 20 wt % or greater. Thus, this would be motivation in and of itself for one skilled in the art because it streamlines (e.g. less steps because you don’t need a desalting AND a concentration step) the process while producing seemingly better results. One skilled in the art would have a reasonable expectation of success in substituting the electrodialysis step of Kim et al. with the diafiltration/TFF concentration + desalting step of Bressner & Tilburey because both methods are for degumming silk fibroin with various steps and successfully and ultimately desalting and concentrating, so there would be no unpredictable outcome in making such a substitution given the specific teachings of both.
Applicant’s Remarks and Examiner’s Rebuttal:
Applicant’s traverse the rejection and state it is entirely unclear how the steps of Kim et al. anticipate the limitations of the instant claims and how they compare to they map and compare to the instant claims, especially given the specific indicated order.
The Examiner’s position is that the specific order and steps were sufficiently clear but to address Applicant’s concerns, the following is provided as to how the Examiner interprets each of the steps.
First, Claim 1, step 1: Kim et al. teach obtaining Raw silk from the Rural Development Administration. This meets the limitation of “providing raw silk” in claim 1, step 1.
Second, Claim 1, step 2: Kim et al. details degumming and effectively dissolving the degummed solution by: degumming twice by adding Marseilles soap (0.5% of weight of fiber) and sodium carbonate (0.3% of weight of fibroin), at a temperature of 100oC for 1 hour, to separate fibroin from the secondary constituent of sericin.”; and “washing the sericin-free solution with distilled water;”. It is noted, additional steps are permitted given the claim recites comprising and as such, the washing with water steps is permissible. In addition, the instant specification stipulates that dissolving is: “dissolving in the context of the present invention means converting a certain substance, such as fibroin, into a flowable, preferably homogeneous, at least apparently homogeneous form”; See paragraph 0004. Thus, given Kim et al. are converting said fibroin into a flowable, homogenous form free from sericin (as it is homogenous), this meets the limitation of claim 1, step 2, also noting there is no definition for “flowable” and the viscosity required to be considered “flowable”.
Third, Claim 1, step 3: Kim et al. teach “lowering the pH by adding 6M HCl and incubating for 5 hours”, which meets the step of “cleaning the fibroin raw solution by lowering the pH of the fibroin raw solution introducing an acidic substance……” because the exact same steps are performed. Thus, even if the wording is slightly different between the two and Kim et al. not state this is a “cleaning” step, this does not mean the cleaning is not inherently performed given all else is identical (MPEP 2112).
Fourth, Claim 1, step 4: Kim et al. teach “the acid degradation was stopped by adding sodium hydroxide” to the solution that was just had 6M HCl added to it, and thus, this meets the limitation of the instant claim of “raising the pH by adding NaOH”.
Fifth, Claim 1, step 5: Kim et al. teach “An electrodialysis system…… was used to remove the salt residues.”, which meets the limitation of desalting the fibroin raw solution to produce the fibroin solution having the fibroin dissolved therein. Again, noting the definition of the dissolving in paragraph 0004.
Regarding applicants remarks for claim 2, the dissolving takes place at 100oC.
Regarding applicants remarks for claim 4, the first solution introduction of 6M HCl will inherently take the pH to less than 2.
Regarding applicants remarks for claims 6-8, of Kim et al. in view of Bressner & Tilburey, and that one skilled in the art would not receive or learn any relevant information from this reference when trying to desalt the fibroin solution of Kim et al. (Remarks, p. 10) is not convincing. Bressner & Tilburey provide ample motivation and because as noted, nearly all of those skilled in the art do employ a desalting step, which does also extract other unwanted components (for example, the instant claims even have a “desalting step” even though no salt was every added in the method step of claim 1); but they do then teach the significant advantages afforded to those skilled in the art to not only “desalt” the fibroin solutions but also provide significantly more pure compositions.
Regarding claims 9-16, and Applicant’s remarks, it is noted the step of degumming and dissolving are performed twice. There is nothing in the specification or the claims which stipulates the first and secondary solution are completely different.
Conclusion
Claims 1-16 are allowed, Claim 17 is objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims.
THIS ACTION IS MADE FINAL. Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to SUZANNE M NOAKES whose telephone number is (571)272-2924. The examiner can normally be reached M-F (7-4).
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/SUZANNE M NOAKES/Primary Examiner, Art Unit 1656 15 September 2026
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