DETAILED ACTION
Previous Rejections
Applicant’s arguments, filed September 19, 2025, have been fully considered. Rejections and/or objections not reiterated from previous office actions are hereby withdrawn. The following rejections and/or objections are either reiterated or newly applied. They constitute the complete set presently being applied to the instant application.
Information Disclosure Statement
The information disclosure statements (IDS) submitted on September 23, 2025 and September 24, 2025 are in compliance with the provisions of 37 CFR 1.97. Accordingly, the information disclosure statements are being considered by the examiner.
Claim Status
Claims 3, 8, 54, 101, 104, and 108 are cancelled.
Claims 30, 34, and 115 are withdrawn.
Claims 1, 2, 4, 5, 10, 12, 14, 20 – 22, 29, 41, and 42 are examined here-in.
Claim Rejections - 35 USC § 103 (Necessitated by Amendment)
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 non-obviousness.
Claims 1, 2, 4, 5, 10, 12, 20 - 22, 41, and 42 are rejected under 35 U.S.C. 103 as being unpatentable over Kaplan 2015 (US 2015/0164117 A1, of record) in view of Kaplan 2017 (US 2017/0333351 A1, of record).
Kaplan 2015 teaches silk particles encapsulating a fragrance or flavoring (paragraph 0007). Kaplan 2015 teaches the silk particles can have a hollow inner core (paragraphs 0214 and 0595) with pores that enables the solvent to enter the empty space (paragraph 0595). Kaplan 2015 teaches that silk particles are swellable when hydrated (paragraph 0109, 0275, 0278, 0288, 0595).
Furthermore, Kaplan 2015 teaches that the silk matrix thickness, porosity, and pore sizes, among other factors can be modulated to control properties such as release rate (paragraph 0280).
Kaplan 2015 teaches that the silk can be genetically engineered for recombinant production in bacteria and yeast, among other recombinant production platforms (paragraph 0283).
Kaplan 2015 teaches that the silk particles can be in included in many different types of composition, solid or liquid, including emulsions (paragraph 0019). Further, Kaplan 2015 teaches that the silk particles in the form of an emulsion can be transitioned to a hydrogel state (paragraph 0034). Kaplan 2015 teaches that a silk-based composition can be made by immersing silk particles into an oil solution (paragraph 0214). Kaplan 2015 teaches that the silk concentration in the composition can be from 1 to 50% w/v (paragraph 0289).
Kaplan 2015 teaches that the diameter of silk particles loaded with oil droplets can range from 100 to 700 µm, that can be reduced by gentle sonication to droplet sizes less than 25 µm (paragraph 0221, figure 2B), suggesting that particle size can be controlled by the relative amounts of oil and aqueous components in the composition (paragraph 0049 and figure 16A-C). Kaplan’s teaching that silk particles are swellable when hydrated (paragraph 0109, 0275, 0278, 0288, 0595) also suggests that particle size increases with the addition of solvent. Kaplan 2015 teaches that the volumetric ratio of silk-based particle shells to oil filling the inner core can be from 10:1 to 1:10 (paragraph 0078).
Kaplan 2015 also teaches that a surfactant can be added to a silk particle-based composition and may serve to maintain particle shape and size (paragraphs 0086 and 0588). Kaplan 2015 teaches that a dye can be added to the composition (paragraph 0115).
Kaplan 2015 does not teach the recombinant silk particle is in the form of a dry powder (claim 3) or spray-drying a composition with recombinant silk polypeptide to form a dry powder (claim 20).
Kaplan 2017 teaches the missing elements of Kaplan 2015.
Kaplan 2017 teaches silk microspheres in the form of a powder which are then mixed with PBS buffer (paragraph 0280). Kaplan 2017 teaches that dehydrated silk powder is swellable when hydrated (paragraph 0072).
Kaplan 2017 teaches that a silk-based composition (silk microspheres in ultrapure water) can be freeze-dried into a dry powder form, noting that powder is a suitable formulation for pharmaceutical compositions (paragraphs 0039, 0085, 0139, 0275).
The combination of Kaplan 2015 and Kaplan 2017 renders claims 1, 2, 4, 5, 10, 12, 20 - 22, 41, and 42 prima facie obvious as combining prior art elements according to known methods to yield predictable results (MPEP 2143(i)(a)). A person of ordinary skill in the art would have been motivated to combine Kaplan 2015’s teaching of making a silk-based composition (paragraphs 0019, 0214, and 0595) with Kaplan 2017’s teaching for spray-drying the silk-based composition to a powder (paragraphs 0275, 0280) because Kaplan 2017 teaches a powder is a suitable form of the composition for a pharmaceutical formulation (paragraphs 0039, 0085, 0139, 0275). Furthermore, a person of ordinary skill in the art would have been motivated to manipulate the recombinant silk particles and the silk-based composition because Kaplan 2015 teaches that the properties of the silk particle, including diameter and shell thickness, among other factors can be modulated to control the composition properties such as concentration and release rate (paragraph 0049, 0078, 0280, 0595, figures 2B and 16A-C). The combination of Kaplan 2015 and Kaplan 2017 is prima facie obvious as combining prior art elements according to known methods to yield predictable results according to MPEP 2143(i)(a).
Kaplan 2015’s teaching for making a silk-based composition by immersing silk particles (which have an outer shell and hollow core and can be produced recombinantly) into an oil solution (paragraphs 0214, 0283, 0595) where the particle diameter can range from 100 to 700 µm (paragraph 0221, figure 2B) in combination with Kaplan 2017’s teaching that silk particles are in the form of a powder (paragraph 0280) and that dry particles swell when hydrated (paragraph 0072) reads on instant claim 1. Kaplan 2015’s teaching for particle diameters ranging from 100 to 700 µm (paragraph 0221, figure 2B) overlaps with the final particle size of 120 µm as recited in instant claim 1. Claimed ranges that overlap with teachings of the prior art are prima facie obvious according to MPEP 2144.05(i).
Furthermore, Kaplan 2017’s teaching that dry particles swell when hydrate (paragraph 0072) implies that dry particles have a smaller diameter than hydrated particles, therefore dry particles would have particle diameters less than Kaplan 2015’s teaching of 100 to 700 µm (paragraph 0221, figure 2B). Notably, Kaplan 2015 also teaches that particle size increases with the addition of solvent (paragraph 0109, 0275, 0278, 0288, 0595). Therefore, Kaplan 2015’s teaching of 100 to 700 µm particle diameter would reasonably be expected to result from swelling of some dry particle diameter of 5 to 25 µm as recited in instant claim 1. Said differently, it would be reasonably expected that the dry diameter of the 100 to 700 µm particles as taught by Kaplan 2015 would be less than 100 µm, thereby overlapping on the instantly claimed range of 5 to 25 µm as recited in instant claim 1.
Kaplan 2015’s teaching that the hollow core silk particles can have pores that enable the solvent to enter the empty space (paragraphs 0214 and 0595) reads on claim 2 of the instant application which recites the recombinant silk particle has an opening in the outer shell.
Kaplan 2015’s teaching that a silk-based composition can be made by immersing silk particles into an oil solution (paragraph 0214) reads on claim 4 of the instant application which recites the solvent is an oil-based solvent. Kaplan 2015 also teaches that oil can be olive oil or a silicone oil (paragraph 0066), reading on claim 5 of the instant application.
Kaplan 2015’s teaching that the silk matrix thickness can be modulated to control properties such as release rate (paragraph 0280) reads on claim 10 of the instant application which recites that the shell thickness is less than 20% of the diameter of the particle. Kaplan 2015’s teaching that silk matrix thickness, i.e. shell thickness can be tuned to change the particle properties motivates a person of ordinary skill in the art to make shell thickness within the claimed range in order to obtain the desired release characteristics.
Kaplan 2015 teaches that the silk concentration in the composition can be from 1 to 50% w/v (paragraph 0289) which overlaps with the claimed range of 1 to 10% w/w recited in instant claim 12.
Kaplan 2017’s teaching that the silk microspheres can be freeze-dried into a dry powder form (paragraph 0275) reads on claim 20 of the instant application.
Kaplan 2015’s teaching that a dye can be added to the composition (paragraph 0115) reads on claim 21 of the instant application. Kaplan 2015’s teaching that surfactant can be added to a silk particle-based composition reads on claim 22 of the instant application.
Kaplan 2015’s teaching that the silk-based composition can be in the form of an emulsion (paragraph 0019) and that the emulsion can be transitioned to a hydrogel state (paragraph 0034) reads on claims 41 and 42 of the instant application.
Claims 14 and 29 are rejected under 35 U.S.C. 103 as being unpatentable over Kaplan 2015 (as cited above) in view of Kaplan 2017 (as cited above), and further in view of Breslauer (US 2018/0111970 A1, of record).
The combination of Kaplan 2015 and Kaplan 2017 does not teach the recombinant silk particle comprises polypeptide SEQ ID NO.: 2 (claim 14) or that the recombinant silk particle comprises at least two concatenated units of SEQ ID NO.: 2 (claim 29).
Breslauer teaches the missing elements of the combination of Kaplan 2015 and Kaplan 2017.
Breslauer teaches a method of making silk fibers with a hollow core and an outer surface (paragraph 0106). Breslauer teaches that recombinant proteins can be engineered to have different mechanical, structural, chemical, and biological properties (paragraph 0055) and shows several silk polypeptide sequences that are suitable to be used as concatenated repeats (paragraph 0085 and Table 1). Breslauer further specifies that the polypeptide sequences of SEQ ID NO.:1 can be concatenated between 1 and 20 times (paragraph 0086). In example 1 Breslauer uses SEQ ID NO.:1 concatenated three times to make the recombinant silk protein (paragraph 0145).
The combination of Kaplan 2015, Kaplan 2017, and Breslauer is prima facie obvious as combining prior art elements according to known methods to yield predictable results (MPEP 2143(i)(a)). A person of ordinary skill in the art would have been motivated to combine Kaplan 2015 and Kaplan 2017’s teachings for making a silk-based composition with Breslauer’s teachings of recombinant silk polypeptides and particles (paragraph 0085 and Table 1) because Breslauer teaches that recombinant proteins can be engineered to have different mechanical, structural, chemical, and biological properties (paragraph 0055), which may be advantageous to tune desired properties. The combination of Kaplan 2015, Kaplan 2017, and Breslauer is prima facie obvious as combining prior art elements according to known methods to yield predictable results according to MPEP 2143(i)(a).
Breslauer’s teaching of polypeptide SEQ ID NO.:1 for use as a concatenated repeat to produce silk proteins (paragraph 0084 and Table 1) is a 99.4% identity match to the instantly claimed SEQ ID NO.: 2. The combination of Breslauer’s SEQ ID NO.:1 with Kaplan 2015 and Kaplan 2017’s teachings for recombinant silk particles with hollow cores and outer shells reads on claim 14 of the instant application which recites the recombinant silk particle with a hollow core and outer shell comprises a polypeptide of SEQ ID NO.: 2.
Instant claim 29 recites the recombinant silk particle is comprised of at least two concatenated repeats of SEQ ID NO.: 2 and is a carrier for the solvent. Breslauer’s teaching that the silk polypeptide SEQ ID NO:1 is suitable to be used as concatenated repeats (paragraph 0085 and Table 1), in combination with Kaplan 2015’s teaching that solvent fills in inner core of the particle (paragraph 0595) reads on claim 29 of the instant application. Further, Breslauer’s teaching that the silk polypeptide SEQ ID NO.:1 can be concatenated between 1 and 20 times (paragraph 0086) overlaps on the claimed range of “at least two” concatenated repeats recited in instant claim 29. Claimed ranges that overlap with teachings of the prior art are prima facie obvious according to MPEP 2144.05(i).
Examiner’s Reply to Attorney Arguments Dated September 19, 2025
Applicant argues that claim 3 was not rejected over Kaplan 2015, and that the inclusion of the limitations of claim 3 into amended claim 1 renders amended claim 1 non-obvious over Kaplan 2015 (Remarks page 6). While claim 3 was not rejected over Kaplan 2015, claim 3 was rejected over Kaplan 2017. Thus amended claim 1 is now rejected over Kaplan 2015 in view of Kaplan 2017.
Applicant argues that Kaplan 2015 does not disclose or suggest a dry recombinant silk particle with an outer shell having a diameter from 5 to 25 µm (Remarks page 7). The Examiner disagrees, because as discussed in the body of the rejection above, Kaplan 2017’s teaching that dry particles swell when hydrate (paragraph 0072) implies that dry particles have a smaller diameter than hydrated particles, therefore the dry particles would have particle diameters less than Kaplan 2015’s teaching of 100 to 700 µm (paragraph 0221, figure 2B). Notably, Kaplan 2015 also teaches that particle size increases with the addition of solvent (paragraph 0109, 0275, 0278, 0288, 0595). Therefore, Kaplan 2015’s teaching of 100 to 700 µm particle diameter would reasonably be expected to result from swelling of some dry particle diameter of 5 to 25 µm as recited in instant claim 1. Said differently, it would be reasonably expected that the dry diameter of the 100 to 700 µm particles as taught by Kaplan 2015 would be less than 100 µm, thereby overlapping on the instantly claimed range of 5 to 25 µm as recited in instant claim 1.
Applicant argues that Kaplan 2017 does not remedy the deficiencies of Kaplan 2015 because “Kaplan 2017 is silent with respect to expanding a dry recombinant silk particle” (Remarks page 7). The Examiner disagrees, because as discussed in the body of the rejection above, Kaplan 2015 and Kaplan 2017 both teach that silk particles are swellable when hydrated (Kaplan 2015 paragraphs 0109, 0275, 0278, 0288, 0595 and Kaplan 2017 paragraph 0072).
Applicant argues that Breslauer does not teach expanding a recombinant silk particle by mixing with a solvent (Remarks pages 7 and 8). In response to Applicant's arguments against the Breslauer reference individually, one cannot show nonobviousness by attacking references individually where the rejections are based on combinations of references. See In re Keller, 642 F.2d 413, 208 USPQ 871 (CCPA 1981); In re Merck & Co., 800 F.2d 1091, 231 USPQ 375 (Fed. Cir. 1986). Claims 14 and 29 are rejected over Kaplan 2015 in view of Kaplan 2017 and further in view of Breslauer. As discussed above, Kaplan 2015 and Kaplan 2017 both teach that silk particles are swellable when hydrated (Kaplan 2015 paragraphs 0109, 0275, 0278, 0288, 0595 and Kaplan 2017 paragraph 0072).
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). 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.
Correspondence
Any inquiry concerning this communication or earlier communications from the examiner should be directed to Toriana N. Vigil whose telephone number is (571)270-7549. The examiner can normally be reached Monday - Friday 9:00 a.m. - 5:00 p.m. EST.
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/TORIANA N. VIGIL/Examiner, Art Unit 1612
/FREDERICK F KRASS/Supervisory Patent Examiner, Art Unit 1612