DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 October 30, 2025 has been entered.
Applicants' arguments, filed October 30, 2025, have been fully considered but they are not deemed to be fully persuasive. The following rejections and/or objections constitute the complete set presently being applied to the instant application.
Claim Rejections - 35 USC § 112 – Scope of Enablement
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.
Claims 1 – 3, 5 and 7 – 22 are rejected under 35 U.S.C. 112(a) or 35 U.S.C. 112 (pre-AIA ), first paragraph, because the specification, while being enabling for making fibers by the claimed method with the required diameter using formulation 28 in Table 1 of the specification, does not reasonably provide enablement for preparation of chitosan-based fibers 2 µm < x < 10 µm as required by the claims using the claimed method with other chitosan and chitosan salt containing solutions. The specification does not enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the invention commensurate in scope with these claims. This rejection is MAINTAINED for the reasons set forth herein.
The disclosure and claims of the application have been compared per the factors indicated in the decision In re Wands, 8 USPQ2nd 1400 (Fed. Cir. 1988) as to undue experimentation
The factors include:
1. The nature of the invention;
2. The breadth of the claims;
3. The predictability or unpredictability of the art;
4. The amount of direction or guidance presented;
5. The presence or absence of working examples
6. The quantity of experimentation necessary;
7. The state of the prior art; and
8. The relative skill of those skilled in the art.
Each relevant factor is addressed below on the basis of comparison of the disclosure, the claims and the state of the art in the assessment of undue experimentation.
The nature of the invention; the breadth of the claims:
The claims are drawn to a method of producing chitosan-based fibers. The active steps of the claimed method are quite broad, reciting preparing a formulation that includes at least 20% (w/w) chitosan and a chitosan salt which is spun from a centrifugal spinner and dried to produce fibers and fibers 2 µm < x < 10 µm in diameter must be present in the produced material. Various chitosan salts are recited in claim 14. Additives such as rheological modifiers (e.g., claim 2) and crosslinking agents (claims 8 – 10) can be present. Crosslinking agents are not required by the independent claim and it appears that rheological modifiers are also not required by the independent claim (see indefiniteness rejection below). The only process parameters claimed are in the claim 17 which requires achieving a spinning rate and mass flow greater than 1 gram per minute through the spinneret. The method of independent claim 19 is similar to that of claim 1 but in addition to the same limitations on fiber diameter, the produced material also must be “capable of resisting dissolution upon exposure to synthetic gastric fluid”. The method of independent claim 20 is similar to that of claim 1 but in addition to the same limitations on fiber diameter, the produced material also must be hemostatically bioactive.
The predictability or unpredictability of the art; the amount of direction or guidance presented; the presence or absence of working examples; the quantity of experimentation necessary; the state of the prior art; the relative skill of those skilled in the art:
The relative skill of those skilled in the art is relatively high, such as polymer chemist. The declaration filed June 16, 2025 reflects that state of the prior art, and indicates that it does not appear to be known in the art to use the claimed method to produce fibers greater than 10 µm in size. Such artisans also know that the size of chitosan-based nanofibers that can be produced by centrifugal spinning such as those disclosed by Erickson et al. (Carbohydrate Polymer, 2015) lie well below the lower limit of the amended claims so one of ordinary skill in the art would not expect to be able to make fibers at least 2 µm in diameter using the centrifugal spinning.
Therefore the specification was analyzed to determine what materials and conditions for spinning were used and the results of those tests to determine conditions that can result in production of chitosan/chitosan salt fibers 2 µm < x < 10 µm in diameter. The specifics of formulations 1 – 9 were not given but did not contain rheological modifier, had chitosan concentrations ranging from 2% to 20% chitosan (no mention of salt given) and were not able to spin using centrifugal spinning (¶ [0056] of the PGPub of the instant application). The addition of 5 – 10% rheological modifier (not further specified) to the materials made formulations that did spin although characterization of the produced fibers such as fiber diameter is not given (¶ [0056]). ¶ [0057] indicates that amounts of acetic acid near or about 70% was tested to reduce drying time and prevent fiber collapse but “a small reduction in percentage acetic acid content in the formulations closer to 60% w/w provided for centrifugal spinning” but again no characteristics such as fiber diameter were given. ¶ [0058] generally discusses experiments in which chitosans of different degrees of acetylation and different viscosities were tested with about 2 – 7% w/w/ chitosan and about 50 – 60% w/w acetic acid but no additional specifics as to the formulations tested were given. It was “generally necessary” to includes about 5 – 10% w/w polyethylene oxide (PEO) in the final dry fiber matrix (¶ [0058]) but no information as to fiber diameter was given. The only formulations completely specified are listed in Table 1 (¶ [0061]) and all but formulation 30 contain PEO. Formulation 30 with the different rheological modifier (polyvinylpyrrolidone; PVP) did not spin. For formulations 25 – 29 with PEO that did spin, the spinning parameters are set forth in table 2 and characteristics of the produced fibers are given in Table 3. Of these 5 formulations, only composition 28 resulted in fibers 0.1 – 3 µm in diameter, overlapping with the claimed size range. Formulations 26 and 27 produced fibers 0.1 – 2 µm in diameter, falling just outside the claimed range. The other two formulations did not produce fibers even close to the claimed range. In looking at the compositions of the 6 compositions in Table 1, PVP did not result in any fibers being produced and there is no clearly discernable trend with the remaining 5 formulations that did produce fibers as to the characteristics that result in fibers of greater than 2 µm in diameter. The amount of chitosan and PEO rheological modifier in formulations 27 and 28 were slightly different but there was a very large difference in viscosity. Formulations 28 and 29 contain the same amount of chitosan and about the same amount of PEO rheological modifier but the largest fibers produced by formulation 29 were 2 µm in diameter and thus smaller than those from formulation 28. What if any effect the amount of salt form and which salt is present on the ability to spin fibers and the properties of those fibers such as diameter is not disclosed.
When the data in the specification is taken as a whole, the presence of a rheological modifier seems to be required for fiber formation but even when present, not all rheologic modifiers can result in fiber production, let alone fibers of the claimed diameter. Fiber diameter seems quite sensitive to the formulation used in spinning based on the data in the specification for compositions 25 – 30, but there is no clear trend to determine what formulations of chitosan, chitosan acetate and PEO can be spun inti fibers of the claimed diameter to indicate some predictability in the formulations that are not only capable of being spun to produce fibers but fibers having the claimed diameter. While one of ordinary skill in the art can make and test various chitosan solutions for the ability to make fibers such as using the techniques disclosed at ¶ [0056], that would be undue experimentation as not only must fibers be produced from a particular chitosan and chitosan salt formulation, fibers 2 µm < x < 10 µm in diameter must also be produced, requiring even more experimentation to determine if the process parameters can be adjusted to alter the fiber diameter to fall within the claimed range. It appears fiber formation as claimed requires the presence of an appropriate rheological modifier, and such ingredients are not clearly required by the independent claim and claimed very broadly. The effect, if any, of crosslinker inclusion, particularly prior to fiber formation, does not appear to have been addressed. Given the state of the art that fibers 2 µm < x < 10 µm cannot be prepared by centrifugal spinning and the numerous formulations that either did not spin and thus did not produce fibers or did produce fibers but not within the claimed range in the specification as filed means that the full scope of the claims is not enabled. Undue experimentation would be required to determine which formulations of chitosan, chitosan salt and optional ingredients such as rheologic modifiers (that appears to be required for any fibers to form) and crosslinking agents produced fibers of the appropriate size. Additional undue experimentation is required to determine formulations that not only make chitosan fibers falling within the claimed size range but also are capable of resisting dissolution upon exposure to synthetic gastric fluid as required by claim 19 although chitosan is often used in hemostatic dressings and therefore chitosan-based fibers would be reasonably be expected to be hemostatically active as additionally required by claim 20.
The dependent claims fall therewith as no claim is limited to the enabled subject matter.
Applicants traverse this rejection on the grounds that resistance to dissolution upon exposure to synthetic gastric fluid is not a feature which requires undue experimentation as such tests are regularly performed by one of ordinary skill in the art and a detailed testing procedure is provided in the disclosure as originally filed.
These arguments are unpersuasive. That a particular property can be assayed such as using a procedure detailed in the specification does not mean that this aspect of the claim is enabled. Undue experimentation is required because various formulations of at least 20% (w/w) of chitosan/chitosan and between 0.00% and 10% (w/w) of a rheological modifier must be prepared, spun and then the properties of the resulting fibers, if they fall within the claimed fiber size, further assayed for resistance to synthetic gastric fluid. Undue experimentation is already required for the preparation of fibers 2 µm < x < 10 µm, then even more experimentation would be required to determine which of the fibers were resistant to dissolution when exposed to synthetic gastric fluid.
Applicants also argue the conclusions made by the Examiner based on Erickson are in error. Erickson adds to body of evidence that a person of ordinary skill of less than 2 microns are possible and teachings nothing new with respect to fiber size diameters achieved by electrospinning. A sentence is highlighted from p 742 about micron sale [sic] C-PCL fibers, which is contrary to the Examiner’s assertion. That one of ordinary skill in the art would not expect to be able to make fibers at least 2 µm in diameter is simply wrong and inconsistent with Erickson itself.
These arguments are unpersuasive. The rejection does not allege that the electrospinning is incapable of producing micron sized fibers, but rather that the full scope of the claimed method of production of chitosan and chitosan salt containing chitosan fibers 2 µm < x < 10 µm in diameter using a centrifugal spinner as required by the instant claims is not fully enabled. The sentence in question from Erickson et al. ends with a citation to Cardoso et al., a copy of which accompanies this Office Action. As can be seen in the abstract, Figure 2 and the bottom half of the page e29508-7 of Cardoso et al., PCL (polycaprolactone) fibers about 15.5 µm in diameter were produced by rotary jet spinning and then coated with chitosan. This is not the method of the instant claims that requires spinning of a chitosan containing solution to produce the chitosan containing fibers and that the resulting fibers are 2 µm < x < 10 µm in diameter and thus do not provide an indication of additional enabled subject matter within the scope of the claims.
Applicants then indicate that analysis is fundamentally flawed analysis and there is a failure to make a prima facie case of deficiency. The starting premise is based on a false belied that centrifugal spinning cannot be used to make micron-sized fibers. The Examiner acknowledges the presence of at least one detailed example and one formulation that resulted in fibers whose size overlapped with the claimed size range. The Examiner appears to hold Applicant’s disclosure of failed experiments against them. That the Examiner mentioned formulations outside the scope of the claims as they contained less than 20% chitosan is not understood. The Examiner makes positive reference to the specification but then criticizes Applicant’s disclosure as lacking complete specification details and fiber diameters for each experiment. Fault was also found by the Examiner for a lack of a clear trend when determining which formulations can be spun into fibers as claimed as there is no clear trend requirement for enablement, particularly for the chemical arts. Sufficient guidance, including at least one complete example, have been given and there is sufficient ease in carrying out any needed assays to achieve the claimed objectives. The nature of the invention and predictability of the art are such that the skilled person could practice the claimed invention without undue experimentation with the specification providing ample and robust guidance and direction to enable the claims.
These arguments are unpersuasive. Based on the state of prior art and the evidence set forth in the declaration filed June 16, 2025, one of ordinary skill in the art would not have reasonably expected that spinning of a chitosan containing solution to produce the chitosan containing fibers 2 µm < x < 10 µm in diameter as claimed could be carried out. The specification was analyzed not to hold Applicants failed experiments against them but to determine if the working examples, forming one of the Wands factors, in the application as filed demonstrated enablement for the full scope of the claims and/or if sufficient direction or guidance, another Wands factor, demonstrated the enablement of the instant claims in view of the nature of the invention and state of the prior art. Trends can establish some predictability when evaluating the predictability or unpredictability of the subject matter, another Wands factor to be considered. This is a scope of enablement rejection with the example given that resulted in fibers whose diameter overlapped with those required by the instant claims has been indicated as enabled. However, even in view of the amendments, the claim scope is much broader than this single enabled example. All of the working examples present in the specification were considered including those that lie outside the claim scope (e.g., those with less than 20% total chitosan/chitosan salt content). When the identity of the rheological modifier is not given, conclusions about the amount and/or particular rheological modifier that could indicate additional enabled subject matter can be used to achieve the production of fibers as claimed is not possible. That is not criticism of the results, merely an indication that not all of the working examples presented contained enough information to determine if the initial materials results in fibers falling within the scope of the claims as many working examples were present but the number that provided sufficient information relating to the claimed features was limited. Any evidence must also be weighed against the scope of the claims and examples that could possibly provide evidence in support of additional embodiments are being enabled is not present because of the incomplete information, e.g., the size of the resulting fibers or the rheological modifier used is not disclosed. Therefore when all of the Wands factors are considered, the full breadth of the instant claims is not enabled.
Claim Rejections - 35 USC § 112 – Indefiniteness
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.
Claims 1 – 3, 5 and 7 – 22 are 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.
Claim 1, from which all other claims depend, has been amended to require a step of “adding an amount between 0.0% and 10% (w/w) of a separate rheologic modifier solution” (emphasis added). The claimed range of amount of material to be added encompasses 0.0%, but this interpretation goes against the plain meaning of adding something requiring an action to be taken in which a non-zero amount of something is added to the composition. Does this mean that someone must go through the motions of addition or add a separate solution containing something but not a rheological modifier? Or does the claimed range not actually include the end points of the claimed range such as that while the claim recites 0.0%, a non-zero amount of the rheological modifier must be added?
Please clarify.
The dependent claims fall therewith.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to Nissa M Westerberg whose telephone number is (571)270-3532. The examiner can normally be reached M - F 8 am - 4 pm.
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/Nissa M Westerberg/Primary Examiner, Art Unit 1618