Prosecution Insights
Last updated: April 19, 2026
Application No. 17/920,135

CELLULOSE-BASED ION-EXCHANGE MEMBRANE, PRODUCTION METHOD FOR SAME, EXOSOME PURIFICATION DEVICE, AND EXOSOME PURIFICATION METHOD

Final Rejection §112
Filed
Oct 20, 2022
Examiner
RIETH, STEPHEN EDWARD
Art Unit
1759
Tech Center
1700 — Chemical & Materials Engineering
Assignee
Toyobo Co. Ltd.
OA Round
2 (Final)
44%
Grant Probability
Moderate
3-4
OA Rounds
3y 3m
To Grant
77%
With Interview

Examiner Intelligence

Grants 44% of resolved cases
44%
Career Allow Rate
283 granted / 637 resolved
-20.6% vs TC avg
Strong +32% interview lift
Without
With
+32.5%
Interview Lift
resolved cases with interview
Typical timeline
3y 3m
Avg Prosecution
64 currently pending
Career history
701
Total Applications
across all art units

Statute-Specific Performance

§101
0.6%
-39.4% vs TC avg
§103
38.8%
-1.2% vs TC avg
§102
15.9%
-24.1% vs TC avg
§112
30.2%
-9.8% vs TC avg
Black line = Tech Center average estimate • Based on career data from 637 resolved cases

Office Action

§112
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 . Response to Amendment The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action. Any rejections and/or objections made in the previous Office action and not repeated below are hereby withdrawn. 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). Claim Rejections - 35 USC § 112 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, 2, 4, and 8 are rejected under 35 U.S.C. 112(a) or 35 U.S.C. 112 (pre-AIA ), first paragraph, as failing to comply with the written description requirement. The claim(s) contains subject matter which was not described in the specification in such a way as to reasonably convey to one skilled in the relevant art that the inventor or a joint inventor, or for applications subject to pre-AIA 35 U.S.C. 112, the inventor(s), at the time the application was filed, had possession of the claimed invention. Claim 1 has been amended to recite a cellulose-based polymer having at least one hydroxyl group or acetyl group at the 2-, 3-, or 6-position being “directly” replaced with a positively charged compound. The generic language “directly replaced” is not found within the specification as originally filed. While the examples appear to illustrate certain positively charged compounds directly replacing hydroxyl moieties, the breadth encompassed by the claim is not seen to be supported. For instance, no instance is described where acetyl groups of cellulose polymers are “directly replaced” with a positively charged compound is described. Therefore, it is concluded claim 1 fails to comply with the written description requirement. As claims 2, 4, and 8 depend from claim 1, they are rejected for the same issue discussed above. Claim 2 has been amended to recite “the positively charged compound… which has a positive charge in a sample liquid containing exosomes”. The limitation at issue is not found within the specification as originally filed. Therefore, claim 2 fails to comply with the written description requirement. Claim 2 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. Claim 2 indicates the positively charged compound can be a tertiary amine. However, a tertiary amine is not positively charged. The specification gives examples such as compounds of Formula (I) at ¶ 17, but the compounds therein are not positively charged. In view of the discrepancy between the express language of the claims and what is indicated by the specification, it is generally unclear what is meant or implied by replacing various groups of cellulose with a “positively charged tertiary amine compound”. Claim 2 requires the compound have “a positive charge in a sample liquid containing exosomes”. The scope of the claim is indefinite as the particulars of the sample liquid are not defined. For instance, a tertiary amine may or may not exhibit a positive charge depending on the pH of the aqueous medium. Response to Arguments Applicant's arguments filed 1/28/2026 have been fully considered but they are only partially persuasive. With respect to the 112(b) rejection pertaining to positively charged compounds, Applicant essentially argues the positively charged groups of the membranes interact with negatively charged exosomes. This is not found persuasive. The relevance of Applicant’s arguments is unclear. Claim 1 requires the membranes be a cellulose-based polymer being replaced with a positively charged compound. Thus, the positively charged compound is not a moiety/group on the membranes; it is a reactant used to create the membrane. See for instance ¶ 17 of the specification: “it is preferable to use a tertiary amine represented by the following formula (I) or a quaternary ammonium compound represented by the following formula (II) as the positively charged compound”. See also ¶ 35: “the cellulose-based porous substrate membrane is immersed in a non-dissolving solvent in the presence of an alkali, and a solution of a positively charged compound is added dropwise, followed by a reaction with heating and then quenching with alcohol”. Applicant’s arguments with respect to Hummersone have been considered and are found persuasive. Specifically, the membranes of Hummersone are different in structure insofar as they are produced via electrospinning cellulose fibers whereas the membranes described are produced via phase separation. Therefore, the claimed specific surface areas are not seen to necessarily be present. 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. Any inquiry concerning this communication or earlier communications from the examiner should be directed to STEPHEN E RIETH whose telephone number is (571)272-6274. The examiner can normally be reached Monday - Friday, 8AM-4PM Mountain Standard Time. Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Duane Smith can be reached at (571)272-1166. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000. /STEPHEN E RIETH/Primary Examiner, Art Unit 1759
Read full office action

Prosecution Timeline

Oct 20, 2022
Application Filed
Sep 24, 2025
Non-Final Rejection — §112
Jan 28, 2026
Response Filed
Feb 23, 2026
Final Rejection — §112 (current)

Precedent Cases

Applications granted by this same examiner with similar technology

Patent 12600671
PROCESS FOR PREPARING FOAMED POLYMER-MODIFIED BITUMEN COMPOSITIONS
2y 5m to grant Granted Apr 14, 2026
Patent 12577363
PROCESS FOR REMOVAL OF CONTAMINANTS FROM CONTAMINATED THERMOPLASTIC
2y 5m to grant Granted Mar 17, 2026
Patent 12577360
Viscoelastic Polyurethane Foam with Coating
2y 5m to grant Granted Mar 17, 2026
Patent 12570827
Sustainable Polyester from Recycled Polyethylene Terephthalate
2y 5m to grant Granted Mar 10, 2026
Patent 12552961
DROPLET FORMING DEVICES AND METHODS HAVING FLUOROUS DIOL ADDITIVES
2y 5m to grant Granted Feb 17, 2026
Study what changed to get past this examiner. Based on 5 most recent grants.

AI Strategy Recommendation

Get an AI-powered prosecution strategy using examiner precedents, rejection analysis, and claim mapping.
Powered by AI — typically takes 5-10 seconds

Prosecution Projections

3-4
Expected OA Rounds
44%
Grant Probability
77%
With Interview (+32.5%)
3y 3m
Median Time to Grant
Moderate
PTA Risk
Based on 637 resolved cases by this examiner. Grant probability derived from career allow rate.

Sign in with your work email

Enter your email to receive a magic link. No password needed.

Personal email addresses (Gmail, Yahoo, etc.) are not accepted.

Free tier: 3 strategy analyses per month