Prosecution Insights
Last updated: April 19, 2026
Application No. 18/009,429

SUPERABSORBENT POLYMER FOR CLASSIFICATION OF PARTICLES AND CLASSIFICATION METHOD USING THE SAME

Final Rejection §102§103
Filed
Dec 09, 2022
Examiner
CHEU, CHANGHWA J
Art Unit
1678
Tech Center
1600 — Biotechnology & Organic Chemistry
Assignee
Egret Lab Ltd.
OA Round
2 (Final)
75%
Grant Probability
Favorable
3-4
OA Rounds
2y 10m
To Grant
99%
With Interview

Examiner Intelligence

Grants 75% — above average
75%
Career Allow Rate
891 granted / 1194 resolved
+14.6% vs TC avg
Strong +48% interview lift
Without
With
+47.6%
Interview Lift
resolved cases with interview
Typical timeline
2y 10m
Avg Prosecution
15 currently pending
Career history
1209
Total Applications
across all art units

Statute-Specific Performance

§101
9.4%
-30.6% vs TC avg
§103
29.3%
-10.7% vs TC avg
§102
18.8%
-21.2% vs TC avg
§112
26.2%
-13.8% vs TC avg
Black line = Tech Center average estimate • Based on career data from 1194 resolved cases

Office Action

§102 §103
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 . Applicants filed response on 1/13/2026 has been received. Claims 9, 12-22 have been canceled. Claims 28-31 are added. Claims 1-8, 10-11 and 23-31 are pending and under examination. Objection on claim 3 is withdrawn because of amendment. The rejection on claims 1, 2, 6-8, 10-12 and 15-16 under 35 U.S.C. 112(b) is withdrawn because of amendment. The rejection on Claim(s) 1-4, 6-8, 11-12, 16, 23-25 and 27 under 35 U.S.C. 102(a)(1) and (a)(2) as being anticipated by Shiku (US 20210239664) is withdrawn because the ion exchange resin used by Shiku does not absorb significantly amount of liquid. The rejection of Claim(s) 12 and 16 under 35 U.S.C. 102(a)(1) and (a)(2) as being anticipated by Deregibus (WO 2017178472; IDS reference) is moot because of cancelation. The prior art rejection under Villiger (US 20190085284) is maintained. Accordingly the rejection on depending claims over Villiger is also maintained (see below). Claim Rejections - 35 USC § 102 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) 1-4, 6-8, 11-12, 16, 23-25 and 27 are rejected under 35 U.S.C. 102(a)(1) and (a)(2) as being anticipated by Villiger (US 20190085284). Villiger teaches using superabsorbent polymer (sepharose gel chromatography) to isolate desired extracellular vesicles particles (including exosomes)(size from 20-300 nm diameter) from sample solution followed by adding sodium chloride (NaCl) to discharge exosome from the solution (See section 0042, 0091, 0116, )(read on claims 1, 3, 4, 12, 25). As to claims 6-7, 23-24, the sodium chloride is a monovalent salt (Na+). As to claim 11, 16 and 27, the size of the chromatography resin usually is about 0.165 mm (165 µm, such as Sepharose CL-2B, 4B, 6B). Applicants’ arguments are summarized below: “It appears that the Office considers sepharose used in Villiger as corresponding to the superabsorbent polymer recited in the present claims. Applicant disagrees and notes that sepharose is not a material that absorbs water and swells on its own, but is rather a carrier for chromatography that can stably bear a water-containing porous structure. It is well understood by one of ordinary skill in the art that sepharose is not a superabsorbent polymer in terms of its design purpose, water absorption behavior, or applications. Because Villiger does not teach each and every feature recited in the present claims, Villiger does not anticipate independent claim 1 and the claims dependent therefrom. See, Verdegall Bros., Inc. v. Union Oil Co., supra. Reconsideration and withdrawal of the rejection is respectfully requested”. Applicant’s arguments have been considered but are not persuasive. As to the sepharose polmer, Toyoda (US 20200216484) indicates that sepharose can absorb water well and swell (section 0009). Also one ordinary skilled person comments on Google: PNG media_image1.png 128 706 media_image1.png Greyscale PNG media_image2.png 430 667 media_image2.png Greyscale So the above evidence (note, not cited as prior art but for clarification purpose) shows that sepharose polymer fits the claimed feature for isolating extracellular vesicles from a biological samples. 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. Claim(s) 5 is rejected under 35 U.S.C. 103 as being unpatentable over Villiger as applied to claims 1-4, 6-8, 11-12, 16, 23-25 and 27 above, and further in view of Ward (WO 2010141862). Villiger reference have been discussed above, but Viliger does not specifically disclose isolating exosome from urine samples. Ward teaches using chromatography methodology to isolate exosomes from human urine samples for further diagnosis renal and/or urinary illness (See page 2-3; Example 2-3). Therefore, it would have been prima facie obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to isolate exosomes from urine using the chromatograph methods. Isolating target molecules, i.e. exosome, from urine is a non-invasive approach often used in medical field and one clinician in the field would have been motivated to do so and would have reasonable expectation of success. Claims 10, 26, and 28-31 are free of prior art. No prior art teaches or fairly suggests using a superabsorbent having a three-dimensional crosslinked polymer having a repeating constituent unit represented by PNG media_image3.png 133 590 media_image3.png Greyscale The closest prior art is the reference of Villiger but Villiger does not teach using the above 3-dimentional crosslinked polymer or a crosslinked 3-dimentional polymer having an acid group, a salt thereof, and an amide thereof as a polymerization component. However claims 10, 26 and 28-31 are objected because depending on rejected claims. Conclusion No claim is allowed. 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 CHANGHWA J CHEU whose telephone number is (571)272-0814. The examiner can normally be reached 8 am to 8 pm. 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, Gregory Emch can be reached at 5712728149. 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. CHANGHWA J. CHEU Primary Examiner Art Unit 1678 /CHANGHWA J CHEU/Primary Examiner, Art Unit 1678
Read full office action

Prosecution Timeline

Dec 09, 2022
Application Filed
Oct 09, 2025
Non-Final Rejection — §102, §103
Jan 13, 2026
Response Filed
Feb 14, 2026
Final Rejection — §102, §103 (current)

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Study what changed to get past this examiner. Based on 5 most recent grants.

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Prosecution Projections

3-4
Expected OA Rounds
75%
Grant Probability
99%
With Interview (+47.6%)
2y 10m
Median Time to Grant
Moderate
PTA Risk
Based on 1194 resolved cases by this examiner. Grant probability derived from career allow rate.

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