Prosecution Insights
Last updated: April 19, 2026
Application No. 16/972,958

CORE-SHELL IRON OXIDE-POLYMER NANOFIBER COMPOSITES FOR REMOVAL OF HEAVY METALS FROM DRINKING WATER

Final Rejection §103
Filed
Dec 07, 2020
Examiner
ROYCE, LIAM A
Art Unit
1777
Tech Center
1700 — Chemical & Materials Engineering
Assignee
UNIVERSITY OF IOWA RESEARCH FOUNDATION
OA Round
3 (Final)
65%
Grant Probability
Moderate
4-5
OA Rounds
2y 10m
To Grant
87%
With Interview

Examiner Intelligence

Grants 65% of resolved cases
65%
Career Allow Rate
339 granted / 522 resolved
At TC average
Strong +22% interview lift
Without
With
+21.7%
Interview Lift
resolved cases with interview
Typical timeline
2y 10m
Avg Prosecution
39 currently pending
Career history
561
Total Applications
across all art units

Statute-Specific Performance

§101
0.6%
-39.4% vs TC avg
§103
44.3%
+4.3% vs TC avg
§102
17.8%
-22.2% vs TC avg
§112
33.2%
-6.8% vs TC avg
Black line = Tech Center average estimate • Based on career data from 522 resolved cases

Office Action

§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 . Response to Arguments The Amendment filed 18JUL2025 has been entered. No new matter has been entered. Applicant's arguments filed 18JUL2025 have been fully considered but they are not persuasive. The Applicant appears to argue against the combination of references (if that is the argument). The references are combinable because the are analogous arts. See e.g. MPEP 2141.01(a)I. MPEP 2141 III (A) and (G) refer to the KSR line of reasoning in supporting the legal conclusion of obviousness. It is obvious to combine the teachings of the primary reference (PATEL) and the teachings of the secondary reference (GAO) which will yield the predictable result (part A) of the claimed invention (a core of polyacrylonitrile (PAN) with embedded hematite nanoparticles and a shell of Fe2O3 nanostructures). Core-shell composite materials are well known in the art. Part G refers to a teaching, suggestion, or motivation in the prior art that would have led one of ordinary skill to modify the prior art reference or to combine prior art reference teachings to arrive at the claimed invention (the prior art may have some benefit for the combination). GAO teaches core/shell nanomaterials made of iron oxides with a high degree of magnetic saturation. It is obvious to one having ordinary skill in the art to modify the materials of PATEL to be core/shell for a higher degree of magnetic saturation for an improved result. The combination provides for a reasonable expectation of success, because they are similar materials (iron oxide nanocomposites) and GAO provides a reason for the combination (e.g. a high degree of magnetic saturation). PATEL already teaches removing metal contamination from a source of water and the combination of GAO will make it better by packing in more magnetic materials. The Applicant argues that chemistry is an unpredictable art. The Examiner respectfully disagrees. Chemistry is predictable by using the scientific method of hypothesis testing and rigorous analysis. The Applicant does not proffer any reasoned explanation or analysis on why chemistry is an unpredictable art or that the combination of references would not lead to a predictable result. The Applicant argues the Examiner fails to identify teachings that explain how the modification of the structure of PATEL with the shell of GAO would result in a material that would enable "removing metal contamination from a source of water." See explanation above. The Examiner respectfully disagrees that removing metal using a magnetic particle is somehow complicated or unpredictable. The reason to modify is to improve the material for a higher degree of magnetic saturation as previously explained. Regarding claims 20-23, see the explanation above. Furthermore, the claims are directed towards a method for removing metal contaminations from a source of water where claims 20-23 specify the various types of heavy metals removed from water, not a composition. DAVE is clear that iron oxide can remove heavy metals from water including the species claimed. Substitution of the composition of DAVE to remove metals for the composition used in PATEL is not the rejection. The rejection clearly states “it would have been obvious to one of ordinary skill in the art to specify the method of PATEL with particular heavy metal removal with iron oxide nanocomposites for its effectiveness as is known in the art.” It is well established that a reference is good for all it fairly teaches a person having ordinary skill in the art, even when the teaching is a cursory mention. In re Mills, 916 F.2d 680, 682 (Fed. Cir. 1990). The Supreme Court has made clear that an obviousness analysis “need not seek out precise teachings directed to the specific subject matter of the challenged claim, for a court can take account of the inferences and creative steps that a person of ordinary skill in the art would employ.” KSR Int’l Co. v. Teleflex Inc., 550 U.S. 398, 418 (2007). That is because “[a] person of ordinary skill is also a person of ordinary creativity, not an automaton.” 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. This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention. Claim(s) 19,24-26,27-29 are rejected under 35 U.S.C. 103 as being unpatentable over PATEL et. al. 2016 “Iron oxide nanoparticle-immobilized PAN nanofibers: synthesis and adsorption studies” in view of GAO et. al. 2009 “The study of novel Fe3O4@g-Fe2O3 core/shell nanomaterials with improved properties”. Regarding claims 19, 28, PATEL teaches iron oxide nanoparticle-immobilized PAN nanofibers (title, Figs.) including a method for removing metal contaminations (P15403/Left C/L7-10) from a source of water (P15402/left C/L4) comprising: exposing the source of water (e.g. waste water; P15402/left C/L4) to a nanofiber composite (abstract) comprising: a polyacrylonitrile (PAN) with embedded hematite (P15405/right C) nanoparticles (see e.g. synthesis of iron oxide nanoparticles 2.2-2.3.1; Fig. 1 PAN/IO(H) or PAN/IO(B)); and removing metal contaminations from the source of water (P15402/left C/L4; P15403/Left C/L7-10). PATEL does not teach a core-shell nanocomposite. However, GAO teaches Fe3O4@γ-Fe2O3 core/shell nanomaterials with improved properties (title, abstract), and that a core/shell structure provides improved stability and a higher magnetic saturation value (abstract). Therefore, at the time the invention was filed, it would have been obvious to one of ordinary skill in the art to modify the iron oxide nanoparticles of PATEL to be a core-shell nanoparticle in order to provide improved stability and a higher magnetic saturation value as is known in the art. The references are combinable, because they are in the same technological environment of nanomaterials. See MPEP 2141 III (A) and (G). Regarding claims 24-25, PATEL teaches the nanoparticles and nanostructures are hematite (α-Fe2O3; P15405/right C). Note that α-Fe2O3 and γ-Fe2O3 are functionally equivalent as both are iron oxides. Regarding claims 26,29, PATEL teaches the embedded hematite nanoparticles have a particle size of 30-70 nm (P15407/right C/first paragraph), which overlaps the instantly claimed range of 10 nm to 40 nm (or e.g. 40 nm) and therefore establishes a case of prima facie obviousness. See MPEP 2144.05 I. It would have been obvious to one of ordinary skill in the art to select the instantly claimed range from the prior art range because prior art teaches the same utility over the selected range. Regarding claims 27, PATEL teaches the embedded hematite nanoparticles are 40 wt. % relative to PAN, which anticipates the claimed range of 8 wt.% to 50 wt.% (a 3:2 PAN/particle ratio is about 40% particles; P15403/right C/2.3.1.). Claim(s) 20-23 are rejected under 35 U.S.C. 103 as being unpatentable over PATEL et. al. 2016 “Iron oxide nanoparticle-immobilized PAN nanofibers: synthesis and adsorption studies” in view of GAO et. al. 2009 “The study of novel Fe3O4@g-Fe2O3 core/shell nanomaterials with improved properties” and DAVE et. al. 2014 “Application of iron oxide nanomaterials for the removal of heavy metals”. Regarding claims 20-23, PATEL’s modified method is silent as to the type of metal contaminant. However, DAVE teaches application of iron oxide nanomaterials for the removal of heavy metals (title) including: arsenic (As(V); P4/left C/second paragraph); chromium (Cr(VI); P6/left C/first paragraph); copper (Cu(II); P4/right C/second paragraph); and, lead (Pb(II); P6/left C/second paragraph). DAVE teaches iron oxide (including hematite variant; P1/right C/first paragraph) is effective at removing heavy metal toxins, which have been extensively studied due to its importance in environmental water treatments (abstract; P1/left paragraph). Therefore, at the time the invention was filed, it would have been obvious to one of ordinary skill in the art to specify the method of PATEL with particular heavy metal removal with iron oxide nanocomposites for its effectiveness as is known in the art. The references are combinable, because they are in the same technological environment of nanocomposite water purification. See MPEP 2141 III (A) and (G). Telephonic Inquiries 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 LIAM A ROYCE whose telephone number is (571)270-0352. The examiner can normally be reached M-F 8:30-4:30. 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, VICKIE KIM can be reached at (571)272-0579. 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. LIAM A. ROYCE Primary Examiner Art Unit 1777 /Liam Royce/ Examiner, Art Unit 1777
Read full office action

Prosecution Timeline

Dec 07, 2020
Application Filed
Dec 15, 2023
Non-Final Rejection — §103
Jun 20, 2024
Response Filed
Sep 24, 2024
Non-Final Rejection — §103
Mar 04, 2025
Response Filed
Mar 04, 2025
Response after Non-Final Action
Oct 23, 2025
Final Rejection — §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

4-5
Expected OA Rounds
65%
Grant Probability
87%
With Interview (+21.7%)
2y 10m
Median Time to Grant
High
PTA Risk
Based on 522 resolved cases by this examiner. Grant probability derived from career allow rate.

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