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 .
Claim Rejections - 35 USC § 112(b)
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 7 and 8 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 7 recites:
7. The method of claim 1, wherein the metal oxide, the metal oxide/polymer composite, or both are biocompatible. Emphasis added.
Claim 7 is indefinite because “the metal oxide” lacks antecedent basis as claim 1 is amended to remove “a metal oxide.” To overcome this rejection, claim 7 could be amended to read:
7. The method of claim 1, wherein
Claim 8 recites:
8. The method of claim 1, wherein the nanostructures comprise the metal oxide, and wherein the metal oxide comprises ZnO. Emphasis added.
Claim 8 is indefinite because the limitation “the nanostructures comprise the metal oxide” contradicts claim 1, which is amended to require that the nanostructures comprise a “metal oxide/polymer composite” (with “metal oxide” removed from the list). The Examiner suggests canceling claim 8 because claim 9 appears to contain the subject matter described in claim 8.
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.
Claims 1, 2, 4–10 and 13 are rejected under 35 U.S.C. 103 as being unpatentable over Kang et al., Hybrid Structure of a ZnO Nanowire Array on a PVDF Nanofiber Membrane/Nylon Mesh for use in Smart Filters: Photoconductive PM Filters, Applied Sciences (published August 29, 2021)1 in view of Joo et al., US 2015/0101979 A1 and in further view of KR 10-2021-0138926 A (“KR-926”).2
Regarding claim 1, Kang teaches a method of preparing a nanofiber membrane for particulate matter filtration, which reads on the claimed “method for preparing a filtration layer.” See Kang abstract.
The method comprises depositing (by electrospinning) nanofibers (the claimed “nanostructures”) onto the fibers of a nylon mesh (the “raw fibers”) to form mesh fibers that include the nanofibers (the “one or more modified fibers”). See Kang abstract. The nanofibers comprise a “metal oxide/polymer composite,” as claimed, because the body of each nanofiber is made from a polymer (such as PVDF) with zinc oxide (ZnO) nanowires forming an array on the nanofiber surface. Id. While Kang is silent as to the polymer in the “metal oxide/polymer composite” consisting of polypropylene, Joo teaches a nanofiber mat useful for filtration, comprising electrospun nanofibers that can be made from various materials including PVDF or polypropylene. See Joo [0010], [0100]. It would have been obvious for the polymer of the nanofibers in Kang to be made from polypropylene instead of PVDF because this would merely represent the selection of a known material based on the suitability of its intended use. See MPEP 2144.07. With this modification, this reads on the claimed step of:
“depositing one or more nanostructures on a plurality of raw fibers to form one or more modified fibers, wherein the nanostructures comprise a metal oxide/polymer composite, wherein the polymer in the metal oxide/polymer composite consists of polypropylene.”
The electrospun nanofibers (the “nanostructures”) comprise “branched nanowires,” as claimed, because the nanofibers comprise the ZnO nanowires (forming a nanowire array on the nanofiber surface), and the ZnO nanowires have a hierarchical structure, with Fig. 2e illustrating branched nanowires on the surface of the nanofibers. See Kang abstract, p. 3.
The fibers of the mesh (the “raw fibers”) are assembled into a fibrous network before the electrospun nanofibers are deposited, as claimed, because the nanofibers are electrospun onto the mesh. See Kang abstract.
The fibrous network forms a filtration layer, as claimed, because it can be used for particulate matter filtration. See Kang abstract.
Kang as modified differs from claim 1 because it is silent as to the ZnO nanowires on the surface of the nanofibers (the ZnO nanofibers are the “branched nanowires”) growing in all directions from the fibers of the mesh (the “raw fibers”), as claimed.
But KR-926 teaches an air filter comprising a mesh 10 that has fibers of a filter layer 20 deposited on the fibers of the mesh 10. See KR-926 Figs. 1–3, p. 2 (under “Description-of-Embodiments”). The fibers of the filter layer 20 comprise a polymer fiber 21 with metal oxide 22 particles attached to the surface. Id. at p. 3 (2nd full paragraph) The fibers of the filter layer 20 surround the fibers of the mesh 10 such that the metal oxide 22 particles extend in all directions from the fibers of the mesh 10, as seen in Fig. 3. This configuration is beneficial because it ensures that there is sufficient coverage of the fibers of the filter layer 20 on the mesh 10.
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It would have been obvious for the electrospun nanofibers of Kang to surround the entirety of the fibers of the mesh to ensure that there is sufficient coverage of the nanofibers on the mesh. With this modification, the ZnO nanowires of Kang (the “branched nanowires”) would grow in all directions from the fibers of the mesh (the “raw fibers”), as claimed, because the ZnO nanowires are grown on the electrospun nanofibers (through hydrothermal synthesis, see Kang abstract) and the electrospun nanofibers surround the fibers of the mesh.
Regarding claim 2, Kang as modified teaches that the “fibrous network” (the mesh with the electrospun nanofibers and ZnO nanowires) is assembled using an electrospinning process, as claimed, because the nanofibers are electrospun onto the mesh. See Kang abstract.
Regarding claim 4, Kang as modified teaches that the ZnO nanowires (which form part of the nanofibers, i.e., the “nanostructures”) are deposited using a hydrothermal synthesis (a “hydrothermal growth process”), as claimed. See Kang abstract.
Regarding claim 5, Kang as modified teaches that the electrospun nanofibers (of the NF layer) (the “nanostructures”) have an average fiber diameter of 260.5 ± 148.8 nm, which is within the claimed range of 10 to 1000 nm. See Kang p. 3 (under “Results”).
Regarding claim 6, Kang teaches that the electrospun nanofibers (of the NF layer) (the “nanostructures”) have an average fiber diameter of 260.5 ± 148.8 nm. See Kang p. 3 (under “Results”). The diameter of each fiber is a “length” because it is the distance across the center of the fiber. The prior art range of 260.5 ± 148.8 nm (0.2605 ± 0.148 µm) is within the claimed range of “up to 1 µm,” as claimed.
Regarding claim 7, Kang as modified teaches that the “metal oxide/polymer composite” is biocompatible because the nanofibers/nanowire composite is made of polypropylene and ZnO, which are both biocompatible materials. See Kang abstract.
Regarding claims 8 and 9, Kang as modified teaches that the nanofibers (the “nanostructures”) comprise the ZnO nanowires (“the metal oxide, and wherein the metal oxide comprises ZnO”). See Kang abstract.
Regarding claim 10, Kang as modified teaches a “filtration layer” prepared by the method of claim 1, which is the material of the mesh with the nanofibers and ZnO nanowires deposited on the mesh. See Kang abstract.
Regarding claim 13, Kang teaches that the nanofiber membrane has the same structure as the “filtration layer” of claim 13. Therefore, the nanofiber membrane of Kang is presumed exhibit the claimed property of being stable over a temperature range of from about -50 to about 300°C. See MPEP 2112.01, subsection I (when the structure recited in the reference is substantially identical to that of the claims, claimed properties or functions are presumed to be inherent).
Claims 11 and 12 are rejected under 35 U.S.C. 103 as being unpatentable over Kang et al., Hybrid Structure of a ZnO Nanowire Array on a PVDF Nanofiber Membrane/Nylon Mesh for use in Smart Filters: Photoconductive PM Filters, Applied Sciences (published August 29, 2021) in view of Joo et al., US 2015/0101979 A1 in view of KR 10-2021-0138926 A (“KR-926”) and in further view of Iiba et al., US 2021/0077930 A1.
Regarding claims 11 and 12, Kang as modified teaches the limitations of claim 10, as explained above.
Kang as modified differs from claim 11 because it teaches that the “filtration layer” has an efficiency of 94.3% for 0.3 µm particles (see Kang abstract), instead of the nanofiber membrane being capable of blocking at least 95% of particles less than 0.3 µm in diameter, as claimed. Kang differs from claim 12 because it is silent as to the efficiency of the “filtration layer” for 1 µm particles, and therefore fails to provide enough information to teach that the nanofiber membrane is capable of blocking at least 95% of particles less than 1 µm in diameter, as claimed.
But Iiba teaches that collection efficiency for a filter material is result effective because it impacts the amount of particles that can be removed by the filter. See Iiba [0004]. Iiba further teaches that efficiency tends to increase when fiber diameter decreases, while efficiency tends to decrease as particle size decreases. Id. Also, Kang teaches that the diameter of the nanofibers can be controlled (i.e., increased or decreased). See Kang p. 7. It would have been obvious to use routine experimentation to determine the optimal filtration efficiency of the nanofiber membrane of Kang to achieve the desired amount of particles removed by the material. See MPEP 2144.05, subsection II (where the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation). A person of ordinary skill in the art would have had a reasonable expectation of success in achieving an efficiency of at least 95% for particles with a diameter less than 0.3 µm or less than 1 µm, as claimed, because the nanofiber membrane of Kang has an efficiency of 94.3% for 0.3 µm particles (which is close to 95%), while the diameter of the nanofibers is adjustable and could be decreased to increase filtration efficiency.
Claims 15 and 17–20 are rejected under 35 U.S.C. 103 as being unpatentable over Kang et al., Hybrid Structure of a ZnO Nanowire Array on a PVDF Nanofiber Membrane/Nylon Mesh for use in Smart Filters: Photoconductive PM Filters, Applied Sciences (published August 29, 2021) in view of Joo et al., US 2015/0101979 A1 in view of KR 10-2021-0138926 A (“KR-926”) and in further view of Niu, US 2010/0173070 A1.
Regarding claim 15, Kang as modified teaches the limitations of claim 10, as explained above.
Kang as modified differs from claim 15 because it is silent as nanofiber membrane (the “filtration layer”) comprising a surface coating.
But Kang teaches that the nanofiber membrane comprises ZnO nanowires. See Kang abstract. Also, Niu teaches a filter material comprising ZnO nanowires comprising a coating formed on the nanowires provided for stabilizing the nanowires. See Niu [0017], [0066]. It would have been obvious to provide the coating of Niu on the ZnO nanowires of Kang to stabilize the nanowires. With this modification, the coating reads on the claimed “surface coating.”
Regarding claim 17, Niu teaches that the coating (the “surface coating”) is hydrophobic or hydrophilic. See Niu [0019].
Regarding claim 18, Niu teaches that the coating (the “surface coating”) comprises an oxide, which reads on “another oxide.” See Niu [0017].
Regarding claims 19 and 20, Kang as modified teaches a smart filter useful for filtering particulate matter from gas, comprising the mesh with the electrospun nanofibers and the ZnO nanowires (the “filtration layer”), which reads on the “device comprising the filtration layer of claim 15…wherein the device is…an air filter.”
Claim 16 is rejected under 35 U.S.C. 103 as being unpatentable over Kang et al., Hybrid Structure of a ZnO Nanowire Array on a PVDF Nanofiber Membrane/Nylon Mesh for use in Smart Filters: Photoconductive PM Filters, Applied Sciences (published August 29, 2021) in view of Joo et al., US 2015/0101979 A1 in view of KR 10-2021-0138926 A (“KR-926”) in view of Niu, US 2010/0173070 A1 and in further view of Lee et al., US 2018/0185678 A1.
Regarding claim 16, Kang as modified teaches the limitations of claim 15, as explained above.
Kang as modified differs from claim 16 because it is silent as to the thickness of the coating (the “surface coating”).
But the nanofiber material of Kang (coated with the coating of Niu) is a porous filter material, designed so that fluid can move through the pores. The coating is at least partially within the pores because the coating is provided to stabilize the nanowires. Also, Lee teaches that pore size for a filter is result effective because decreasing pore size affects pressure drop. See Lee [0014]. It would have been obvious to use routine experimentation to determine the optimal thickness of the coating to ensure that the pores remain a desired size to maintain a desired pressure drop. See MPEP 2144.05, subsection II (where the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation).
Response to Arguments
35 U.S.C. 112(b) Rejections
The Examiner withdraws the previous 35 U.S.C. 112(b) rejections. Note, however, that claims 7 and 8 remain rejected for being indefinite, as explained above.
35 U.S.C. 102 & 103 Rejections
The Applicant notes that claim 1 is amended to recite that the polymer consists of polypropylene. See Applicant Rem. filed March 11, 2026 (“Applicant Rem.”) 4. The Applicant argues that claim 1 is distinguishable from Kang, asserting that in Kang, PVDF nanofibers are electrospun onto a nylon mesh that is not removed at any point. Id. Therefore, it is argued that the materials in Kang are different because PVDF and nylon are different from polypropylene, as claimed. Id.
The Examiner respectfully disagrees. Claim 1 requires that the polymer in the “metal oxide/polymer composite” consists of polypropylene. The claim does not require that the “raw fibers” consist of polypropylene. In Kang, the fibers of the nylon mesh read on the “raw fibers.” Therefore, Kang can read on the claim, even though the mesh is manufactured from nylon, because claim 1 does not require that the raw fibers consist of polypropylene.
It is also noted that in Kang, the polymer of the electrospun nanofibers reads on the “polymer in the metal oxide/polymer composite” because the “composite” electrospun nanofibers are a composite of the polymer making the fibers and the ZnO nanowires formed as an array on the nanofiber surface. While Kang teaches that the polymer is PVDF, it would have been obvious to use polypropylene instead of PVDF as the polymer of the nanofibers, as explained above. With this modification, the “polymer in the metal oxide/polymer composite consists of polypropylene,” as claimed.
Elections/Restrictions
The previous issue with respect to election/restriction is overcome because claim 21 is cancelled.
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 T. BENNETT MCKENZIE whose telephone number is (571)270-5327. The examiner can normally be reached Mon-Thurs 7:30AM-6:00PM.
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T. BENNETT MCKENZIE
Primary Examiner
Art Unit 1776
/T. BENNETT MCKENZIE/Primary Examiner, Art Unit 1776
1 Kang is in the record as the 9-page Non Patent Literature document dated January 14, 2026.
2 An original, untranslated copy of KR-926 is in the record as the 17-page Foreign Reference dated May 16, 2026. A translation is in the copy as the 10-page Foreign Reference dated May 16, 2026. The original, untranslated copy is cited for figures and the translation is cited for text.
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