Prosecution Insights
Last updated: April 19, 2026
Application No. 17/621,908

ARTIFICIAL MELANIN NANOPARTICLES AND METHODS INCLUDING POROUS MELANIN MATERIALS

Non-Final OA §103§112
Filed
Dec 22, 2021
Examiner
KAHN, RACHEL
Art Unit
1766
Tech Center
1700 — Chemical & Materials Engineering
Assignee
Northwestern University
OA Round
3 (Non-Final)
28%
Grant Probability
At Risk
3-4
OA Rounds
3y 9m
To Grant
44%
With Interview

Examiner Intelligence

Grants only 28% of cases
28%
Career Allow Rate
179 granted / 649 resolved
-37.4% vs TC avg
Strong +16% interview lift
Without
With
+15.9%
Interview Lift
resolved cases with interview
Typical timeline
3y 9m
Avg Prosecution
65 currently pending
Career history
714
Total Applications
across all art units

Statute-Specific Performance

§101
0.2%
-39.8% vs TC avg
§103
48.5%
+8.5% vs TC avg
§102
15.5%
-24.5% vs TC avg
§112
23.7%
-16.3% vs TC avg
Black line = Tech Center average estimate • Based on career data from 649 resolved cases

Office Action

§103 §112
DETAILED ACTION The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA . 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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 10/15/2025 has been entered. Claims 1, 3-6, 8, 10, 12, 15, 16, 19, 22-26, 30, 31, 33, 53, 83 and 108 are pending as amended on 10/15/2025. Claims 16, 22-26, 33, 53, 83 and 108 stand withdrawn from consideration. Any rejections and/or objections made in the previous Office action and not repeated below are hereby withdrawn. The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office Action. Claim Rejections - 35 USC § 112 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, 3-6, 8, 10, 12, 15, 19, 30 and 31 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 recites (in line 3) “the plurality of artificial melanin nanoparticles” (emphasis added), however, there is no previous recitation of a plurality, and therefore, the term lacks antecedent basis. Because it is not clear whether “the plurality of artificial melanin nanoparticles” refers to the same group of “artificial melanin nanoparticles” as recited in line 1, the scope of the claim (and claims which depend from claim 1) is unclear. The examiner suggests inserting “a plurality of” prior to “artificial” in line 1 of claim 1. Claim 1 recites nanoparticles “characterized by a polydispersity index corresponding to a width of a particle size distribution being less than or equal to 0.10…”. Due to the sentence structure, it is not clear whether the “polydispersity index” must be less than or equal to 0.10, or, whether “a width of a particle size distribution” must be less than or equal to 0.10. The scope of claim 1 (as well as claims which depend from claim 1) is therefore unclear. The instant specification discloses “a polydispersity index selected to be less than or equal to 0.10” [0005], and therefore, the claims have been interpreted as requiring a polydispersity index of less than or equal to 0.10. The examiner suggests deleting “corresponding to a width of a particle size distribution” from the claim. The following is a quotation of 35 U.S.C. 112(d): (d) REFERENCE IN DEPENDENT FORMS.—Subject to subsection (e), a claim in dependent form shall contain a reference to a claim previously set forth and then specify a further limitation of the subject matter claimed. A claim in dependent form shall be construed to incorporate by reference all the limitations of the claim to which it refers. The following is a quotation of pre-AIA 35 U.S.C. 112, fourth paragraph: Subject to the following paragraph [i.e., the fifth paragraph of pre-AIA 35 U.S.C. 112], a claim in dependent form shall contain a reference to a claim previously set forth and then specify a further limitation of the subject matter claimed. A claim in dependent form shall be construed to incorporate by reference all the limitations of the claim to which it refers. Claim 19 is rejected under 35 U.S.C. 112(d) or pre-AIA 35 U.S.C. 112, 4th paragraph, as being of improper dependent form for failing to further limit the subject matter of the claim upon which it depends, or for failing to include all the limitations of the claim upon which it depends. Claim 19 depends from claim 1 and recites two alternatives, one being that the plurality of nanoparticles are characterized by a peak size selected from the range of 100 nm to 300 nm. This is already recited in claim 1, and therefore, claim 19 fails to further limit claim 1. Applicant may cancel the claim(s), amend the claim(s) to place the claim(s) in proper dependent form, rewrite the claim(s) in independent form, or present a sufficient showing that the dependent claim(s) complies with the statutory requirements. Claim Rejections - 35 USC § 103 Claim(s) 1, 3-6, 8, 10, 12, 15, 19, 30 and 31 is/are rejected under 35 U.S.C. 103 as being unpatentable over Dong et al (CN107298873A; machine translation cited herein) in view of Gianneschi et al (WO 2018/013609, cited by Applicant on IDS filed 7/18/22). As to claims 1, 8, 10 and 19, Dong discloses a melanin particle of small grain diameter for preparation of a film with ultraviolet shielding ability (p 2 of trans, middle). Dong teaches reacting melanin precursor, surface active agent and oxidizer to obtain the melanin (p 2 of trans, bottom half), which is used in the field of ultraviolet resistant polymer materials (p 3, bottom half). Dong teaches that the melanin precursor is not particularly limited, and names fourteen examples, including 1,8-dihydroxynaphthalene (p 3, top half). Dong teaches that the melanin particle size can be controlled between 5-500 nm (p 3, bottom half), which encompasses the presently claimed range of 100-300 nm. One having ordinary skill in the art would have recognized that particle properties must depend on the structure of the melanin precursor and on the size of the melanin particles. Therefore, when preparing a melanin particle by reaction of melanin precursor, as disclosed by Dong, it would have been obvious to the person having ordinary skill in the art to have selected any type of melanin precursor from those named by Dong, including 1,8-dihydroxynaphthalene, in order to tailor the properties of the melanin particle as appropriate for a given application. Additionally, it would have been obvious to the person having ordinary skill in the art to have selected any appropriate particle size within Dong’s disclosed range of 5-500 nm in order to tailor properties associated with melanin particle size, including a size within the presently claimed range of 100-300 nm. Case law has established that a prima facie case of obviousness is established where the claimed ranges overlap the ranges disclosed by the prior art. See MPEP 2144.05. A melanin particle formed by an oxidation reaction of 1,8-dihydroxynaphthalene, as suggested by Dong, comprises a plurality of melanin oligomers, polymers or a combination thereof, the base units of the melanin are unsubstituted naphthalene, and the melanin is free of nitrogen (because there is no nitrogen in 1,8-dihydroxynaphthalene). However, Dong is silent as to the polydispersity index (PDI) of the nanoparticles, and therefore, fails to teach that the nanoparticles are characterized by a PDI of less than or equal to 0.10. Gianneschi discloses a method for protecting a cell from UV damage by contacting a cell with a synthetic melanin nanoparticle comprising one or more melanin polymers, wherein the nanoparticle is capable of functioning as a pigment for protecting the cell from UV damage [0004, 0109]. Gianneschi teaches that the synthetic melanin nanoparticles have similar photoprotection capability as natural melanins [0110]. A melanin polymer is defined by Gianneschi as comprising two or more melanin monomers [0034]. Gianneschi discloses that the synthetic melanin nanoparticles can be in the form of a sphere, nanorod or worm, with a size from about 100 nm-300 nm, preferably with a high aspect ratio [0117]. Gianneschi further teaches that synthetic melanin nanoparticles can be monodisperse [0110]. (As evidenced by the instant specification ([0108]) the term “monodisperse” is typically used to refer to particles characterized by a polydispersity index of less than 0.1.) Both Gianneschi and Dong disclose fabricating nanoparticles using synthetic melanin in order to provide protection from ultraviolet light. Gianneschi discloses artificial melanin formed from dihydroxyindole monomers [0322], which is one of the types of melanin precursors also named by Dong (p 3, top half). Given Gianneschi’s disclosure of artificial melanin nanoparticles formed from one of the types of precursors named by Dong, and given that both references seek to use artificial melanin nanoparticles to solve a similar problem (protection from ultraviolet damage), one would have considered the teachings in Gianneschi to be relevant to Dong’s disclosure. Additionally, one having ordinary skill in the art would have generally been motivated to increase monodispersity when preparing particles in order to improve the uniformity and predictability of properties associated with the particles. Therefore, the person having ordinary skill in the art would have been motivated to form melanin particles having a monodisperse particle size distribution in order to provide a uniform material useful for protection against UV damage (as taught by Gianneschi). It would have been obvious to the person having ordinary skill in the art, therefore, to have formed a material comprising melanin particles from 1,8-dihydroxynaphthalene having a size of 100-300 nm, as suggested by Dong, with a particle size distribution as taught by Gianneschi (i.e., monodisperse, PDI of 0.10 or less), in order to provide a synthetic melanin material for UV protection having uniform and predictable properties. As to claim 3, modified Dong suggests a material according to claim 1, as set forth above. Dong fails to teach that the particles exhibit structural color. However, the claim is not limited to any particular color, or to any intensity of “structural color.” Therefore, given that modified Dong suggests particles which are substantially the same as the particles which, according to the instant specification, exhibit structural color, there is reasonable basis to conclude that the particles suggested by modified Dong exhibit at least some degree of some structural color. As to claims 4, 12 and 15, modified Dong suggests a material according to claim 1, as set forth above. Claims 4, 12 and 15 depend from claim 1, and further limit the melanin oligomer component of claim 1. However, in view of the amendment to claim 1 reciting melanin oligomer or polymer, claim 1 no longer requires the material to include melanin oligomer. Therefore, because they do not limit claim 1 to require the material to contain oligomer rather than polymer, modified Dong suggests a material according to dependent claims 4, 12 and 15 for at least the same reasons set forth for claim 1 above. As to claim 5, modified Dong suggests a material according to claim 1, as set forth above. Dong fails to teach that each nanoparticle has a shape as recited in claim 5, and a sphericity which is less than 0.90. Gianneschi discloses that synthetic melanin nanoparticles can be in various forms, including a sphere, cylinder or worm-like configuration, preferably with a high aspect ratio [0117]. One having ordinary skill in the art would have recognized that there are nanoparticle properties which depend on the shape thereof. Considering Gianneschi’s disclosure that synthetic melanin particles for UV protection can have a variety of shapes, the person having ordinary skill in the art would have been motivated to select an appropriate nanoparticle shape in order to achieve desired properties for an intended application. It would have been obvious to the person having ordinary skill in the art, therefore, to have formed a material comprising synthetic melanin nanoparticles, as suggested by modified Dong, having any desired form from those named by Gianneschi, including e.g., a “worm-like configuration,” thereby arriving at a particle having a sphericity of less than 0.90 and a shape which could be characterized as collapsed ellipsoid. As to claims 6, 30 and 31, modified Dong fails to disclose a comparison of scavenging activity to that of polydopamine nanoparticles, and fails to teach radical scavenging activity using DPPH in the same units recited in claim 31. However, given that Dong’s nanoparticles are formed from the same monomers (1,8-DHN) as presently claimed and which result in the presently recited increase in scavenging activity and non-covalent associations, there is reasonable basis to conclude that modified Dong suggests nanoparticles which are characterized by a scavenging activity as presently recited. Response to Arguments Applicant's arguments filed 10/15/2025 have been fully considered. Applicant’s arguments that the previously set forth rejections under 35 USC 102 (over Manini) and under 35 USC 103 (citing Manini as primary reference) have been overcome by amendment are persuasive. However, the claims are not in condition for allowance in view of the new rejection under 35 USC 103 above, citing Dong as a primary reference. Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to RACHEL KAHN whose telephone number is (571)270-7346. The examiner can normally be reached Monday to Friday, 8-5. 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, Randy Gulakowski can be reached at 571-272-1302. 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. /RACHEL KAHN/Primary Examiner, Art Unit 1766
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Prosecution Timeline

Dec 22, 2021
Application Filed
Jan 14, 2025
Non-Final Rejection — §103, §112
Apr 16, 2025
Response Filed
Jun 12, 2025
Final Rejection — §103, §112
Oct 15, 2025
Request for Continued Examination
Oct 17, 2025
Response after Non-Final Action
Jan 29, 2026
Non-Final Rejection — §103, §112 (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
28%
Grant Probability
44%
With Interview (+15.9%)
3y 9m
Median Time to Grant
High
PTA Risk
Based on 649 resolved cases by this examiner. Grant probability derived from career allow rate.

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