Ultra Small Fibers, LLC

Patent Trials and Appeals Board

Aug 18, 2021

2021000775 (P.T.A.B. Aug. 18, 2021)

UNITED STATES PATENT AND TRADEMARK OFFICE
UNITED STATES DEPARTMENT OF COMMERCE
United States Patent and Trademark Office
Address: COMMISSIONER FOR PATENTS
P.O. Box 1450
Alexandria, Virginia 22313-1450
www.uspto.gov
APPLICATION NO. FILING DATE FIRST NAMED INVENTOR ATTORNEY DOCKET NO. CONFIRMATION NO.
14/560,833 12/04/2014 William Hudson Hofmeister 756.00050 1021
153348 7590 08/18/2021
Pitchford Fugett, PLLC
110 Meadowpointe W
Hendersonville, TN 37075
EXAMINER
SHAFI, LEITH S
ART UNIT PAPER NUMBER
1744
MAIL DATE DELIVERY MODE
08/18/2021 PAPER
Please find below and/or attached an Office communication concerning this application or proceeding.
The time period for reply, if any, is set in the attached communication.
PTOL-90A (Rev. 04/07)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE PATENT TRIAL AND APPEAL BOARD
____________

Ex parte WILLIAM HUDSON HOFMEISTER,
ALEXANDER YURYEVICH TEREKHOV,
JOSE LINO VASCONCELOS DE COSTA,
KATHLEEN STACIA LANSFORD,
DEEPAK RAJPUT, and LLOYD M. DAVIS
____________

Appeal 2021-000775
Application 14/560,833
Technology Center 1700
____________

Before JEFFREY B. ROBERTSON, ELIZABETH M. ROESEL, and
DEBRA L. DENNETT, Administrative Patent Judges.

ROESEL, Administrative Patent Judge.

DECISION ON APPEAL
Appellant1 appeals under 35 U.S.C. § 134(a) from the Examiner’s
decision rejecting claims 44–55. We have jurisdiction under 35 U.S.C.
§ 6(b).2

1 Ultra Small Fibers, LLC is identified as a real party in interest. Appeal
Br. 2.
2 In our opinion below, we reference the Specification filed December 4,
2014 (Spec.), the Final Office Action mailed December 4, 2019 (Final Act.),
the Appeal Brief filed May 29, 2020 (Appeal Br.), the Examiner’s Answer
mailed September 11, 2020 (Ans.), the Reply Brief filed November 11, 2020
(Reply Br.), and a transcript of the July 20, 2021 oral hearing (“Tr.”).
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We REVERSE.
STATEMENT OF THE CASE
Claimed Invention
Appellant claims a method for fabricating a nanofiber array. Appeal
Br. 27 (claim 44). According to the claimed method, a template is prepared
by ablating a plurality of nanoholes in a substrate using a single femtosecond
laser pulse to ablate each hole. The nanoholes are filled with a polymer
solution, and an array of polymer nanofibers is then extracted from the
template. Id.; Spec ¶ 22. According to the Specification, solution-based
replication of a template has several advantages over film-based replication.
Spec. ¶¶ 96, 153, 193; see also id. ¶¶ 92, 94, 95 (discussing cellulose acetate
(“CA”) film replication of rigid templates, as disclosed in White).
Claim 44 is the only independent claim on appeal and is reproduced
below from Appellant’s Claims Appendix:
44. A method for fabricating a nanofiber array,
comprising:
(a) providing a template comprising a transparent
substrate having a surface, the surface comprising a plurality of
nanoholes, each nanohole of said plurality being ablated in said
surface using a single femtosecond laser pulse;
(b) filling said plurality of nanoholes with a polymer
solution; and
(c) extracting an array of polymer nanofibers from the
template;
wherein said nanofibers have an aspect ratio of at least
ten-to-one and a diameter of less than 1000 nanometers.
Appeal Br. 27.
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References
The appealed rejections are based on the following references:
Zhang et al., US 2009/0047478 A1, Feb. 19, 2009 (“Zhang”);
Ross, US 2011/0270221 A1, Nov. 3, 2011 (“Ross”); and
Yelena V. White et al., Single-pulse ultrafast-laser machining of high aspect
nano-holes at the surface of SiO2, Optics Express, Vol. 16, No. 19, 14411–
14420 (Sept. 15, 2008) (“White”).
Rejections
The Examiner maintains the following rejections under 35 U.S.C.
§ 103(a):
1. Claims 44–47 and 50–55 over Ross in view of White. Final
Act. 3–7.
2. Claims 48 and 49 over Ross, White, and Zhang. Id. at 7–8.
ANALYSIS
Regarding claim 44, the Examiner finds that Ross teaches a method
for fabricating a nanofiber array, including providing a template having a
plurality of nanoholes, filling the nanoholes with a polymer solution, and
extracting an array of polymer nanofibers from the template, where the
nanofibers have a diameter of less than 1000 nanometers. Final Act. 3
(citing Ross ¶¶ 62, 68, 69, 77, 86, 160, 164). The Examiner finds that Ross
teaches nanofibers having an aspect ratio ranging from between 0.15 and 30,
which the Examiner asserts overlaps the claimed range, establishing a prima
facie case of obviousness. Id. at 4 (citing Ross ¶ 86). The Examiner finds
that White teaches the claim recitation, “a template comprising a transparent
substrate having a surface, the surface comprising a plurality of nanoholes,
each nanohole of said plurality being ablated in said surface using a single
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femtosecond laser pulse.” Id. (citing White, last paragraph of Introduction,
Fig. 1). The Examiner finds that it would have been obvious to substitute a
template formed by single femtosecond ablation, as taught by White, for the
template formation of Ross, citing the advantages of femtosecond laser
processing, as disclosed by White. Id. (citing White, Introduction). The
Examiner finds there would have been a reasonable expectation of success
for the proposed substitution “[b]ecause of the structural similarity and the
unchanged function” of the templates. Id.; see also Ans. 4–5 (repeating
essentially the same findings).
Appellant disputes almost all of the Examiner’s findings about Ross
and also disputes the Examiner’s findings about combining Ross and White
with a reasonable expectation of success. Appeal Br. 9–25. For example,
Appellant argues that Ross does not disclose filling nanoholes with a
polymer solution and that the Examiner does not show that the asserted
combination of Ross and White would have had a reasonable expectation of
success of forming nanofibers with an aspect ratio of at least ten-to-one, as
claimed. Id. at 9–14.
Responding to Appellant’s argument, the Examiner relies on Ross’s
disclosure of “formation of a master die” and “[r]eplication . . . to form the
device including an array of microneedles,” where “[c]ommon replication
methods include . . . solvent-assisted micromolding and casting.” Ans. 9
(quoting Ross ¶ 160). The Examiner introduces Gates3 as an “evidentiary
reference” to explain the meaning of “solvent-assisted micromolding.” Id.
The Examiner relies on Gates’ disclosures that “[s]olvent-assisted

3 Byron D. Gates, Nanofabrication with molds & stamps, 8.2 Materials
Today 44–49 (February 2005) (“Gates”).
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micromolding (SAMIM) uses a solvent to restructure a polymer film by
swelling or dissolving the polymer” and that “SAMIM can pattern nanoscale
structures.” Id. at 9–11 (quoting Gates, 46). The Examiner asserts that an
ordinarily skilled artisan would have known that “the replication technique
of solvent-assisted micromolding in Ross meant ‘filling’ of the nanoholes
with a polymer solution.” Id. at 10. The Examiner also relies on White’s
disclosure of sample replication using a cellulose acetate film softened with
acetone, asserting that it “surely reads on the reads on the plain meaning
interpretation of ‘filling’ nanoholes with a polymer solution.” Id. at 10–11.
Appellant elects to maintain the appeal despite the Examiner’s
reliance on a new reference (Gates) without designating a new ground of
rejection. Reply Br. 4 n.6. Appellant argues that the Examiner wrongly
equates the “polymer solution” of claim 44 with a polymer film that is
softened or partially dissolved, as taught by Ross, Gates, and White. Id.
at 4–5. At the oral hearing, Appellant argued that the Examiner conceded
this distinction in a December 18, 2015 final office action. Tr. 5:3–8.
After considering Appellant’s arguments and the record on appeal, we
determine that the rejection of claim 44 over Ross and White should not be
sustained.
This is the second ex parte appeal in this application. In the first
appeal, the Board reversed the Examiner’s rejection of claims 44–55, which
are the same claims at issue in this appeal. Ex parte Hofmeister, Appeal
No. 2018-005178 (PTAB Feb. 21, 2019) (“2019 Decision” or “2019 Dec.”).
In the previously appealed final action, as well as the earlier final action
referenced by Appellant at the oral hearing, the Examiner found that White
teaches filling nanoholes with cellulose acetate film that has been softened
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by acetone, but does not explicitly teach filling nanoholes with a polymer
solution, as recited in claim 44. Final Act. 3 (Mar. 6, 2017); Final Act. 3
(Dec. 18, 2015). We agree with Appellant that, with this earlier finding, the
Examiner conceded that a “polymer solution,” as recited in claim 44, differs
from a polymer film that is softened or partially dissolved, as disclosed by
White. White, 14416. The Examiner’s concession in the 2015 and 2017
final actions directly contradicts the Examiner’s finding in the Answer that
the step of filling nanoholes with a polymer solution, as recited in claim 44,
reads on White’s disclosure of sample replication using a cellulose acetate
film softened with acetone. Ans. 10–11.
In view of this contradiction, we are persuaded by Appellant’s
argument that that the Examiner wrongly equates the “polymer solution” of
claim 44 with a polymer film that is softened or partially dissolved, as taught
by Ross, Gates, and White. Reply Br. 4–5. According to the Specification,
cellulose acetate (CA) replication of single-pulse amplified femtosecond
laser (SP-AFL) machined fused silica substrate, as disclosed in White,
“resembles” the SAMIM technique, with the only difference being the type
of mold used. Spec. ¶ 95. Accordingly, the Examiner’s concession that
White does not teach filling nanoholes with a polymer solution (see, e.g.,
Final Act. 3 (Mar. 6, 2017)) applies equally to the SAMIM technique
referenced in Ross and described in Gates. Like the cellulose acetate film
replication technique disclosed in White, the SAMIM technique does not
involve filling nanoholes with a polymer solution, as recited in claim 44.
This distinction is supported by the Specification, which distinguishes
solution-based replication from film-based replication. Spec. ¶¶ 96, 153,
193.
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We are also persuaded by Appellant’s argument that the Examiner
does not show that the asserted combination of Ross and White would have
had a reasonable expectation of success of forming nanofibers with an aspect
ratio of at least ten-to-one, as claimed. Appeal Br. 12–14. A similar
deficiency resulted in the Board’s 2019 Decision reversing the Examiner’s
rejection of claim 44 over the combination of White and another reference.
The Board found that the Examiner did not establish that there would have
been a reasonable expectation of achieving an aspect ratio of at least ten-to-
one after modifying White’s replication method to use a polymer solution
instead of an acetate film. 2019 Dec. 5–6. We find that the Examiner’s
rejection based on Ross and White fails to remedy this deficiency. Here, the
Examiner relies on Ross, not White, to show a range of aspect ratios that
overlaps the claimed range of at least ten-to-one. Final Act. 4 (citing Ross
¶ 86); Ans. 16–17 (citing Ross ¶¶ 68, 70, 86).4 The Examiner does not
address whether a person of ordinary skill in the art would have expected to
obtain an overlapping range of aspect ratios after modifying Ross’s
replication method to use White’s template of nanoholes. Nor does the
Examiner address whether the aspect ratio of claim 44 would have been a
predictable result of combining the teachings of Ross and White.
Appellant directs us to disclosures in Ross and White supporting its
position that the aspect ratio of claim 44 may not have been an expected
result. Appellant argues that none of the microneedles formed by Ross

4 In the Final Action, the Examiner relies on Ross’s disclosure of the aspect
ratio of nanostructures on Ross’s microneedles. Final Act. 4. In the
Answer, the Examiner presents an alternative theory that relies on a
calculation of aspect ratio based on Ross’s disclosure of the dimensions of
the microneedles themselves. Ans. 17.
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displayed the aspect ratio and diameter recited in claim 44. Appeal Br. 7.
Appellant’s argument is supported by Ross Figure 2, which shows
microneedles 14 having a length of about 160 micrometers and a diameter of
about 100 micrometers, which is well outside the claimed ranges for both
diameter and aspect ratio. See Ross ¶¶ 64, 321 (describing Figure 2).
Appellant argues that eight out of nine of Ross’s sample nanostructure films
had an aspect ratio well below the claimed range and, although one sample
had an aspect ratio within the claimed range, it was made by dissolving the
template, not by extracting an array of polymer nanofibers from the
template, as claimed. Appeal Br. 7. Appellant’s argument is supported by
Ross Table 4, which shows that eight out of nine samples had an aspect ratio
of 3.4 or less, and by Ross Example 2, which discloses that sample no. 8 was
made by flowing a melted polymer film through a mold and then dissolving
the mold with a solvent. Ross ¶ 245.
In addition, Appellant directs us to White’s teaching that “high aspect
ratio features may resist accurate replication.” White, 14417; Appeal Br. 12.
Appellant also relies on White’s disclosure that the film-based replication
technique “most probably underestimates the depths,” which “might be due
to the difficulty of the polymer to reach the bottom of the nano-hole.”
White, 14418; Appeal Br. 11–12. The Examiner does not dispute
Appellant’s evidence, nor respond persuasively to Appellant’s argument
that, based on the teachings of Ross and White, there would have been no
expectation that a polymer solution would fill White’s nanoholes so as to
produce a nanofiber with an aspect ratio of at least ten-to-one after
extraction. Appeal Br. 12–14; see Ans. 13–14, 16–17 (relying on Ross’s
teachings to show the claimed aspect ratio, but not addressing whether the
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proposed modification of Ross would have the claimed aspect ratio). The
burden was on the Examiner to show that the combination of Ross and
White would have reasonably been expected to achieve the aspect ratio
limitation of claim 44. In re Stepan Co., 868 F.3d 1342, 1348 (Fed. Cir.
2017) (“it was the PTO’s—not Stepan’s—burden to show that achieving
[claim limitation] would have been obvious to a person of ordinary skill in
the art”); Honeywell Int’l Inc. v. Mexichem Amanco Holding S.A. DE C.V.,
865 F.3d 1348, 1355 (Fed. Cir. 2017) (“the burden is on the Examiner to
show that one of ordinary skill would have had a motivation to combine the
references with a reasonable expectation of success”).
The foregoing deficiencies in the Examiner’s findings and conclusions
regarding independent claim 44 are not remedied by the Examiner’s findings
or conclusions regarding dependent claims 45–47 and 50–55 or separately
rejected dependent claims 48 and 49.
Accordingly, for all of the foregoing reasons, we do not sustain the
rejections listed above.
CONCLUSION OF LAW AND DECISION
The decision of the Examiner is reversed.
Claims
Rejected
35 U.S.C.
§
Reference(s)/Basis Affirmed Reversed
44–47,
50–55
103(a) Ross, White 44–47,
50–55
48, 49 103(a) Ross, White,
Zhang
48, 49
Overall
Outcome
44–55
REVERSED