Prosecution Insights
Last updated: April 18, 2026
Application No. 18/032,540

PERFUSION SYSTEMS FOR DRIFT-FREE MICROSCOPY

Final Rejection §103
Filed
Apr 18, 2023
Examiner
ST CYR, DANIEL
Art Unit
2876
Tech Center
2800 — Semiconductors & Electrical Systems
Assignee
Fei Deutschland GmbH
OA Round
2 (Final)
81%
Grant Probability
Favorable
3-4
OA Rounds
2y 4m
To Grant
95%
With Interview

Examiner Intelligence

Grants 81% — above average
81%
Career Allow Rate
1131 granted / 1390 resolved
+13.4% vs TC avg
Moderate +13% lift
Without
With
+13.2%
Interview Lift
resolved cases with interview
Typical timeline
2y 4m
Avg Prosecution
45 currently pending
Career history
1435
Total Applications
across all art units

Statute-Specific Performance

§101
0.8%
-39.2% vs TC avg
§103
43.1%
+3.1% vs TC avg
§102
32.0%
-8.0% vs TC avg
§112
3.1%
-36.9% vs TC avg
Black line = Tech Center average estimate • Based on career data from 1390 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 . Claim Rejections - 35 USC § 103 In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status. 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) 1 and 17-25 is/are rejected under 35 U.S.C. 103 as being unpatentable over Alajoki et al, US Pub. 2002/0179445, in view of Byun et al, Electrophoresis , Vol 35. Both references cited by the applicant Regarding claims 1, 22-23, Alajoki et al disclose a method and an apparatus for continuous liquid flow in microscale channels using pressure injection, wicking, and electrokinetic injection comprising (see Fig. 3A-3C, pars. 0009-0011, 0061, 0089, 0125-0138): a sample chamber (reading area 345) having an inlet opening associated therewith; an inlet opening (any of ports 315, 320, 325); an outlet opening (waste well 310) associated with the sample chamber; and a wick (350) having a first portion thereof forming a fluid tight connection with the outlet opening, wherein a capillary tension of the wick (see par. 0009) contributes to a laminar flow of fluid (see par. 0123: "In the devices of the present invention, the microscale channels or chambers preferably have at least one cross-sectional dimension between about 0. 1 [mu] and 200[mu], more preferably between about 0.1[mu] and 100[mu], and often between about 0.1[mu] and 20[muj." and par. 0061: " ... 100 [mu]m channel cross section." ) across an optical detection area (see par. 0089: "The microfluidic device includes a detection window ... ") of the sample chamber. Alajoki et al fail to disclose that a reservoir is in fluid communication with the inlet opening and positioned above the inlet opening in a direction opposite the force of gravity (i.e. the inlet is fed by gravity-driven flow based on hydrostatic pressure) and that the wick has a portion thereof disposed within a waste tank, for providing means to supply and discard fluid from the perfusion system. However, the application of hydrostatic pressure at the input port to supply fluid (i.e. providing a reservoir which is in fluid communication with the inlet opening and positioned above the inlet opening in a direction opposite the force of gravity) is merely one of several straightforward possibilities from which the skilled person would select, in accordance with circumstances, without the exercise of inventive skill, in order to solve the problem posed (see also par. 0097: " ... cell suspension is injected into main injection well 110 and transported through the channel system by any of a variety of methods, such as [. .. ] hydrostatic pressure [. .. ], both with and without downstream modulation as discussed above."). Furthermore, Alajoki et al teach that wick 350 extends beyond waste well 310 (see Fig. 3A) and that "Waste products of an experiment are optionally collected and/or removed from the waste well." (see par. 0032). Thus, Alajoki et al point the skilled person towards collecting waste products in a separate vessel (i.e. waste tank). Byun et al the use of hydrostatic pressure ("gravity-driven flow") and the collection of waste products in a separate waste tank is common and obvious in the field of microfluidics (see review article, Fig. 1 B) and does, therefore, not involve an inventive activity. It would have been obvious to modify the teachings of Alajoki et al to include a reservoir is in fluid communication with the inlet opening and positioned above the inlet opening in a direction opposite the force of gravity (i.e. the inlet is fed by gravity-driven flow based on hydrostatic pressure) and that the wick has a portion thereof disposed within a waste tank, for providing means to supply and discard fluid from the perfusion system. Therefore, it would have been an obvious extension as taught by Alajoki et al. Regarding claim 17, wherein the sample chamber is protected against ambient gas atmosphere as disclose in the general teachings of Alajoki et al (see the rejection of claim 1 above). Regarding claim 18, Alajoki et al teach a method to regulate the flow velocity using a wick and the common flow rates are in the range of 1 µm/sec - 50 µm/sec (example see Brewer et al p. 519, right-hand column: "A flow velocity of v = 30 µmis implies that...."). Therefore, it would have been obvious for ordinary artisan to employ a flow rate within the common flow rates range for transporting the fluid. Regarding claim 19, it is obvious from Alajoki et al, see par. 0011: " ... a cellulosic material such as a piece of paper, e.g., a Kimwipe, paper towel, cellulose membrane, nylon membrane, Whatman(TM) filter, blotting paper, filter paper, cloth or fibrous material, or a polymer'. Regarding claim 20, wherein the laminar flow runs directionally away from the reservoir and towards the wick (see Fig. 2). Regarding claim 21, wherein a substantially even spatial pressure gradient is formed through a volume of the sample chamber ( Implicit from the feature "laminar flow' of claim 1 ( above). Furthermore, Laminar flow is commonly applied in microfluidic devices (example, see Brewer et al, title and abstract, cited by the applicant). Regarding claims 24-25, the limitations have been met above. Allowable Subject Matter Claim2, 6-8, 10, and 12-16 are objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims. The following is a statement of reasons for the indication of allowable subject matter: The applicant teaches a perfusion system for reducing sample drift during microscopy imaging which includes a sample chamber having an inlet opening, a reservoir in fluid communication with the inlet opening and positioned above the inlet opening, a wick having a first portion thereof forming a fluid tight connection with the outlet opening of the chamber and having a second portion thereof disposed within a waste tank, wherein a capillary tension of the wick contributes to a laminar flow of fluid across an optical detection area of the sample chamber is formed on at least a first side thereof by a coverslip having a diameter between 10 mm-40 mm. These limitations in conjunction with other limitations in the claims were not shown by the prior art of record. Response to Arguments Applicant's arguments filed 03/05/26 have been fully considered but they are not persuasive. See examiner remarks. Remarks: In response to applicant's argument that the examiner's conclusion of obviousness is based upon improper hindsight reasoning, it must be recognized that any judgment on obviousness is in a sense necessarily a reconstruction based upon hindsight reasoning. But so long as it takes into account only knowledge which was within the level of ordinary skill at the time the claimed invention was made, and does not include knowledge gleaned only from the applicant's disclosure, such a reconstruction is proper. See In re McLaughlin, 443 F.2d 1392, 170 USPQ 209 (CCPA 1971). The applicant argument regarding collecting waste is not sufficient to include a waste tank, the examiner respectfully disagrees. Any vessel used for collecting the waste can be considered a waste tank and the waste can be removed from such vessel. With respect to providing additional vessels, such additional could just duplication of elements for meeting specific customer requirements. The applicant further argued that the prior art (Alajoki) does not disclose a fluid-tight connection between the wick and the outlet opening, the examiner disagrees. Alajoki discloses placing the wick in the waste well and there is no leakage in the structure. Without any leakage, it is considered a fluid-tight connection. The applicant argument regarding claim 1 is not persuasive. Regarding claims 2, 6-8, 10, and 12-16, the rejection has been withdrawn. With respect to claim 23, in addition to the rejection of claim 1, the position of the reservoir is just merely a matter of choice for meeting customer requirements, wherein each reservoir is gravity driven. The applicant’s general argument is not persuasive. Refer to the rejection above. .Conclusion 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 DANIEL ST CYR whose telephone number is (571)272-2407. The examiner can normally be reached M to F 8:00-8:00. 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, Michael G Lee can be reached at 571-272-2398. 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. DANIEL ST CYR Primary Examiner Art Unit 2876 /DANIEL ST CYR/ Primary Examiner, Art Unit 2876
Read full office action

Prosecution Timeline

Apr 18, 2023
Application Filed
Dec 09, 2025
Non-Final Rejection — §103
Mar 05, 2026
Response Filed
Apr 02, 2026
Final Rejection — §103 (current)

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Prosecution Projections

3-4
Expected OA Rounds
81%
Grant Probability
95%
With Interview (+13.2%)
2y 4m
Median Time to Grant
Moderate
PTA Risk
Based on 1390 resolved cases by this examiner. Grant probability derived from career allow rate.

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