Prosecution Insights
Last updated: April 19, 2026
Application No. 18/721,223

METHOD FOR CLEANING A MICROFLUIDIC DEVICE USING AN IONIC LIQUID

Non-Final OA §103
Filed
Jun 18, 2024
Examiner
RIVERA-CORDERO, ARLYN I
Art Unit
1714
Tech Center
1700 — Chemical & Materials Engineering
Assignee
Lumicks Ca Holding B V
OA Round
1 (Non-Final)
62%
Grant Probability
Moderate
1-2
OA Rounds
3y 3m
To Grant
89%
With Interview

Examiner Intelligence

Grants 62% of resolved cases
62%
Career Allow Rate
216 granted / 346 resolved
-2.6% vs TC avg
Strong +27% interview lift
Without
With
+26.9%
Interview Lift
resolved cases with interview
Typical timeline
3y 3m
Avg Prosecution
20 currently pending
Career history
366
Total Applications
across all art units

Statute-Specific Performance

§103
62.0%
+22.0% vs TC avg
§102
10.9%
-29.1% vs TC avg
§112
23.9%
-16.1% vs TC avg
Black line = Tech Center average estimate • Based on career data from 346 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 Status Claims 1-20 are currently pending. Specification The disclosure is objected to because of the following informalities: The disclosure does not recite that the application claims the benefits of an international application, PCT/EP2022/087004 filed on 12/20/2022. The applicant is reminded to update the continuity data of their invention. Correction is required. 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. Claims 1, 3-9, 14, 16-18 and 20 are rejected under 35 U.S.C. 103 as being unpatentable over US 2014/0238444 to Arai (hereinafter “Arai”) in view of US 2006/083654 to Small (hereinafter “Small”). Regarding claim 1, Arai teaches a method for cleaning a microfluidic device comprising the steps of removing biological matter (nucleic acid, e.g., DNA, RNA) [0002, 0009, 0013, and 0031] from inside of the microfluidic device by flushing the microfluidic device [0054] with a cleaning agent comprising a polar organic solvent [0041]. Arai does not teach that the cleaning agent comprises an ionic liquid. However, it was known in the art to use ionic liquid as a solvent in a cleaning process. For example, Small teaches that ionic liquids can have advantageous environmental properties over other solvents, and that ionic liquids are substantially non-volatiles, less toxic than other solvents or even non-toxic, can effectively dissolve residues, and that high solubility of residues in ionic liquids allows process intensification ([0046, and 0049-0050] and table 2). In addition, Small teaches examples of ionic liquid solvents including 1-ehthyl-3-methylimidazolium chloride, 1-ehthyl-3-methylimidazolium acetate, and 1-ehthyl-3-methylimidazolium thiocyanate (polar organic solvents) (see table 2 of Small). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the method disclosed by Arai wherein the polar organic solvent is an ionic liquid, with a reasonable expectation of success, since Arai teaches that a cleaning liquid can comprise polar organic solvents in general ([0041] of Arai), and Small teaches that it is effective to use ionic liquid solvents such as 1-ehthyl-3-methylimidazolium chloride, 1-ehthyl-3-methylimidazolium acetate, and 1-ehthyl-3-methylimidazolium thiocyanate (polar organic solvents) in a cleaning process, since ionic liquids can have advantageous environmental properties over other solvents, are substantially non-volatiles, and less toxic than other solvents or even non-toxic ([0046, and 0049-0050] and table 2 of Small). Regarding claim 3, Arai/Small further teaches that the method for cleaning is an in-situ cleaning method ([0054] of Arai). Regarding claim 4, Arai/Small further teaches that the ionic liquid comprises at least one cation selected from 1-ehthyl-3-methylimidazolium (table 2 of Small). Regarding claim 5, Arai/Small further teaches that the ionic liquid comprises at least one anion selected from chloride, acetate and thiocyanate (table 2 of Small). Regarding claim 6, Arai/Small further teaches that a contact time between the microfluidic device and the cleaning agent is 0.1 to 4 hours ([0055] of Arai). In the case where the claimed range overlaps or lies inside ranges disclosed by the prior art a prima facie case of obviousness exists. Consult MPEP 2144.05. Regarding claim 7, Arai/Small further teaches that the cleaning can be performed at a room temperature (e.g., 20°C ± 15°C) ([0056] of Arai). Arai/Small does not explicitly teach the ionic liquid is at a temperature between 15 and 100 °C. However, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the method disclosed by Arai/Small wherein the ionic liquid is at a temperature between 15 and 25 °C, with a reasonable expectation of success, since Arai teaches that the cleaning can be performed at a room temperature (e.g., 20°C ± 15°C) ([0056] of Arai). Moreover, the temperature of the ionic liquid is a result effective variable modifying the cleaning results. For example, if the temperature of the ionic liquid is too low, it risks insufficient removal of residues or contaminants from the microfluidic device, while if the temperature of the ionic liquid is too high, it wastes energy. Without evidence of unexpected results, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to determine the appropriate temperature of the ionic liquid with predictable results, since it has been held that where the general conditions of a claim are disclosed in the prior art, discovering the optimum or workable ranges involves only routine skill in the art. Consult MPEP 2144.05II. Regarding claim 8, Arai/Small further teaches the step of reusing the microfluidic device after flushing the microfluidic device with the cleaning agent ([0011, and 0057] of Arai). Regarding claim 9, Arai/Small does not explicitly teach that the microfluidic device can be cleaned at least 10 times by the method of cleaning without altering the acoustic, hydrodynamic, optical, and/or electrical properties of the device. However, since Arai teaches that the cleaning of the microfluidic device can be regularly performed every time the microfluidic device is used several tens to several hundreds of times ([0057] of Arai), and the processing conditions and cleaning steps disclosed by Arai/Small are similar to those instantly claimed, it would be reasonably expected that the microfluidic device can be cleaned at least 10 times by the method of cleaning without altering the acoustic, hydrodynamic, optical, and/or electrical properties of the device. Regarding claim 16, Arai/Small further teaches that a contact time between the microfluidic device and the cleaning agent is 0.1 to 4 hours ([0055] of Arai). In the case where the claimed range overlaps or lies inside ranges disclosed by the prior art a prima facie case of obviousness exists. Consult MPEP 2144.05. Regarding claim 17, Arai/Small further teaches that the cleaning can be performed at a room temperature (e.g., 20°C ± 15°C) ([0056] of Arai). Arai/Small does not explicitly teach the ionic liquid is at a temperature between 30 and 50°C. However, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the method disclosed by Arai/Small wherein the ionic liquid is at a temperature between 15 and 25 °C, with a reasonable expectation of success, since Arai teaches that the cleaning can be performed at a room temperature (e.g., 20°C ± 15°C) ([0056] of Arai). Moreover, the temperature of the ionic liquid is a result effective variable modifying the cleaning results. For example, if the temperature of the ionic liquid is too low, it risks insufficient removal of residues or contaminants from the microfluidic device, while if the temperature of the ionic liquid is too high, it wastes energy. Without evidence of unexpected results, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to determine the appropriate temperature of the ionic liquid with predictable results, since it has been held that where the general conditions of a claim are disclosed in the prior art, discovering the optimum or workable ranges involves only routine skill in the art. Consult MPEP 2144.05II. Regarding claim 18, Arai/Small does not explicitly teach that the microfluidic device can be cleaned at least 150 times by the method of cleaning without altering the acoustic, hydrodynamic, optical, and/or electrical properties of the device. However, since Arai teaches that the cleaning of the microfluidic device can be regularly performed every time the microfluidic device is used several tens to several hundreds of times ([0057] of Arai), and the processing conditions and cleaning steps disclosed by Arai/Small are similar to those instantly claimed, it would be reasonably expected that the microfluidic device can be cleaned at least 150 times by the method of cleaning without altering the acoustic, hydrodynamic, optical, and/or electrical properties of the device. Regarding claim 20, Arai/Small further teaches that the method for cleaning is an in-situ cleaning method ([0054] of Arai). Regarding claim 14, Arai teaches a kit of parts comprising a microfluidic device [0002, and 0069], a disposable syringe (reads on “container”) containing a cleaning liquid [0069], wherein the cleaning liquid comprises a polar organic solvent [0041] for removing biological matter (nucleic acid, e.g., DNA, RNA) from the microfluidic device [0002, 0009, 0013, and 0031]. Arai does not teach that the cleaning agent comprises an ionic liquid. However, it was known in the art to use ionic liquid as a solvent in a cleaning process. For example, Small teaches that ionic liquids can have advantageous environmental properties over other solvents, and that ionic liquids are substantially non-volatiles, less toxic than other solvents or even non-toxic, can effectively dissolve residues, and that high solubility of residues in ionic liquids allows process intensification ([0046, and 0049-0050] and table 2). In addition, Small teaches examples of ionic liquid solvents including 1-ehthyl-3-methylimidazolium chloride, 1-ehthyl-3-methylimidazolium acetate, and 1-ehthyl-3-methylimidazolium thiocyanate (polar organic solvents) (see table 2 of Small). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the kit disclosed by Arai wherein the polar organic solvent is an ionic liquid, with a reasonable expectation of success, since Arai teaches that a cleaning liquid can comprise polar organic solvents in general ([0041] of Arai), and Small teaches that it is effective to use ionic liquid solvents such as 1-ehthyl-3-methylimidazolium chloride, 1-ehthyl-3-methylimidazolium acetate, and 1-ehthyl-3-methylimidazolium thiocyanate (polar organic solvents) in a cleaning process, since ionic liquids can have advantageous environmental properties over other solvents, are substantially non-volatiles, and less toxic than other solvents or even non-toxic ([0046, and 0049-0050] and table 2 of Small). Claims 2, 10-13 and 19 are rejected under 35 U.S.C. 103 as being unpatentable over US 2014/0238444 to Arai (hereinafter “Arai”) in view of US 2006/083654 to Small (hereinafter “Small”), and in further view of US 2008/0191170 to Walker et al. (hereinafter “Walker”). Regarding claim 2, Arai/Small does not teach that the biological material comprises a component selected from the group consisting of mammalian cells, mammalian cell organelles, mammalian cell residues, extracellular matrix from mammalian cells and combinations thereof. Walker teaches that ionic liquids have the ability to dissolve a wide range of organic and biological materials [0023]. It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to perform the method disclosed by Arai/Small for cleaning a microfluidic device comprising biological material, wherein the biological material comprises a component selected from the group consisting of mammalian cells, mammalian cell organelles, mammalian cell residues, extracellular matrix from mammalian cells and combinations thereof, with a reasonable expectation of success, since Walker teaches that ionic liquids have the ability to dissolve a wide range of organic and biological materials in general ([0023] of Walker). Regarding claim 19, Arai/Small further teaches that the ionic liquid comprises at least one cation selected from 1-ehthyl-3-methylimidazolium, and at least one anion selected from chloride, acetate and thiocyanate (table 2 of Small). Arai/Small does not teach that the biological material comprises a component selected from the group consisting of mammalian cells, mammalian cell organelles, mammalian cell residues, extracellular matrix from mammalian cells and combinations thereof. Walker teaches that ionic liquids have the ability to dissolve a wide range of organic and biological materials [0023]. It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to perform the method disclosed by Arai/Small for cleaning a microfluidic device comprising biological material, wherein the biological material comprises a component selected from the group consisting of mammalian cells, mammalian cell organelles, mammalian cell residues, extracellular matrix from mammalian cells and combinations thereof, with a reasonable expectation of success, since Walker teaches that ionic liquids have the ability to dissolve a wide range of organic and biological materials in general ([0023] of Walker). Regarding claim 10, Arai teaches a method for cleaning a microfluidic device comprising the steps of removing biological matter (nucleic acid, e.g., DNA, RNA) [0002, 0009, 0013, and 0031] from inside of the microfluidic device by flushing the microfluidic device [0054] with a cleaning agent comprising a polar organic solvent [0041]. Arai does not teach that the cleaning agent comprises an ionic liquid. However, it was known in the art to use ionic liquid as a solvent in a cleaning process. For example, Small teaches that ionic liquids can have advantageous environmental properties over other solvents, and that ionic liquids are substantially non-volatiles, less toxic than other solvents or even non-toxic, can effectively dissolve residues, and that high solubility of residues in ionic liquids allows process intensification ([0046, and 0049-0050] and table 2). In addition, Small teaches examples of ionic liquid solvents including 1-ehthyl-3-methylimidazolium chloride, 1-ehthyl-3-methylimidazolium acetate, and 1-ehthyl-3-methylimidazolium thiocyanate (polar organic solvents) (see table 2 of Small). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the method disclosed by Arai wherein the polar organic solvent is an ionic liquid, with a reasonable expectation of success, since Arai teaches that a cleaning liquid can comprise polar organic solvents in general ([0041] of Arai), and Small teaches that it is effective to use ionic liquid solvents such as 1-ehthyl-3-methylimidazolium chloride, 1-ehthyl-3-methylimidazolium acetate, and 1-ehthyl-3-methylimidazolium thiocyanate (polar organic solvents) in a cleaning process, since ionic liquids can have advantageous environmental properties over other solvents, are substantially non-volatiles, and less toxic than other solvents or even non-toxic ([0046, and 0049-0050] and table 2 of Small). Arai/Small does not teach that the biological material comprises a component selected from the group consisting of mammalian cells, mammalian cell organelles, mammalian cell residues, extracellular matrix from mammalian cells and combinations thereof. Walker teaches that ionic liquids have the ability to dissolve a wide range of organic and biological materials [0023]. It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to perform the method disclosed by Arai/Small for cleaning a microfluidic device comprising biological material, wherein the biological material comprises a component selected from the group consisting of mammalian cells, mammalian cell organelles, mammalian cell residues, extracellular matrix from mammalian cells and combinations thereof, with a reasonable expectation of success, since Walker teaches that ionic liquids have the ability to dissolve a wide range of organic and biological materials in general ([0023] of Walker). Regarding claim 11, Arai/Small/Walker further teaches that the cleaning agent consist of the ionic liquid ([0041] of Arai). Regarding claim 12, Arai/Small/Walker further teaches that the ionic liquid comprises at least one cation selected from 1-ehthyl-3-methylimidazolium (table 2 of Small). Regarding claim 13, Arai/Small/Walker further teaches that the ionic liquid comprises at least one anion selected from chloride, acetate and thiocyanate (table 2 of Small). Claim 15 is rejected under 35 U.S.C. 103 as being unpatentable over US 2014/0238444 to Arai (hereinafter “Arai”) in view of US 2006/083654 to Small (hereinafter “Small”), and in further view of US 2013/0186433 to Wang et al. (hereinafter “Wang”). Regarding claim 15, Arai/Small further teaches that the kit further comprises a disposable syringe (reads on “container”) containing water ([0069] of Arai). Arai/Small does not teach a container holding an aqueous soap solution. Wang teaches a device and method for cleaning a microfluidic device comprising the step of supplying a nucleic acid inactivation solution for flushing the microfluidic device, wherein the nucleic acid inactivation solution can include water, saline solution, and detergent solution [0050, 0064, and 0071-0074]. It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the kit disclosed by Arai/Small with a container holding an aqueous soap solution, with a reasonable expectation of success, since Arai teaches that a disposable syringe can be used for delivering a liquid such as water to the microfluid device ([0069] of Arai), and Wang teaches a method and device for flushing a microfluidic device with a nucleic acid inactivation solution including water, saline solution, and detergent solution ([0050, 0064, and 0071-0074] of Wang). Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to ARLYN I RIVERA-CORDERO whose telephone number is (571)270-7680. The examiner can normally be reached Monday to Friday, 9:00 AM to 2:00 PM. 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, Kaj Olsen can be reached at 571-272-1344. 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. /A.I.R/Examiner, Art Unit 1714 /KAJ K OLSEN/Supervisory Patent Examiner, Art Unit 1714
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Prosecution Timeline

Jun 18, 2024
Application Filed
Sep 25, 2025
Non-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

1-2
Expected OA Rounds
62%
Grant Probability
89%
With Interview (+26.9%)
3y 3m
Median Time to Grant
Low
PTA Risk
Based on 346 resolved cases by this examiner. Grant probability derived from career allow rate.

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