DETAILED ACTION
Summary
This is a Final Office Action in reply to the Remark for Non-Final Office Action filed 10 June 2025 for the application filed 27 July 2021. Claims 17, 19-33 are pending.
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 .
Priority
Acknowledgment is made of applicant’s claim for foreign priority (BE2019/5061, filed on 31 January 2019) under 35 U.S.C. 119 (a)-(d). Receipt is acknowledged of certified copies of papers required by 37 CFR 1.55.
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 text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
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:
Determining the scope and contents of the prior art.
Ascertaining the differences between the prior art and the claims at issue.
Resolving the level of ordinary skill in the pertinent art.
Considering objective evidence present in the application indicating obviousness or nonobviousness.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claims 17, 19-27, and 30-32 are rejected under 35 U.S.C. 103 as being unpatentable over DESMET (US20100166611A1) in view of TACHIBANA et al. (US20160199835A1, hereinafter TACHIBANA) and KIYOMOTO et al. (US20100032357A1, hereinafter KIYOMOTO).
Regarding Claim 17, DESMET discloses a flow-distribution region designed to spread a liquid uniformly across the lateral width of a flat-rectangular separation channel containing a separation medium (¶[0017]).
FIG. 1a illustrates a flow-distribution region preceding a separation channel 5 containing a separation medium. It includes a short open region 10 with minimal lateral flow resistance, directly connected to inlet 1, followed by a flow-distribution region 20 with micro-machined pillars 30 having a lateral-to-axial width ratio greater than 3/2 and packed to induce a lateral permeability at least twice the axial permeability. The pillars decrease in size from the inlet, and at the outlet the regions are arranged in the opposite order, ending with an open region (¶[0025]).
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FIG. 1a from DESMET (US20100166611)
FIG. 3 illustrates a configuration where open region 10b and flow-distribution region 20b are etched to the same depth as the separation channel containing separation medium 5. Selecting pillar sizes and inter-pillar dimensions in region 20b to achieve low axial permeability helps induce a downward convective flow through open region 10b, enhancing fluid mixing across the depth of the separation channel (¶[0028]).
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FIG. 3 from DESMET (US20100166611)
FIG. 4, a variant of FIG. 3, uses a perpendicularly etched connection channel 25 so that at least a part of 20a is arranged on a surface different from the surface carrying the separation channel—either on the surface of substrate body 40 carrying the separation channel filled with separation medium 5, or on a surface of substrate body 60 used to close off the channel. The perpendicular connection channel 25 induces a perpendicular flow to the separation channel, promoting mixing in the depth of the channel. (¶[0029])
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FIG. 4 from DESMET (US20100166611)
As FIG. 4 illustrates, open region 10b is deeper than flow-distribution region 20b, so there is a sudden decrease in depth at their interface, with depth understood as the dimension measured perpendicular to the substrate. Region 10b corresponds to the first duct part, and 20b corresponds to the second duct part. The step occurs at the entrance to 20b, which is part of the filter element and contains filter pillars. Although DESMET does not expressly describe a filtration mechanism at this step, it is reasonably interpreted that the sudden constriction in depth, combined with the onset of the pillar array, creates a passive filtering effect by modulating flow resistance and encouraging inertial or convective particle separation.
Notably, FIGs. 3 and 4 depict pillars extending in the inlet, whereas FIG. 1a illustrates the inlet as free of pillars. This contrast illustrates a design variant regarding whether to include pillars in the inlet, rather than a required structural feature. Therefore, it is reasonable to interpret FIGS. 1a as showing a pillar-free inlet region.
The limitation “a depth of the second duct part is less than 50% to 5% of a depth of the first duct part” is considered a result of routine optimization. FIG. 3 and FIG. 4 illustrate two configurations with different depth relationships between open region 10b and flow-distribution region 20b. In FIG. 3, regions 10b and 20b appear to have similar depths, while in FIG. 4, region 10b is visibly deeper than region 20b. This variance demonstrates that the relative depth of these regions is an adjustable design choice. A person having ordinary skill in the art would recognize that selecting a particular depth ratio within the claimed range would be an expected engineering adjustment based on flow dynamics, fabrication constraints, and performance goals in microfluidic system (In re Aller, 220 F.2d 454, 456–57; 1955).
The limitations “the filter element for reducing or preventing materials from causing a blockage...,” “a part located downstream...,” and “configured to induce a filtering effect at the sudden step decrease” are functional language describing intended results and do not add patentable weight to the claim (In re Casey, 370 F.2d 576, 1967).
However, DESMET does not explicitly disclose “wherein the inlet has a first depth dhigh, the first depth dhigh referring to a dimension of the inlet measured perpendicular with respect to the substrate,” and “wherein the part located downstream of the filter element has a second depth d1ow smaller than the first depth dhigh of the inlet, the second depth d1ow referring to the dimension measured perpendicular with respect to the substrate.”
TACHIBANA discloses a microfluidic device including a channel for transporting a reaction solution (abstract). In certain variations, the cross-sectional area of the channel decreases along the flow direction, and fluid control is further enhanced by incorporating one or more pillars within the channel to adjust that area (¶[0020]).
As shown in FIG. 8B, TACHIBANA illustrates channel 100 within reaction section 110, where the cross-sectional area decreases in the direction of flow of reaction solution 300. Unlike a prior embodiment that narrows in width while maintaining a constant depth, this variation retains constant width and instead gradually reduces depth. This tapering in depth ensures a controlled decrease in cross-sectional area, providing a consistent feed velocity through channel 100. As a result, the reaction solution 300 resides in each temperature zone of first heater block 141 and second heater block 142 for a uniform duration, improving chemical reaction efficiency (¶[0121]–[0126]).
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Fig. 8B from TACHIBANA et al. (US20160199835A1)
FIG. 10B illustrates a variation of the microfluidic device in which the cross-sectional area of channel 100 is adjusted using cylindrical pillars 160, rather than relying solely on a tapered structure. In this configuration, a plurality of cylindrical pillars 160 are arranged upright within channel 100, reducing the cross-sectional area in the region where they are present. This structural modification achieves similar benefits to the prior embodiment, enabling precise control of reaction solution 300 flow and maintaining a consistent feed velocity. As a result, the reaction solution 300 remains within each temperature zone for a uniform duration, thereby enhancing chemical reaction efficiency (¶[0135]–[0137]).
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Fig. 8B from TACHIBANA et al. (US20160199835A1)
FIG. 8B and FIG. 10B collectively illustrate a microfluidic device where the cross-sectional area of channel 100 decreases in the fluid flow direction. In FIG. 8B, the upstream region can be understood as the inlet, where channel 100 initially exhibits a greater depth (dhigh) measured perpendicular to the substrate. As the reaction solution flows downstream, the depth of the channel gradually decreases while its width remains constant, resulting in a reduced downstream depth (dlow). In FIG. 10B, cylindrical pillars 160 are positioned upright within channel 100, further reducing the cross-sectional area in the region corresponding to the decreased depth. The inclusion of pillars in this section complements the tapered design by providing an additional means of controlling flow characteristics (¶[0020]).
TACHIBANA’s tapered structure provides a controlled reduction in cross-sectional area, which regulates fluid flow and maintains a constant feed velocity (¶[0113]–[0114]). This design minimizes pressure loss and capillary fluctuations, ensuring stable flow through the reaction section (¶[0115]). While the entire reaction section may incorporate this taper, even a partial reduction is sufficient to regulate velocity and improve reaction efficiency (¶[0116]). It would be beneficial to incorporate the tapered channel structure disclosed by TACHIBANA into the microfluidic device of DESMET to enhance flow control and improve reaction stability.
Therefore, it would have been obvious to a person having ordinary skill in the art, prior to the effective filing date of the claimed invention, to incorporate the tapered channel design disclosed by TACHIBANA into the fluidic channel of the chromatographic separation device by DESMET.
However, modified DESMET does not explicitly discloses “the first duct part has a diverging width so that the first duct part has a widening of the width in a downstream direction from the duct inlet towards the part located downstream of the filter element.”
KIYOMOTO discloses a microfluidic device (abstract). FIG. 1 illustrates a top view of the chromatography column, showing the layout of recess 21 with trapezoidal ends and the arrangement of pillars 22 within it (i.e., the first duct part has a diverging width so that the first duct part has a widening of the width in a downstream direction from the duct inlet towards the part located downstream of the filter element and the first duct part is free from pillar structures; ¶[0049]).
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Diagram: Fig. 1 from KIYOMOTO et al. (US20100032357A1)
The trapezoidal-shaped inlet design disclosed by KIYOMOTO promotes smooth sample flow by gradually widening toward the center of the channel (¶[0049]). This configuration minimizes turbulence at the entry and exit points, promoting stable, laminar flow. Based on fundamental fluid dynamics principles, a progressive expansion in channel width mitigates abrupt changes in velocity and pressure, reducing instability in microfluidic systems. These improvements contribute to enhanced separation efficiency and operational stability within chromatography. It would be beneficial to incorporate KIYOMOTO’s trapezoidal-shaped inlet into the first duct part of DESMET’s chromatographic separation device to ensure a controlled transition from the inlet to the downstream section, thereby reducing backpressure fluctuations and flow disturbances (KSR Int’l Co. v. Teleflex Inc., 550 U.S. 398, 415–421 (2007)).
Therefore, it would have been obvious to a person of ordinary skill in the art, prior to the effective filing date of the claimed invention, to incorporate the trapezoidal-shaped inlet, as disclosed by KIYOMOTO, with the duct part of the chromatographic separation device by modified DESMET.
Regarding Claim 19, modified DESMET makes obvious a microfluidic device of claim 17. DESMET disclose “wherein said device further comprises a sample injector connected to said inlet channel through a cylindrical connection capillary” (Claim 10).
The limitation “the fluid and/or the gas supplied by the capillary” merely describes the material acted upon by the reactor’s structure and does not impart any patentable weight to the claims (In re Young, 75 F.2d 996, 1935).
The limitation “the fluid and/or the gas supplied by the capillary has a drop in distance…” is considered inherent in DESMET, as FIG. 4 shows fluid from deeper region 10b entering shallower region 20b, naturally producing a vertical displacement (In re Best, 562 F.2d 1252, 1977).
Since DESMET is structurally capable of producing the claimed drop, the limitation reflects an intended result, not a structural distinction (In re Schreiber, 128 F.3d 1473, 1997).
Regarding Claim 20, modified DESMET makes obvious a microfluidic device of claim 17. FIG. 1a shows inlet 1 leading into short open region 10, which corresponds to the first duct part and has the same depth as the inlet. Flow then proceeds into distribution region 20 with pillars 30, corresponding to the filter element, which continues to a downstream separation channel of equal depth (FIG. 1a, ¶[0020]).
Regarding Claim 21, modified DESMET makes obvious a microfluidic device of claim 17. DESMET discloses that the micro-fabricated pillars have a lateral-to-axial width ratio greater than 3/2, which reads upon the claimed length/width aspect ratio between 2 and 0.5 (¶[0026]).
Regarding Claim 22, modified DESMET makes obvious a microfluidic device of claim 17. KIYOMOTO discloses pillars that are typically circular in shape, with alternatives including semicircular, rectangular, or polygonal forms (¶[0083]).
Regarding Claim 23, modified DESMET makes obvious a microfluidic device of claim 17. DESMET discloses that separation medium 5 downstream of region 20 can include additional micro-pillar structures, forming part of the downstream section (¶[0017]). FIG. 1a shows inlet 1 leading to open region 10 and flow distribution region 20 containing pillars 30, which constitute the second duct part. FIG. 4 further illustrates region 20b with pillars having defined sizes and inter-pillar distances (¶[0028]).
The limitation “the smallest distance between the filter pillars in the second duct part is at most the distance between the pillar structures downstream” is a design parameter subject to routine optimization. A person skilled in the art, based on modified DESMET and its disclosure of defined pillar spacing in region 20b, would find it obvious to adjust dimensions accordingly (In re Aller, 220 F.2d 454, 456, 1955).
Regarding Claim 24, modified DESMET makes obvious a microfluidic device of Claim 17. KIYOMOTO discloses five filter pillars in the first row transversely across the duct downstream from the inlet (FIG. 1), which reads upon the claimed “at least 5.”
Regarding Claim 25, modified DESMET makes obvious a microfluidic device of Claim 17. DESMET discloses pillar zones with the largest pillars positioned closest to the inlet, followed by smaller pillars downstream (¶[0023]). KIYOMOTO further discloses that pillars are typically cylindrical (¶[0083]).
Regarding Claim 26, modified DESMET makes obvious a microfluidic device of Claim 17. FIG. 1a shows region 20 leading into a downstream channel containing separation medium 5, which can include another micro-pillar array or any other suitable chromatographic medium designed to enhance separation (¶[0017]). Based on this structure and function, the downstream part would have been understood as a separation duct.
Regarding Claim 27, modified DESMET makes obvious a microfluidic device of Claim 26. DESMET discloses that the separation duct may be filled with micro-fabricated pillars having an elongated diamond-like or ellipsoidal shape (¶[0022]), and that the pillars are oriented laterally, perpendicular to the average direction of flow (¶[0027]).
Regarding Claim 30, modified DESMET makes obvious a microfluidic device of Claim 17. DESMET discloses a micro-fabricated separation channel that enhances the distribution of sample and carrier liquids, improving dispersion and permeability (¶[0006]). The channel, having a flat-rectangular cross-section, contains separation medium 5, which may consist of a micro-pillar array, bead packing, or monolithic support, as used in chromatographic separation (¶[0017]). The disclosed structure embodies the core functionalities of a chromatographic column in separating chemical species.
Regarding Claim 31, modified DESMET makes obvious a microfluidic device of Claim 17. DESMET discloses a device for liquid chromatographic separation (¶[0001]).
Regarding Claim 32, modified DESMET makes obvious a microfluidic device of Claim 31. DESMET discloses a micro-fabricated separation channel designed to enhance distribution of sample and carrier liquids, improving dispersion and permeability through flow distribution zones that prioritize lateral over axial flow (¶[0006]). These design features correspond to core aspects of a high-performance fluid chromatography system.
Regarding Claim 33, modified DESMET makes obvious a microfluidic device of Claim 17. FIG. 1a of DESMET shows inlet 1 leading directly into open region 10, which precedes the pillar-containing flow distribution region 20 (¶[0020]). As the inlet opens into region 10 without intervening pillars, the inlet is free of pillar structures.
Claims 28 and 29 are rejected under 35 U.S.C. 103 as being unpatentable over DESMET in view of TACHIBANA and KIYOMOTO as applied to claim 17, and further in view of HOCHGRAEBER et al. (US20120061955A1, hereinafter HOCHGRAEBER).
Regarding Claim 28, modified DESMET makes obvious a microfluidic device of Claim 17. Claim 10 of DESMET discloses a sample injector connected to the inlet channel through a cylindrical connection capillary. However, modified DESMET does not explicitly disclose the inlet is “provided with a stop element for accurately positioning the capillary in the inlet duct.”
HOCHGRAEBER discloses a plug unit and connection system for efficiently connecting capillary tubes, designed for use in high-performance liquid chromatography (title). FIG. 1 illustrates connection system 1 comprising a bushing unit 3 with housing 9, including a capillary tube receptacle opening 7 (i.e., inlet duct) and a central bushing capillary tube opening 11 formed in floor wall 13 (i.e., a stop element), as well as a plug unit 5 with housing 17 that threads into receptacle opening 15. This configuration enables precise capillary alignment and a pressure-tight seal essential for chromatographic performance (¶[0034]).
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Fig 1 from HOCHGRAEBER (US20120061955A1)
HOCHGRAEBER’s inlet design simplifies capillary tube connection by accommodating various outer diameters and ensuring a pressure-tight seal with minimal dead volume. The sealing element, positioned around the front end of the plug capillary, ensures precise alignment and enhances reliability in high-performance liquid chromatography systems (¶[0013]). It would be beneficial to incorporate this inlet structure into modified DESMET to achieve a secure and accurate capillary connection, improving fluid stability and overall system performance (KSR International Co. v. Teleflex Inc., 550 U.S. 398, 415–421, 2007).
Therefore, it would have been obvious to a person having ordinary skill in the art, prior to the effective filing date of the claimed invention, to incorporate the plug unit and connection system disclosed by HOCHGRAEBER into the microfluidic device by modified DESMET.
The limitation “for accurately positioning the capillary in the inlet duct” is interpreted as an intended use. DESMET discloses a sample injector integrated with the inlet channel via a cylindrical capillary, which inherently enables precise positioning (In re Schreiber, 128 F.3d 1473, 1477, 1997).
Regarding Claim 29, modified DESMET makes obvious a microfluidic device of Claim 28. HOCHGRAEBER discloses a bushing housing 9 with a central bushing capillary tube opening 11 formed within floor wall 13 (i.e., a stop element) of the capillary tube receptacle opening 7. The narrowing at this junction provides a structural stop by reducing the diameter within the inlet duct (¶[0034]).
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Front end of the bushing house 9, Fig 1 from HOCHGRAEBER (US20120061955A1)
Response to Amendment
Applicant’s arguments, see Remarks filed June 10, 2025, with respect to the previous rejection, have been fully considered and are not persuasive. The rejection under 35 U.S.C. §103 is maintained and updated to address the amendments made to claims 17 and 33. The current rejection regarding claims 17, 19–27, and 30–33 under 35 U.S.C. §103 as being unpatentable over DESMET et al. (US20100166611A1) in view of TACHIBANA et al. (US20160199835A1) and KIYOMOTO et al. (US20100032357A1), and claims 28–29 further in view of HOCHGRAEBER et al. (US20120061955A1), is maintained and updated.
The Examiner respectfully disagrees with the Applicant’s arguments:
Argument #1: Applicant contends that DESMET does not disclose a sudden step decrease in depth. However, FIG. 4 clearly shows region 10b is deeper than 20b, with a sharp transition between them (¶¶[0028]–[0029]). It is reasonably interpreted that this structural change inherently results in a filtering effect, as flow passes through the narrowed depth, consistent with inherency principles (In re Best, 562 F.2d 1252, 1255, 1977). TACHIBANA’s tapering variants, including those using pillar structures, are reasonably combinable to promote controlled flow behavior in microfluidic devices.
Argument #2: Applicant argues that DESMET lacks a diverging inlet geometry. However, KIYOMOTO discloses a trapezoidal-shaped inlet with widening toward the channel center (FIG. 1, ¶[0049]). It would have been obvious to incorporate this geometry into DESMET’s inlet to improve sample flow and minimize turbulence.
Argument #3: Applicant alleges DESMET is incompatible with TACHIBANA’s tapered channel containing pillars. However, FIG. 1a of DESMET shows a first duct part (region 10) free of pillars, while TACHIBANA presents the use of pillars as an optional configuration. The references are not mutually exclusive and do not teach away. A combination would yield predictable structural benefits.
Global Response: The applied references collectively teach all claim limitations. The combination is supported by sound design incentives grounded in fluid mechanics and device performance. Prima facie obviousness is therefore established (KSR Int’l Co. v. Teleflex Inc., 550 U.S. 398, 415–421, 2007).
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 TAK L. CHIU whose telephone number is (703)756-1059. The examiner can normally be reached M-F: 9:00am - 6:00pm (CST).
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, VICKIE Y KIM can be reached at (571)272-0579. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/TAK L CHIU/Examiner, Art Unit 1777
/KRISHNAN S MENON/Primary Examiner, Art Unit 1777