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 .
Continued Examination Under 37 CFR 1.114
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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 13 April 2026 has been entered.
Response to Amendment
This is an office action in response to Applicant’s arguments and remarks filed on 13 April 2026. Claims 1-4, 6-9, 11-19, and 21-23 are pending in this applicant. Claims 1-4, 6-9, 11-12, and 23 are withdrawn from consideration. Claims 13-19 and 21-22 are being examined herein.
Status of Objection and Rejections
The rejections of claims 13-18 and 22 under 35 U.S.C. § 103 in view of Sarkar, et. al. (US 20170307488 A1) in view of Burke, et. al. (US 20140093867 A1) are withdrawn in view of amendments.
The rejection of claim 19 under 35 U.S.C. § 103 in view of Sarkar, et. al. (US 20170307488 A1) in view of Burke, et. al. (US 20140093867 A1) and in further view of Lim, et. al. (US 20130130226 A1) is withdrawn in view of amendments
The rejection of claim 21 under 35 U.S.C. § 103 in view of Sarkar, et. al. (US 20170307488 A1) in view of Burke, et. al. (US 20140093867 A1) and in further view of Hou, et. al. (US 20180185846 A1) is withdrawn in view of amendments
Response to Arguments
Applicant’s arguments, see Remarks, pages 6-9, filed 13 April 2026, with respect to the rejection(s) of claim(s) 13-18 and 22 under 35 U.S.C. § 103 in view of Sarkar, et. al. (US 20170307488 A1) in view of Burke, et. al. (US 20140093867 A1) have been fully considered and are persuasive. Therefore, the rejection has been withdrawn. However, upon further consideration, a new ground(s) of rejection is made in view of Sarkar, et. al. (US 20170307488 A1) in view of Bhagat, et. al. (US 20160303565 A1).
Applicant argues Sarkar in view of Burke teaches away from the amendments of claim 13, as Burke teaches outlet channels branching away from the main channel all along the outer spiral, and do not “branch from the second end” as required by independent claim 13 (Remarks, pg. 8, par. 02-04).
Examiner notes that the use of Sarkar, et. al. (US 20170307488 A1) as the primary art is maintained as Sarkar teaches other elements of the device outside of the specific configuration of the outlet channels as recited in independent claim 13. The use of Lim, et. al. (US 20130130226 A1) and Hou, et. al. (US 20180185846 A1) also remains because no additional arguments have been made by Applicant against them.
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 13-19 and 21-22 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 13 recited the limitation “a container in fluid communication with at least one of the outlet ports, wherein: the at least two outlet ports comprise a first outlet port which is in fluid communication with the container” in lines 7-10 of the claim. In the
Claims 14-19 and 21-22 are rejected based on their dependence to claim 13.
Claim 22 recites the limitation "wherein the first channel" in lines 1-2 of the claim. There is insufficient antecedent basis for this limitation in the claim as no “first channel” has been previously recited. Examiner believes "the first channel" recited is referring to "the first outlet channel" and will be examined as such. Examiner recommends amending the claim to recite "wherein the first outlet channel has an output flow rate..." or an equivalent thereof.
Claim Rejections - 35 USC § 103
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
Claims 13-18 and 22 are rejected under 35 U.S.C. 103 as being unpatentable over Sarkar, et. al. (US 20170307488 A1) in view of Bhagat, et. al. (US 20160303565 A1).
Regarding claim 13, Sarkar teaches a spiral microfluidic device to separate parts of biological samples (Abstract) (a microfluidic device). Sarkar teaches a Dean Flow Fractionation (DFF) microfluidic device 100 with a spiral shaped channel with a first end comprising two inlets 105 and a second end comprising at least two outlets 106 (Fig. 1; par. 0021) (a spiral-shaped channel comprising a first end and a second end, wherein the first end is in fluid communication with two inlet ports, and the second end is in fluid communication with at least two outlet ports). One of the two inlets is proximal to an inner wall and the other inlet is proximal to an outer wall (Fig. 1 and 2A) (wherein one of the two inlet ports is proximal to an inner wall of the spiral-shaped channel and the other inlet port is proximal to an outer wall of the spiral-shaped channel). At the second end, the spiral microfluidic channel branches into at least two separate channels, wherein each channel leads to a respective outlet port (Fig. 2A, 2B; par. 0035) (the spiral-shaped channel in fluid communication with the first outlet port comprises a first outlet channel which connects the second end of the spiral-shaped channel to the first outlet port) (other outlet channels respectively connecting the second end of the spiral- shaped channel to the other outlet ports), wherein at least one of the outlet channels is closest to the inner side of the spiral based on the branched configuration (Fig. 1, 2A, 2B) (the first outlet channel is proximal to the inner wall of the spiral-shaped channel, and the first outlet channel and the other outlet channels branch from the second end).
Sarkar teaches the output streams from each outlet, comprising the separated particles, are collected for downstream processing and later analysis (par. 0021, 00036). While Sakar does not explicitly disclose a container for collecting the output streams at each outlet, because the output stream is collected and later analyzed, one of ordinary skill in the art will understand a collection container of sort is required and therefore the microfluidic device must further comprise a container in fluid communication with at least one of the outlet ports, wherein: the at least two outlet ports comprise a first outlet port which is in fluid communication with the container.
Sakar is silent to a first outlet channel being longer than other outlet channels.
Bhagat teaches a microfluidic device comprising at least one spiral channel for isolating cells in a circulating sample (Abstract). Bhagat teaches an embodiment of the microfluidic device 800 comprising a microchannel 802 with curvilinear sections 804a, 804b (a spiral shaped channel) with a sheath inlet 806, sample inlets 808a, 808b (two inlet ports), and two outlet ports 812, 814 that branch from curvilinear section 804a (Fig. 8a; par. 0058-0059). Figure 8a has been provided below with the uppermost arrow indicating to the spiral shaped channel and the lowermost arrow indication the channel branching into two outlet channels. As seen in provided Figure 8a, outlet channel connected to outlet 812 is the innermost outlet channel and is longer than the outlet channel connected to outlet 814 (the spiral-shaped channel in fluid communication with the first outlet port comprises a first outlet channel which connects the second end of the spiral-shaped channel to the first outlet port and is longer than other outlet channels respectively connecting the second end of the spiral- shaped channel to the other outlet port) (the first outlet channel is proximal to the inner wall of the spiral-shaped channel, and the first outlet channel and the other outlet channels branch from the second end). Bhagat teaches this configuration creates a highly controllable flow resistance, particularly when used with a pump (par. 0059-0060).
PNG
media_image1.png
662
713
media_image1.png
Greyscale
It would have been obvious for one of ordinary skill in the art before the effective filing date of the invention to modify the length of the first outlet channel of Sarkar to be longer than the other outlet channels as taught by Bhagat because the geometry of the channels, including length, modifies the flow resistance of the device to be highly controllable (Bhagat, par. 0059-0060) with reasonable expectation of success. MPEP 2143(I)(G).
Regarding claim 14, modified Sarkar teaches the inlet port closest to the inside of the spiral channel is capable of supporting a sheath fluid that has an optimized flow rate of 1750 µL/min (compared to the sample inlet along the outer wall with a flow rate of 170 µL/min) (Sakar, Fig. 2A; par. 0013) (the inlet port proximal to the inner wall of the spiral-shaped channel is operable to introduce the sheath fluid at a higher flow rate than the inlet port proximal to the outer wall of the spiral-shaped channel).
Regarding claim 15, modified Sarkar teaches the inlet port closest to the outer wall introduces a sample at an optimized flow rate of 170 µL/min and the inlet port closest to the inner wall introduces a sheath fluid at an optimized flow rate 1750 µL/min, a ratio of approximately 1:10 (Sakar, Fig. 2A; par. 0013) (the inlet port proximal to the (outer) wall of the spiral-shaped channel and the inlet port proximal to the inner wall of the spiral-shaped channel are operable to introduce a sample and the sheath fluid at a flow rate ratio of 1:5 to 1:50).
Regarding claim 16, modified Sarkar teaches multiple dimensions for the spiral channel, including a specific embodiment with a width of 500 µm, a height of 87 µm, giving a width to height aspect ratio of 5.7 (Sakar, par. 0036), and the spiral itself have a length of at least 3 cm (Sakar, par. 0032) (a width ranging from 150 µm to 500 µm; a height ranging from 30 µm to 100 µm; a width to height aspect ratio ranging from 3 to 7; a length ranging from 3 cm to 10 cm).
Regarding claim 17, modified Sarkar teaches the microfluidic channel can have a variety of shapes including a curved shaped based on desired separation qualities (Sakar, par. 0029) (wherein the spiral- shaped channel is a semi-spiral-shaped channel).
Regarding claim 18, modified Sakar teaches the two inlet ports are located in the middle of the spiral channel and the spiral channel moves outwardly horizontal to the inlets before terminating in the outlets that are horizontally away from the spiral channel (Sakar, Fig. 1; Fig. 2A) (the two inlet ports are arranged in a manner where the spiral- shaped channel horizontally spirals around the inlet ports and the at least two outlet ports are arranged away from the spiral-shaped channel).
Regarding claim 22, modified Sarkar teaches the outlet channels each have different widths; this allows for particles of different sizes to be separated (Sakar, Fig. 2B). Because the flow rate must be conserved, the total flow rate from the spiral channel must equal the sum of the flow rates from the outlet channels, and cross-sectional area directly impacts the flow rate of within a channel, channels with a smaller width will ultimately have smaller flow rates than the channels with larger width. Additionally, this claim is drawn to a functional limitation of the channel and does not carry patentable weight. Because first channel has a smaller width (thus smaller cross-sectional area), it is reasonable to assume it can achieve an output flow rate of 1% to 10% of the total flow rate of all outlet channels. Further, no claims recite any components of the device that will create a flow rate, like a pump, syringe, etc.
Claim 19 is rejected under 35 U.S.C. 103 as being unpatentable over Sarkar, et. al. (US 20170307488 A1) in view of Bhagat, et. al. (US 20160303565 A1) as applied to claim 13, and in further view of Lim, et. al. (US 20130130226 A1).
Regarding claim 19, modified Sarkar teaches the size and shape of the microfluidic channel influences separation qualities of the device (Sarkar, par. 0009, 0033-0034).
Modified Sakar is silent to wherein the first outlet channel has a length ranging from 0.5 cm to 1.5 cm.
Lim teaches separation and isolation of parts in blood samples with a microfluidic device by alternating channel dimensions (Abstract). Lim teaches a microfluidic separation device with at least one inlet coupled to a spiral channel that separates components of a sample mixture based on channel size (length, height, width), before ending in at least one outlet (par. 0033). Lim teaches the length and width to height aspect ratio of the channel(s) are adapted to isolate the target particle in the sample (par. 0033).
However, Lim teaches wherein the length of the channel is a result effective variable. Specifically, Lim teaches that the length of the channel is based on the size of particles being separated and Dean drag forces (par. 0054). Sarkar and Bhagat, as outlined above, also discuss the importance of channel dimensions being based on separation. Since this particular parameter is recognized as a result-effective variable, i.e., a variable which achieves a recognized result, the determination of the optimum workable ranges of said variable can be characterized as routine experimentation. MPEP § 2144.05(II)(A)-(B). Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to modify the length of the first outlet channel (to have) a length ranging from 0.5 cm to 1.5 cm with reasonable expectation of success of creating a channel that will separate the desired element from the sample mixture.
Claim 21 is rejected under 35 U.S.C. 103 as being unpatentable over Sarkar, et. al. (US 20170307488 A1) in view of Bhagat, et. al. (US 20160303565 A1) as applied to claim 13, and in further view of
Regarding claim 21, modified Sakar teaches an expansion of the spiral channel near the second end, as it can be seen in Figures 1 and 2A (Sakar) the spiral channel expanding in width before splitting into the outlet channels (wherein the spiral-shaped channel gradually expands (in width)).
Modified Sakar is silent to the expanding specifically being to a width of 500 µm to 3000 µm.
Hou teaches a spiral-shaped microfluidic device for separation components of a blood sample (Abstract). Hou teaches the device comprises two inlets, and at least two outlets connected by a spiral-shaped microfluidic channel for separation of particles for blood (Fig. 1A, 1B; par. 0026-0028). Hou teaches, as seen in Figure 1B, the width of the spiral channel expanding before splitting into multiple outlet channels. Hou teaches an embodiment wherein the width expands to 1000 µm (par. 0028, 0115) (the spiral- shaped channel gradually expands to a width of 500 µm to 3000 µm). Hou teaches increasing the width to better help separate the components within the (blood) sample (par. 0125).
It would have been obvious to one skilled in the art before the effective filing date of the invention to modify the expanded end of spiral-shaped channel of Sarkar to more exactly expand to 1000 µm as taught by Hou because such an expansion helps separate the components within the (blood) sample and provides likewise sought functionality with reasonable expectation of success. MPEP § 2143(I)(G).
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to MADISON T HERBERT whose telephone number is (571)270-1448. The examiner can normally be reached Monday-Friday 8:30a-5:00p.
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, Maris Kessel can be reached at (571) 270-7698. 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.
/M.T.H./Examiner, Art Unit 1758
/MARIS R KESSEL/Supervisory Patent Examiner, Art Unit 1758
Prosecution Insights