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 .
Response to Amendment
This is an office action in response to Applicant’s arguments and remarks filed on 6 November 2025. 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 Claims 1-4, 6-9, 11-12, and 23 are withdrawn from consideration.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 the Objections and Rejections
The objection to claim 15 is withdrawn in view of amendments.
The rejection of claims 14 and 15 under 35 U.S.C. § 112(b) is withdrawn in view of amendments.
The rejection of claims 13-18 and 22 under 35 U.S.C. § 103 in view of Sarkar, et. al. (US 20170307488 A1) in view of Bhagat, et. al. (US 20190151847 A1) is withdrawn in view of amendments.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 Bhagat, et. al. (US 20190151847 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 (US 20130130226 A1) is withdrawn in view of amendments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 Bhagat, et. al. (US 20190151847 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 (US 20180185846 A1) is withdrawn in view of amendments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 pg. 06, par. 05 – pg. 08, filed 6 November 2025, with respect to the rejection(s) of claim(s) 13-19 and 21-22 under Sarkar, et. al. (US 20170307488 A1) in view of Bhagat, et. al. (US 20190151847 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 Therefore, the rejection has been withdrawn.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 Burke, et. al. (US 20140093867 A1).
Sarkar in view of Burke teaches remedies the missing element of the “first outlet channel is proximal to the inner wall of the spiral-shaped channel” in newly amendment claim 13 (see Remarks pg. 07, par. 01-02).
Applicant offers no additional arguments for claims 14-19 and 21-22 outside of their dependence on claims 13 (see Remarks pg. 08, par. 06). Examiner notes Applicant offers arguments regarding the functional application and limitations of the device drawn to the separation of particles; however, no such functional limitations are integrated into the claims (see Remarks pg. 08, par. 03-05).
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 Burke, et. al. (US 20140093867 A1).
With regards to Claim 13, Sarkar teaches a spiral microfluidic device to separate parts of biological samples (Abstract). Sarkar teaches a Dean Flow Fractionation (DFF) device 100 (microfluidic device) with spiral shaped channel with two inlets 105 and at least two outlets 106 (Fig. 1; par. 0021) (a spiral-shaped channel in fluid communication with (i) two inlet ports and (ii) 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 2) (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). Of the at least two outlets, there are outlet channels for each outlet that connect each outlet port to the spiral channel; this is seen where the spiral channel spits (Fig. 1 and 2) (wherein the spiral-shaped channel in fluid communication with the first outlet port comprises a first outlet channel which connects the spiral-shaped channel to the first outlet port). Additionally, the output streams of the outlets are collected for downstream processing (par. 0021, 0036); this implies at least one of the outlet ports are connected to a container to collect the output stream (and 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).
Sarkar is silent to a first outlet channel (being) longer than other outlet channels respectively connecting the spiral- shaped channel to the other outlet ports and the first outlet channel is proximal to the inner wall of the spiral-shaped channel.
Burke teaches a spiral inertial filtration device for particle separation (Abstract). Burk teaches the spiral inertial filtration device comprises an inlet, a main channel in a spiral shape and multiple outlets (Fig. 4; par. 0022, 0028). Burke teaches there are two different types of outlet channels, waste channels (W1-W6) and a branched collection channel (Fig. 4; 0132-0133). Burke teaches each waste channel branches away from the main channel and at the final branch, the main channel becomes the final collection channel and maintains its length along the inner wall of the spiral shaped channel (Fig. 4, 5A, 6A) (a first outlet… is longer than other outlet channels respectively connecting the spiral-shaped channel to the other outlet ports) (the first outlet channel is proximal to the inner wall of the spiral-shaped channel). Burke teaches the use of multiple waste outlet channels prior to collection outlet channels increases concentration and purity of the separated and collected sample (par. 0011)
It would have been obvious for one of ordinary skill in the art before the effective filing date of the invention to modify the outlet channels of Sarkar to be different lengths as taught by Burke in order to concentrate and purify the collected sample from the spiral microfluidic device. Because both devices use spiral flow cells to separate particles from a bulk fluid sample, modifying the outlet channels to be of different length as provided by Burke, provides likewise sought functionality with reasonable expectation of success. MPEP 2143(I)(G).
With regards to 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) (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).
With regards to 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 (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).
With regards to 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 (par. 0036), and the spiral itself have a length of at least 3 cm (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).
With regards to Claim 17, modified Sarkar teaches the microfluidic channel can have a variety of shapes including a curved shaped based on desired separation qualities (par. 0029) (wherein the spiral- shaped channel is a semi-spiral-shaped channel).
With regards to 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 (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).
With regards to Claim 22, modified Sarkar teaches the outlet channels each have different widths; this allows for particles of different sizes to be separated (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) and Burke, et. al. (US 20140093867 A1) as applied to claim 13 above, and further in view of Lim, et. al. (US 20130130226 A1).
With regards to Claim 19, modified Sarkar in view of Burke teaches outlet 23. channels of different length as seen in claim 13 above. Further, Sarkar teaches the size and shape of the microfluidic channel influences separation qualities of the device (Sarkar par. 0009, 0033-0034).
Modified Sarkar is silent to the first outlet channel (specifically having) 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) and Burke, et. al. (US 20140093867 A1) as applied to claim 13 above, and further in view of Hou, et. al. (US 20180185846 A1).
With regards to Claim 21, it can be seen in Figures 1 and 2A of modified Sarkar that the spiral channel expands in width before splitting into the outlet channels.
Modified Sarkar does not specify that the spiral-shaped channel gradually expands 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 in order to help separate the components within the (blood) sample. Because both spiral-shaped microfluidic devices expand at the end of the spiral channel, having an exact size to expand to as taught by Hou, provides likewise sought functionality with reasonable expectation of success. MPEP § 2143(I)(G).
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.
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/M.T.H./Examiner, Art Unit 1758
/MARIS R KESSEL/Supervisory Patent Examiner, Art Unit 1758