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
As of the Final Office Action mailed 9/25/2025, claims 1-3, 5-6, and 8-10 were pending.
In Applicant's Response filed on 12/29/2025, claims 1, 5-6, and 8-10 were amended.
As such, claims 1-3, 5-6, and 8-10 are pending and have been examined herein.
Withdrawn Objections/Rejections
The objections and rejections presented herein represent the full set of objections and rejections currently pending in this application. Any objections or rejections not specifically reiterated are hereby withdrawn.
Claim Rejections - 35 USC § 112(b) – Maintained and New Grounds Based on Amendments
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 1-3, 5-6, and 8-10 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 1 contains the trademark/trade name Matrigel. Where a trademark or trade name is used in a claim as a limitation to identify or describe a particular material or product, the claim does not comply with the requirements of 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph. See Ex parte Simpson, 218 USPQ 1020 (Bd. App. 1982). The claim scope is uncertain since the trademark or trade name cannot be used properly to identify any particular material or product. A trademark or trade name is used to identify a source of goods, and not the goods themselves. Thus, a trademark or trade name does not identify or describe the goods associated with the trademark or trade name. In the present case, the trademark/trade name is used to identify/describe a solubilized basement membrane matrix cell culture substrate and, accordingly, the identification/description is indefinite. Claim 2-3, 5-6, and 8-10 are included in this rejection for being ultimately dependent on indefinite claim 1.
Claim 1 recites “so as to allow the mixed matrix material to form a gel and thereby to obtain a gelled 3D organ-on-a-chip” and “which can be used for hepatotoxic drug screening.” This limitation appears to be narrative in format. Thus, the claim is indefinite. Claim 2-3, 5-6, and 8-10 are included in this rejection for being ultimately dependent on indefinite claim 1.
Response to Arguments
Although Applicant states that claim 1 is amended to address the rejection, the claim still contains the phrase “Matrigel” both with and without the trademark symbol. Thus, it is not sufficient to overcome the rejection.
Claim Rejections - 35 USC § 102
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 the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention.
(a)(2) the claimed invention was described in a patent issued under section 151, or in an application for patent published or deemed published under section 122(b), in which the patent or application, as the case may be, names another inventor and was effectively filed before the effective filing date of the claimed invention.
Claim(s) 9 is/are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Prodanov et al (Biotechnol Bioeng. 26 Aug 2015;113(1):241-6; of record).
Prodanov teaches long term maintenance of a microfluidic 3-D human liver sinusoid (title). The aim of this study was to mimic the liver sinusoidal microenvironment more accurately than standard culture techniques and re-create human liver physiology and functions on-a-chip (Introduction, para 2). A co-culture of human primary hepatocytes with cell lines representing the non-parenchymal liver cell fraction can be maintained over a period of 28 days (same para). The assembled 3D model allows culture of human hepatocytes in small numbers (< 10 000) and in a low total volume of media of 24 μL /per day in flow conditions or 1 μL /per day in static condition for up to 28 days. The co-cultured primary human hepatocytes maintained a consistent morphology and nuclear clarity for the first three weeks (see Fig. 2). This anticipates “A 3D human liver organ model, wherein the liver cells inoculated to the cultivation micropores are grown in an aggregated form, exhibit globular morphology, extend pseudopodia, and remain viable and proliferative for 12 days” as in instant claim 9.
Claim 9 is a product-by-process claim, which is not limited to the manipulations of the recited steps, only by the structure implied by the steps. MPEP 2113 states that “[e]ven though product-by-process claims are limited by and defined by the process, determination of patentability is based on the product itself. The patentability of a product does not depend on its method of production. If the product in the product-by-process claim is the same as or obvious from a product of the prior art, the claim is unpatentable even though the prior product was made by a different process.” In re Thorpe, 777 F.2d 695, 698, 227 USPQ 964, 966 (Fed. Cir. 1985) (citations omitted). Furthermore, "[b]ecause validity is determined based on the requirements of patentability, a patent is invalid if a product made by the process recited in a product-by-process claim is anticipated by or obvious from prior art products, even if those prior art products are made by different processes." Amgen Inc. v. F. Hoffmann-La Roche Ltd., 580 F.3d 1340, 1370 n. 14, 92 USPQ2d 1289, 1312, n. 14 (Fed. Cir. 2009).
Accordingly, Prodanov anticipates the invention of instant claim 9.
Response to Arguments
Applicant’s arguments have been fully considered but are not persuasive.
On p. 6 of Remarks, Applicant argues that the 3D human liver organ model prepared according to claim 1 and Prodanov are structurally different. In sum, Applicant argues that Prodanov discloses a structure of a 3D human liver sinusoid that is different from the organ model prepared by the method of claim 1 because of how the organ of Prodanov is made. Applicant argues that the morphology of the hepatocytes in Prodanov are different because they do not grow in an aggregate form exhibit globular morphology. or extend pseudopodia as in claim 9.
In response, the examiner disagrees. First, claim 9 is a product-by-process claim, which is not limited to the manipulations of the recited steps, only by the structure implied by the steps. MPEP 2113 states that “[e]ven though product-by-process claims are limited by and defined by the process, determination of patentability is based on the product itself. The patentability of a product does not depend on its method of production. If the product in the product-by-process claim is the same as or obvious from a product of the prior art, the claim is unpatentable even though the prior product was made by a different process.” In re Thorpe, 777 F.2d 695, 698, 227 USPQ 964, 966 (Fed. Cir. 1985) (citations omitted). Furthermore, "[b]ecause validity is determined based on the requirements of patentability, a patent is invalid if a product made by the process recited in a product-by-process claim is anticipated by or obvious from prior art products, even if those prior art products are made by different processes." Amgen Inc. v. F. Hoffmann-La Roche Ltd., 580 F.3d 1340, 1370 n. 14, 92 USPQ2d 1289, 1312, n. 14 (Fed. Cir. 2009). The limitation “wherein the liver cells inoculated to the cultivation micropores are grown in an aggregated form, exhibit globular morphology, extend pseudopodia, and remain viable and proliferative for 12 days” as recited in claim 9 is how the cells in the organ model are deposited and the structural and functional characteristics of the cells used to create the organoid (i.e., another product-by-process limitation). Once a product appearing to be substantially identical is found and a prior art rejection is made, the burden shifts to applicant to come forward with evidence establishing an nonobvious difference between the claimed product and the prior art product. In re Marosi, 710 F.2d 799, 803, 218 USPQ 289, 292-33 (Fed. Cir. 1983) (see MPEP 2113). Moreover, arguments presented by applicant cannot take the place of evidence in the record. See In re De Blauwe, 736 F.2d 699, 705, 222 USPQ 191, 196 (Fed. Cir. 1984); In re Schulze, 346 F.2d 600, 602, 145 USPQ 716, 718 (CCPA 1965); In re Geisler, 116 F.3d 1465, 43 USPQ2d 1362 (Fed. Cir. 1997). The examiner requests Applicant submit empirical evidence on the record showing non-obvious differences (i.e., unexpected results, functions, etc.) between the organ model of Prodanov and that instantly claimed. Absent evidence to the contrary, the model of Prodanov anticipates the model as instantly claimed and the rejection is maintained.
Claim Interpretation
Claim 1 recites, inter alia, “preparing human primary liver cells, or mixed cells of the human primary liver cells and liver non-parenchymal cells, or human liver cancer cell lines” and “the number of inoculated cells of the human primary liver cells is 2500-12000, and the number of inoculated cells of the human liver cancer cell lines is 3000-5000”. As the preparation step lists the types of cells to be prepared listed in the alternative, the examiner is interpreting that the number of inoculated cells for human primary liver cells and liver cancer cell lines are also in the alternative (i.e., finding one is sufficient to meet the claim limitation).
Claim 2 recites “digesting human primary liver cells into a single cell suspension, and carrying out centrifugation and resuspension to obtain a single cell suspension with a density of 4.45 x 106 -44.5 x 106 cell/mL”. It has been interpreted as an intended result of the positively recited method step of digestion, centrifugation, and resuspension. Claim 3 recites “resuscitating and diluting human primary liver cells into a single cell suspension, and carrying out centrifugation and resuspension to obtain a single cell suspension with a density of 8.9 x 106 cell/mL”. It has been interpreted as an intended result of the positively recited method steps of resuscitating, diluting, centrifugation, and resuspension. Claim 5 recites “digesting human liver cancer cell lines hepG2 into a single cell suspension, and carrying out centrifugation and resuspension to obtain a single cell suspension with a density of 0.89 x 106 -8.9 x 106 cell/mL”. It has been interpreted as an intended result of the positively recited method step of digestion, centrifugation, and resuspension. Claim 6 recites “digesting human liver cancer cell lines hepG2 into a single cell suspension, and carrying out centrifugation and resuspension to obtain a single cell suspension with a density of 3.56 x 106 cell/mL”. It has been interpreted as an intended result of the positively recited method step of digestion, centrifugation, and resuspension.
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) 1-3 is/are rejected under 35 U.S.C. 103 as being unpatentable over Prodanov et al (Biotechnol Bioeng. 26 Aug 2015;113(1):241-6) in view of Hamilton et al (WO2017096282A1, 2 Dec 2016; Published 8 June 2017; previously cited), and Eddington et al (US 10,571,461 B2, 12 Oct 2016; Published 25 Feb 2020).
Prodanov teaches long term maintenance of a microfluidic 3-D human liver sinusoid (title). The aim of this study was to mimic the liver sinusoidal microenvironment more accurately than standard culture techniques and re-create human liver physiology and functions on-a-chip (Introduction, para 2). A co-culture of human primary hepatocytes with cell lines representing the non-parenchymal liver cell fraction can be maintained over a period of 28 days (same para). The reference teaches that, due to the limited availability of primary non-parenchymal human cells, for this early attempt to re-create a liver sinusoid on-a-chip, three cell lines of human origin EA.hy926, LX-2 and U937 that have been extensively characterized were used as substitutes for endothelial, stellate and KCs, respectively (Introduction, para 3). Primary human hepatocytes were thawed according to the manufacturer protocol, and a cell suspension was prepared in plating media at a final concentration of 6.5 × 106 (M) mL−1 (“Cell seeding in the device” para 1) (“preparing human primary liver cells . . . into a single cell suspension” as in instant claim 1 in-part; overlaps with “resuspension to obtain a single cell suspension with a density of 4.45 × 106 – 44.5 × 106 cells/mL” as in instant claim 2 in-part; “resuscitating and diluting human primary liver cells into a single cell suspension” as in instant claim 3 in-part). Four hours after the cell seeding, the plating media was replaced with maintenance media and the following day, collagen/LX-2 cell suspension was prepared by mixing one part of collagen gel solution (9 parts 1.25 mg mL−1 type I rat tail collagen mixed with 1 part 10 × DMEM) with one part of LX-2 cells 0.5 × 106 (M) mL−1 LX-2 cells (same para) (“mixing the single cell suspension with a matrix material to obtain a mixed cell suspension” as in instant claim 1 in-part). EA.hy926 cells were added on top of the membrane in the top chamber with a density of 10 × 106 (M) mL−1 on day 2 (same para). After the differentiation the U937 were trypsinized and introduced in the top chamber with a cell density of 0.25 × 106 (M) mL−1. The devices were maintained in maintenance media at 37 °C for 28 days (same para). The assembled 3D model allows culture of human hepatocytes in small numbers (< 10 000) and in a low total volume of media of 24 μL /per day in flow conditions or 1 μL /per day in static condition for up to 28 days (overlaps with “the number of inoculated cells of the human primary liver cells is 2500-12000” as in instant claim 1 in-part; “adding a culture medium into liquid storage holes of the gelled 3D organ-on-a-chip and carrying out cultivation at 37C to obtain a 3D human liver organ model for hepatotoxic drug screening” as in instant claim 1 in-part). The co-cultured primary human hepatocytes maintained a consistent morphology and nuclear clarity for the first three weeks (Fig. 2)
Prodanov differs from the instant invention in that it does not teach that the inoculation volume of the mixed cell suspension is 6-10 uL or that the matrix material is a mixed matrix material including collagen and Matrigel where the volume ratio of the collagen to Matrigel is 1:0.5-1:2 (related to claim 1 in-part). It also does not teach digesting, centrifugation, and resuspension (instant claim 2 in-part and 3 in-part).
Hamilton teaches devices for stimulating the function of a human liver tissue using primary human cryopreserved hepatocytes to create liver-on-a-chip (abstract and see claim 2 of Hamilton). The reference teaches that isolated hepatocytes are frozen using conventional freezing techniques, stored in liquid nitrogen tanks until used (para 00417) (“resuscitating and diluting human primary liver cells” as instant claim 3 in-part; see p. 10 of instant specification where human primary liver cells are “resuscitated” from being preserved by liquid nitrogen). Seeding density of hepatocytes into liver-on-chips effects liver-chip viability (para 454 of Hamilton). Overseeding or under-seeding reduces liver chip viability and function while optimal seeding, ranging from 2.1 to up to 3.4 million cells/mL (i.e., 2100 cells/uL to 3400 cells/uL) provides a healthy liver-on-chip (same para) (such that if 6 uL of cell suspension is seeded, 12,600 cells minimum would be seeded [2100 cells/uL times 6 uL]; “inoculation volume of the mixed cell suspension is 6-10 uL” as in instant claim 1 in-part). Please note that 12,600 cells is close to 12,000 cells and, as per MPEP 2144.05(I), a prima facie case of obviousness exists where the claimed ranges or amounts do not overlap with the prior art but are merely close. Titanium Metals Corp. of America v. Banner, 778 F.2d 775, 783, 227 USPQ 773, 779 (Fed. Cir. 1985).
Eddington teaches a micropatterned substrate (abstract) containing hepatocytes (see claims 1 and 16 of Eddington). The reference teaches that the nonparenchymal fraction of liver was recovered via centrifugation following digestion of the liver with collagenase and a suspension with different types of liver cells (hepatocytes, sinusoidal endothelial cells, and Kupffer cells) were obtained (Nonparenchymal cell culture, para 1) (“digesting human primary liver cells into a single cell suspension, and carrying out centrifugation and resuspension to obtain a single cell suspension” as in instant claim 2 in-part; “carrying out centrifugation and resuscitation to obtain a single cell suspension” as in instant claim 3 in-part). The reference further teaches that hepatocyte culture models typically employed in the pharmaceutical industry rely on manipulating the extracellular microenvironment of hepatocytes with Matrigel and/or collagen (col 25, para 2) (“wherein the matrix material is a mixed matrix material including collagen and Matrigel” as in instant claim 1 in-part). When utilized with near confluent (80-100%) monolayers of hepatocytes, these models allow better retention of hepatocyte cytoarchitecture (i.e. bile canaliculi, tight junctions) and activity of specific CYP450 enzymes for a few more days (˜1 week) than that seen in monolayers on rigid collagen (same para). Extracellular matrix modifications improved specific hepatic functions, including CYP450 isoenzyme activities (up to 22% of fresh levels after 1 week of culture) (same para). While the Eddington reference does not explicitly teach that the volume ration of Matrigel to collagen is at a ratio of 1:0.5 to 1:2, differences in concentration or temperature will not support the patentability of subject matter encompassed by the prior art unless there is evidence indicating such concentration or temperature is critical. "[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation." In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955) (see MPEP 2144.05(II)(A)). Thus, one of ordinary skill would have reasonably selected an appropriate concentration ratio of Matrigel to collagen as a mode of routine optimization of standard laboratory techniques available at the time of filing to successfully create hepatocyte culture substrate to improve specific hepatic functions as taught by Eddington.
Therefore, it would have been obvious prior to the effective filing date of the instantly claimed invention to create a microfluidic 3D human liver as taught by Prodanov, where 6 uL of cell suspension is seeded as taught by Hamilton, to arrive at the instantly claimed invention. As Hamilton shows 6 uL of suspension can be used to create a 3D liver organ on a chip, one of ordinary skill would have been motivated to modify the method of Prodanov to include a similar seeding amount with a reasonable expectation of advantageously producing a healthy liver-on-a-chip with the optimal functioning and viability as taught by the prior art.
It also would have been obvious prior to the effective filing date of the instantly claimed invention to create a microfluidic 3D human liver as taught by Prodanov, where the matrix material is a Matrigel/collagen mix as taught by Eddington, to arrive at the instantly claimed invention. As Eddington shows that the extracellular environment of a multi-well organ chip model can be manipulated one of ordinary skill would have been motivated to simply substitute one known element [collagen matrix] for another [collagen/Matrigel mix] to obtain the predictable result of advantageously having better retention of hepatocyte cytoarchitecture and activity of specific CYP450 enzymes as taught by the prior art.
Response to Arguments
Applicant’s arguments have been fully considered but are not persuasive.
On p. 7-8 of Remarks, Applicant argues that the resulting 3D human liver organ model made by the method of claim 1 is more bionic, has enhanced response sensitivity to hepatotoxic drugs, and exhibits stronger hepatotoxic damage effect and can reduce the screening difference of hepatotoxic drug due to species differences. Applicant argues that Prodanov does not disclose the structure of the 3D liver organ model according to claim 1. Applicant also argues, in sum, that Hamilton and Eddington do not remedy the deficiencies of Prodanov because (1) Hamilton is purportedly directed to a microfluidic device and there is no factual basis that the cell numbers used in a microfluidic system can be applied in the system of claim 1, and (2) Eddington does not teach cell suspensions within gel droplets and does not teach or suggest mixing a single cell suspension with matrix material as claimed. Finally, Applicant argues that even if Prodanov is modified according to Hamilton and Eddington, there is no reason to expect that the method of claim 1 would be obtained and the one of ordinary skill would not have expected the beneficial effects the method of claim 1 would provide.
In response, the examiner disagrees. Prodanov teaches long term maintenance of a microfluidic 3-D human liver sinusoid to mimic the liver sinusoidal microenvironment more accurately than standard culture techniques and re-create human liver physiology and functions on-a-chip. The reference shows that the cell suspensions of hepatocytes can be inoculated into microfluidic wells to produce a 3D organ-on-a-chip. Second, Applicant’s instant claims recite “a 3D organ-on-a-chip.” Organ-on-a-chip technology replicates human organ-level physiology via integration of cells/microtissue within microfluidic devices. The breadth of the claims necessarily encompass microfluidic devices such as those disclosed by at least previously cited Hamilton. Eddington was cited to show that a micropatterned substrate can contain hepatocytes and be subjected to digestion, centrifugation, and resuspension to create hepatocyte cytoarchitecture, etc. The “use for hepatotoxic drug screening” as claimed in claim 1 and argued in the remarks are an intended use of the liver organ model created by the method of claim 1. Absent empirical evidence to the contrary (in the form of an affidavit or declaration), the organ model produced by the method as described by Prodanov, Hamilton, and Eddington in combination would be suitable for that claimed intended use. Thus, Applicant’s argument is not persuasive.
Claim(s) 5-6 remain rejected under 35 U.S.C. 103 as being unpatentable over Prodanov et al (Biotechnol Bioeng. 26 Aug 2015;113(1):241-6) in view of Hamilton et al (WO2017096282A1, 2 Dec 2016; Published 8 June 2017; previously cited), and Eddington et al (US 10,571,461 B2, 12 Oct 2016; Published 25 Feb 2020) as applied to claims 1-3 above, and further in view of Deng et al (Biomicrofluidics. 2019 Mar 7;13(2):024101).
The teachings of Prodanov, Hamilton, and Eddington in combination were recited in the above 35 U.S.C. 103 rejection as applied to claim 1 of which claims 5-6 depend. The teachings will not be repeated here.
The difference between the combined teachings and the invention as instantly claimed is that they do not teach digesting human liver cancer cell lines hepG2 into a single cell suspension and carrying out centrifugation and resuspension to obtain a single cell suspension (related to instant claims 5 and 6).
Deng teaches a microfluidic liver model for investigation of hepatotoxicity induced by drug-drug interaction (title). The reference teaches a liver sinusoid-on-a-chip device composed of four kinds of transformed cell lines (HepG2 cells, LX-2 cells, EAhy926 cells, and U937 cells) that can culture a high density of HepG2 cells such as 1x107 cells/mL (abstract). Human hepatocellular carcinoma HepG2 cells were cultured and, when cell confluence reached 75-90%, the cells were subcultured after trypsin digestion, cultured in suspension, and centrifuged (Materials and Methods, para 1) (“digesting human liver cancer cell lines hepG2 into a single cell suspension and carrying out centrifugation and resuspension to obtain a single cell suspension” as in instant claims 5 and 6). The cell lines derived device enabled the investigation of a drug-drug interaction study to test the hepatotoxicity of acetaminophen and the following combinations: “acetaminophen + rifampicin,” “acetaminophen + omeprazole,” and “acetaminophen + ciprofloxacin” (abstract). The biomimetic microenvironments in the liver chip were capable of enhancing the phenotypes of liver function of HepG2 cells (“Reproduction of the synthesis and metabolism of liver function” para 1). The intercellular communication between HepG2 cells and the three other cell lines enhanced APAP induced hepatotoxicity and regulated the activity of metabolic enzymes of HepG2 cells (“Testing drug-drug interaction” para 1). The reference concludes that the device was able to improve the accuracy of hepatotoxicity testing and made it possible to detect potential drug-drug interaction using HepG2 cells (Conclusion para 1).
Therefore, it would have been obvious prior to the effective filing date of the instantly claimed invention to create a 3D liver-on-a-chip as taught by Prodanov, Hamilton, and Eddington in combination, where hepG2 cells are used in the organoid as taught by Deng, to arrive at the instantly claimed invention. As Deng shows that a microfluidic device can utilize HepG2 cells in a microfluidic device, one of ordinary skill would have been motivated to modify the 3D liver chip of Prodanov, Hamilton, and Eddington in combination to include this cell type with a reasonable expectation of advantageously having a liver chip capable of improving the accuracy of hepatotoxicity testing and made it possible to detect potential drug-drug interaction of hepatotoxic drugs such as acetaminophen as taught by the prior art.
Response to Arguments
On p. 9 of Remarks, Applicant argues that the Deng reference is cited for teaching HepG2 cells but does not remedy the deficiencies of the combination of Prodanov, Hamilton, and Eddington. In response, the examiner disagrees. The combination of Prodanov, Hamilton, and Eddington render at least claim 1 prima facie obvious for the reasons set forth above. Applicant has not challenged the Deng reference for the specific teachings it was cited for (rendering prima facie obvious the limitations of claims 5-6). Thus, the rejection is maintained.
Claim(s) 8 is/are rejected under 35 U.S.C. 103 as being unpatentable over Prodanov et al (Biotechnol Bioeng. 26 Aug 2015;113(1):241-6) in view of Hamilton et al (WO2017096282A1, 2 Dec 2016; Published 8 June 2017; previously cited), and Eddington et al (US 10,571,461 B2, 12 Oct 2016; Published 25 Feb 2020) as applied to claims 1-3 above, and further in view of Xia et al (US 10488320; previously cited).
The teachings of Prodanov, Hamilton, and Eddington in combination were recited in the above 35 U.S.C. 103 rejection as applied to claim 1 of which claim 8 depends. The teachings will not be repeated here.
The difference between the combined teachings and the invention as instantly claimed is that they do not teach adding a buffer solution into an anti-evaporation structure of the gelled 3D organ-on-a-chip.
Xia teaches a microfluidic chip (abstract). The reference teaches that the microfluidic chip has a plurality of structural layers creating microchannels from which buffer fluids can be added (i.e., anti-evaporation structure) (CITE). The buffer fluid can be any buffer fluid known in the art of microfluidics and that the buffer contains nutrients well known in the art to maintain the viability of the components in the fluid mixture (“Microfluidic chip assembly” para 3). This shows that a microfluidic device can have microchannels through which buffer can be added to maintain viability of cells within the microfluidic device.
Therefore, it would have been obvious prior to the effective filing date of the instantly claimed invention to create a 3D liver-on-a-chip as taught by Prodanov, Hamilton, and Eddington in combination, where buffer is added into microchannels as taught by Xia, to arrive at the instantly claimed invention. As Xia shows that a microfluidic device can have microchannels specifically for the perfusion of buffer solutions, one of ordinary skill would have been motivated to add buffer solution to channels of a 3D liver-organ-on-a-chip with a reasonable expectation of advantageously maintaining the viability of cells within the microfluidic device as taught by the prior art.
Response to Arguments
Applicant argues that the Xia reference is cited for teaching microfluidic chip but does not remedy the deficiencies of the combination of Prodanov, Hamilton, and Eddington. However, Applicant has not provided any arguments challenging the specific teachings of previously cited references Xia et al nor has Applicant attempted to distinguish instant claim 8 rejected using this reference from the teachings of this specific reference as applied in the above 103 rejection.
Claim(s) 10 is/are rejected under 35 U.S.C. 103 as being unpatentable over Prodanov et al (Biotechnol Bioeng. 26 Aug 2015;113(1):241-6) in view of Ma et al (Lab Chip, 21 Aug 2018; 18(17):2547-2562) and Skardal et al (WO2018071354A1, 10 Oct 2017; Published 19 Apr 2018).
Prodanov teaches long term maintenance of a microfluidic 3-D human liver sinusoid (title). The aim of this study was to mimic the liver sinusoidal microenvironment more accurately than standard culture techniques and re-create human liver physiology and functions on-a-chip (Introduction, para 2). A co-culture of human primary hepatocytes with cell lines representing the non-parenchymal liver cell fraction can be maintained over a period of 28 days (same para). The assembled 3D model allows culture of human hepatocytes in small numbers (< 10 000) and in a low total volume of media of 24 μL /per day in flow conditions or 1 μL /per day in static condition for up to 28 days. The co-cultured primary human hepatocytes maintained a consistent morphology and nuclear clarity for the first three weeks (see Fig. 2). The reference teaches that the hepatocytes had sustained CYP3A4 activity over a long time, which is important for drug-related studies (p. 3, para 3). This reads on “ A method for screening hepatotoxic drugs using the 3D human liver organ model according to claim 9, comprising constructing the 3D human liver organ model” as in instant claim 10 in-part.
Prodanov differs from the instantly claimed invention in that it does not teach culturing the constructed 3D liver cell line organ model for 4 days, removing culture medium and adding 100 uL of a cell culture medium containing 100 uM of hepatotoxic drug, and culturing the 3D liver organ model for 3 to 8 days.
Ma teaches the design and fabrication of liver-on-a-chip platform (title). To assess the liver-specific functions under different culture conditions, albumin and urea production were analyzed as key function markers (“Determination of albumin and urea production”). Briefly, after culturing for 4, 6, 8, 10, and 12 days, the medium remaining in the waste medium container was collected (same para). The liver-on-a-chip demonstrated to allow convenient and safe perfusion culture of hepatic spheroids with a uniform size, smooth surface, high cell viability, and extremely low spheroid loss. (Introduction, para 3). Also, up to 12 days in culture, the hepatic polarity, liver-specific functions, and metabolic activity of the hepatic spheroids in 3D-LOC were also remarkably improved and exhibited better long-term maintenance over conventional perfusion methods (same para). This shows that after organoid construction, the organoid can be cultured for at least 4 days, reading on “culturing the constructed 3D liver cell line organ model for 4 days; removing the culture medium” as in instant claim 10 in-part.
Finally, Skardal teaches body-on-a-chip containing liver-on-a-chip (abstract). The reference teaches that the liver-on-a-chip is a 3D liver and that LIVE/DEAD staining of the 3D liver can be used to screen FDA-recalled drugs (para 00014). The apparatus can be used in a method of in vitro drug screening, toxicology screening and/or disease modeling by providing the apparatus, circulating a growth medium containing at least one test compound and detecting a pharmacological and/or toxicological response to the test compound (para 108). The apparatus may draw the common aqueous growth media from a reservoir at a rate of about 5, 10, 15, 20, 25, 30, 35, 40, 45, or 50 μL/min or any range and/or individual value (para 000079). The test compound may comprise cadmium, such as, e.g., CdCl2, optionally in a concentration in a range of about 0.1 μΜ to about 100 μΜ (para 111). Fig. 13 shows the on-chip response to acetaminophen responding to acetaminophen toxicity and rescue by n-acetyl-L-cysteine (para 00023). The platform can be employed to demonstrate basic cell toxicity in drug screens with Doxorubicin, Atorvastatin, Valproic Acid, Acetaminophen and N-Acetyl-m- aminophenol (para 124). The medium can circulate through the chambers for 1 to 30 days for a sufficient time (para 118) (“adding 100 uL of a cell culture medium containing 100 uM of a hepatotoxic drug; and culturing the 3D human liver organ model for 3 to 8 days” as in instant claim 10 in-part). This platform can be used to precisely and reproducibly integrate the liver with other organs to assess physiological responses to drugs and toxic agents, and be employed for environmental and biological monitoring while responding to a variety of external stimuli similar to organ dynamics found in the human body (para 125).
Response to Arguments
Applicant argues that the Ma and Skardal references are cited for teaching liver-on-a-chip fabrication but does not remedy the deficiencies of the combination of Prodanov, Hamilton, and Eddington. However, Applicant has not provided any arguments challenging the specific teachings of previously cited references Ma and Skardal et al from instant claim 10 as applied in the above 103 rejection. Thus, the rejection is maintained.
Conclusion
No claim is allowed.
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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/G.R./Examiner, Art Unit 1632
/KARA D JOHNSON/Primary Examiner, Art Unit 1632
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