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 .
Claims 1-21, of record 10/30/2025, are pending.
Election/Restrictions
Applicant’s election without traverse of group I, claims 1-9, in the reply filed on 10/30/2025, is acknowledged. Claims 1-9 are subject to examination.
Claims 10-21 are withdrawn from further consideration pursuant to 37 CFR 1.142(b) as being drawn to a nonelected invention, there being no allowable generic or linking claim. Election was made without traverse in the reply filed on 10/30/2025.
Priority
The instant application is a national stage entry of PCT/CN2022/128137 (filed 10/28/2022). Acknowledgement is made of the applicant’s claim for foreign priority to Chinese applications 202111433970.7 (filed 11/29/2021) and 202210245504.4 (filed 3/14/2022).
Specification
The use of the terms 3M, Novec, Fluorinert, TECCEM, Fluoronox, Pluronic, and Millicell, which are trade names or marks used in commerce, has been noted in this application. The terms should be accompanied by the generic terminology; furthermore, the terms should be capitalized wherever they appear or, where appropriate, include a proper symbol indicating use in commerce such as ™, SM , or ® following the terms.
Although the use of trade names and marks used in commerce (i.e., trademarks, service marks, certification marks, and collective marks) are permissible in patent applications, the proprietary nature of the marks should be respected and every effort made to prevent their use in any manner which might adversely affect their validity as commercial marks.
Claim Interpretation
Independent claim 1 recites a culture method of adherent cells generating a tight junction structure. The claim is interpreted as requiring a method of culturing of adherent cells, thereby generating a structure comprising tight junctions.
Claim 9 recites the limitation “cell sheet”. This limitation is not defined in the instant specification and is therefore interpreted as requiring one or more confluent layers of cells.
Claim 9 further recites a membranous cell sheet having a tight junction structure cultured by the method of claim 1. The cell sheet is defined using product-by-process limitations. Thus claim 9 is a product-by-process claim. Product-by-process claims are considered only in so far as the method of production imparts distinct structural or chemical characteristics or properties to the product. Therefore, if the product as claimed is the same or obvious over a product of the prior art (i.e., is not structurally or chemically distinct), the claim is considered unpatentable over the prior art, even though the prior art product is made by a different process. See MPEP 2113. In the instant application, because the method of claim 1 does not distinguish the cell sheet structurally from cell sheets generated by other methods, the cell sheets are interpreted as comprising any cell sheets comprising tight junctions.
Claim Rejections - 35 USC § 101
35 U.S.C. 101 reads as follows:
Whoever invents or discovers any new and useful process, machine, manufacture, or composition of matter, or any new and useful improvement thereof, may obtain a patent therefor, subject to the conditions and requirements of this title.
Claim 9 is rejected under 35 U.S.C. 101 because the claimed invention is directed to a judicial exception (i.e., a law of nature, a natural phenomenon, or an abstract idea) without significantly more.
The claim has been analyzed for eligibility in accordance with its broadest reasonable interpretation.
Regarding claim 9: Claim is directed to a membranous cell sheet having a tight junction structure, cultured by the method according to claim 1. The broadest reasonable interpretation of the resulting cell sheet is considered to comprise any cell sheet or confluent layer(s) of cells comprising tight junctions. Based upon this interpretation, the claim is analyzed as follows:
Step 1: The claim is to a composition of matter, which is a statutory category of invention (Step 1: YES).
Step 2A, prong 1: The claimed cell sheet is described using product-by-process language, which is considered for the markedly different characteristics analysis. Cell sheets can be nature-based products. When a claimed composition includes a nature-based product, further analysis is taken to determine if the claimed composition recites a nature-based product judicial exception by comparing the claimed composition to the closest naturally occurring counterpart to determine if the claimed composition has markedly different characteristics than the counterpart.
The closest naturally occurring counterpart of a cell sheet comprising tight junctions is naturally occurring cell sheets or confluent cell layers. Hu et al. teach that keratinocytes naturally form multilayer sheets (See page 14, col. 1, full ¶4), and Komine et al. teach that the epidermis comprises multiple intact and discrete layers of keratinocytes and that tight junctions connect the granular layer of keratinocytes (See fig. 4). A naturally occurring layer of keratinocytes in skin would therefore read on the claimed “membranous cell sheet having a tight junction structure”. There is no evidence that the cell sheet as claimed differ from cell sheets in nature in terms of structural or functional characteristics. The claimed composition therefore does not have markedly different characteristics from what occurs in nature and is a "product of nature" exception. Accordingly, the claim is directed to an exception (Step 2A, prong 1: YES).
Step 2A, prong 2: The claim is directed to a product and does not recite any structure that serves to integrate the composition into a practical application (Step 2A, prong 2: NO).
Step 2B: There are no additional elements required by the claim. The claim does not qualify as eligible subject matter and is properly rejected under 35 U.S.C. 101.
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.
Claims 1-6 and 9 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Ando et al. (In Vitro Cellular and Developmental Biology, 1991), evidenced by Schneeberger et al. (American Journal of Physiology – Lung Cellular and Molecular Physiology, 1992) and further evidenced by Corning (Product data sheet, 2023).
Ando et al. teach the culture of human endothelial cells on a liquid-liquid interface formed from culture medium overlaid on a fluorocarbon solvent (See Abstract).
Regarding claims 1-3, 5, and 9: Ando et al. teach the formation of liquid-liquid interfaces using culture medium and FC43 (heptacosafluorotributylamine, which reads on “bottom support liquid” and “fluorinated oil”) (See Abstract and page 526, col. 1, full ¶1 and 3). FC43 was used with and without pentafluorobenzyl chloride and with and without cell attachment proteins (which reads on “a mixture”) (See page 527, col. 2, ¶3 and fig. 3-4). Endothelial cell (which reads on “adherent cell”) suspensions were pipetted onto the fluorocarbon layer and grown as confluent monolayers (which read on “a membranous cell sheet”) (See page 526, col. 2, full ¶2-3 and page 527, col. 2, ¶1). The cells were seeded at a density of 3 × 104 cells/cm2 (which reads on “a concentration of 2*104 -2*108 pcs/cm2”) (See page 526, col. 2, full ¶3).
Ando et al. do not expressly teach the endothelial cell monolayer as comprising tight junctions. However, Schneeberger et al. teach that tight junctions are part of the hallmark junctional complexes of endothelial cell monolayers (See page L647, col. 1, ¶1-2). The monolayers of Ando et al. would therefore inherently comprise tight junction structures.
Regarding claim 4: Following the discussion of claims 1-3, 5, and 9, Ando et al. teach that FC43 was added to 48-well plates at 0.4 ml/well and to 12-well plates at 0.6ml/well (See page 526, col. 1, full ¶3). Corning teaches that each well of a 48-well plate has an approximate area of 0.95 cm and that each well of a 12-well plate has an approximate area of 3.8 cm (See page 2). Because commercial well plate configurations are highly standardized, the volume of FC43 in either well plate would therefore read on “an amount greater than 0.8 mL/cm2”.
Regarding claim 7: Following the discussion of claims 1-3, 5, and 9, Ando et al. teach that the endothelial cells had been subcultured by trypsinization (which reads on “cells after passage digestion”) prior to seeding on the interface (See page 526, col. 1, full ¶2-3).
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.
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 1-7 and 9 are rejected under 35 U.S.C. 103 as being unpatentable over Ando et al. (In Vitro Cellular and Developmental Biology, 1991), evidenced by Schneeberger et al. (American Journal of Physiology – Lung Cellular and Molecular Physiology, 1992) and further evidenced by Corning (Product data sheet, 2023).
The teachings of Ando et al., Schneeberger et al., and Corning are set forth in the rejection above and are incorporated herein in their entirety.
Regarding claim 6: Following the discussion of claims 1-5, 7, and 9, Ando et al. teach the culture of endothelial cell monolayers on a fluorocarbon liquid substrate for 0-10 days (which reads on “1-28 days”) (See fig. 2-3 and 6) but do not expressly teach culturing at 35-39°C. However, Ando et al. teach that the cells were incubated under standard conditions for proliferation assays and that cells were allowed to attach to the interface at 37°C (See page 526, col. 2, full ¶2-3).
It would have been obvious to one having ordinary skill in the art to modify the express method of Ando et al. to comprise culturing of the cells at 37°C, as Ando et al. teach that this temperature is appropriate for, at least, endothelial cell attachment (See page 526, col. 2, full ¶2-3). One of ordinary skill would also recognize that 37°C would fall under “standard conditions” for mammalian cell culture. Such a modification could be readily made.
Claims 1-9 are rejected under 35 U.S.C. 103 as being unpatentable over Ando et al. (In Vitro Cellular and Developmental Biology, 1991), evidenced by Schneeberger et al. (American Journal of Physiology – Lung Cellular and Molecular Physiology, 1992) and further evidenced by Corning (Product data sheet, 2023), further in view of Masters et al. (Nature Protocols, 2007).
The teachings of Ando et al., Schneeberger et al., and Corning are set forth in the rejection above and are incorporated herein in their entirety.
Regarding claim 8: Following the discussion of claims 1-7 and 9, Ando et al. teach the culture of endothelial cell monolayers on a fluorocarbon liquid substrate, wherein the cells were re-fed with fresh culture medium twice a week (See page 526, col. 2, full ¶3). Ando et al. do not teach replacement of 70-90% of the culture medium every 10-15 h.
Masters et al. provide an overview of cell culture protocols and teach that how frequently the culture medium needs to be changed depends on the cell line and type of medium and that medium changes must be related to cell health and any experiments (See page 2278, col. 2, full ¶3-4).
It would have been obvious to one having ordinary skill in the art prior to the effective filing date of the claimed invention to optimize the method of Ando et al. to comprise more frequent medium changes, such as twice daily (which would read on “once every 10-15 hours”). Masters et al. establish that medium changes constitute a result-effective variable (See page 2278, col. 2, full ¶3-4), which would be ripe for optimization. One would be motivated to make the modification of more frequent medium change because Ando et al. teach that some of the volume of the wells is taken up by fluorocarbon solvent (See page 526, col. 1, full ¶3), thereby reducing the amount of nutrients and waste metabolite buffering capacity of the available medium. Ando et al. also teach that care must be taken when removing the aqueous layer, so as to avoid emulsifying the fluorocarbon solvent in the aqueous layer (See page 526, col. 2, full ¶2). One of ordinary skill would therefore also be motivated to avoid removing all of the spent medium at each change in order to prevent disturbing the fluorocarbon layer, instead removing only the majority (which could encompass “70-90%”), which would further prioritize more frequent medium changes. Such modifications could be readily carried out in conjunction with the method of Ando et al.
Conclusion
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/J.S.S./Examiner, Art Unit 1633
/CHRISTOPHER M BABIC/Supervisory Patent Examiner, Art Unit 1633