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 Interpretation
Claim 1 has been amended to state “the method does not need to use an extracellular matrix coating”. This is interpreted to mean that the claimed invention may use an extracellular matrix coating, but is also considered complete without one. (i.e., use of an extracellular matrix coating is optional) Therefore, art reading on claim 1 comprising use of an extracellular matrix coating will read on the claims, and art reading on claim 1 without use of an extracellular matrix coating will read on claim 1.
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, 2, 4, 5 are rejected under 35 U.S.C. 103 as being unpatentable over Lin et al. (US 2020/0197572 A1) in view of Youngblood et al. (Microporous scaffolds support assembly and differentiation of pancreatic progenitors into ß- cell clusters, 2019) and Yao et al. (Animal-cell culture media: History, characteristics, and current issues, 2017)
Regarding claim 1: Lin teaches a perfusion bioreactor system that uses an alginate porous scaffold seeded with mesenchymal stem cells (MSCS) that allows the formation of 3D cell clusters (0075) seeded at a density of about 1x105 to 2x106 MSCs per scaffold (0067). This reads on the claimed method of implanting pluripotent stem cells directly into the pores of a porous scaffold at a density of at least 1x104 or more MSCs per scaffold. Lin further teaches a culture method using incubation at 37°C and a CO2 percentage of 5% (0066), along with an embodiment of the invention being cultured in xeno-free culture conditions (0074). This reads on the claimed method of immersing the porous scaffold seeded with pluripotent stem cells in a xeno-free medium and performing amplification culture at the claimed ranges of 35.5-39.5°C and CO2 at a concentration of 5%. Lastly, Lin teaches that the invention uses alginate scaffolds (further defining that the term “scaffold” may refer to a calcium alginate scaffold throughout the embodiments of the invention), which refer to scaffolds comprising alginate which may be cross-linked with calcium ions (0054-0055) which reads on the claimed method of use of calcium-alginate scaffolds. Lin fails to teach use of a specific culture medium consisting of E8 with DMEM/F12, insulin, sodium selenite, transferrin, L-ascorbic acid, bFGF, TGF-ß, and sodium bicarbonate and use of a microporous scaffold structure.
Yao et al. teaches that since the establishment of human embryonic stem cells in culture, a simple, low-cost and highly productive method of culture was needed and that as a result, xeno and feeder-free medias were developed. (Pg 108, 2.8.2) One of these medias developed, E8, became popular due to its simple composition which comprises DMEM/F12 supplemented with insulin, sodium selenite, transferrin, ascorbic acid (specifically the stable form L-ascorbic acid), FGF2, TGFß, and sodium bicarbonate. (Pg 108, 2.8.2) This reads on the claimed method of use of a culture medium being an E8 culture medium consisting of a DMEM/F12 culture medium, insulin, sodium selenite, transferrin, L-ascorbic acid, bFGF, TGF-β, and sodium bicarbonate (NaHCO3).
Youngblood teaches that porous scaffolds are useful to provide a 3D environment to facilitate assembly of human pluripotent stem cells into organoid-like structures and that specifically, microporous scaffolds allow for cell to cell and cell to matrix signaling that supports the self-organization of the cells into functional tissue structures and aid differentiation. (Pg 2-3, Introduction) Youngblood also teaches an experimental set up testing different size microporous scaffold structures and their impacts on the culture of ß-cell clusters when compared to traditional suspension culture and human islets and found that pore size directly correlates to the expression levels of differentiation and maturation markers and that marker levels were higher in micropore cultures when compared to suspension culture. (pg 7, 3.2) This reads on the claimed method of use of a micropore network structure within the porous scaffold.
It would have been obvious to a person of ordinary skill in the art before the effective filing date of the claimed invention to combine the perfusion bioreactor culture method taught by Lin with the use of E8 media taught by Yao and the microporous structure taught by Youngblood to create a culture system for pluripotent stem cells that uses a microporous calcium alginate scaffold with xeno-free media, cultured at 35.5-39.5°C and CO2 at a concentration of 5%. One would have been motivated and had a reasonable success at doing so due to the teachings of Yao, who detail that E8 culture media is xeno-free, simple, and low-cost and Youngblood, who show that micropore size is directly correlated in higher expression of differentiation and maturation markers when compared with suspension culture.
Regarding Claim 2: Lin teaches a method of preparation of alginate scaffolds that are prepared by freeze-drying to generate a porous structure and cross-linked with divalent metal ions, including calcium. (0062-0063)
Regarding Claims 4 and 5: Yao et al. teaches that pluripotent stem cells are useful for disease modeling, drug discovery, cytotoxicity studies and regenerative medicine, which reads on the method of claim 4. (Pg 108, 2.8.2) Lin teaches a culture method to generate “three-dimensional tissue-like implants” which is defined as a mass of cells which form a cell cluster that are functionally bound to each other and capable of responding on an individual cellular level and also function together like a tissue or organ. (0047) This reads on the method of claim 5 of the cells aggregating to present an embryoid body appearance state. Lin fails to teach use of pluripotent stem cells.
It would have been obvious to a person of ordinary skill in the art before the effective filing date of the claimed invention to combine the perfusion bioreactor culture method taught by Lin which generates three-dimensional tissue-like implants with incorporation of stem cells to be used in culture as taught by Yao. One would have been motivated and had a reasonable expectation of success at doing so based on the teachings of Yao, who details that stem cells are useful for a variety of purposes, including regenerative medicine and disease modeling.
Claim 3 is rejected under 35 U.S.C. 103 as being unpatentable over Lin et al. (US 2020/0197572 A1) in view of Youngblood et al. (Microporous scaffolds support assembly and differentiation of pancreatic progenitors into ß- cell clusters, 2019), Yao et al. (Animal-cell culture media: History, characteristics, and current issues, 2017), and Mahammod et al. (Investigation of Physico-mechanical Behavior, Permeability and Wall Shear Stress of Porous HA/PMMA Composite Bone Scaffold, 2019)
The teachings of Lin, Youngblood, and Yao are disclosed above. Lin, Youngblood, and Yao fail to teach a specified porosity of the scaffold at 65% or more, as measured by liquid displacement.
Regarding Claim 3: Mahammod teaches a method of measuring the percentage of porosity of fabricated scaffolds through the liquid displacement technique (pg 5507, 2.3.3) and that permeability of a scaffold increases with an increase in porosity. (Pg 5512, 3.5.1) Mahammod further teaches that the fabricated scaffolds have a maximum porosity of 75+/-2%, reading on the claimed range of the porous scaffold having a porosity of 65% or more as measured by liquid displacement. (Pg 5505, Abstract)
It would have been obvious to a person of ordinary skill in the art before the effective filing date of the claimed invention to use the porosity measurement technique as taught by Mahammod to ensure the alginate scaffold of the claimed invention has a porosity of at least 65%. One would have had a reasonable expectation of success and motivation at doing so based on the teachings of Mahammod, who states that a higher porosity increases the permeability of a scaffold and the method of liquid displacement as a tool of measurement to determine porosity.
Claim 6 is rejected under 35 U.S.C. 103 as being unpatentable over Lin et al. (US 2020/0197572 A1) in view of Youngblood et al. (Microporous scaffolds support assembly and differentiation of pancreatic progenitors into ß- cell clusters, 2019), Yao et al. (Animal-cell culture media: History, characteristics, and current issues, 2017), and Chen et al. (3D Porus Calcium-Alginate Scaffolds Cell Culture System Improved Human Osteoblast Cell Clusters for Cell Therapy, 2015)
The teachings of Lin, Youngblood, and Yao are disclosed above. While Lin discloses use of a chelating agent, Lin fails to teach use of a chelating agent at a specified concentration of 20-60 mM.
Chen teaches a method of dissolving a calcium alginate scaffold to release tissues from the scaffold by use of EDTA (a chelating agent) at a concentration of 50mM. (Pg 646, Cell cluster size distribution) This reads on the claimed range of 20-60mM.
It would have been obvious to a person of ordinary skill in the art before the effective filing date of the claimed invention to incorporate the concentration of a chelating agent as taught by Chen to release the cells by dissolving the porous calcium alginate scaffold. One would have had a reasonable expectation of success and motivation at doing so based on the teachings of Chen of use of a concentration of 50mM of a chelating agent to dissolve a calcium alginate scaffold.
Claims 8 and 9 are rejected under 35 U.S.C. 103 as being unpatentable over Lin et al. (US 2020/0197572 A1) in view of Youngblood et al. (Microporous scaffolds support assembly and differentiation of pancreatic progenitors into ß- cell clusters, 2019), Yao et al. (Animal-cell culture media: History, characteristics, and current issues, 2017), and Kim et al. (US 2019/0376046 A1)
The teachings of Lin, Youngblood, and Yao are disclosed above. Lin, Youngblood, and Yao fail to teach use of either mouse embryonic fibroblasts (MEF) or human foreskin fibroblasts (HFF) as feeder cells in culture and use of ROCK in culture.
Regarding Claim 8: Kim et al. teaches use of mouse embryonic feeder (MEK) cells in the culture of human induced pluripotent stem cells to be used in the process of generating iPSC lines. (0263)
Regarding Claim 9: Kim et al. teaches that ROCK inhibitor can be used in culture in order to promote cell survival and reduce vulnerability of cell death, especially during the process of single-cell dissociation. (0104)
It would have been obvious to a person of ordinary skill in the art before the effective filing date of the claimed invention to incorporate the teachings of Kim et al. of use of MEK feeder cells and use of ROCK inhibitor with the perfusion bioreactor culture method taught by Lin which generates three-dimensional tissue-like implants to create a culture system which uses feeder MEK cells and ROCK inhibitor. One would have been motivated and had a reasonable expectation of success at doing so due to the teachings of Kim, who states that ROCK is useful in aiding cell survival and that feeder cells are useful in the generation of iPSC cell lines.
Response to Arguments
Applicant's arguments filed 10/10/2025 have been fully considered but they are not persuasive.
Applicant argues that Lin fails to read on the teachings of claim 1 due to the fact that Lin teaches use of differentiation of multipotent stem cells (mesenchymal stem cells) into specific specialized stem cells, whereas the claimed method teaches the amplification of stably pluripotent stem cells. This is unpersuasive because while Lin does teach use of mesenchymal stem cells which are multipotent, not pluripotent, Yao teaches methods of culture for human embryonic stem cells, which are pluripotent. (Pg 108, 2.8.2) Furthermore, the definition of “amplification” as provided by the applicant is to “produce a large amount of pluripotent stem cells” (Specification, pg. 16, first partial paragraph) Therefore, the very act of maintaining pluripotent stem cells in culture (as taught by Yao, with the same media claimed by the Applicant) reads on the amplification of pluripotent stem cells. In addition to this, Lin teaches a method of expanding isolated MSCs in culture for about 3-4 passages (0066) and that the MSCs were expanded ex vivo to “obtain sufficient amounts of cells” (0164). This method of amplification (as defined by producing large amounts of pluripotent stem cells) of MSCs may be combined with the teachings of Yao of the culture of embryonic stem cells in the claimed E8 media, resulting in the amplification of a population of pluripotent stem cells.
Applicant further argues that segments of the Specification of the claimed invention teach the shortcomings of use of an extracellular matrix coating system, and argue that Yao requires use of vimentin in addition to the use of the taught E8 media and that due to the stated drawbacks of use of an extracellular matrix coating system (as listed in the Specification), one skilled in the art would not have motivation to use the teachings of Yao. However, in response to applicant's argument that the references fail to show certain features of the invention, it is noted that the features upon which applicant relies (i.e., the recited drawbacks of extracellular matrix coating systems) are not recited in the rejected claim(s). Although the claims are interpreted in light of the specification, limitations from the specification are not read into the claims. See In re Van Geuns, 988 F.2d 1181, 26 USPQ2d 1057 (Fed. Cir. 1993). As noted in the Claim Interpretation section, the use of an extracellular matrix coating has been interpreted to be optional in light of the amended claim 1.
Applicant further argues that Youngblood fails to teach use of calcium alginate scaffolds and instead teaches use of PLG and PEG scaffolds. This is unpersuasive because while Youngblood does not make use of calcium alginate scaffolds, Lin specifically teaches use of alginate scaffolds which have been cross-linked with calcium ions. (0054-0055)
Lastly, Applicant argues that due to Lin requiring use of a perfusion bioreactor system and the claimed invention not requiring use of one and due to Yao disclosing the claimed medium but failing to disclose use of the medium specifically for pluripotent stem cells, a person of ordinary skill in the art would lack motivation to combine the teachings of Lin, Yao, and Youngblood. However, per MPEP 2141.II.C, “a person of ordinary skill in the art is also a person of ordinary creativity, not an automaton." KSR, 550 U.S. at 421, 82 USPQ2d at 1397. "[I]n many cases a person of ordinary skill will be able to fit the teachings of multiple patents together like pieces of a puzzle." Id. at 420, 82 USPQ2d at 1397. Office personnel may also take into account "the inferences and creative steps that a person of ordinary skill in the art would employ." Id. at 418, 82 USPQ2d at 1396.
Regarding claims 2-6 and 8-9, Applicant argues that as the claims listed depend from claim 1, they should be allowable on the same basis. As discussed above, the arguments pertaining to claim 1 were found unpersuasive and therefore, claims 2-6 and 8-9 have the rejections upheld on the same basis.
Conclusion
THIS ACTION IS MADE FINAL. 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 HANNA M THUESON whose telephone number is (571) 272-3680. The examiner can normally be reached M-F 7:30-5 EST. 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.
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/HANNA MARIE THUESON/ Examiner, Art Unit 1638
/Tracy Vivlemore/ Supervisory Primary Examiner, Art Unit 1638