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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 04/08/2026 has been entered.
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), Yao et al. (Animal-cell culture media: History, characteristics, and current issues, 2017), and Biological Industries (An Introduction to the Evolution of Human Pluripotent Stem Cell Culture Systems, 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.
The article by Biological Insights teaches that the ideal hPS culture environment is made of all known components, with little or no variables involved. In short, a fully defined environment. (Pg 2, third paragraph) They further teach that use of feeder cells modifies the microenvironment and impacts cultured stem cells in ways that aren’t fully understood, introducing variability into the culture system and creating an undefined microenvironment. (Pg 2, 5th paragraph) Lastly, they teach that culture of hPS cells without feeder cells results in fewer variables and is becoming the basis for most human stem cell labs, resulting in a xeno-free and chemically defined environment. (Pg 3, paragraphs 3-5)
As it stands, none of the aforementioned sources teaches use of ROCK inhibitor, thereby reading on the culture system being free of a ROCK inhibitor.
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.
One skilled in the art would be further motivated to incorporate the teachings of Biological Industries regarding the absence of ROCK inhibitor and feeder cells in the culture media. Motivation and a reasonable expectation of success is found in the teachings of Biological Industries, who teach away from use of feeder cells as they can introduce variables to an otherwise defined environment.
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.
Response to Arguments
Applicant's arguments filed 04/08/2026 have been fully considered but they are not persuasive.
Applicant argues that Lin teaches optional use of serum-containing culture media and therefore does not teach xeno-free conditions. However, by the Applicant’s own admission, Lin describes in paragraphs 0074 and 0195 use of xeno-free culture conditions and admits that Lin expressly states that use of serum is optional. Therefore, the invention as taught by Lin does teach use of xeno and serum free conditions.
Applicant further argues that one skilled in the art would have no reason to combine the teachings of the secondary references with the teachings of Lin for the following reasons:
The objectives of Lin and Yao are different as Lin teaches a method regarding MSCs when compared to the method involving PSCs by Yao.
The teachings of Youngblood cannot be abstracted from its specific material context and directly applied to the calcium alginate porous particle
Yao teaching that E8 is a known stem cell culture medium, but that does not necessarily mean that one skilled in the art would take this teaching and apply it to the culture method of claim 1.
The combined references fail to teach a method not using ROCK or feeder cells (Examiner notes this amendment was added after the final rejection was sent)
Mahammod is different in its technical purpose and material system, giving a person skilled in the art no reason to combine with Lin
Chen teaches a different technical purpose, therefore giving a person skilled in the art no reason to combine.
These arguments fail to be persuasive because a person skilled in the art does not operate within a vacuum; in fact, per MPEP 2141.03, "A person of ordinary skill in the art is also a person of ordinary creativity, not an automaton." KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398, 421, 82 USPQ2d 1385, 1397 (2007). "[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 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. One skilled in the art would have been motivated to incorporate the teachings of Yao, Youngblood, Mahammod, and Chen with the teachings of Lin for the following reasons:
In addition to teaching use of E8, Yao further teaches that E8 culture media is xeno-free, simple, and cost effective, making it an attractive option for any form of stem cell culture
Youngblood does not merely teach a different material system. Youngblood teaches a detailed study of how micropore size impacts differentiation and maturation markers in stem cell culture, testing multiple pore sizes when compared to suspension culture. This information is crucial when taken in the context of Yao, as it can aid in increasing or preventing differentiation.
Mahammod clearly demonstrates that a higher porosity increases the permeability of a scaffold, using liquid displacement to demonstrate said porosity. This gives one skilled in the art a sound motivation to have a scaffold porosity of 65% or more.
Chen teaches the proper concentration of a chelating agent to dissolve a calcium alginate scaffold
Conclusion
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
Prosecution Insights