DETAILED ACTION
Status of the Claims
Claims 1-3, 5-10, and 12 are pending in the instant application. Claims 6-10 have been withdrawn based upon Restriction/Election as discussed below. Claims 1-3, 5 and 12 are being examined on the merits in the instant application.
Advisory Notice
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
All rejections and/or objections not explicitly maintained in the instant office action have been withdrawn per Applicants’ claim amendments and/or persuasive arguments.
Priority
The U.S. effective filing date has been determined to be 10/27/2020, the filing date of document KR 10-2020-0139899.
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 1-3, 5 and 12 are rejected under 35 U.S.C. 103 as being unpatentable over CHOI (WO-2017/222321-A1; US-2019/0359928-A1 relied on as English language translation herein) in view of Ceylan et al. (“3D-Printed Biodegradable Microswimmers for Theranoistic Cargo Delivery and Release,” 2019; American Chemical Society, ASC Nano, Vol. 13, pp. 3353-3362); Nichols et al. (“Cell-laden microengineered gelatin methacrylate hydrogels,” 2010; ELSEVIER; Biomaterials, Vol. 31, pp. 5536-5544); Yue et al.1 (“Synthesis, properties, and biomedical application of gelatin methacryloyl (GelMA) hydrogels,”2015; ELSEVIER; Biomaterials, Vol. 73, pp. 254-271); MA (US 2017/0081638; published March 2017);
and as evidenced by Fang et al. (“Three-Dimensional Cell Cultures in Drug Discovery and Development,” 2017, SLAS Discovery: Advancing the Science of Drug Discovery, Vol. 22, No. 5, pp. 456-472).
Applicants Claims
Applicant claims a microbot comprising: a spherical structure body; and a plurality of cells cultured on and attached to a surface of the spherical structure body, wherein the spherical structure body comprises: a spherical core comprising a mixture of a biodegradable material; a plurality of biocompatible magnetic nanoparticles; and a plurality of drugs, and wherein the plurality of cells comprise a stem cell, wherein the biodegradable material comprises gelatin methacryloyl (GelMA), and wherein the plurality of cells are cultured simultaneously with the spherical structure body in a U-bottom well treated with an ultra-low attachment (ULA) surface for preventing cell adhesion (instant claim 1).
Determination of the scope
and content of the prior art (MPEP 2141.01)
CHOI teaches a microbot-based biomimetic system (see whole document), and particularly “for delivering a drug or cell, organizing microorgans, and controlling fluid flow. The microrobot-based biomimetic system according to one aspect of the present invention comprises: a network for interconnecting microorgans constituting a biometric organ model; a microrobot for delivering a targeted drug or cell while moving in the network; and a magnetic field control unit for controlling an operation of the microrobot.” (abstract).
CHOI teaches that: “a microrobot configured to move within the network to perform target-directed delivery of a drug or cell, and a magnetic field controller configured to control operation of the microrobot.” ([0012]), and “can deliver a drug or cell to an in vivo local portion in a network of various body organ models interconnected in the biometric system, thereby monitoring physiological responses to and effects of a new drug.” ([0013]). And further that: “microrobots are moved by a magnetic field applied from the outside. Accordingly, it is unnecessary to provide an additional inlet and channel for guiding a micro-tissue into an artificial organ chamber, and the positions of the microrobots constituting various artificial organs including three-dimensional cultured cells can be precisely controlled to accurately load the microrobots at a target position.” ([0014]).
CHOI teaches that “The bio-scaffold type microrobot 100a is a porous bio-scaffold of a three-dimensional structure and can be configured in a hexahedral, cylindrical, elliptical, polygonal, or conical shape.” ([0035]). And that: “For example, the bio-scaffold type microrobot 100a is manufactured in lithography using a photocurable polymer and is thus formed as a porous bio-scaffold type microrobot of a micro-sized three-dimensional structure, which facilitates cell or drug delivery in the network 300 of the biometric system.” And further that: “The bio-scaffold type microrobot 100a, which is a porous scaffold, loads a three-dimensional cultured cell or a drug into the internal space of the scaffold having gaps and moves in the network 300.” ([0037])(instant claim 2, “the structured body is formed in a porous structure”; instant claim 3).
CHOI teaches that: “As another example, the microrobots 100a, 100b, and 100c configured to perform cell or drug delivery may be formed of a biodegradable material. In this case, coating the surfaces of the microrobots is avoided to ensure smooth in vivo bio-degradation. Instead, the scaffold is constructed with a mixture of iron oxide nanoparticles, which are a biocompatible magnetic material, and another bio-degradable material.” [emphasis added]([0041])(instant claim 1, “: a structure body having a three-dimensional (3D) structure formed by mixing a biodegradable first material, biocompatible magnetic nanoparticles”). CHOI further teaches that: “The above-described magnetic materials exhibit a certain intensity of magnetism and are composed of metals which have low corrosiveness. For example, iron, cobalt or neodymium may be used alone or in combination in addition to the above-described magnetic materials, and the entirety or a part of the outer circumferential surfaces of the microrobots 100a, 100b, and 100c configured to perform cell or drug delivery may be coated therewith.” ([0042]).
CHOI teaches that: “As shown in FIG. 1, regarding the brain 200c, a spherical microrobot 100d includes spherical scaffolds. The spherical microrobot 100d has a cell provided in a gap formed between the scaffolds and thus three-dimensionally cultures the cell.” ([0047]):
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(instant claim 1, “a spherical structure body; and a plurality of cells cultured on and attached to a surface of the spherical structure body” ). CHOI further teaches that: “The microrobot pumps 100f and 100g are formed of or coated with a magnetic material (Fe2O3, Fe3O4, etc.).” ([0053])(instant claim 12).
Ascertainment of the difference between
the prior art and the claims (MPEP 2141.02)
The difference between the rejected claims and the teachings of CHOI is that CHOI does not expressly teach (1) the cells are stem cells; (2) the inclusion of a drug and cells cultured on the surface of the structured 3D body, inclusion of a photoinitiator (claim 5) or the biodegradable first material is gelatin methacryloyl (GelMA).
While CHOI does not expressly teach delivery of a drug and a cell together, it would have clearly been prima facie obvious to combine the two, for example, a drug that positively directs cell growth (cell growth factors) or adhesion (e.g. RGD cell adhesion peptide).
Ceylan et al. teaches 3D-Printed biodegradable microswimmers for theranostic cargo delivery and release (see whole document), and particularly that: “The present study reports a hydrogel-based, magnetically powered and controlled, enzymatically degradable microswimmer, which is responsive to the pathological markers in its microenvironment for theranostic cargo delivery and release tasks. We design a double helical architecture enabling volumetric cargo loading and swimming capabilities under rotational magnetic fields and a 3D-printed optimized 3D microswimmer ([…]) using two-photon polymerization from a magnetic precursor suspension composed from gelatin methacryloyl and biofunctionalized superparamagnetic iron oxide nanoparticles.” [emphasis added](abstract). The examiner notes that CHOI teaches that: “The microbots may include a helical-scaffold type microbot 100c to perform a corkscrew motion to secure a larger propulsion force.” ([0032]).
Ceylan et al. teaches that: “We accomplish the fabrication of magnetically powered, environmentally responsive microswimmers by 3D printing of a nanocomposite magnetic precursor. The precursor comprises iron oxide nanoparticles dispersed in gelatin methacryloyl, a photo-cross-linkable semisynthetic polymer derived from collagen. Gelatin also contains target cleavage sites for MMP-2, thereby appealing as a biodegradable structural material for microrobots. We show that upon the enzymatic breakdown of the microswimmer network, anti-ErbB 2 antibody-tagged magnetic contrast agents are released into the local environment for targeted cell labeling of ErbB 2 overexpressing SKBR3 cancer cells, thereby promising follow-up evaluation strategy of the preceding therapeutic intervention. Altogether, the findings of the present work represent a leap toward in vivo mobile microrobots that are capable of sensing, responding to the local microenvironment, and performing specific diagnostic or therapeutic tasks using their smart composite material architectures in physiologically complex environments.” (p. 3354, col. 2, lines 7-25).
Nichols et al. teaches cell-laden microengineered gelatin methacrylate hydrogels (see whole document), and particularly that: “The cellular microenvironment plays an integral role in improving the function of microengineered tissues. Control of the microarchitecture in engineered tissues can be achieved through photopatterning of cell-laden hydrogels. However, despite high pattern fidelity of photopolymerizable hydrogels, many such materials are not cell-responsive and have limited biodegradability. Here, we demonstrate gelatin methacrylate (GelMA) as an inexpensive, cell-responsive hydrogel platform for creating cell-laden microtissues and microfluidic devices. Cells readily bound to, proliferated, elongated, and migrated both when seeded on micropatterned GelMA substrates as well as when encapsulated in microfabricated GelMA hydrogels.” [emphasis added](abstract).
Nichols et al. teaches that: “As specific microarchitectural features of the cell niche and the micromechanical environment have been demonstrated to be vital to controlling cell differentiation [6-9], researchers have sought materials with improved biological, chemical and mechanical properties.” (p. 5536, col. 1, lines 5-9). The examiner notes that References [6-9] of Nichols et al. are directed to stem cells (instant claim 1, “wherein the plurality of cells comprises a stem cell.”).
Nichols et al. further teaches that: “Gelatin methacrylate (GelMA) is a photopolymerizable hydrogel comprised of modified natural ECM components, making it a potentially attractive material for tissue engineering applications. Gelatin is inexpensive, denatured collagen that can be derived from a variety of sources, while retaining natural cell binding motifs, such as RGD, as well as MMP-sensitive degradation sites. Addition of methacrylate groups to the amine-containing side groups of gelatin can be used to make it light polymerizable into a hydrogel that is stable at 37 °C. Long term cell viability, and limited encapsulated cell elongation, have been demonstrated.” [emphasis added]. And “We hypothesized that as a light polymerizable hydrogel based on collagen motifs, GelMA could successfully be micropatterned into a variety of shapes and configurations for tissue engineering and microfluidic applications, while retaining its high encapsulated cell viability and cell-responsive elements (i.e. binding and degradation). In this report, we investigated the surface and 3D cell binding, cell elongation and migration properties of GelMA microgels. In addition, we investigated whether cell-laden GelMA could be made into perfusable microchannels which could be seeded with endothelial cells, for creating perfusable engineered tissues.” (p. 5537, col. 1, paragraphs 2-3).
Nichols et al. teaches that: “HUVECs2 were chosen as a model cell type for the potential application of GelMA in vascularized tissue engineering as well as to explore the compatibility of GelMA with a human cell type. HUVECs readily bound to GelMA surfaces of all concentrations with roughly the same affinity following initial seeding.” (p. 5540, col. 1, lines 5-10). And further teaches selective adhesion onto micropatterned GelMA surfaces (p. 5541, §3.6), and particularly that: “Following GelMA micropattern fabrication and incubation in DPBS to remove uncrosslinked gelatin from PEG surfaces, HUVEC cells (2 x 106 cells/mL) were pipetted onto the surface and incubated for 12 h to allow for adhesion to occur, washed with DPBS to remove non-adherent cells, then incubated for an additional 12 h to demonstrate persistence. As demonstrated, HUVEC cells bound only to GelMA surfaces, and not to PEG surfaces, quickly creating a confluent monolayer on GelMA patterns (Fig. 7).” (instant claim 1, “cells cultured on a surface of the structure body three-dimensionally.”).
Nichols et al. further teaches that: “One advantage of GelMA is the presence of binding sites distributed throughout the hydrogel on all polymer chains, potentially improving the probability of cell binding. Cells easily bound to, and formed a monolayer on GelMA surfaces, and elongated and migrated within GelMA demonstrating its positive cell-binding behavior.” (p. 5543, col. 1, lines 37-42). And that: “Overall we present evidence that GelMA would be suitable for a number of tissue engineering applications. For instance, GelMA allowed rapid cell adhesion, proliferation and migration on the surface of micropatterns. This could make GelMA well suited for controlled 2D cell interaction or cell shape studies by providing a rapid technique to create selectively binding regions of GelMA on PEG surfaces.” (p. 5543, col. 2, lines 1-7).
Nichols et al. concludes that: “In this report we demonstrated the use of GelMA for microscale tissue engineering applications, highlighting the unique properties that make GelMA an attractive material for creating cell-laden microtissues. The physical properties of GelMA were demonstrated to be controllable through variation of the degree of methacrylation and the gel concentration yielding a tunable range of mechanical and swelling properties for different applications. GelMA was easily patterned down to 100 µm resolution with the fidelity and robustness needed to perform as a cell-laden microgel or as a microfluidic device, similar to other commonly used hydrogels. However, unlike other synthetic UV crosslinkable hydrogels, cells readily adhered to, migrated within, proliferated and organized both on 2D and in 3D GelMA micropatterns. These data suggest that GelMA could be used for many microscale applications where other hydrogels are not well suited, such as for creating endothelial-lined vasculature within engineered tissues.” (p. 5543, §Conclusion).
Yue et al. (cited by Ceylan as reference 26, p. 3354, col. 2, lines 10-13), teaches that: “GelMA hydrogels closely resemble some essential properties of native extracellular matrix (ECM) due to the presence of cell attaching and matrix metalloproteinase responsive peptide motifs, which allow cells to proliferate and spread in GelMA-based scaffolds.” (abstract, lines 2-5)(instant claim 1, “cells cultured on and attached to a surface”).
Yue et al. teaches that: “GelMA undergoes photoinitiated radical polymerization (i.e. under UV light exposure with the presence of a photoinitiator) to form covalently crosslinked hydrogels. As the hydrolysis product of collagen, the major component of ECM in most tissues, gelatin contains many arginine-glycine-aspartic acid (RGD) sequences that promote cell attachment, as well as the target sequences of matrix metalloproteinase (MMP) that are suitable for cell remodeling.” [emphasis added](p. 255, col. 1, 3rd paragraph, lines 1-8).
Yue et al. teaches that: “We have reviewed several important aspects of GelMA-based hydrogel systems for biomedical applications. GelMA is developed from a natural polymer gelatin via one-step chemical modification. The introduction of photocrosslinkable methacryloyl substitution groups enables convenient and fast gelation upon exposure to light irradiation at the presence of photoinitiators. Many physical parameters of GelMA hydrogels, such as mechanical properties, pore sizes, degradation rates, and swell ratio can be readily tailored by changing the degree of methacryloyl substitution, concentration of the GelMA prepolymer, initiator concentration, and UV exposure time. Moreover, the resulting GelMA hydrogels retain the excellent biocompatibility and bioactivity of gelatin, such as promoting adhesion, spreading, and proliferation of various cell lines, due to the existence of cell adhesive RGD motifs and MMP-degradable amino acid sequences.” (p. 269, col. 1, lines 1-15)(instant claim 2).
MA teaches materials and methods for expansion of stem cells (title, see whole document), and particularly teaches that: “The subject invention utilizes cell self-aggregation in a microcarrier bioreactor as a non-genetic means to enhance stem cell therapeutic potency. The subject invention integrates a cell aggregation process in a scalable bioreactor system.” ([0006]). And that: “In one embodiment of the method, thermally responsive microcarriers (TRMs) are utilized in conjunction with a scalable bioreactor system […]. Cells are cultured in a container or vessel in the presence of the TRMs wherein cells adhere to the surface of the TRMs.” ([0007]).
MA teaches that: “cells are cultured in a container or vessel in the presence of the TRMs wherein cells adhere to the surface of the TRMs. In one embodiment, the surface of the container or vessel is one that inhibits or prevents cell attachment thereto. In one embodiment, the surface is an ultra-low attachment surface, […].” [emphasis added[([0027], lines 11-16)(instant claim 1, “wherein the plurality of the cells are cultured simultaneously with the spherical structure body in a U-bottom well treated with an ultra-low attachment (ULA) surface for preventing cell adhesion.”).
MA teaches that: “Microcarrier beads and containers or vessels utilized in the present invention can be composed of any material suitable for tissue culture, including, […] gelatin […]. Microcarrier beads of the invention can also comprise a material that is magnetic or can become magnetic, such as Fe3O4. Micro carrier beads of the invention can be of any suitable size and/or shape for culturing cells. In one embodiment, microcarrier beads can have a diameter of from about 50 µm to about 500 µm. In a further embodiment, microcarrier beads can have a diameter of between about 100 µm and about 200 µm.” ([0029]). And that: “In one embodiment, the surface of the container or vessel is one that inhibits or prevents cell attachment thereto. In one embodiment, the surface is an ultra-low attachment surface, […].” ([0030])(instant claim 1, “a spherical core comprising a mixture of a biodegradable material [i.e. gelatin]; a plurality of biocompatible magnetic nanoparticles […].”; instant claim 12).
Finding of prima facie obviousness
Rationale and Motivation (MPEP 2142-2143)
It would have been prima facie obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to produce a spherical microbot for cell and drug delivery, as suggested by CHOI, and to utilize GelMA (gelatin methacryloyl or gelatin methacrylate), as suggested by Ceylan et al. and Nichol et al., based on the advantageous properties of GelMA including photocrosslinking, cell adhesion, among others; the cell being attached to the surface of the GelMA via the “many arginine-glycine-aspartic acid (RGD) sequences that promote cell attachment”, as suggested by Yue et al. in order to deliver cells to a site of action, and further to culture stem cells with a microcarrier in an ultra low, the cells adhered to the surface of the microcarrier as suggested by XU, and the cell being a stem cell as suggested by Nichol et al. and XU.
From the teachings of the references, it is apparent that one of ordinary skill in the art would have had a reasonable expectation of success in producing the claimed invention. Therefore, the invention as a whole would have been prima facie obvious to one of ordinary skill in the art before the effective filing date of the claimed invention, as evidenced by the references, especially in the absence of evidence to the contrary.
In light of the forgoing discussion, the Examiner concludes that the subject matter defined by the instant claims would have been obvious within the meaning of 35 USC 103.
Response to Arguments:
Applicant's arguments filed 07/03/2026 have been fully considered but they are not persuasive.
Applicant argues that: “Choi discloses bio-scaffold type microrobots that can be configured in various shapes including spherical, formed of photocurable polymer or biodegradable material mixed with iron oxide nanoparticles (magnetic material) in certain embodiments, and capable of carrying cells (in gaps between scaffolds or 3D cultured) or drugs for targeted delivery under magnetic control.” Applicant characterizes that “Choi fails to disclose or suggest: (1) the use of gelatin methacryloyl (GelMA) specifically as the biodegradable and photocurable material for forming the spherical core; (2) mixing a plurality of drugs directly into the core mixture together with the magnetic nanoparticles to form an integrated spherical core from which drugs can be released upon biodegradation; (3) culturing stem cells on the surface of the spherical body via simultaneous co-culturing of the cells and the forming structure body in a Li-bottom well having an ultra-low attachment (ULA) surface; and (4) the resulting unique structure in which stem cells are stably attached in a three-dimensional manner on the exterior surface of a spherical mixed core, enabling targeted delivery of both cells and drugs with reduced cell loss during in vivo migration.” And that: “While Choi mentions spherical scaffolds and cells in gaps (see, e.g., [0047] and FIG. 1), it does not disclose the specific ULA U-bottom well simultaneous culture technique that produces the claimed surface-attached stem cell configuration on a pre-mixed spherical core.” (p. 7 item A).
In response to applicant's arguments against the references individually, one cannot show nonobviousness by attacking references individually where the rejections are based on combinations of references. See In re Keller, 642 F.2d 413, 208 USPQ 871 (CCPA 1981); In re Merck & Co., 800 F.2d 1091, 231 USPQ 375 (Fed. Cir. 1986).
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., (4) the resulting unique structure in which stem cells are stably attached in a three-dimensional manner on the exterior surface of a spherical mixed core, enabling targeted delivery of both cells and drugs with reduced cell loss during in vivo migration.) 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). The examiner further argues that Gelatin Methacryloyl (GelMA) is well-known as a highly biocompatible and biodegradable photo-curable biomaterial.
Applicant argues that: “Ceylan discloses 3D-printed (two-photon polymerization) biodegradable microswimmers having a double helical architecture, fabricated from a magnetic precursor suspension of GelMA mixed with biofunctionalized superparamagnetic iron oxide nanoparticles. The microswimmers are designed for theranostic cargo delivery (e.g., release of anti-ErbB2 antibody-tagged agents upon enzymatic degradation by MMP-2) and swimming under rotational magnetic fields.” Applicant characterizes that: “However, Ceylan fails to disclose or suggest: (1) a spherical (rather than helical) structure body or core; (2) stem cells cultured on and attached to the surface; (3) simultaneous culturing in a Li-bottom ULA well; (4) mixing of therapeutic drugs into the core for co-delivery with cells; and (5) the use of the microrobot as a spherical scaffold for stem cell attachment and targeted delivery rather than a swimming helical cargo carrier.” Applicant further argues that: “The fabrication method (two-photon lithography) and architecture (helical for corkscrew propulsion) of Ceylan are fundamentally different from the claimed spherical core formed by UV irradiation of a mixture and subsequent or simultaneous ULA well culture for surface cell attachment.” (pp. 7-8, item B).
In response to applicant's arguments against the references individually, one cannot show nonobviousness by attacking references individually where the rejections are based on combinations of references. See In re Keller, 642 F.2d 413, 208 USPQ 871 (CCPA 1981); In re Merck & Co., 800 F.2d 1091, 231 USPQ 375 (Fed. Cir. 1986).
Applicant further argues that: “Nichols discloses GelMA as an inexpensive, cell-responsive, photopolymerizable hydrogel platform for creating cell-laden microtissues and microfluidic devices. Cells bind, proliferate, elongate, and migrate in GelMA hydrogels, which retain natural cell-binding motifs (RGD) and MMP-sensitive degradation sites. Yue provides a review of GelMA synthesis, properties, and biomedical applications. While Nichols and Yue establish that GelMA is well-known and suitable for stem cell culture and tissue engineering, neither reference teaches or suggests: (1) incorporating biocompatible magnetic nanoparticles (e.g., Fe3O4) and drugs into a spherical core mixture to create a magnetically guidable microrobot; (2) using the GelMA-based structure as a mobile microrobot for targeted in vivo delivery under external magnetic field control; (3) the specific simultaneous co-culture of stem cells with the forming spherical structure body in a Li-bottom well with ULA surface to achieve 3D surface attachment; and (4) combining GelMA with magnetic nanoparticles and drugs for a biodegradable spherical microrobot that delivers both stem cells on its surface and drugs from its core.” And further that: “Nichols and Yue are directed to static or microfluidic tissue engineering constructs, not to mobile, magnetically actuated microrobots for therapeutic delivery.” (p. 8, item C).
In response to applicant's arguments against the references individually, one cannot show nonobviousness by attacking references individually where the rejections are based on combinations of references. See In re Keller, 642 F.2d 413, 208 USPQ 871 (CCPA 1981); In re Merck & Co., 800 F.2d 1091, 231 USPQ 375 (Fed. Cir. 1986).
Applicant characterizes their distinction’s over WANG, however as WANG is no longer relied upon, the distinctions are moot.
Applicant further argues (E) there is no suggestion, motivation, or reasonable expectation of success to combine the cited references (pp. 9-11, item E). And particularly that: “A person of ordinary skill in the art would not have been motivated to combine the cited references to arrive at the claimed invention for several independent reasons:
First, the references are from disparate technical fields with fundamentally different purposes and design constraints. Choi is directed to biomimetic organ model systems and microrobot-based delivery within interconnected micro-organ networks, where cells are typically loaded into internal gaps or pores of scaffolds. Ceylan focuses on magnetically powered helical microswimmers fabricated by two-photon polymerization for theranostic cargo release (e.g., antibody-tagged contrast agents) upon enzymatic degradation in a cancer microenvironment. Nichols and Yue relate to static or micropatterned GelMA hydrogels for in vitro tissue engineering, cell encapsulation, and microfluidic devices-explicitly not mobile therapeutic microrobots. There is no common objective or field of endeavor that would have prompted a person of ordinary skill in the art to select GelMA from Ceylan/Nichols, mix therapeutic drugs (beyond generic growth factors or RGD peptides) and Fe3O4 nanoparticles into a spherical core, and then co-culture stem cells on its surface using Li-bottom ULA wells.”
And, “Second, the specific ULA simultaneous co-culture limitation is not suggested or predictable from the art. U-bottom ultra-low attachment wells are a specialized technique primarily used to promote non-adherent spheroid formation or 3D cell aggregation in suspension culture. The prior art (including Nichols) teaches seeding cells onto pre-formed GelMA gels or encapsulating them during gelation, not co-culturing stem cells simultaneously with a forming drug- and nanoparticle-loaded GelMA spherical core in ULA conditions to achieve stable 3D surface attachment. A person of ordinary skill in the art would have had no reasonable expectation that stem cells would attach and thrive in this configuration without interfering with the core's magnetic properties, drug release kinetics, or photocured structural integrity.”
And, “Third, combining the helical swimming architecture and two-photon fabrication of Ceylan with Choi's spherical scaffold concept (or Nichols' hydrogel platform) would have been counterintuitive. The claimed spherical core is formed by simple UV irradiation of a bulk mixture-not complex 3D printing-and is designed for surface cell attachment and biodegradation-mediated dual delivery, not propulsion or bulk cargo release inside the material. There is no teaching that drugs mixed into the GelMA precursor would remain bioactive and release appropriately while supporting external stem cell attachment under ULA conditions.”
And, “Fourth, any motivation to combine would require knowledge of the invention itself-i.e., hindsight. The Office's proposed combination only becomes apparent when viewing the references through the lens of the claims. This is the classic "obvious to try" or "piecemeal" reconstruction prohibited by KSR and its progeny when there is no articulated reason in the art for the specific combination and no reasonable expectation of success in achieving the claimed benefits (stable 3D stem cell attachment on a magnetic/drug-loaded spherical core, reduced cell loss during migration, and synergistic targeted co-delivery).”
And finally, “In short, the claimed microrobot is not the predictable result of combining known elements according to known methods; it is a non-obvious integration of elements from unrelated fields that produces unexpected technical advantages in targeted stem cell and drug delivery.” (p. 10, last paragraph).
In response to Applicant’s argument that: “the references are from disparate technical fields with fundamentally different purposes and design constraints.” The examiner argues that the primary reference CHOI is clearly directed to biocompatible delivery systems for delivery of drugs and cells, and composed of biocompatible material in combination with magnetic nanoparticles useful for using an external magnetic field to perform target-directed drug or cell delivery. However, while CHOI does teach that “the bio-scaffold type microbot 100a is manufactured in lithography using a photocurable polymer […].” ([0035]), CHOI does not teach GelMA as a species of “the bio-scaffold” material. Ceylan et al. is also directed to: “The present study reports a hydrogel-based, magnetically powered and controlled, enzymatically degradable microswimmer, which is responsive to the pathological markers in its microenvironment for theranostic cargo delivery and release tasks. We design a double helical architecture enabling volumetric cargo loading and swimming capabilities under rotational magnetic fields and a 3D-printed optimized 3D microswimmer (length = 20 µm and diameter = 6 µm) using two-photon polymerization from a magnetic precursor suspension composed from gelatin methacryloyl and biofunctionalized superparamagnetic iron oxide nanoparticles.” (abstract). And that: “gelatin methacryloyl, a photo-cross-linkable semisynthetic polymer derived from collagen. Gelatin also contains target cleavage sites for MMP-2, thereby appealing as a biodegradable structural material for microrobots.” (p. 3354, col. 2, lines 11-15). Therefore, Ceylan et al. is highly relevant to the teachings of CHOI and, Applicant’s argument is not convincing. Nichols et al. and Yue et al. both teach GelMa, “Cell-laden microengineered gelatin methacrylate hydrogels,” and “Synthesis, properties, and biomedical applications of gelatin methacryloyl (GelMA) hydrogels”, respectively. And are therefore clearly relevant to the teachings of CHOI and Ceylan et al., CHOI teaching the bio-scaffold of their microbot is composed of a “photocurable polymer”, and Ceylan et al. teaching the same using GelMA.
In response to Applicants arguments regarding the use of an ultra-low attachment surface for preventing cell adhesion, this is clearly known in the prior art. The examiner cites MA teaching culturing cells with microcarriers, “cells are cultured in a container or vessel in the presence of the TRMs wherein cells adhere to the surface of the TRMs. In one embodiment, the surface of the container or vessel is one that inhibits or prevents cell attachment thereto. In one embodiment, the surface is an ultra-low attachment surface,” as discussed above. Additionally, Fang et al. teaches 3-D cell culture technologies including “There are four different approaches to enable spheroid cultures. The first approach is to use low-adhesion plates to promote spheroids (Fig. 1a). These plates not only have an ultralow attachment surface coating to minimize cell adherence but also possess a well defined geometry (e.g., round, tapered, or v-shaped bottom) to drive and position a single spheroid within each well. The key advantage of this approach is to form, propagate, and assay the spheroids within the same plate, thus enabling high-throughput screening (HTS) or high-content screening (HCS).” (p. 457, col. 2, 2nd paragraph, p. 458, Figure 1).
In response to Applicant’s arguments directed at the method of making in Ceylan et al., the examiner argues that one of ordinary would have understood how to produce spherical GelMA particles. For example, Jung et al. (“Swelling characterization of photo-cross-linked gelatin methacrylate spherical microgels for bioencapsulation,” 2014, DE GRUYTER; e-Polymers, Vol. 14, No. 3, pp. 161-168) clearly teaching how to produce spherical GelMA microgels (see whole document, particularly Figure 1B). And Antunes et al. (“In-air production of 3D co-culture tumor spheroid hydrogels for expedited drug screening,” 2019; ELSEVIER; Acta Biomaterialia, Vol. 94, pp. 392-409) teaching “Aiming to face this drawback and
mimic tumors-ECM, herein we rapidly fabricated in-air hyaluronan-methacrylate (HA-MA) and gelatin-methacrylate (GelMA) photocrosslinkable 3D spheroid microgels by using superhydrophobic surfaces.” (abstract, see whole document), and particularly In-air production of spheroid 3D microgels (p. 394, §2.2.6). Additionally, Antunes et al. cultures cells on the surface of their microgels in ultra-low-adhesion (ULA) round-bottom 96-wels plate, purchased from corning (p. 394, 1st paragraph; p. 395, §2.2.9). Therefore, Applicants argument directed to the method of making is not convincing as methods for the production of spherical GelMA microgels were known in the art. CHOI is directed at drug delivery using microbots, and therefore one of ordinary skill would recognize that this could have been done at the time of the CHOI reference. Applicants argument “There is no teaching that drugs mixed into the GelMA precursor would remain bioactive” is not convincing because the claims are generic to any drug(s).
In response to applicant's argument that the examiner's conclusion of obviousness is based upon improper hindsight reasoning, it must be recognized that any judgment on obviousness is in a sense necessarily a reconstruction based upon hindsight reasoning. But so long as it takes into account only knowledge which was within the level of ordinary skill at the time the claimed invention was made, and does not include knowledge gleaned only from the applicant's disclosure, such a reconstruction is proper. See In re McLaughlin, 443 F.2d 1392, 170 USPQ 209 (CCPA 1971).
Applicant further argues (F) that the claimed process limitation produces a structurally and functionally different product (pp. 9-11, item E). Applicant particularly argues that: “The process limitation at the end of claim 1, "wherein the plurality of cells are cultured simultaneously with the spherical structure body in a U-bottom well treated with an ultra-low attachment (ULA) surface for preventing cell adhesion," is not merely a method of making; under the product-by-process doctrine, it imparts specific structural and functional characteristics to the final microrobot product that distinguish it from anything taught or suggested by the cited references, alone or in combination.” And that: “In the claimed product, the simultaneous co-culture of stem cells with the forming spherical structure body in U-bottom wells having an ultra-low attachment (ULA) surface forces the cells to attach exclusively to the exterior surface of the spherical core in a true three-dimensional configuration. The ULA surface and U-bottom geometry prevent cell adhesion to the well plate itself, so the only available substrate for attachment and aggregation is the spherical body. This produces a microrobot in which stem cells form stable, multi-layer or spheroid-like attachments on the outside of the particle.”
In response the examiner argues that the process limitation at the end of claim 1 is clearly a process step in a product claim and therefore is a product-by-process claim, limited by the implied structure and not the actual method steps. Indeed the examiner cites Fang et al. teaching various different and distinct methods of achieving so-called spheroids (multicellular spheroid cultures) including: (1) using ultra-low attachment surfaces; (2) hanging droplet plates (HDPs); (3) a bioreactor (e.g. spinner flask or microgravity bioreactor) to drive cells to aggregate into spheroids; and (4) micro-/nano-patterned surfaces as the scaffolds to control cell adhesion and migration, thus enabling spheroid cultures (see p. 457, col 2, 2nd paragraph through p. 458, col. 1, 2nd paragraph; and Figure 1). Thus, same structure could more likely than not be produced by different 3D cell culture technologies, as suggested by Fang et al. Additionally, the use of ULA surface in cell cultures was well-know before the time of the claimed invention, as per newly cited MA and Fang et al. teaching the same.
Conclusion
Claims 1-3, 5 and 12 are pending and have been examined on the merits. Claims 1-3, 5 and 12 are rejected under 35 U.S.C. 103. No claims allowed at this time.
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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/IVAN A GREENE/Examiner, Art Unit 1619
/TIGABU KASSA/Primary Examiner, Art Unit 1619
1 Of Record as cited by the examiner on 12/20/2023, PTO-892, NPL citation No. “W”.
2 Immortalized human umbilical vein endothelial cells (p. 5538, §2.7).
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