Prosecution Insights
Last updated: April 19, 2026
Application No. 17/784,346

MELT-EXTRUDABLE 3D PRINTING INKS

Final Rejection §102§103
Filed
Jun 10, 2022
Examiner
MAEWALL, SNIGDHA
Art Unit
1612
Tech Center
1600 — Biotechnology & Organic Chemistry
Assignee
President and Fellows of Harvard College
OA Round
2 (Final)
58%
Grant Probability
Moderate
3-4
OA Rounds
3y 4m
To Grant
69%
With Interview

Examiner Intelligence

Grants 58% of resolved cases
58%
Career Allow Rate
611 granted / 1044 resolved
-1.5% vs TC avg
Moderate +10% lift
Without
With
+10.2%
Interview Lift
resolved cases with interview
Typical timeline
3y 4m
Avg Prosecution
59 currently pending
Career history
1103
Total Applications
across all art units

Statute-Specific Performance

§101
0.6%
-39.4% vs TC avg
§103
51.6%
+11.6% vs TC avg
§102
8.7%
-31.3% vs TC avg
§112
17.5%
-22.5% vs TC avg
Black line = Tech Center average estimate • Based on career data from 1044 resolved cases

Office Action

§102 §103
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 . Detailed Action Previous Rejections Applicants' arguments, filed 09/05/25 have been fully considered. Rejections and/or objections not reiterated from previous office actions are hereby withdrawn. The following rejections and/or objections are either reiterated or newly applied. They constitute the complete set presently being applied to the instant application. Claim Rejections - 35 USC § 102 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 1-4, 7-8 and 10-12 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Black et al. (WO 2018/152065 A1, presented in IDS). Black et al. discloses tissue graft and 3D printing of a mechanically anisotropic tissue graft, see title. Black teaches the 3D printing composition comprises a polymeric ink, see abstract. The reference teaches that polyurethanes are formed by using a hard segment comprising diisocyanate with a soft segment comprising a polyol, see [0038], Fig.3 and [0049] examples. A chain extender may be included. Isophorene diisocyanate (IPDI) and polycaprolactone diol and putrescine, a chain extender is disclosed in [0038] and Fig. 3. A suitable molar ratio of the components is 1:2:1(soft segment : hard segment : chain extender). Black further teaches that the diisocyanate (hard segment) may be selected from among isophorene diisocyanate (IPDI), methyl diphenyl diisocyanate (MDI), l-lysine diisocyanate (LDI), 1 ,4-butane diisocyanate (BDI), hexamethylene diisocyanate (HDI), and trimethylhexamethylene diisocyanate (TMDI). The chain extender may combine individual polyurethane chains through urea bonds or additional urethane bonds, see [0039] . The chain extender may comprise a diol or a diamine, such as ethylene glycol, 1 ,4-butanediol, 1 ,4-cyclohexanedimethanol, 1 ,2- ethanediamine, 1 ,4-butanediamine, combinations including 2-amino-1 - butanol, or another degradable linkage such as 2-hydroxyethyl-2- hydroxyproponoate, see [0039]. Black teaches that the soft segment, may include a diol (polyol) formed from polycaprolactone (PCL), poly(ethylene glycol) (PEG), poly(hexamethylene carbonate) (PHC), poly(ethylene oxide) (PEO), poly(propylene oxide) (PPO), polylactide, (PLA), polyglycolide (PGA), poly(hydroxybutyrate) (P3HB and P4HB), or amino acids, see [0040]. Poly(ethylene glycol) and poly(ethylene oxide) read on fugitive porogen, see [0040]. Synthesis of an exemplary biodegradable polyurethane is done through a two-step melt reaction to create poly(ester urethane urea) (PEUU), where the soft segment is polycaprolactone diol (PCL) with hydrolysable ester bonds, the hard segment is isophorene diisocyanate (IPDI), and the chain extender is 1, 4-diaminobutane (putrescine, PU), as shown schematically in FIG. 3. They are combined in a molar ratio of 1 :2:1 soft segment : hard segment : chain extender, see [0049]. Black further teaches that then, IPDI (TCI America) is added to the flask along with a few drops of stannous octoate catalyst (Spectrum Chemical). This first step forms the urethane bonds in the polymer. After 1 hour, the putrescine (Sigma- Aldrich) is mixed in dimethyl sulfoxide (DMSO) solvent at 20 wt.%, then added to the solution. The reaction continues for two more hours under nitrogen. This extends the chains with urea bonds, making the polymer stiffer and more biocompatible, as the urea bonds resemble peptide bonds to cells. After the reaction is complete, the reaction product is purified in water and ethyl acetate to remove residual monomers and dried in a vacuum oven at 70°C to obtain the final polymer, which in this example is PEUU. As shown in FIGs. 6A and 6B, this polymer demonstrates good biocompatibility with human neonatal dermal fibroblasts compared to a PCL control and a reasonable degradation rate, faster than that of PCL. (Instant specification teaches similar process on page 26). Thus, the end product or the biodegradable ink does not comprise solvent as water and ethyl acetate were dried in a vacuum oven at 70°C to obtain the final polymer as discussed above, and therefore would be melt-extrudable because it comprises the same components as claimed and is made by the similar process as disclosed in the instant specification and is substantially free of solvents. Claim Rejections - 35 USC § 103 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. Claims 1-4, 7-8, 10-14 and 17-19 are rejected under 35 U.S.C. 103 as being unpatentable over Black et al. (WO 2018/152065 A1) in the alternative for claims 1-4, 7-8 and 10-12 and unpatentable under obviousness for claims 14 and 17-19. Black et al. discloses tissue graft and 3D printing of a mechanically anisotropic tissue graft, see title. Black teaches the 3D printing composition comprises a polymeric ink, see abstract. The reference teaches that biodegradable polyurethanes are formed by using a hard segment comprising diisocyanate with a soft segment comprising a polyol, see [0038], Fig.3 and [0049] examples. A chain extender may be included. Isophorene diisocyanate (IPDI) and polycaprolactone diol and putrescine, a chain extender is disclosed in [0038] and Fig. 3. A suitable molar ratio of the components is 1:2:1(soft segment : hard segment : chain extender). Black further teaches that the diisocyanate (hard segment) may be selected from among isophorene diisocyanate (IPDI), methyl diphenyl diisocyanate (MDI), l-lysine diisocyanate (LDI), 1 ,4-butane diisocyanate (BDI), hexamethylene diisocyanate (HDI), and trimethylhexamethylene diisocyanate (TMDI). The chain extender may combine individual polyurethane chains through urea bonds or additional urethane bonds, see [0039] . The chain extender may comprise a diol or a diamine, such as ethylene glycol, 1 ,4-butanediol, 1 ,4-cyclohexanedimethanol, 1 ,2- ethanediamine, 1 ,4-butanediamine, combinations including 2-amino-1 - butanol, or another degradable linkage such as 2-hydroxyethyl-2- hydroxyproponoate, see [0039]. Black teaches that the soft segment, may include a diol (polyol) formed from polycaprolactone (PCL), poly(ethylene glycol) (PEG), poly(hexamethylene carbonate) (PHC), poly(ethylene oxide) (PEO), poly(propylene oxide) (PPO), polylactide, (PLA), polyglycolide (PGA), poly(hydroxybutyrate) (P3HB and P4HB), or amino acids, see [0040]. Block et al. teaches in claims 1, a method of 3D printing a mechanically anisotropic tissue graft, the method comprising: flowing a polymeric ink formulation into a deposition nozzle, the polymeric ink formulation including a block copolymer with hydrogen bonding segments and a volatile solvent; extruding a continuous filament comprising the polymeric ink composition from the deposition nozzle, the volatile solvent evaporating rapidly upon extrusion; and depositing the continuous filament on a substrate as a deposited filament comprising the block copolymer while the deposition nozzle moves relative to the substrate in a print direction, at least a surface region of the deposited filament being substantially absent the volatile solvent, wherein the deposition and/or extrusion induces elongation of the block copolymer and densification of the hydrogen bonding segments, the deposited filament thereby exhibiting a higher average stiffness along the print direction than along a direction transverse to the print direction, and wherein, upon completion of the deposition, one or more of the deposited filaments are arranged in a predetermined architecture on the substrate, thereby defining a 3D printed mechanically anisotropic tissue graft. Black et al. teaches regarding the process that “Synthesis of an exemplary biodegradable polyurethane” is done through a two-step melt reaction to create poly(ester urethane urea) (PEUU), where the soft segment is polycaprolactone diol (PCL) with hydrolysable ester bonds, the hard segment is isophorene diisocyanate (IPDI), and the chain extender is 1,4-diaminobutane (putrescine, PU), as shown schematically in FIG. 3. They are combined in a molar ratio of 1 :2:1 soft segment : hard segment : chain extender. First, the PCL is dried under vacuum at 50°C to remove the residual water before synthesis. Then, it is added to a 3-neck flask under the flow of nitrogen at 70°C to completely melt the polyol, see [0049]. Black further teaches that then, IPDI (TCI America) is added to the flask along with a few drops of stannous octoate catalyst (Spectrum Chemical). This first step forms the urethane bonds in the polymer. After 1 hour, the putrescine (Sigma- Aldrich) is mixed in dimethyl sulfoxide (DMSO) solvent at 20 wt.%, then added to the solution. The reaction continues for two more hours under nitrogen. This extends the chains with urea bonds, making the polymer stiffer and more biocompatible, as the urea bonds resemble peptide bonds to cells. After the reaction is complete, the reaction product is purified in water and ethyl acetate to remove residual monomers and dried in a vacuum oven at 70°C to obtain the final polymer, which in this example is PEUU. As shown in FIGs. 6A and 6B, this polymer demonstrates good biocompatibility with human neonatal dermal fibroblasts compared to a PCL control and a reasonable degradation rate, faster than that of PCL. (Instant specification teaches similar process on page 26). Thus, the end product or the biodegradable ink does not comprise solvent and would be melt-extrudable because it comprises the same components as claimed and is made by the similar process as disclosed in the instant specification. Black et al. further teaches that by varying the components, the reaction can be modified to be done under argon or vacuum and for variations in temperature and time scale for each of the two steps. The entire reaction can also be conducted under a solvent such as dimethyl sulfoxide (DMSO) in lieu of the first step being performed as a melt reaction, see [0051]. Therefore, the reference teaches both the melt, heating and extruding process as discussed above and it would appear reasonable to conclude that the biodegradable ink would be extrudable since there is no solvent in the end product, i.e. the biodegradable ink produced and it would have been obvious to one of ordinary skill to skill to have produced the biodegradable ink without the melting step and by using DMSO solvent motivated by the teachings of Black et al. teachings as alternative, which can also be prepared by using DMSO as suggested above. Black teaches that block copolymers such as soft segment or hard segment is present in the polymeric ink formulation at a concentration from about 20 wt% to about 60 wt.% as disclosed in claim 8 and this amount overlaps with the claimed amount of no more than 50 wt.% of fugitive material ((poly(ethylene glycol) (PEG) and poly(ethylene oxide) (PEO) as taught and claimed) and thus create a case of obviousness because in the case where the claimed ranges “overlap or lie inside ranges disclosed by the prior art” a prima facie case of obviousness exists. MPEP 2144.05 A. Applicant’s arguments are moot in view of rejections made above addressing substantially free of solvents. Action is final 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. Correspondence Any inquiry concerning this communication or earlier communications from the examiner should be directed to SNIGDHA MAEWALL whose telephone number is (571)272-6197. The examiner can normally be reached Monday thru Friday; 8:30 AM to 5PM. 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. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Sahana S. Kaup can be reached on 571-272-6897. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000. /SNIGDHA MAEWALL/Primary Examiner, Art Unit 1612
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Prosecution Timeline

Jun 10, 2022
Application Filed
May 16, 2025
Non-Final Rejection — §102, §103
Aug 29, 2025
Applicant Interview (Telephonic)
Sep 05, 2025
Response Filed
Sep 06, 2025
Examiner Interview Summary
Dec 11, 2025
Final Rejection — §102, §103 (current)

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Study what changed to get past this examiner. Based on 5 most recent grants.

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Prosecution Projections

3-4
Expected OA Rounds
58%
Grant Probability
69%
With Interview (+10.2%)
3y 4m
Median Time to Grant
Moderate
PTA Risk
Based on 1044 resolved cases by this examiner. Grant probability derived from career allow rate.

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