DETAILED ACTION
Notice of Pre-AIA or AIA Status
1. The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Response to Amendments
2. Applicant’s response dated 17 November 2025 has been entered into the record and is considered fully responsive. The applicant’s amendment to Claim 1 did not add any new matter as supported by the ¶49, 52, and 83 (cited as US Pub. No. 2023/0193498 A1). Claims 1, 2, 3, 4, 5, 6, 7, 8, and 9 are pending and under examination. Claims 10-12 were withdrawn as a result of the restriction requirement (dated 05 June 2025).
3. Claims 1, 2, 3, 4, 5, 6, 7, 8, and 9 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
4. The term “similar” in Claim 1 is a relative term which renders the claim indefinite. The term “similar” is not defined by the claim, the specification does not provide a standard for ascertaining the requisite degree, and one of ordinary skill in the art would not be reasonably apprised of the scope of the invention. The phrase “similar in speed” is listed in ¶52 and ¶83, but is not further defined by a quantitative standard (e.g.: deposition thickness per unit time or #H2 bubbles formed per unit time).
5. The term “steady” in Claim 1 is a relative term which renders the claim indefinite. The term “steady” is not defined by the claim, the specification does not provide a standard for ascertaining the requisite degree, and one of ordinary skill in the art would not be reasonably apprised of the scope of the invention. The phrase “steady manner” is listed in ¶52 and ¶83, but is not further defined by a quantitative standard.
6. Claims 2, 3, 4, 5, 6, 7, 8, and 9 are rejected under 112(b) since they all depend from Claim 1, which is currently stands rejected under 112(b).
Claim Rejections - 35 USC § 103
7. 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.
8. The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
9. Claims 1, 2, 3, 6, and 9 are rejected under 35 U.S.C. 103 as being unpatentable over Halada in view of Altomare et al. with evidence of inherency from “Chemistry of the Elements – 2nd Edition.”
Halada et al. (US Pub. No. 2013/0011492 A1) is drawn toward the electrochemical deposition of noble metal and chitosan coating (title). Altomare et al. (“Morphology tuning of chitosan films via electrochemical deposition,” Materials Let. 2012, 78, 18-21) is directed toward factors which influence the structure of chitosan films. “Chemistry of the Elements – 2nd Edition” (on pg. 1180-1182) discusses the descriptive inorganic chemistry of oxides and sulfide of copper, silver, and gold.
Regarding amended Claim 1, Halada et al. discloses a method for preparing a three-dimensional composite chitosan/silver scaffold (2-10 microns thick ¶32 and 51) according to FIG. 2 which shows a cross-section of the resultant electrodeposited film from a chitosan/silver nitrate electrolyte on to stainless steel (¶30, 38 and 48-52). Halada et al. further teaches mixing an acidic aqueous chitosan solution (chitosan acidified with either acetic acid or hydrochloric acid) and a deposition accelerating agent (e.g.: silver nitrate) to form a suspension as per ¶48. In ¶47-8, Halada et al. teaches the concentration in the electrolyte of chitosan ranges from ~0.1 w/v % to ~3.0 w/v % with a specific example of ~1.0 w/v% and the concentration of silver ranges from 1 mM to 1000 mM (or 0.1 M to 1.0 M) with an example of 100 mM. It has been held that a prima facie case of obviousness exists when the prior art discloses a range that overlaps within the claimed range (e.g.: silver and chitosan concentrations in the electrolyte). See MPEP 2144.05(I) - OVERLAPPING, APPROACHING, AND SIMILAR RANGES, AMOUNTS, AND PROPORTIONS
Halada et al. further describes spacedly disposing a cathode (e.g.: stainless steel working electrode) and an anode (e.g.: Pt counter electrode) in the suspension as described in ¶54. Halada et al. also teaches applying the electric field to the cathode and the anode so that the suspension undergoes electrodeposition at the cathode (¶27-29 and FIG. 1). At said cathode, the silver ion in suspension undergoes reduction to form silver metal, and the water in the suspension undergoes electrolysis to form hydroxide ions which deprotonate the charged chitosan forming neutral chitosan which deposits as indicated in ¶27-29 and shown schematically in FIG. 1.
Halada et al. does not explicitly discuss the formation of silver oxide in the electrolyte; however, it is well known that silver hydroxide is not very stable in aqueous (alkali) solutions and forms (insoluble) silver oxide. Alkali (as hydroxide ions) is present in the electrolyte primary from the reduction of protons via the electrolysis of water at the deposition interface. “Chemistry of the Elements – 2nd Edition” provides evidence for the inherent instability of silver hydroxide on pg. 1181 by teaching that the addition of alkali to soluble Ag+ salts results in primarily in the formation of Ag2O because of the low affinity of silver ions toward oxygen. The silver oxide that forms is then deposited at the cathode (i.e.: stainless steel) when positively charged chitosan is deprotonated by the hydroxide formed at the cathode interface.
Halada et al. with evidentiary support from “Chemistry of the Elements – 2nd Edition” does not discuss the effect of hydrogen gas (formed from the reduction of acid or water) on the developing structure of the depositing film. Halada et al. with evidentiary support from “Chemistry of the Elements – 2nd Edition” is also silent on the porosity (or column formation) of the chitosan scaffold.
Altomare et al. evaluated the effect of acid and pH on the formation of electrodeposited chitosan films using a fluorescent tag to visualize the porosity and structure of said films (pg. 18-19: 2. Materials and Methods). Altomare et al. discusses the deposition mechanism of chitosan under an applied electric field on pg. 19 in the discussion section, which supports the teachings of Halada et al. (Altomare et al. – pg. 19: reactions 1, 2, and 3). Altomare et al. found that the acid identity impacts the formation of pores (“columns” according to the present application) because acetic acid and malonic acid facilitate growth of hydrogen bubbles on the surface of the cathode (pg. 19: 3. Results). These bubbles eventually detach resulting in the formation of columns or pores in the depositing film as evidenced by FIG. 2a and 2b. (pg. 19-20: results) as the bubble moves away from the cathode toward the anode with increasing size. Altomare et al. further discloses that higher pH bath resulted in films with greater pore interconnection and dimension (pg.20: discussion) as well as higher deposition rates (i.e.: faster generation of H2) resulted in films with greater porosity (pg. 20: discussion).
It would be obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to modify the chitosan/silver electrolyte bath of the electrodeposition method of Halada et al. by using a higher pH bath to neutralize chitosan as taught by Altomare et al. with the reasonable expectation of controlling or modulating the porosity and columnar structure of the silver/chitosan scaffold as per the limitation of Claim 1 (i.e.: the scaffold includes a plurality of columnar through-holes which extend in a same extension direction, each of the columnar through-holes having a first opening and a second opening that is opposite to the first opening in the extension direction and that is not less in width than the first opening).
Further regarding amended Claim 1, the new limitation: “wherein deposition of the silver oxide and the neutral chitosan is similar in speed to formation of the hydrogen gas bubbles so that the hydrogen gas bubbles are guided to grow in size only in the direction from the cathode to the anode in a steady manner and to be elongated in such direction for the plurality of columnar through-holes to be formed” is rendered obvious by the combination of Halada et al. in view of Altomare et al. as these references teach the structure of Claim 1 (e.g.: concentration of silver and chitosan, application of voltage, etc.).
In the specification of the instant application cited as US Pub. No, 2023/0193498 A1, electrolyte formulation details and deposition parameters not necessarily included in the limitations of Claim 1 are disclosed. The electrolyte further comprises acetic acid as per ¶47 which puts the pH of the silver salt/chitosan deposition bath in the pH range of 0 to 6.5. Regarding electrodeposition parameters, the instant application in ¶52 further describes an applied field strength of 1 to 10 V/cm (and 3.3 V/cm in Ex. 1) using a deposition time ranging from 1 minute to 60 minutes (and 10 minutes in Ex. 1).
The combination of Halada et a. in view of Altomare et al. also teaches electrolyte formulation details and deposition parameters not necessarily included in the limitations of Claim 1. Both references disclose the use of acetic acid in the electrolyte bath where the pH of the electrolyte is in the range of 3-4 in Altomare et al. (pg. 18: 2. Materials and methods) and 4-5 in Halada et al. (¶48). The deposition time taught in Altomare et al. is in the range of 2-8 minutes (pg. 19: Fig. 1) and 3 seconds to 5 minutes in Halada et al. (¶49). On pg. 19, Altomare et al. discloses the current density during deposition as 20 mA/cm2 which can be converted to electric field strength. Using the electrolyte electrical conductivity (i.e.: chitosan in acetic acid) of ~1 S/m and Ohms law yields an electric field strength of ~2 V/cm.
Comparing the electrolyte formulation parameters and electrodeposition parameters not cited in Claim 1 to the same features in the combination of Halada et al. and Altomare et al. reveals the electrolyte composition and method are substantially similar. According to MPEP 2112.01(I), when the structure recited in the references is substantially identical to that of the claims (and the disclosure) of the instant application, the claimed properties (i.e.: deposition and bubble formation speeds in amended Claim 1) are presumed to be inherent.
Regarding Claim 2, Halada et al. in view of Altomare et al. discloses the method of Claim 1, wherein the soluble silver is a water-soluble silver salt by the use of silver nitrate (abstract and ¶38, 48, and 44). Nitrate is a non-coordinating anion, which means it does not interact with other cations in solution, rather the addition of silver nitrate to water results in the complete separation of the ion pair. Therefore, Halada et al. in view of Altomare further discloses that the anion from the soluble silver salt is free from interaction with the protonate chitosan in suspension.
Regarding Claim 3, Halada et al. in view of Altomare et al. discloses the method of Claim 2, wherein the soluble salt is silver nitrate (abstract, and ¶38, 48, and 44).
Regarding Claim 6, Halada et al. in view of Altomare et al. discloses the method of Claim 1, wherein the acidic aqueous chitosan solution is obtainable by dissolving chitosan in an acidic aqueous solution having a pH value ranging from 0 to 6.5 as indicated in ¶48 of Halada et al. where either acetic acid or hydrochloric is used to prepare acidified chitosan.
Regarding Claim 9, Halada et al. in view of Altomare et al. discloses the method of Claim 1 wherein the first openings of the columnar through-holes of the three-dimensional chitosan/silver composite scaffold are formed on a surface of the three-dimensional chitosan/silver composite scaffold in contact with the cathode as evidenced by the discussion about hydrogen bubbles adhering to the surface of the cathode and the release of said bubble causing the formation of pores/columns in the resultant film (Altomare et al. on pg. 19: results and pg. 20: discussion). Fig. 3b, 3c, and 3d further support the growth of pores from the cathode surface through the scaffold (Altomare et al. on pg. 20).
However, the combination of Halada et al. and Altomare et al. does not explicitly teach the first openings of the columnar through-holes having a width ranging from 60 microns to 1,000 microns, the second openings of the columnar through-holes having a width ranging from 200 microns to 1,000 microns, each of the columnar through-holes having a depth and a ratio of the first opening to the depth that ranges from 1:1 to 1:35 as per Claim 9.
Halada et al. in view of Altomare et al. does disclose that the porosity (i.e. width and depth) can be tailored depending upon the end use application of the scaffold (pg. 20: conclusion). The porosity can be controlled by the rate of hydrogen generation, in that faster evolution of hydrogen from the electrolysis of water/acid results in more porous materials. Therefore, the rate of hydrogen formation, which drives the depth and width of the pores in the chitosan/silver scaffold, is a result-effective variable, i.e., a variable which achieves a recognized result, and the determination of the optimum or workable ranges of said variable might be characterized as routine experimentation (See MPEP 2144.0.II.B.). Accordingly, it would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to have discovered the optimum or workable ranges of pore width and depth by changing the rate of hydrogen formation, including values within the claimed range, through routine experimentation. One would have been motivated to do so in order to form a more porous material facilitating the more facile release of silver from the scaffold for use in antibacterial applications.
10. Claims 4 and 5 are rejected under 35 U.S.C. 103 as being unpatentable over Halada et al. in view of Altomare et al. as applied to Claim 1 above, and further in view of Thinakaran et al.
Halada et al. (US Pub. No. 2013/0011492 A1) is drawn toward the electrochemical deposition of noble metal and chitosan coating (title). Altomare et al. (“Morphology tuning of chitosan films via electrochemical deposition,” Materials Let. 2012, 78, 18-21) is directed toward factors which influence the structure of chitosan. Thinakaran et al. (“Electrophoretic deposition of chitosan/nano silver embedded microsphere on centrifugal spun fibrous matrices – A facile biofilm resistant biocompatible material,” Int. J. Biol. Macromol. 2020, 148, 68-78) is directed at electrophoretic deposition of chitosan/nano silver (pg. 68: title and abstract).
Regarding Claim 4, Halada et al. in view of Altomare et al. discloses the method of Claim 1 indicating that the rate of hydrogen formation impact the porosity of the deposited scaffold (Altomare et al. – pg. 20: discussion). Halada et al. in view of Altomare does not disclose the inclusion of a stabilizing agent for slowing the electrolysis of water in the electrolyte.
Thinakaran discloses the addition of polyethylene glycol (“PEG”) to a silver/chitosan electrolyte (pg. 68: introduction). The addition of PEG to the electrolyte results in a film with smaller silver nanoparticles which is hypothesized to form from a metallopolymer of chitosan, PEG, and silver (pg. 73: Fig. 5). Said metallopolymer will electrophoretically be driven to the surface of the cathode and deposit (pg. 72-73: 3.2. UV spectroscopy and TEM analysis). Smaller nanoparticles capped with polymer provided more sustained release of antimicrobial nano silver (pg. 75: 3.6. Release profile of silver nanoparticle).
The addition of polyethylene glycol to the electrolyte comprised of silver nitrate and acidified chitosan would reduce the rate of water electrolysis in the electrolyte in a few ways. First, the viscosity of the electrolyte will increase when PEG is added thereby reducing the rates of reactions (i.e.: slower electrolysis of water) as reaction kinetics tends to me slower in more viscous media. Moreover, the inclusion of a solvents other than water will reduce the concentration of water and therefore reduce the rate of water electrolysis. Finally, PEG present in the deposited film likely will decrease the wet film conductivity (of the scaffold) reducing the rate of electron transfer from cathode to the electrolyte thereby lowering the rate of water electrolysis.
It would be obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to modify the chitosan/silver electrolyte bath of the electrodeposition method of Halada et al. in view of Altomare et al. by the addition of PEG to the electrolyte with the reasonable expectation improving the control of the scaffold’s pore depth and width by a slower rate of hydrogen gas bubble formation (from a reduced rate of water electrolysis).
Regarding Claim 5, Halada et al. in view of Altomare et al. and further in view of Thinakaran discloses the method of Claim 4, wherein the stabilizing agent is polyethylene glycol (“PEG”) as indicated on pg. 69 in the introduction section and pg. 69-70 in the materials section. In particular, PEG co-deposits with chitosan and silver resulting in smaller particle size silver nanoparticles and an increase in the hydrophilicity of the composite material (pg. 72-73: 3.2. UV Spectroscopy and TEM Analysis).
11. Claims 7 and 8 are rejected under 35 U.S.C. 103 as being unpatentable over Halada et al. in view of Altomare et al. as applied to Claim 1 above, and further in view of Wei et al.
Halada et al. (US Pub. No. 2013/0011492 A1) is drawn toward the electrochemical deposition of noble metal and chitosan coating (title). Altomare et al. (“Morphology tuning of chitosan films via electrochemical deposition,” Materials Let. 2012, 78, 18-21) is directed toward factors which influence the structure of chitosan. Wei et al. (“Electrodeposition of a biopolymer hydrogel in etch micropores,” Soft Matter 2013, 9, 2131-2135) is directed at electrophoretic deposition of chitosan (pg. 2131: title)
Regarding Claim 7, Halada et al. in view of Altomare et al. discloses the method of Claim 1, but does not disclose the addition of a hydrogen gas inhibitor for reducing an amount of the hydrogen gas bubbles. As discussed above, the porosity of the scaffold can be controlled by the rate of hydrogen generation, in that faster evolution of hydrogen from the electrolysis of water/acid results in more porous materials
Wei et al. discloses the cathodic electrodeposition of chitosan at a bath pH of 5 (pg. 2132: Methods). Wei et al. further indicates that the deposition occurs from the pH gradient generated during the electrolytic process which neutralizes the positively charged chitosan resulting in film growth at the cathode (pg. 2131: introduction). Wei et al. also discloses the inclusion of H2O2 into the electrolyte bath indicating that the cathodic reduction of hydrogen peroxide provides a means to generate the aforementioned pH gradient without the generation of H2 gas bubbles (pg. 2132). Therefore, H2O2 functions as a hydrogen gas inhibitor during the electrodeposition process.
It would be obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to modify the chitosan/silver electrolyte bath of electrodeposition method of Halada et al. in view of Altomare et al. by adding hydrogen peroxide with the reasonable expectation of reducing the formation of hydrogen gas bubbles resulting in better control over the depth and width of the pores in the silver/chitosan scaffold.
Regarding Claim 8, Halada et al. in view of Altomare et al. and further in view of Wei et al. discloses the method of Claim 7, wherein the hydrogen gas inhibitor is hydrogen peroxide and present in the amount of 0.068 w/v % (derived from 20 mM H2O2 on pg. 2132 of Method in Wei et al.). It has been held that a prima facie case of obviousness exists when the prior art discloses an example that falls within the claimed range (0 w/v % < hydrogen peroxide concentration < 11 w/v %). See MPEP 2144.05(I) - OVERLAPPING, APPROACHING, AND SIMILAR RANGES, AMOUNTS, AND PROPORTIONS.
Response to Arguments
12. Applicant's arguments filed 17 November 2025 have been fully considered but they are not persuasive. On pages 6 and 7 of their response, the applicant has argued that the amendment to Claim 1 citing the equalizing of the deposition rate of the silver oxide/chitosan porous material is in balance with the formation of H2 bubbles overcomes the rejection based on the combination of Halada et al. in view of Altomare et al. The examiner disagrees with this assertion as explained in the rejection of amended Claim 1 above. The amendment to Claim 1 is rendered obvious by the combination of Halada et al. in view of Altomare et al. as these references teach the structure of Claim 1 (e.g.: concentration of silver and chitosan, application of a voltage, etc.). As per MPEP 2112.01(I), when the structure recited in the references are is substantially identical to that of the claims, the claimed properties (i.e.: deposition and bubble formation speeds) are presumed to be inherent.
13. The applicant appears to argue that the concentration of soluble silver and protonated chitosan are results effective variables (pages 6 and 7) and that the concentrations disclosed by the combination of references would not allow for optimization to arrive at the concentrations of amended Claim 1. However, the examiner does not find this argument to have merit as Halada et al. teaches the concentration in the electrolyte of chitosan ranges from ~0.1 w/v % to ~3.0 w/v % with a specific example of ~1.0 w/v% and the concentration of silver ranges from 1 mM to 1000 mM (or 0.1 M to 1.0 M) with an example of 100 mM (¶47-48). Regarding the soluble silver concentration, Halada et al. discloses a lower range of 1 mM and an example of 100 mM which are both just outside the claimed range of the instant application (i.e.: 4 mM to 60 mM), so one of ordinary skill in the art would reasonably be expected to arrive at the concentrations of the claimed range through routine experimentation. Regarding the chitosan concentrations, the prior art and the instant application have nearly identical ranges.
14. The examiner contends that the deposition rate of the scaffold and the rate of hydrogen bubble formation are (partially) controlled by electrolyte bath parameters and/or electrochemical parameters not claimed nor cited by the applicant. The pH of the electrolyte is an important factor for numerous reasons. For example, the pH of the electrolyte will directly control the solubility of the silver salt and the (protonated) chitosan and determine the surface charge on these species. The surface charge on the silver species and chitosan species in solution will influence both the rate and direction of migration in the applied field (i.e.: the zeta potential for each species). Lastly, the magnitude of the applied voltage and/or the current will directly impact the rate of migration of the chitosan and silver species in solution, the rate of deposition of silver oxide/neutral chitosan at the electrode, and the rate of H2 bubble formation.
15. There are a number of features and properties the applicant purports as advantages of the method described in the instant application such as metal absorbability and/or antibacterial activity based on the structure of the scaffold, but these are not included in limitations of the claims. The applicant has also argued that the molecular weight of the chitosan is important in controlling the rates of scaffold deposition and H2 bubble formation, but the applicant has failed to include this parameter into the claim limitations. For these aforementioned benefits/properties to be considered relevant to patentability, they must be incorporated into the claim limitations.
Conclusion
16. 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.
17. Any inquiry concerning this communication or earlier communications from the examiner should be directed to KEVIN SYLVESTER whose telephone number is (703)756-5536. The examiner can normally be reached Mon - Fri 8:15 AM to 4:30 PM EST.
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, James Lin can be reached at 571-272-8902. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/KEVIN SYLVESTER/Examiner, Art Unit 1794
/JAMES LIN/Supervisory Patent Examiner, Art Unit 1794