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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 June 9, 2026 has been entered.
Status of the Claims
Claims 1-4 and 7-22 were pending. Claims 21 and 22 are canceled. Claims 23-26 are added.
Claims 1-4, 7-20, and 23-26 are examined herein.
Withdrawn Rejections
The objection to claims 21 and 22 is withdrawn in view of claims cancelation.
The rejection of claims 21 and 22 is withdrawn in view of claims cancelation.
The rejection of claims 1-24 under 35 U.S.C. 112(b) is withdrawn in view of claims 1 and 2 amendments to the calculation step.
Claim Rejections - 35 USC § 112
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION. —The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claims 1-26 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.
Claims 1 and 2 recite “measuring an amount of current until a total amount of the magnetic metal nanoparticles is ionized”. The meaning of “amount of current” is unclear because current measurements provide instant current measurement values or average values over a brief interval of time defined by a specific design of a given ammeter model. The instant claims are interpreted as measuring current as demonstrated in Fig. 7-10, wherein current is measured as instant current without integration over time.
Claims 23-24 recite “applying the magnetic field to the magnetic metal nanoparticles directly”. The meaning of “applying … directly” is unclear because it is unclear how one could apply the magnetic field to the magnetic metal nanoparticles indirectly in this assay format.
Claims 3-26 are rejected because they depend from rejected claims 1 and 2.
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.
The factual inquiries set forth in Graham v. John Deere Co., 383 U.S. 1, 148 USPQ 459 (1966), that are applied for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
Determining the scope and contents of the prior art.
Ascertaining the differences between the prior art and the claims at issue.
Resolving the level of ordinary skill in the pertinent art.
Considering objective evidence present in the application indicating obviousness or nonobviousness.
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, 3, 15, 19, 23 and 25 are rejected under 35 U.S.C. 103 as being unpatentable over Feldbrugge et al. (IDS; US 2004/0110230) in view of Dong et al. (Interdiscip Rev Nanomed Nanobiotechnol. 2017 Sep;9(5) Epub 2017 Feb 20), Chen et al. (IDS; US 2011/0046013), and Szymanski et al. (Electroanalysis, (2010) 22 (2). pp. 191-198) and as evidenced by Wikipedia (Nickel electroplating – Wikipedia).
Regarding claim 1, Feldbrugge teaches a method for determining the concentration of analytes using metal particles as labels and an electrochemical detection technique (Abstract, [0009]-[0011]), the method comprising:
using a sensor having a working electrode, a reference electrode, and a counter electrode ([0030]) for binding the test substance via the primary antibodies fixed on a surface of the working electrode ([0039]);
detecting the test substance using a dispersion liquid of magnetic nanoparticles including conductive solvent and magnetic nanoparticles dispersed in the solvent – specifically, the reference teaches an electrolytic solution used as a solvent ([0032]). The reference also teaches secondary antibodies being fixed to surfaces of the magnetic nanoparticles ([0039] and [0025]). Feldbrugge teaches the magnetic particle has an average particle diameter in the range of 0.1 to 5 µm ([0040]), therefore the magnetic particle is a magnetic nanoparticle;
a magnetic field applying step of applying a magnetic field to the magnetic metal nanoparticles connected to the test substance in the presence of a solvent and bringing the magnetic metal nanoparticles into contact with the working electrode – specifically, Feldbrugge teaches “it is also possible to focus the particles in advance onto the electrode by means of an electrical or magnetic field and in this way to further increase the sensitivity” ([0025]); which also meets claim 23 limitation of applying the magnetic field to the magnetic nanoparticles causes the magnetic nanoparticles to be in contact with the electrode;
a current amount measuring step - specifically, Feldbrugge teaches a constant potential is applied to the working electrode, electrical current flows through the solution ([0031]), and the current flow registered at the microelectrode ([0033]). Since the magnetic nanoparticles are bound to the electrode via antibody-analyte interactions, which are not affected by electrical current, Feldbrugge inherently teaches claim 25 limitation of the magnetic nanoparticles remaining in contact with the electrode during the current measuring step.
Regarding the limitation of the analysis method is performed free of re-depositing the magnetic metal nanoparticles on the working electrode, Feldbrugge does not explicitly teach omitting the re-deposition step, and teaches direct dissolution of the metal present in the particles without any intermediate steps (see Fig. 3A and B). As such, the teaching of Feldbrugge meets the claim limitation.
Feldbrugge does not specifically teach the order of binding events as recited in claim 1: binding of the test substance to the antibody fixed on the working electrode, removing the test substance solution, binding the magnetic nanoparticles to the captured test substance, and removing the dispersion liquid. Instead, Feldbrugge teaches the following order of binding events: binding of the test substance to the antibody fixed on the magnetic nanoparticles and then contacting the nanoparticles with the antibody fixed on the working electrode ([0009] and [0010]).
Regarding claim 1, Dong teaches microfluidic methods performed in ELISA format (Title). Fig. 1(a) teaches sandwich assay format recited in claim 1, where a target is bound to an immobilized antibody and then a labeled secondary antibody is contacted with the immobilized target. Both approaches (Dong and Feldbrugge) are well-known in the art of sandwich immunoassays, both approaches are interchangeable, and one of ordinary skill in the art would have chosen either approach with a reasonable expectation of success.
Feldbrugge and Dong do not explicitly teach the washing steps between the binding steps. However, the washing steps are inherent to the immunoassays performed in the sandwich format and Dong teaches that wash steps are needed to remove excess unreacted antigen or antibody (pg. 2, col. 1, last par.). The wash step needed to remove excess unreacted antigen is equivalent to the first washing step of claim 1 and the wash step needed to remove excess unreacted antibody is equivalent to the second washing step of claim 1.
Feldbrugge and Dong do not specifically teach the magnetic nanoparticles being magnetic metal nanoparticles, current measuring step of applying a voltage between the working electrode and the counter electrode to ionize the magnetic metal nanoparticles in contact with the working electrode, and a calculation step of calculating an amount of the test substance from the current according to a calibration curve with current values and test substance concentrations.
Regarding claim 1, Chen teaches preparation of antibodies fixed to magnetic particles ([0056], [0057]), containing Co or Ni ([0058]), in order to provide patterning of biomolecules on a substrate for use in bioanalysis and diagnostics ([0017]). Cobalt and nickel meet the limitation of claim 1, reciting wherein the magnetic metal nanoparticles include at least one magnetic metal selected from a group consisting of iron, cobalt, and nickel.
Additionally, Chen teaches sizes of the magnetic particles - “micro- or nanoparticles may be composed of a variety of materials and may range in size from 1 nm-100 μm” ([0057]), a range falling within and therefore meeting the limitation of claim 15, which recites a range of 1 nm to 50 nm.
It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to have modified the method of Feldbrugge and Dong by employing Co or Ni in magnetic metal nanoparticle as taught by Chen, as an obvious matter of simple substitution of one known element (Co- or Ni-containing magnetic metal nanoparticle) for another (generic magnetic particle of Feldbrugge and Dong) to obtain predictable results.
Both kinds of magnetic particles preserve their magnetic properties and metals taught by Chen do not negatively affect these properties. Therefore, one of ordinary skill would have a reasonable expectation of success.
Feldbrugge, Dong, and Chen do not specifically teach current measuring step of applying a voltage between the working electrode and the counter electrode to ionize the magnetic metal nanoparticles in contact with the working electrode, and a calculation step of calculating an amount of the test substance from the current according to a calibration curve with current values and test substance concentrations.
Regarding claim 1, Szymanski teaches an electrochemical immunoassay, wherein the amount of captured silver nanoparticles acting as a label was measured by oxidizing the silver metal and detecting it by anodic stripping voltammetry (Abstract and pg. 194, col. 2, par. 4). As such, Szymanski teaches measuring current proportional to the amount of bound analyte.
Regarding a calibration curve, Szymanski teaches a calibration curve of total current values (microcoulombs) from test substance concentrations (myoglobin) (Fig. 6).
Szymanski does not specifically teach dissolving metals present in the magnetic particles taught by Chen. However, Wikipedia provides evidence that nickel when connected to an electric current circuit is capable of dissolving as nickel ions (Nickel electroplating – Wikipedia, pg. 1, par. 2, and the process is known since 1837 – par. 4). Therefore, Ni-containing particles taught by Chen would inherently dissolve upon applying voltage between electrodes.
It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to have modified the method of Feldbrugge, Dong, and Chen, by employing oxidation of metal present in the metal magnetic particles of Chen and electrochemical detection of ionized metals (e.g., Ni) as taught by Szymanski and evidenced by Wikipedia, in order to provide a very sensitive detection for immunoassays. One having ordinary skill in the art would have been motivated to make such a change because Szymanski teaches “high sensitivity of electrochemical immunoassays with metal nanoparticles as the bio-label is related to the release of huge number of metal ions from one single nanoparticle (i.e. 106 from 40-nm particle) and their subsequent detection at a carbon electrode using ASV” (pg. 191, col. 2, last par.). This combination would have been desirable to those of ordinary skill in the art for the reasons mentioned above.
One having ordinary skill in the art would have had a reasonable expectation of success in combining the prior art references because Feldbrugge, Dong, Chen, and Szymanski are similarly drawn to using magnetic nanoparticles in immunoassays, and detection of oxidized metal label has been demonstrated by Szymanski.
The limitation of current measuring step of applying a voltage between the working electrode and the counter electrode to ionize the magnetic metal nanoparticles in direct contact with the working electrode would have been obvious to one having ordinary skill in the art because metal oxidation as taught by Szymanski and evidenced by Wikipedia requires direct contact with the working electrode in order for the electrical current to reach the magnetic particles. This also meets the limitation of direct contact in claims 23 and 25.
Regarding claim 3, Feldbrugge teaches the working electrode is a metal (platinum) electrode ([0034]).
Regarding claim 19, Feldbrugge, Dong, Chen, Szymanski, and Wikipedia teach magnetic metal nanoparticles are an electrochemically measurable label for the complex of the secondary antibodies and the test substance. Feldbrugge teaches secondary antibodies being fixed to surfaces of the magnetic nanoparticles ([0039] and [0025]), and Szymanski and Wikipedia teach electrochemical method of detection (Szymanski, anodic stripping voltammetry in Abstract and pg. 194, col. 2, par. 4).
Claim 7 is rejected under 35 U.S.C. 103 as being unpatentable over Feldbrugge in view of Dong, Chen, Szymanski, and Wikipedia as applied to claim 1, and further in view of Cao et al. (J. Mater. Chem. C, 2016,4, 951-957), and as evidenced by Zhang (CN 104446420).
The teachings of Feldbrugge, Dong, Chen, Szymanski, and Wikipedia have been set forth above.
Feldbrugge, Dong, Chen, Szymanski, and Wikipedia fail to teach the magnetic metal nanoparticles contain sulfur.
Regarding claim 7, Cao teaches “Nonmetal sulfur-doped coral-like cobalt ferrite nanoparticles with enhanced magnetic properties” (Title). Cao also teaches magnetic particles containing sulfur. Specifically, Cao teaches preparation of sulfur-doped cobalt ferrite nanoparticles with sulfur atoms introduced during particle synthesis (pg. 952, Col.1, 1st paragraph of “Experiment section” and Fig. 1).
It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to have modified the method of Feldbrugge, Dong, Chen, Szymanski, and Wikipedia, by employing magnetic metal nanoparticles containing sulfur atoms as taught by Cao and evidenced by Zhang, in order to create magnetic metal nanoparticles with enhanced properties. One having ordinary skill in the art would have been motivated to make such a change because the sulfur-containing nanoparticles have better stability and biocompatibility (Zhang, par. 3). This combination would have been desirable to those of ordinary skill in the art for the reasons mentioned above.
One having ordinary skill in the art would have had a reasonable expectation of success in combining the prior art references because Feldbrugge, Dong, Chen, and Cao are drawn to using magnetic nanoparticles that require good biocompatibility.
Claims 9 and 11 are rejected under 35 U.S.C. 103 as being unpatentable over Feldbrugge in view of Dong, Chen, Szymanski, and Wikipedia as applied to claim 1, and further in view of Lin et al. (US 2008/0292545).
The teachings of Feldbrugge, Dong, Chen, Szymanski, and Wikipedia have been set forth above.
Feldbrugge, Dong, Chen, Szymanski, and Wikipedia fail to teach the reference electrode is a silver-silver chloride electrode.
Regarding claims 9 and 11, Lin teaches an apoferritin nanoparticle for diagnostic applications (Abstract); the apoferritin nanoparticle generating an electrochemical signal that can be measured in an electrochemical process ([0006]). Lin also teaches Ag/AgCl reference electrode and the counter electrode is a carbon electrode.
Specifically, Lin teaches a biosensor comprising a working electrode having an immobilized antibody ([0044]), an Ag/AgCl reference electrode and a carbon counter electrode ([0054]).
It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to have modified the method of Feldbrugge, Dong, Chen, Szymanski, and Wikipedia, by employing an Ag/AgCl reference electrode and a carbon counter electrode as taught by Lin, as an obvious matter of using of known technique (specific electrode materials) to improve similar methods in the same way. Ag/AgCl reference electrode and a carbon counter electrode are widely known in the art as “gold” standard electrodes with wide application range, therefore, one of ordinary skill in the art would have a reasonable expectation of success.
Claims 13 and 17 are rejected under 35 U.S.C. 103 as being unpatentable over Feldbrugge, in view of Dong, Chen, Szymanski, and Wikipedia as applied to claim 1, and further in view of Wang et al. (Biosens Bioelectron. 2016 Jun 15; 80:640-646) and as evidenced by CSH (Cold Spring Harb Protoc; 2006; https://cshprotocols.cshlp.org/content/2006/1/pdb.rec8247).
The teachings of Feldbrugge, Dong, Chen, Szymanski, and Wikipedia have been set forth above.
Feldbrugge, Dong, Chen, Szymanski, and Wikipedia fail to teach an electrolyte of the conductive solvent is chloride.
Regarding claims 13 and 17, Wang teaches a method for the detection of thrombin using an electrochemical aptasensor (Abstract). Wang also teaches the electrolyte of the conductive solvent is chloride.
Specifically, Wang teaches the method, wherein the working solution is the PBS buffer (pg. 642, col. 2, par. 4). The PBS buffer is widely known in the art as phosphate-buffered saline solution with two chloride-containing salts present: NaCl and KCl. CSH provides evidence that PBS buffer contains 140 mM chloride (or 1.4M in 10x buffer), falling in range of chloride concentrations of claim 17, reciting 0.005 M/L to 1.0M/L.
It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to have modified the method of Feldbrugge, Dong, Chen, Szymanski, and Wikipedia, by employing a chloride-containing electrolyte as taught by Wang. One having ordinary skill in the art would have been motivated to make such a change because Wang teaches that pH optimization of the PBS buffer allows to obtain the largest current response (pg. 642, col. 2, par. 4). This combination would have been desirable to those of ordinary skill in the art for the reasons mentioned above.
One having ordinary skill in the art would have had a reasonable expectation of success in combining the prior art references because Feldbrugge, Dong, Chen, Szymanski, and Wang are drawn to detection of biological molecules using electrochemical methods, and Feldbrugge, Dong, and Chen, are generic with respect to the type of electrolytic solution in which the magnetic nanoparticles are dispersed.
Claims 2, 4, 16, 20, 24, and 26 are rejected under 35 U.S.C. 103 as being unpatentable over Feldbrugge et al. (IDS; US 2004/0110230) in view of Dong et al. (Interdiscip Rev Nanomed Nanobiotechnol. 2017 Sep;9(5) Epub 2017 Feb 20), Chen et al. (IDS; US 2011/0046013), and Szymanski et al. (Electroanalysis, (2010) 22 (2). pp. 191-198), and Immink et al. (WO 2008/102218), and as evidenced by Wikipedia (Nickel electroplating – Wikipedia).
Regarding claim 2, Feldbrugge teaches a method for determining the concentration of analytes using metal particles as labels and an electrochemical detection technique (Abstract, [0009]-[0011]), the method comprising:
using a sensor having a working electrode, a reference electrode, and a counter electrode ([0030]) for binding the test substance via the primary antibodies fixed on a surface of the working electrode ([0039]);
detecting the test substance using a dispersion liquid of magnetic nanoparticles including conductive solvent and magnetic nanoparticles dispersed in the solvent – specifically, the reference teaches an electrolytic solution used as a solvent ([0032]). The reference also teaches secondary antibodies being fixed to surfaces of the magnetic nanoparticles ([0039] and [0025]). Feldbrugge teaches the magnetic particle has an average particle diameter in the range of 0.1 to 5 µm ([0040]), therefore the magnetic particle is a magnetic nanoparticle;
a magnetic field applying step of applying a magnetic field to the magnetic metal nanoparticles connected to the test substance in the presence of a solvent and bringing the magnetic metal nanoparticles into contact with the working electrode – specifically, Feldbrugge teaches “it is also possible to focus the particles in advance onto the electrode by means of an electrical or magnetic field and in this way to further increase the sensitivity” ([0025]); which also meets claim 24 limitation of applying the magnetic field to the magnetic nanoparticles causes the magnetic nanoparticles to be in contact with the electrode;
a current amount measuring step - specifically, Feldbrugge teaches a constant potential is applied to the working electrode, electrical current flows through the solution ([0031]), and the current flow registered at the microelectrode ([0033]). Since the magnetic nanoparticles are bound to the electrode via antibody-analyte interactions, which are not affected by electrical current, Feldbrugge inherently teaches claim 26 limitation of the magnetic nanoparticles remaining in contact with the electrode during the current measuring step.
Regarding the limitation of the analysis method is performed free of re-depositing the magnetic metal nanoparticles on the working electrode, Feldbrugge does not explicitly teach omitting the re-deposition step, however the reference teaches direct dissolution of the metal present in the particles without any intermediate steps (see Fig. 3A and B). As such, the teaching of Feldbrugge meets the claim limitation.
Feldbrugge does not specifically teach the order of binding events as recited in claim 2: binding of the test substance to the antibody fixed on the working electrode, removing the test substance solution, binding the magnetic nanoparticles to the captured test substance, and removing the dispersion liquid. Instead, Feldbrugge teaches the following order of binding events: binding of the test substance to the antibody fixed on the magnetic nanoparticles and then contacting the nanoparticles with the antibody fixed on the working electrode ([0009] and [0010]).
Regarding claim 2, Dong teaches microfluidic methods performed in ELISA format (Title). Fig. 1(a) teaches sandwich assay format recited in claim 2, where a target is bound to an immobilized antibody and then a labeled secondary antibody is contacted with the immobilized target. Both approaches (Dong and Feldbrugge) are well-known in the art of sandwich immunoassays, both approaches are interchangeable, and one of ordinary skill in the art would have chosen either approach with a reasonable expectation of success.
Feldbrugge and Dong do not explicitly teach the washing steps between the binding steps. However, the washing steps are inherent to the immunoassays performed in the sandwich format and Dong teaches that wash steps are needed to remove excess unreacted antigen or antibody (pg. 2, col. 1, last par.). The wash step needed to remove excess unreacted antigen is equivalent to the first washing step of claim 2 and the wash step needed to remove excess unreacted antibody is equivalent to the second washing step of claim 2.
Feldbrugge and Dong do not specifically teach removing the magnetic nanoparticles which are not connected to the test substance from the surface of the working electrode or a vicinity thereof by an external magnetic field, the magnetic nanoparticles being magnetic metal nanoparticles, current amount measuring step of applying a voltage between the working electrode and the counter electrode to ionize the magnetic metal nanoparticles in direct contact with the working electrode, and a calculation step of calculating an amount of the test substance from the current according to a calibration curve with current values and test substance concentrations.
Regarding claim 2, Chen teaches preparation of antibodies fixed to magnetic particles ([0056], [0057]), containing Co or Ni ([0058]), in order to provide patterning of biomolecules on a substrate for use in bioanalysis and diagnostics ([0017]). Cobalt and nickel meet the limitation of claim 2, reciting wherein the magnetic metal nanoparticles include at least one magnetic metal selected from a group consisting of iron, cobalt, and nickel.
Additionally, Chen teaches sizes of the magnetic particles - “micro- or nanoparticles may be composed of a variety of materials and may range in size from 1 nm-100 μm” ([0057]), a range falling within and therefore meeting the limitation of claim 16, which recites a range of 1 nm to 50 nm.
It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to have modified the method of Feldbrugge and Dong by employing Co or Ni in magnetic metal nanoparticle as taught by Chen, as an obvious matter of simple substitution of one known element (Co- or Ni-containing magnetic metal nanoparticle) for another (generic magnetic particle of Feldbrugge and Dong) to obtain predictable results.
Both kinds of magnetic particles preserve their magnetic properties and metals taught by Chen do not negatively affect these properties. Therefore, one of ordinary skill would have a reasonable expectation of success.
Feldbrugge, Dong, and Chen do not specifically teach removing the magnetic nanoparticles which are not connected to the test substance from the surface of the working electrode or a vicinity thereof by an external magnetic field, current amount measuring step of applying a voltage between the working electrode and the counter electrode to ionize the magnetic metal nanoparticles in direct contact with the working electrode, and a calculation step of calculating an amount of the test substance from the current according to a calibration curve with current values and test substance concentrations.
Regarding claim 2, Immink teaches a method of sensing magnetic particles (Title). Immink also teaches removing unbound magnetic metal nanoparticles by an external magnetic field.
Specifically, Immink teaches a method step for attracting or repelling the magnetic particles by a magnetic force for removing unbound magnetic particles from the sensing unit (pg. 13. Lines 1-2).
It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to have modified the method of Feldbrugge, Dong, and Chen by employing external magnetic field to remove unbound magnetic metal nanoparticles as taught by Immink. One having ordinary skill in the art would have been motivated to make such a change because unbound magnetic metal nanoparticles must be removed during sandwich-format immunoassays. This combination would have been desirable to those of ordinary skill in the art because this step is required.
One having ordinary skill in the art would have had a reasonable expectation of success in combining the prior art references because Feldbrugge, Dong, Chen, and Immink are drawn to similar methods of using magnetic nanoparticles, and Feldbrugge, Dong, and Chen are generic with respect to the details of the washing steps.
Feldbrugge, Dong, Chen, and Immink do not specifically teach current measuring step of applying a voltage between the working electrode and the counter electrode to ionize the magnetic metal nanoparticles in contact with the working electrode, and a calculation step of calculating an amount of the test substance from the current according to a calibration curve with current values and test substance concentrations.
Regarding claim 2, Szymanski teaches an electrochemical immunoassay, wherein the amount of captured silver nanoparticles acting as a label was measured by oxidizing the silver metal and detecting it by anodic stripping voltammetry (Abstract and pg. 194, col. 2, par. 4). As such, Szymanski teaches measuring current proportional to the amount of bound analyte.
Regarding a calibration curve, Szymanski teaches a calibration curve with total current values (microcoulombs) and test substance concentrations (myoglobin) (Fig. 6).
Szymanski does not specifically teach dissolving metals present in the magnetic particles taught by Chen. However, Wikipedia provides evidence that nickel when connected to an electric current circuit is capable of dissolving as nickel ions (Nickel electroplating – Wikipedia, pg. 1, par. 2, and the process is known since 1837 – par. 4). Therefore, Ni-containing particles taught by Chen would inherently dissolve upon applying voltage between electrodes.
It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to have modified the method of Feldbrugge, Dong, Chen, and Immink, by employing oxidation of metal present in the metal magnetic particles of Chen and electrochemical detection of ionized metals (e.g., Ni) as taught by Szymanski and evidenced by Wikipedia, in order to provide a very sensitive detection for immunoassays. One having ordinary skill in the art would have been motivated to make such a change because Szymanski teaches “high sensitivity of electrochemical immunoassays with metal nanoparticles as the bio-label is related to the release of huge number of metal ions from one single nanoparticle (i.e. 106 from 40-nm particle) and their subsequent detection at a carbon electrode using ASV” (pg. 191, col. 2, last par.). This combination would have been desirable to those of ordinary skill in the art for the reasons mentioned above.
One having ordinary skill in the art would have had a reasonable expectation of success in combining the prior art references because Feldbrugge, Dong, Chen, Immink, and Szymanski are similarly drawn to using magnetic nanoparticles in immunoassays, and detection of oxidized metal label has been demonstrated by Szymanski.
The limitation of current measuring step of applying a voltage between the working electrode and the counter electrode to ionize the magnetic metal nanoparticles in direct contact with the working electrode would have been obvious to one having ordinary skill in the art as taught by Szymanski and evidenced by Wikipedia requires direct contact with the working electrode in order for the electrical current to reach the magnetic particles.
Regarding claim 4, Feldbrugge teaches the working electrode is a metal (platinum) electrode ([0034]).
Regarding claim 20, Feldbrugge, Dong, Chen, Immink, Szymanski, and Wikipedia teach magnetic metal nanoparticles are an electrochemically measurable label for the complex of the secondary antibodies and the test substance. Feldbrugge teaches secondary antibodies being fixed to surfaces of the magnetic nanoparticles ([0039] and [0025]), and Szymanski and Wikipedia teach electrochemical method of detection (Szymanski, anodic stripping voltammetry in Abstract and pg. 194, col. 2, par. 4).
Claim 8 is rejected under 35 U.S.C. 103 as being unpatentable over Feldbrugge in view of Dong, Chen, Immink, Szymanski, and Wikipedia as applied to claim 2, and further in view of Cao et al. (J. Mater. Chem. C, 2016,4, 951-957), and as evidenced by Zhang (CN 104446420).
The teachings of Feldbrugge, Dong, Chen, Immink, Szymanski, and Wikipedia have been set forth above.
Feldbrugge, Dong, Chen, Immink, Szymanski, and Wikipedia fail to teach the magnetic metal nanoparticles contain sulfur.
Regarding claim 8, Cao teaches “Nonmetal sulfur-doped coral-like cobalt ferrite nanoparticles with enhanced magnetic properties” (Title). Cao also teaches magnetic particles containing sulfur. Specifically, Cao teaches preparation of sulfur-doped cobalt ferrite nanoparticles with sulfur atoms introduced during particle synthesis (pg. 952, Col.1, 1st paragraph of “Experiment section” and Fig. 1).
It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to have modified the method of Feldbrugge, Dong, Chen, Immink, Szymanski, and Wikipedia, by employing magnetic metal nanoparticles containing sulfur atoms as taught by Cao and evidenced by Zhang, in order to create magnetic metal nanoparticles with enhanced properties. One having ordinary skill in the art would have been motivated to make such a change because the sulfur-containing nanoparticles have better stability and biocompatibility (Zhang, par. 3). This combination would have been desirable to those of ordinary skill in the art for the reasons mentioned above.
One having ordinary skill in the art would have had a reasonable expectation of success in combining the prior art references because Feldbrugge, Dong, Chen, Immink, and Cao are drawn to using magnetic nanoparticles that require good biocompatibility.
Claims 10 and 12 are rejected under 35 U.S.C. 103 as being unpatentable over Feldbrugge in view of Dong, Chen, Immink, Szymanski, and Wikipedia as applied to claim 2, and further in view of Lin et al. (US 2008/0292545).
The teachings of Feldbrugge, Dong, Chen, Immink, Szymanski, and Wikipedia have been set forth above.
Feldbrugge, Dong, Chen, Immink, Szymanski, and Wikipedia fail to teach the reference electrode is a silver-silver chloride electrode.
Regarding claims 10 and 12, Lin teaches an apoferritin nanoparticle for diagnostic applications (Abstract); the apoferritin nanoparticle generating an electrochemical signal that can be measured in an electrochemical process ([0006]). Lin also teaches Ag/AgCl reference electrode and the counter electrode is a carbon electrode.
Specifically, Lin teaches a biosensor comprising a working electrode having an immobilized antibody ([0044]), an Ag/AgCl reference electrode and a carbon counter electrode ([0054]).
It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to have modified the method of Feldbrugge, Dong, Chen, Immink, Szymanski, and Wikipedia, by employing an Ag/AgCl reference electrode and a carbon counter electrode as taught by Lin, as an obvious matter of using of known technique (specific electrode materials) to improve similar methods in the same way. Ag/AgCl reference electrode and a carbon counter electrode are widely known in the art as “gold” standard electrodes with wide application range, therefore, one of ordinary skill in the art would have a reasonable expectation of success.
Claims 14 and 18 are rejected under 35 U.S.C. 103 as being unpatentable over Feldbrugge, in view of Dong, Chen, Immink, Szymanski, and Wikipedia as applied to claim 2, and further in view of Wang et al. (Biosens Bioelectron. 2016 Jun 15; 80:640-646) and as evidenced by CSH (Cold Spring Harb Protoc; 2006; https://cshprotocols.cshlp.org/content/2006/1/pdb.rec8247).
The teachings of Feldbrugge, Dong, Chen, Immink, Szymanski, and Wikipedia have been set forth above.
Feldbrugge, Dong, Chen, Immink, Szymanski, and Wikipedia fail to teach an electrolyte of the conductive solvent is chloride.
Regarding claims 14 and 18, Wang teaches a method for the detection of thrombin using an electrochemical aptasensor (Abstract). Wang also teaches the electrolyte of the conductive solvent is chloride.
Specifically, Wang teaches the method, wherein the working solution is the PBS buffer (pg. 642, col. 2, par. 4). The PBS buffer is widely known in the art as phosphate-buffered saline solution with two chloride-containing salts present: NaCl and KCl. CSH provides evidence that PBS buffer contains 140 mM chloride (or 1.4M in 10x buffer), falling in range of chloride concentrations of claim 18, reciting 0.005 M/L to 1.0M/L.
It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to have modified the method of Feldbrugge, Dong, Chen, Immink, Szymanski, and Wikipedia, by employing a chloride-containing electrolyte as taught by Wang. One having ordinary skill in the art would have been motivated to make such a change because Wang teaches that pH optimization of the PBS buffer allows to obtain the largest current response (pg. 642, col. 2, par. 4). This combination would have been desirable to those of ordinary skill in the art for the reasons mentioned above.
One having ordinary skill in the art would have had a reasonable expectation of success in combining the prior art references because Feldbrugge, Dong, Chen, Szymanski, and Wang are drawn to detection of biological molecules using electrochemical methods, and Feldbrugge, Dong, and Chen, are generic with respect to the type of electrolytic solution in which the magnetic nanoparticles are dispersed.
Response to Arguments
Applicant’s arguments filed June 9, 2026 have been fully considered.
Applicant argues that “the pending application discloses that a voltage is applied so as to cause a redox reaction of the magnetic metal nanoparticles themselves, and then a total amount of current consumed by ionization of the magnetic metal nanoparticles is measured and quantified” (pg. 10, par. 2) and “In contrast, Feldbrugge fails to teach or suggest the current amount measuring step and the calculation step as recited in claim 1 and similarly claim 2. Rather, in Feldbrugge, the measurement method discloses controlling contact between an electrode and an electrolyte containing a redox compound by positioning particles near the electrode through an antigen-antibody reaction. Feldbrugge at [0009]- [0012]. Thus, in Feldbrugge, the particles themselves are not electrochemically active, but merely function as physical blocking members” (par. 3).
The arguments are not persuasive. While Feldbrugge does not explicitly teach the particles themselves are electrochemically active, it is not relied upon for that since it is evidenced by Wikipedia (Nickel electroplating) that nickel is an electrochemically active metal. Feldbrugge was cited of its teaching of a method for determining the concentration of analytes using metal particles as labels and an electrochemical detection technique (Abstract, [0009]-[0011]), the method comprising: using a sensor having electrodes; detecting the test substance using a dispersion liquid of magnetic nanoparticles including conductive solvent and magnetic nanoparticles dispersed in the solvent; applying a magnetic field to the magnetic metal nanoparticles connected to the test substance; and a current amount measuring step.
Applicant argues that “the particles in Feldbrugge to function as physical blocking members, the particles must not dissolve, must not react with the electrode, and must not be ionized. Id.” (pg. 10, par. 3). The argument is not persuasive because in paragraphs [0009]-[0012] Feldbrugge does not teach that “the particles must not dissolve, must not react with the electrode, and must not be ionized”. Therefore, Feldbrugge does not teach away. There is nothing in Feldbrugge’s method that would prevent it from being used in the method of instant invention.
Applicant argues that “Feldbrugge does not teach or suggest, "bringing the magnetic metal nanoparticles into direct contact with the working electrode" as recited in claim 1, and similarly claim 2. Rather, in Feldbrugge, the function of the magnetic particles is limited to acting as a lid or blocking member, and it is sufficient that the particles approach the electrode only to such an extent that voids on the electrode surface are filled” (pg. 11, par. 2).
The argument is not correct because in order to act as “a lid or blocking member” Feldbrugge’s particles must be in direct contact with the working electrode. A reasonable expectation of success in arriving at the claimed limitations based on the teachings of Feldbrugge comes from the fact that Feldbrugge teaches binding particles on the electrode surface and that particles have nickel, which according to Wikipedia is electrochemically active. Other references address different limitations of claims 1-2 and do not have direct effect on reasonable expectation of success of this particular aspect of Feldbrugge’s teaching. Claims 1 and 2 do not differentiate instant method well enough and Feldbrugge’s particles bound to the electrode and containing electrochemically active nickel read on the claims.
Applicant argues that “the Office Action asserts that Feldbrugge teaches the magnetic field applying step because Feldbrugge discloses "it is also possible to focus the particles in advance onto the electrode by means of an electrical or magnetic field and in this way to further increase the sensitivity." Feldbrugge at [0025]” (pg. 11, last par. – pg. 12, par. 1) and “"focusing" the particles onto the electrode does not necessarily mean that a magnetic force is applied specifically to cause the magnetic particles to come into contact with the working electrode, as is disclosed in the pending application” (pg. 12, par. 2).
The argument is not persuasive because Feldbrugge does teach “focusing” the particles onto the electrode ([0025]) and Applicant fails to explain why “"focusing" the particles onto the electrode does not necessarily mean …”. Magnetic force applied by Feldbrugge “focuses” particles. After the particles are brought to the electrode antibodies hold the particles via a sandwich with a target molecule - “the corresponding particles are added to the electrode array, which can bind both the particles covered with antibodies” (Feldbrugge [0019]).
Applicant argues that “Feldbrugge teaches "[a]t the moment of the detachment of the microparticle, there is a discontinuous rise in the electrochemical conversion and thus in the current flow through the electrode, such that the associated force can be registered and detected as a measurement for the number of binding sites and thus also as a measurement for the concentration of analytes" (emphasis added)” (pg. 12, par. 3). The argument is not persuasive because Feldbrugge was not cited of its teaching of detachment of the particles. Feldbrugge was cited of its teaching of a method for determining the concentration of analytes using metal particles as labels and an electrochemical detection technique (Abstract, [0009]-[0011]), the method comprising: using a sensor having electrodes; detecting the test substance using a dispersion liquid of magnetic nanoparticles including conductive solvent and magnetic nanoparticles dispersed in the solvent; applying a magnetic field to the magnetic metal nanoparticles connected to the test substance; and a current amount measuring step.
Applicant argues that “New claims 23 and 24 depend from claim 1 and, thus, distinguish over the applied references for at least the reasons discussed above with respect to claim 1, as well as for the additional features that they recite. New claims 25 and 26 depend from claim 2 and, thus, distinguish over the applied references for at least the reasons discussed above with respect to claim 2, as well as for the additional features that they recite” (pg. 13, par. 1).
The arguments are not persuasive because: (a) claims 1 and 2 are still rejected (see §103 rejection above for details) and (b) Applicant fails to explain what specific limitations of claims 23-26 distinguish them over the applied references.
As presented in §103 rejection above, Szymanski teaches an electrochemical immunoassay, wherein the amount of captured silver nanoparticles acting as a label was measured by oxidizing/dissolution of the silver metal (Title). Therefore, the nanoparticles must be in direct contact with the working electrode in order for the electrical current to reach the nanoparticles. This direct contact is important in the method of Feldbrugge because without initial (claims 23 and 24) and maintained (claims 25 and 26) direct contact the current measuring step would not work and the assay without magnetic nanoparticles attached to the electrode would not make sense.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to Alexander Volkov whose telephone number is (571) 272-1899. The examiner can normally be reached M-F 9:00AM-5:00PM (EST).
If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Bao-Thuy Nguyen can be reached on (571) 272-0824. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
Information regarding the status of an application may be obtained from Patent Center. Status information for published applications may be obtained from Patent Center. Status information for unpublished applications is available through Patent Center for authorized users only. Should you have questions about access to Patent Center, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free).
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) Form at https://www.uspto.gov/patents/uspto-automated- interview-request-air-form.
/ALEXANDER ALEXANDROVIC VOLKOV/
Examiner, Art Unit 1677
/REBECCA M GIERE/Primary Examiner, Art Unit 1677
Prosecution Insights