The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Claim 16-17 and 20 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. With respect to claim 16, it is not clear if applicant is requiring the limit of detection to fall between the stated values irrespective of the analyte or if applicant is attempting to claim values for a particular analyte rather than all analytes in general. For examination purposes claim 16 will be treated as the limit of detection needs to fall within that range so that a limit of detection outside of that range is not covered by claim 16. With respect to claim 17, it is not clear what “operable at a relative humidity of up to 90%” actually requires. Does it require simplify that there is some measurable difference based on analyte presence or does it require that the sensor is not significantly affected by humidity levels up to that point? Since the below applied Chow paper (Sensors and Actuators B 2010) teaches that placing a chemiresistor in water increases the impedance by 200% (see the first full paragraph on page 700 of Chow) and is used to detect organics in aqueous solution (see the title), the claim will be treated, for examination purposes, as simply requiring the ability to measure the analyte under humidity levels up to 90%. With respect to claim 20, it is not clear if the concentration range is for a specific analyte or if it is for all potential analytes regardless of whether the chemiresistor shows a measurable difference in the presence of the analyte at concentrations within the required range. Alternatively it is not clear if applicant is attempting to require that each analyte be measurable by the chemiresistor over the require concentration range.
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 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.
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 1-20 are rejected under 35 U.S.C. 103 as being unpatentable over Xie (Sensors 2020) in view of Hostetler (Langmuir 1999) and Kim (Sensors and Actuators B 2005, hereinafter called Kim ’05 or US 2005/0142030, hereinafter called Kim ‘030) or Chow (Sensors and Actuators B 2010). With respect to claim 1, Xie teaches a composition comprising a plurality of modified noble metal nanoparticles (abstract, thiol-functionalized gold nanoparticles), wherein each of said plurality of modified noble metal nanoparticles comprises a noble metal nanoparticle bound to a first ligand (see section 2.3 on page 4 for the formation of the gold nanoparticles and addition of the thiols shown in Table 1 to form thiol-coated AuNPs) wherein the first ligand is assembled to form a shell on top of said noble metal nanoparticle, the first ligand having a formula within the scope of the formula shown in claim 1. Xie does not teach a second ligand in which the second ligand is a linear or branched C1-C10 mercaptoalkyl, or a linear or branched C1-C10 mercaptoalkyl-aryl.
In the paper, Hostetler investigated the dynamics of ligand place-exchange reactions on monolayer-protected gold cluster molecules. Monolayer-protected gold clusters (Au MPCs) are stable, easily synthesized, organic solvent-soluble, nanoscale materials. MPCs with protecting monolayers composed of alkanethiolate ligands (RS) can be functionalized (R'S) by ligand place-exchange reactions, i.e., x(R'SH) + (RS)mMPC --> x(RSH) + (R'S)m(RS)m-xMPC, where x is the number of ligands place-exchanged (1 to 108) and m is the original number (ca. 108) of alkanethiolate ligands per Au314 cluster. The dynamics and mechanism of this reaction were probed by determining its kinetic order and final equilibrium position relative to incoming (R'S) and initial (RS) protecting thiolate ligands. The reactions were characterized by 1H NMR and IR spectroscopy, and the dispersity of place-exchange reaction products was preliminarily inspected by chromatography. The results of these experiments show that ligand exchange is an associative reaction and that the displaced thiolate becomes a thiol solution product. Disulfides and oxidized sulfur species are not involved in the reaction. Cluster-bound thiolate ligands differ widely in susceptibility to place-exchange, presumably owing to differences in binding sites (Au core edge and vertex sites are presumably more reactive than terrace sites). The rate of place-exchange decreases as the chain length and/or steric bulk of the initial protecting ligand shell is increased. The exchange results and proposed mechanism are compared to those for place-exchange reactions on self-assembled monolayers confined to flat gold surfaces.
In the paper Kim ’05 teaches mixed-ligand nanoparticles of chlorobenzenemethanethiol and n-octanethiol as chemical sensors. A series of mixed-ligand gold nanoparticles were synthesized, characterized and used to form transducer films to investigate and enhance vapor-sensing properties. Chlorobenzenemethanethiol (CBMT, a linear C1 mercaptoalkyl-aryl) nanoparticle, prepared using a two-phase method, was used for place-exchange reactions with a varying amount of n-octanethiol (OT, a linear C8 mercaptoalkyl) to produce a series of mixed-ligand gold nanoparticles (Au CBMT-OT-1, Au CBMT-OT-2, and Au CBMT-OT-3, see at least scheme 1 on page 190 and Table 1 on page 193). The nanoclusters were characterized by 1H NMR spectroscopy, thermal gravimetric analysis (TGA), and transmission electron microscopy (TEM). Thin film transducers of the monolayer-protected nanoparticles were formed through a dip-coating procedure on glass substrates mounted with interdigitated gold electrodes. SEM analysis indicated that mostly the surfaces of the sensors films were smooth. Nanoparticle sensors experienced repeated cycles of analyte vapors and blank air gas as the analyte concentrations were varied. Mostly the nanoparticle sensors produced rapid and reversible responses toward the vapors of 1-propanol, acetone and cyclohexane (see at least figure 4). Linear relationship between maximum resistance changes and vapor concentrations were observed. Above all the variations in compositions of the ligand molecules (CBMT and OT) resulted in differences in signal amplitudes.
In the patent publication Kim ‘030 teaches mixed ligand metal nanoparticle chemical sensors in which metal nanoparticles are encapsulated by at least two kinds of different molecule ligands having a relatively low conductivity and various composition ratios, and a chemical sensor array in which a film of the metal nanoparticle sensor is formed on the substrate. The metal nanoparticle sensor using the mixed ligand improves sensitivity and reaction speed with respect to an analyte, and selectivity with respect to various analytes, and a kind and a composition of a ligand of the mixed ligand constituting the metal nanoparticle sensor are adjusted to allow the high sensitivity nanoparticle sensor to be applied to the sensor array technology, thereby enabling a design of sensor properties as well as systematic access to a configuration of the sensor array the most efficient for the analytes (see the abstract and paragraph [0076]). Paragraph [0020] teaches that the combination of the chemically different molecules may be, for example, between a polar molecule and a non-polar molecule, a combination of a halogen compound and a non-halogen compound, or a cross combination thereof. Paragraph [0021] teaches that the non-polar molecules for example may be composed of an aliphatic hydrocarbon and an aromatic hydrocarbon. The aliphatic hydrocarbon can be composed of a saturated hydrocarbon and an unsaturated hydrocarbon. The halogen compound refers to a hydrocarbon molecule in which hydrogen is substituted by a halogen atom such as F, Cl, Br and I. The polar molecule has several exemplified functional groups including one or more nitrogen, oxygen or sulfur atoms. Paragraphs [0063]-[0065] and [0069]-[0075] appear to be describing mixed ligand nanoparticles using chlorobenzenemethanethiol (CBMT, a linear C1 mercaptoalkyl-aryl) and n-octanethiol (OT, a linear C8 mercaptoalkyl) as the ligand pair.
In the paper Chow teaches detection of organics in aqueous solution using gold nanoparticles modified with mixed monolayers of 1-hexanethiol (a linear C6 mercaptoalkyl) and 4-mercaptophenol. Gold nanoparticles functionalized with mixtures of 1-hexanethiol and 4-mercaptophenol were investigated as chemiresistor sensors for use in aqueous solutions. X-ray photoelectron spectroscopy (XPS) studies confirmed that it was possible to form mixed ligand compositions on the surface of the nanoparticles. Nanoparticle films with a higher proportion of 1-hexanethiol as the ligand resulted in higher impedances than those with lower proportions. The electrical response of the chemiresistor to toluene, dichloromethane, hexane and ethanol dissolved in water was found to depend strongly on the composition of the organic ligand used to cap the gold nanoparticles. 1-Hexanethiol-coated gold nanoparticles were sensitive to non-polar analytes whereas the sensitivity was reduced upon increasing the composition of 4-mercaptophenol on the surface. It was also shown that the sensitivity to ethanol could be enhanced 3-fold by using a sensor that was functionalized with a mixture of 60% 1-hexanethiol and 40% 4-mercaptophenol compared to a sensor functionalized with pure thiols only. The paragraph bridging pages 704-705 teaches that these two thiols were chosen because the different structure, polarity and hydrogen bonding ability of the two molecules should enable them to tune the selectivity of the sensor by varying the amount of each thiol constituent on the nanoparticle. Using a mixture of two ligands on the nanoparticle surface can either result in sensors with a systematic change in sensing properties or a response that is enhanced or reduced for a particular analyte.
With respect to claim 1, it would have been obvious at the time the application was filed to modify the Xie nanoparticles by adding a second ligand with a polarity different from the first ligand such as the hexanethiol or octanethiol used by Kim ’05, Kim’030 or Chow or the alkanethiols/alkanethiolates of Hostetler because of the change in response, sensitivity and/or selectivity to one or more analytes taught by Kim ’05, Kim’030 or Chow for the mixed ligand nanoparticles compared to single ligand nanoparticles when incorporated into a chemiresistive sensor or the ability to functionalize a monolayer-protected gold nanoparticle as taught by Hostetler. With respect to claims 2 and 7, the ligands of Xie have between 6 or 10 and 30 carbon atoms. With respect to claim 3, Hostetler and Kim ’05, Kim’030 or Chow teach compositions wherein a molar ratio between the first ligand and the second ligand within said composition is between 5:95 and 95:5 so that modification of Xie with Hostetler and Kim ’05, Kim’030 or Chow would have shown the obviousness of claim 3 for the reasons given relative to claim 1. With respect to claims 4-6, the modified particles of Xie would have been expected to be sensitive to an analyte such as the acetone to which the Xie particles were sensitive. With respect to claim 8, the particles of Xie, Kim ’05, Kim’030 or Chow are placed on a substrate in the formation of the chemiresistor in a manner that they can be considered bound to a substrate. With respect to claim 9, the particles of Xie, Kim ’05, Kim’030 or Chow are placed on a substrate in the formation of the chemiresistor in a manner that they would inherently have a porosity within the claimed range.
With respect to claim 10, the particles of Hostetler, Kim ’05, Kim’030 or Chow are produced through a ligand exchange method in which the particles having a first ligand thereon are contacted with a solution of the second ligand or a ligand mixture for a time sufficient to replace at least a portion of the first ligand. Hostetler, Kim ’05, Kim’030 or Chow show that one of ordinary skill in the art would have expected the place exchange reactions to occur to some extent whether the alkythiols are the molecule originally on the nanoparticles or are the exchanging thiol. Thus it would have been obvious at the time the application was filed to use such a ligand exchange method to exchange a portion of alkylthiol ligands on a plurality of nanoparticles with the Xie thiol as taught by Hostetler because Hostetler teaches ligand place exchange as a method of functionalizing nanoparticles and Hostetler, Kim ’05, Kim’030 or Chow each use a ligand exchange method in which different ligands are exchanged so that one of ordinary skill in the art would have expected the ligands of Xie to exchange at least a portion of alkylthiol ligands on a plurality of nanoparticles. The conditions taught by Kim ’05, Kim’030 or Chow are within the conditions of claims 11-13. With respect to claims 14 and 18, since each of Xie, Kim ’05, Kim’030 or Chow are producing a chemiresistor having at least two electrodes, a sensing element electrically connected to the two electrodes and a composition including nanoparticles with at least one ligand assembled to form a shell on the nanoparticles, it would have been obvious to one of ordinary skill in the art at the time the application was filed to exchange the nanoparticles of Xie with the modified nanoparticle of Xie in view of Kim ’05, Kim’030 or Chow for the reasons given above for claim 1. With respect to claims 15-16, Xie either teaches a structure that meets the required elements (claim 15) or the combination of Xie in view of at least Kim ’05, Kim’030 or Chow would point to an expectation by one of ordinary skill in the art that a chemiresistor as taught by Xie using the obviously modified nanoparticles of claim 1 would meet the required selective detection of claim 16. With respect to claim 17the teaching in Chow that a chemiresistor can be operable in water even though there is a change in the impedance of the chemiresistor in water compared to air shows that the one of ordinary skill in the art would have expected a measurable difference in the presence of the analyte that be used to operate the modified chemiresistor. With respect to claims 19-20, the combination of Xie in view of at least Kim ’05, Kim’030 or Chow would point to an expectation by one of ordinary skill in the art that a chemiresistor as taught by Xie using the obviously modified nanoparticles of claim 1 would meet the required analyte detection being required.
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. The additionally cited art teaches chemiresistor structures using monolayer protected nanoparticles, the production of those particles and ligand exchange methods for those nanoparticles. Of note, the Kado paper (Analytical Science 2009) and the Riccardi paper (Journal of Physical Chemistry Letter 2021) teach monolayer-protected gold nanoparticles in which the monolayer contains a ligand that is related to the formula of the second ligand as defined in claim 1.
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/ARLEN SODERQUIST/ Primary Examiner, Art Unit 1797
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