DETAILED ACTION
This is the Office action based on the 16265305 application filed February 1, 2019, and in response to applicant’s argument/remark filed on December 3, 2025. Claims 1-15, 17-20 and 50 are currently pending and have been considered below. Applicant’s cancelation of claims 21-49 and 51 acknowledged. Claim 16 withdrawn from consideration.
Notice of Pre-AIA or AIA Status
The present application is being examined under the pre-AIA first to invent provisions.
Claim Rejections - 35 USC § 103
The following is a quotation of pre-AIA 35 U.S.C. 103(a) which forms the basis for all obviousness rejections set forth in this Office action:
A patent may not be obtained though the invention is not identically disclosed or described as set forth in section 102 of this title, if the differences between the subject matter sought to be patented and the prior art are such that the subject matter as a whole would have been obvious at the time the invention was made to a person having ordinary skill in the art to which said subject matter pertains. Patentability shall not be negatived 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:
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.
Claims 1-3, 18-19 and 50 rejected under pre-AIA 35 U.S.C. 103(a) as being unpatentable over Jacobson (U.S. Pub. No. 20050263452), hereinafter “Jacobson”, in view of Lai et al. (U.S. Pub. No. 20090178276), hereinafter “Lai”, Chen et al. (U.S. Pub. No. 20100084747), hereinafter “Chen”, and Tringe et al. (U.S. Pub. No. 20120037591), hereinafter “Tringe”:
--Claims 1, 3: Jacobson teaches a method of fabricating a microfilter with precise sizes and shapes by using lithography ([0017]), wherein the microfilter is preferably a photosensitive polymer ([0026, 0031]), comprisingi) forming a silicon oxide layer on a silicon wafer ([0089], Fig. 12a-12g);ii) spin coating a photosensitive polyimide layer on the silicon oxide layer, then baking to cure the photosensitive polyimide layer ([0090]), wherein the photosensitive polyimide layer may be positive or negative ([0031, 0046, 0097]);iii) exposing the photosensitive polyimide layer to define a support structure layer [0091]);iv) spin coating a polyimide layer on the photosensitive polyimide layer, then baking to cure the polyimide polymer ([0092]);v) forming a mask layer and a photoresist layer over the polyimide polymer ([0092]), exposing the photoresist layer to define a pattern of pores, then develop the photoresist layer to form a pattern of pore openings [0093]);vi) etching the polyimide layer through the pore openings to form the pore layer for the microfilter ([0094]);vii) submerging the silicon wafer in a hydrofluoric acid bath, the hydrofluoric acid dissolves the silicon oxide layer and release the microfilter ([0095]). Jacobson further teaches that “the filter membrane of the present invention may be fashioned from a single polymeric film or from multiple polymeric films that are joined, for example, by heat curing to form a single monolithic membrane with no discernible line of distinction between the filter and support layers” ([0017]), that “(t)he filter membrane may be made monolithic by forming the filter and support layers from a single film or from separate films of the same or sufficiently compatible materials to allow the layers to become monolithic when bonded together” ([0041]), and that the photosensitive polymer may be positive or negative ([0031]). It is noted that steps ii)-vi) are equivalent to stacking a photosensitive film comprising a single photoresist layer on a wafer, forming pores in the photosensitive film, then removing the photosensitive film with pores from the water to form a freestanding unattached microfilter comprising the photoresist layer. Furthermore, in another embodiment Jacobson teaches that a microfilter may be fabricated by providing a supply of photosensitive film having a top side and a bottom side ([0098], Fig. 14), wherein the bottom side of the photosensitive film is embossed or precasted with a support structure ([0101]), the photosensitive film may be polyimide polymer ([0103]).exposing a top side of the film to UV light through a mask to define a pattern of pores in the film ([0046, 0098]);immersing the film in a solvent bath 134 to develop the patterns of pores, thereby forming the microfilter ([0046, 0099]). Jacobson fails to teach the photosensitive polyimide layer may be a resist dry film. Lai, also directed to a method of forming patterned photoresist layer on a substrate by exposing and developing, teaches that a patterned photoresist layer may be formed by either spin-coating a liquid photoresist on the substrate or by laminating a dry photoresist layer on the substrate, then exposing the photoresist layer to light beams and then developing the exposed photoresist layer to a developer ([0021-0022]). Chen teaches that a formation and patterning of a photosensitive layer may be preferably performed by laminating a dry photosensitive polyimide layer on a wafer ([0046]). Therefore, it would have been obvious to one of ordinary skill in the art at the time the invention was made, in routine experimentations, to fabricate the microfilter in the invention of Jacobson by laminating the dry photosensitive polyimide film having the bottom side precasted with a support structure on the silicon oxide layer on the silicon wafer, then exposing the top side of the film to UV light through a mask to define a pattern of pores in the film, immersing the film in a solvent bath to develop the patterns of pores, then submerging the silicon wafer in a hydrofluoric acid bath to dissolve the silicon oxide layer, thereby releasing the microfilter because Lai teaches that using dry photoresist may substitute for using liquid resist and Chen teaches that using dry resist is preferable. It is noted that using commercially available dry photoresist layer would advantageously simplify manufacturing and avoid expensive spin-coating and baking equipment that liquid photoresist method would require. It is noted that the released microfilter would be freestanding and unattached.
Jacobson fails to teach the exposing comprise using UV light from at least two directions at an angle.
Tringe teaches that, when defining a pattern of pores in a photosensitive film of a microfilter, standard lithographic processes is difficult because of poor pore size uniformity and repeatability ([0006]). Instead, Tringe teaches to use an interferometric lithography technique, wherein the photosensitive film is exposed to at least two interferometrically-arranged lasers from at least two directions at an angle with respect to the surface of the photosensitive film to form a pattern of exposure areas at a period of A/2 sin Ɵ, where A is the wave length of the laser and Ɵ is the angle to the normal to the surface ([0046, 0055], Fig. 3, 17). A copy of Fig. 3 in Tringe is shown below, showing the laser is applied from a first direction at a first angle Ɵ with respect to the surface, then the laser is applied from a second direction at a second angle Ɵ+90° with respect to the surface. The applying of the laser results in a selected periodicity of pores on the surface ([0046], Fig. 4)
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Therefore, it would have been obvious to one of ordinary skill in the art at the time the invention was made to use the method as taught by Tringe above to expose the photosensitive polyimide layer in the invention of Jacobson because Tringe teaches that this would improve pore size uniformity and repeatability, and also because this would immediately remove materials from the dry photosensitive film to form pores, thereby eliminating the photoresist development step. Jacobson further teaches that the microfilter may be used to separate blood components, cells components ([0003-0004]).
--Claims 18, 19, 50: Jacobson further teaches that the pores may be less than about 20 µm ([0023]), and the dry photosensitive polyimide film may have a thickness about 37 µm ([0103]) . It is noted that this overlaps the ranges recited in claim 18, 19 and 50.--Claim 2: Jacobson further teaches the process of forming the microfilter may be by continuous feeding a roll of the pre-cast photosensitive film through an apparatus ([0048, 0098, 0101]), wherein a top side of the photosensitive film is exposed to a first UV light at a first imaging station ([0098]), then indexing the photosensitive film to a second imaging station and expose the photosensitive film to a second UV light, then developing the photosensitive film to form the pores ([0099]). Jacobson further teaches that a microfilter may be sized and shaped so that it can be placed inside a separator ([0032-0039, 0085-0088]).
Claims 4, 6-8, 11,14-15 and 17 rejected under pre-AIA 35 U.S.C. 103(a) as being unpatentable over Jacobson in view of Lai, Chen and Tringe as applied to claim 1 above, and further in view of Li et al. (U.S. PGPub. No. 20120107925), hereinafter “Li”:
--Claims 4, 6, 7, 8, 11: Jacobson as modified by Lai, Chen and Tringe teaches the invention as above. Jacobson further teaches that the microfilter may be used to separate blood components or cells components ([0003-0004]), such as separating blood cells from a plasma ([0012, 0022]), removing bacteria or a certain cells from a liquid ([0083]). Jacobson is silent about the type of cells to be separated, and fails to teach that the microfilter may be used to filter CTC from blood.
Li teaches that CTC may be separated from blood by using a filter having a plurality of pores ([0027], Fig. 13).
Therefore, it would have been obvious to one of ordinary skill in the art at the time the invention was made to use the microfilter in the invention of Jacobson to filter CTC from blood because Jacobson teaches that the microfilter may be used to separate blood components or cells components, such as separating blood cells from a plasma or a certain cells from a liquid but is silent about the type of cells to be separated, and Li teaches that CTC may be separated from blood by using such microfilter.
--Claim 14: Li further teaches that the filter may comprise parylene ([0095]).
--Claim 15, 17: Li further teaches that the filter is securely within a housing having an inlet and an outlet, wherein the cell components get trapped at the filter (Fig. 5A)
Claims 5-8 and 11-13 rejected under pre-AIA 35 U.S.C. 103(a) as being unpatentable over Jacobson in view of Lai, Chen and Tringe as applied to claim 1 above, and further in view of Schueler et al. (U.S. PGPub. No. 20030165852), hereinafter “Schueler”:
--Claims 5, 6, 7, 8, 11, 12, 13: Jacobson as modified by Lai, Chen and Tringe teaches the invention as above. Jacobson further teaches that the microfilter may be used to separate blood components or cells components ([0003-0004]), such as separating blood cells from a plasma ([0012, 0022]), removing bacteria or a certain cells from a liquid ([0083]). Jacobson is silent about the type of cells to be separated, and fails to teach that the microfilter may be used to filter fetal blood cells.
Schueler teaches that fetal cells may be separated from a liquid medium by using a mesh screen having 74 pm pores ([0333]), wherein the fetal cells are analyzed using PCR ([0034-0041,0075]).
Therefore, it would have been obvious to one of ordinary skill in the art at the time the invention was made to use the microfilter in the invention of Jacobson to filter fetal blood cells because Jacobson teaches that the microfilter may be used to separate blood components or cells components, such as separating blood cells from a plasma or a certain cells from a liquid but is silent about the type of cells to be separated, and Schueler teaches that fetal blood cells may be separated from a liquid medium by using such mesh screen having pores with micrometer size.
Claims 4-11 and 20 rejected under pre-AIA 35 U.S.C. 103(a) as being unpatentable over Jacobson in view of Lai, Chen and Tringe as applied to claim 1 above, and further in view of Golkorn et al. (U.S. PGPub. No. 20110053152), hereinafter “Golkorn”:
--Claims 4, 5, 6, 7, 8, 9, 10, 11, 20: Jacobson as modified by Lai, Chen and Tringe teaches the invention as above. Jacobson as modified by Lai, Chen and Tringe fail to teach using the microfilter to perform the function described in each of the above claims.
Golkorn teaches that CTCs may be isolated by a microfilter then measured and analyzed by staining mRNA expression level ([0010-0023]).
Therefore, it would have been obvious to one of ordinary skill in the art at the time the invention was made to use the microfilter in the invention of Jacobson to isolate CTCs and measured and analyzed by staining mRNA expression level because Golkorn teaches that the microfilter may be effectively used for such purpose.
Response to Arguments
Applicant's arguments filed December 3, 2025 have been fully considered as follows:--Regarding Applicant’s argument that Chen is not an analogous art to Applicant’s claimed embodiments because Chen discloses effectiveness of laminating dry film over semiconductor die for protection of electric contacts in semiconductor device manufacturing, which has nothing to do with microfilters for medical applications, this argument is not persuasive. It is noted that Jacobson clearly teach a process of manufacturing a microfilter by exposing and developing a photosensitive layer, and one of skill in the art would be motivated to combine Jacobson and Chen because both Jacobson and Chen are directed to a method of forming a patterned polymer layer by exposing a photosensitive layer with radiation then developing the exposed photosensitive layer to form openings having microscopic dimensions.
Regarding Applicant’s argument that Chen and Lai are not an analogous art to Applicant’s claimed embodiments because the purpose of Lai have nothing to do with Applicant’s claimed embodiments, and the problem addressed by Chen and Lai have nothing to do with the problems addressed by Applicant’s claimed embodiments. This argument is not persuasive. According to MPEP 2141.01(a) I., “In order for a reference to be proper for use in an obviousness rejection under 35 U.S.C. 103 the reference must be analogous art to the claimed invention. In re Bigio, 381 F.3d 1320, 1325, 72 USPQ2d 1209, 1212 (Fed. Cir. 2004). A reference is analogous art to the claimed invention if: (1) the reference is from the same field of endeavor as the claimed invention (even if it addresses a different problem); or (2) the reference is reasonably pertinent to the problem faced by the inventor (even if it is not in the same field of endeavor as the claimed invention). Note that "same field of endeavor" and "reasonably pertinent" are two separate tests for establishing analogous art; it is not necessary for a reference to fulfill both tests in order to qualify as analogous art. See Bigio, 381 F.3d at 1325, 72 USPQ2d at 1212.”. First, Applicant’s arguments are directed against the references individually; however, one cannot show nonobviousness by attacking references individually where the rejections are based on combinations of references. See In re Keller, 642 F.2d 413, 208 USPQ 871 (CCPA 1981); In re Merck & Co., 800 F.2d 1091, 231 USPQ 375 (Fed. Cir. 1986). In the instant case, Applicant’s invention is directed to a method for making a microfilter by forming microscopic holes in a thin film by using photolithography technique to expose a photoresist layer then developing the exposed photoresist layer to form a , and the current rejection is based on Jacobson modified by Lai, Chen and Tringe. Jacobson clearly teaches a process of manufacturing a microfilter by exposing and developing a photosensitive layer, and one of skill in the art would be motivated to combine Jacobson and Chen because both Jacobson and Chen are directed to a method of forming a patterned polymer layer by exposing a photosensitive layer with radiation then developing the exposed photosensitive layer to form openings having microscopic dimensions.
Conclusion
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 extension fee 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.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to THOMAS PHAM whose telephone number is (571)270-7670. The examiner can normally be reached on MTWThF10to7 EST.
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/THOMAS T PHAM/Primary Examiner, Art Unit 1713