US 11402396

I'll search for this specific patent number across USPTO records and CAFC dockets, then summarize.

Let me check for any litigation or PTAB proceedings specifically involving this patent and its owner.

Search Results Summary

Searches performed: (1) web search for US 11,402,396 / "Process record slide"; (2) CAFC 2026 docket/appeal searches; (3) owner-name searches (Shenzhen PRS, Sunstone Scientific, "Process Record Slide"); (4) literal-ID search for "11,402,396".

Litigation/enforcement finding — nothing exists for this patent number. I found no CAFC 2026 appeal, no IPR/PGR, and no district court case involving US 11,402,396. The only literal-ID hits for "11,402,396" were unrelated: U.S. 11,633,396 (Kudos/AstraZeneca formulation, D.N.J. 3:24-cv-07346) and HK publication 40039693. I cannot access USPTO Patent Center / PACER / PTAB APIs directly here, so I cannot rule out a very recent or unindexed filing — flagging that as residual uncertainty. Everything below comes from the authoritative patent text supplied plus corroborating bibliographic records.

Bibliographic Data (US 11,402,396 B2)

Metadata anomaly (noted, not corrected): the citation table renders WO2018228567A1 as Huawei's "Bandwidth resource configuration method," while the specification repeatedly cites WO 2018/228576 by the same inventors for the chemical-target chemistry. Also, the non-patent citation reads "PCT/B2020/062554" (the family record shows PCT/IB2020/062554). I am reporting these as they appear.

Abstract (verbatim)

"The present application relates to process record slide and method of using the same for loose cells. A single to multi-region slide wherein each region contains one to four control targets and is suitable for processing through Special Stains, IHC or CC, and others. Each region may be bonded by a hydrophobic barrier to form a well. The slide has an adhesive coating suitable for capturing loose cells and cell debris."

Independent Claim 1 — plain language

A microscope slide with two cooperating areas:

• A detection area for holding a sample of loose cells (cytology-type material: Pap smears, blood smears, multi-well/multi-patient slides), made of at least one region;
• A control area positioned around that region, containing at least one control target, where the control area is functionally defined as being configured to do two things:
  1. indicate an error and a performance measure of intermediate steps in an IHC or cytochemical detection process (i.e., process QC on reagent/processing performance); and
  2. provide a reference for qualitatively or quantitatively determining the antigen density and color density of the stained loose cells (or the color density on and within the stained cells).

The two "configured to" clauses are functional language. Notably, no structural chemistry is required by claim 1 itself — the capture chemistry is pushed into claims 6, 13–16.

Independent Claim 17 — plain language

A method of using the claim-1 slide to detect cells:

1. place the loose-cell sample in the detection area;
2. place the at least one control target in the control area;
3. stain both the loose cells and the control target, where staining includes applying (a) at least one primary target, or (b) at least one primary target conjugated with the moiety, or (c) at least one secondary target conjugated with a moiety, to the control area, plus applying a color-producing stain reagent to both the detection area and control area;
4. assess quality of the staining process by assessing the staining result of both the loose cells and the control target; and
5. qualitatively determine the status of the loose cells.

Dependent-claim architecture (for context)

• Structure/geometry (2–5, 7–11): hydrophobic-barrier-bounded well; round/square/rectangular well; control area at a corner, inside the well, or outside the region; control dot or control strip; control area bounded by partial/complete hydrophobic barrier; epoxy or urethane hydrophobic coating.
• Chemistry (6, 13–16): adhesive coating with end groups —ROH, —R(C═O)OH, —RNH₂, —R(C═O)NH₂, —RNH₃ (amino-silane in the spec); control target captures mouse, rabbit, or mouse+rabbit primary/secondary antibody, or hematoxylin and eosin; primary antibody captured at its FcyRI site by Protein A, Protein G, Protein A/G, or an FcyRI binding peptide on a carrier protein or activated bead; H&E captured by a chemical target on an activated bead; paired primary-antibody targets at 100% and 30–70%.
• Method dependents (18–20): mirror the capture-chemistry limitations of 13–15.

Drafting observations (flagged, not corrected)

• Claim 10 recites "the at least one well of the detection area," but claim 1 recites "at least one region"; the "well" antecedent lives only in claim 2, from which claim 10 does not depend.
• Claim 17 recites "the moiety" with no antecedent basis in claim 17 or claim 1 — the moiety is only introduced in claim 6. Same concern applies to "qualitative determining" (adverbial use of the adjective).
• Claim 16 recites "a pair of the primary antibody," whereas the specification describes "a pair of the primary target."
• "FcyRI" / "FcyR1" / "FcγRI" are used inconsistently throughout (rendering faithfully reproduced above).

Technical substance in one paragraph

The invention addresses the problem that IHC/ICC and special-stain reagents degrade (antibody hinge failure, DAB color drift, hematoxylin/eosin/phosphotungstic-acid drift) while slide-based QC controls are essentially absent for loose-cell cytology (Pap smears, ThinPrep, blood smears, multi-well slides). The slide puts co-resident control targets — primary surrogate-antigen targets (donkey anti-mouse / anti-rabbit blended with donkey-IgG dummy protein at stepped ratios to hold constant maximum monolayer density), secondary targets, antigen-retrieval targets, 2D and 3D (bead/scaffold-based) targets, chemical targets for special stains, and black/white/clear imaging-reference dots — either around each well or as fiducial marks in a ~1.5 cm × 1.5 cm single-sample working area where no hydrophobic barrier is viable (e.g., blood smears, ThinPrep-style contact-printed slides). Specific numeric teachings include 3D targets between 80 nm and 0.5 µm staining comparably to 4–10 µm tissue, carbon dust <2 µm for black, Al₂O₃/TiO₂/BaSO₄ for white within 5–10% of perfect white, and control-pair concentrations of 100% and 50%.

Uncertainty statement: Bibliographic and claim data are high-confidence (taken from the authoritative patent text and the family record). Litigation status is reported as not found rather than confirmed-absent, because I could not query USPTO Patent Center, PACER, or PTAB dockets directly.

I'll search litigation databases for US patent 11402396.

Initial searches didn't surface anything specific. Let me query litigation-specific databases directly.

No litigation surfaced yet. Let me check a few more litigation-specific sources.

Litigation Search Results for U.S. Patent No. 11402396

Bottom line: I found no evidence of any litigation involving U.S. Patent No. 11402396.

Based on the searches I was able to run (general web, litigation-oriented queries, and searches aimed at the patentee entities), no district court action, ITC investigation, or Federal Circuit appeal asserting or challenging U.S. Patent No. 11402396 surfaced.

What I searched

• Direct queries on the patent number ("11402396") combined with litigation/court/docket/complaint terms — no relevant hits.
• The known patent owner/assignee names from the face of the patent (Shenzhen Prs Ltd, Process Record Slide Limited, Sunstone Scientific Ltd.) combined with "infringement," "lawsuit," and "litigation" — no relevant hits.
• Unified Patents litigation portal, CourtListener, and PACER-style queries — no responsive records for this number.

Important caveats on the negative result

1. This is a negative finding, not proof of absence. My tool access to the primary litigation databases was limited, and I was not able to complete live queries against PACER, Unified Patents' caselist, CourtListener, Docket Alarm, or Lex Machina before my search budget ran out. A negative web result alone cannot establish that no suit exists.
2. Do not confuse adjacent records with litigation. The patent's Google Patents page lists:
   • Prior-art citations (e.g., US20070141723A1 Immunohistochemistry staining controls; WO2014165327A1 Microscope slides with quality controls thereon) — these are references cited during prosecution, not lawsuits.
   • "Families Citing this family" (e.g., CN115615789A, WO2024138651A1, US2025128991A1) — these are later patent publications citing the family, not litigation.
   • Related/similar family patents (e.g., US11300485B2; US10921223B2; WO2018228575A1) — same-family filings, not litigation.
3. The patent is recorded as Active, with the most recent legal event being a maintenance-fee reminder mailed 2026-03-23 — consistent with an unasserted (or at least unlitigated-from-the-record) patent.

Recommended verification steps

Because this is a legal question where a false negative is costly, confirm directly against authoritative litigation sources:

• PACER (pacer.uscourts.gov) — search by patent number in the "Nature of Suit 830 – Patent" docket text, and by the assignee names.
• Unified Patents litigation portal — https://portal.unifiedpatents.com/litigation/caselist (also check its PTAB/IPR tab for any inter partes review petitions on '396).
• CourtListener / RECAP — https://www.courtlistener.com (full-text docket search).
• Docket Alarm / Lex Machina — for district court, ITC (Section 337), and CAFC coverage.
• USPTO Patent Trial and Appeal Board — PTABS/PTAB for any AIA trial involving the patent.

If you'd like, I can draft the exact search strings to run in PACER and Docket Alarm, or (with your approval to use additional searches) run a further targeted pass now that the specific databases and search terms are identified.

I do not have high confidence that no litigation exists — I have high confidence only that my searches returned no results, which is a different thing. I'd recommend verifying via PACER/Unified Patents before relying on this for any filing or opinion.

PTAB proceedings overview

Total AIA trial proceedings on US 11402396: 0. The USPTO Open Data Portal returns no IPR, PGR, or CBM proceeding naming this patent as of the most recent ingest, and independent web searches for PTAB activity limited to the patent, to Patent Owner Shenzhen PRS Ltd. / Process Record Slide Ltd. / Sunstone Scientific Ltd., and to the inventors (Husher, Shum) surfaced no petition, institution decision, Final Written Decision, or Federal Circuit appeal. There is nothing in the "active / claims invalidated / claims sustained / settled / institution denied" columns because there is nothing to place there.

Bottom-line defensive posture: the complete absence of PTAB activity means the patent is untested, not hardened. All 20 claims — including independent claims 1 and 17 — stand unadjudicated by the Board. A defendant cannot point to a canceled claim, and equally cannot rely on any prior petitioner's estoppel or on a Board-construed claim term. The patent is exposed on all fronts and a first-filer still owns the PTAB runway.

Proceedings detail

No proceeding exists to detail. For the avoidance of doubt, I checked and am not reporting the following as proceedings on this patent, because they are not:

• The IPR petitions that appear in search results (e.g., IPR2020-01049, Glux Visual Effects v. UltraVision; IPR2022-00590/00591/00592, Microsoft v. SurfCast; IPR2021-00843, Alcon v. AMO Development; IPR2023-00996, Sony v. Quantum Imaging) are unrelated patents and unrelated parties. They are search-engine noise from broad query terms and must not be cited as proceedings on 11402396.
• The "Families Citing this family" entries (CN115615789A, WO2024138651A1, WO2025128991A1, CN119246846B) are later-published third-party applications citing this family. A citation is not a challenge.
• The examiner-cited references of record — US20070141723A1 (Sompuram, "Immunohistochemistry staining controls"), WO2014165327A1 (Clarient Diagnostic Services, "Microscope slides with quality controls thereon"), and WO2018228567A1 — are prosecution art, not PTAB art. They are nonetheless the most obvious seed set for a first IPR.

If a proceeding is filed in the interim between the ODP ingest and today (2026-09-29), it would not appear above; I found none on the public sources.

Strategic summary

Claim status. Independent claims 1 and 17 and dependent claims 2–16 and 18–20 are all UNTESTED. Nothing is CANCELED and nothing is SUSTAINED by the Board. The only validity determination of any kind in the file is the examiner's allowance, which carries no preclusive effect in litigation and no deference in an AIA trial. Claim 1 is broad — it requires only "a detection area configured to hold a sample comprising loose cells," "a control area around the at least one region" with "at least one control target," and a functional recitation that the control area "indicate an error and performance measure of intermediate steps" and "provide a reference for qualitatively or quantitatively determining the antigen density and color density." That functional drafting (particularly the "configured to" language) is the kind of claim that IPR petitioners attack on § 103, and that district courts may find indefinite or purely functional under § 112(f) — but no tribunal has yet said so.

Estoppel landscape. Because there are zero petitioners, § 315(e)(2) estoppel is empty. A defendant is not constrained by, and gains no benefit from, any earlier petitioner's grounds. Every prior-art theory — § 102 anticipation, § 103 obviousness, and § 112 written description/enablement/indefiniteness (the last only in district court or PGR, not IPR) — remains fully available. Conversely, nothing in the record tells you how the Board reads "control target," "loose cells," or "provide a reference for qualitatively or quantitatively determining the antigen density." Those constructions are wide open.

Pattern signals. (1) No serial-petitioner pattern — no petitioner has filed once, let alone twice. (2) No Patent Owner appeal activity at the Federal Circuit. (3) No defensive aggregator (Unified Patents, RPX, etc.) appears anywhere in the chain; the assignment history is purely internal (inventors → Sunstone Scientific Ltd. (2020-12-30) → Process Record Slide Limited (2021-03-12) → Shenzhen PRS Limited (2022-06-16)), which is consistent with a focused operating/NPE-style entity, not a party that has been through PTAB before. (4) The family has seen significant foreign attrition — EP4085250A1 is Withdrawn, KR20220113788A is Ceased, and WO2021137178A1 is Ceased — while US, CN (CN115605753A, Pending), JP (JP2023509056A, Pending), and TW (TWI864215B, Active) remain live. The European withdrawal is not a validity adjudication and offers no estoppel or res judicata value, but it does suggest the owner is prosecuting selectively and may be more willing to litigate in the US than abroad.

Related family patents worth watching. US11300485B2 ("Process record slide for staining") and the WO2018228575A1/WO2018/228576 family (the "process recording slide for immunohistochemical staining" line, including EP3639079A4 and KR102378095B1) share inventors and the same technical disclosure. None of them shows PTAB activity either. If a defendant is asserted against more than one family member, IPR strategy should be coordinated across them, because a single petitioner can file parallel petitions and any estoppel it creates attaches per-patent.

Recommended next steps

1. No FWD to link to. There is no Final Written Decision, institution decision, or settlement on this patent, so there is nothing to quote and nothing to rely on defensively. Do not represent to a court or to opposing counsel that any claim has been invalidated.
2. Absence of PTAB activity is itself the signal. This patent issued 2022-08-02 and its statutory IPR window (one year from service of an infringement complaint, § 315(b)) has not been triggered by any publicly reported litigation I could find. Its expiry remains 2040-12-30, with a maintenance-fee reminder mailed 2026-03-23 — the owner is paying to keep it alive. If you receive a demand letter or complaint, calendar the § 315(b) one-year bar immediately; filing first preserves your ability to be the petitioner and to lock in a favorable claim construction before any district court Markman.
3. Build the § 103 case around the examiner-cited references. US20070141723A1 (Sompuram) and WO2014165327A1 (Clarient) are quality-control-slide references already of record, so they are squarely available; combining them with a conventional adhesive-coated slide reference (the patent itself concedes Erie Gold Plus and amino-silane slides are known) attacks the "adhesive coating" and "loose cells" limitations directly.
4. Consider a § 112 or PGR angle for the functional language. Claims 1 and 17 are drafted as functional capabilities ("configured to indicate an error and performance measure of intermediate steps"). If you are within the one-year PGR window (post-grant review under § 321, available only for patents subject to the AIA first-inventor-to-file provisions, and this patent has a 2019 priority date), § 112 grounds are available in a PGR but not in an IPR. If the PGR window has closed for you, that theory survives only in district court.
5. Monitor. Because ODP has no record and the family's foreign counterparts are being dropped (EP withdrawn, KR ceased), watch for a US litigation filing that would start the § 315(b) clock, and re-check PTAB E2E (https://ptacts.uspto.gov/) and CourtListener (https://www.courtlistener.com/) before finalizing any invalidity contentions.

Confidence note: I have high confidence that no AIA trial proceeding on US 11402396 is on file, based on the structured ODP block (which is expressly empty) plus the absence of any corroborating public record. I could not verify this against a live ODP API call in this session, and I found no Federal Circuit docket entry either; if the Patent Owner has been sued in a district court action not indexed in my searches, a recently-filed petition could exist that this analysis does not capture. Treat the "zero proceedings" conclusion as current as of 2026-09-29 and re-verify before relying on it in a filing.

I'll start by pulling the assignment-record and entity data from live sources to supplement the authoritative patent text.

Let me drill into the specific reel/frame records, correspondent of record, and any litigation activity.

Ownership Reconstruction — US 11,402,396 B2

Patent: Process record slide and method of using the same for loose cells
Application: US 17/137,911 · Priority 2019-12-31 (US 62/955,501) · Filed 2020-12-30 · Granted 2022-08-02
Sources used: the authoritative patent text (Google Patents legal events, fetched 2026-09-24); corroborating family bibliographic data (Espacenet/Tianyancha); targeted searches for the recorded reel/frame strings and for assertion activity.

Data-quality caveat up front: The legal-events strip in the authoritative text gives me reel/frame numbers and assignor/assignee names, but it does not expose the "correspondent of record" field. My searches on the specific reel/frame strings (054777/0066, 055578/0550, 060223/0646) returned no matching USPTO assignment abstracts, and I was unable to open a live USPTO Assignment Center abstract in this session. Where a field below is marked not retrieved, treat it as a genuine gap, not as an absence of that data in the Office record. I flag one correspondent lead under Signal 3.

Inventors

Unusual-pattern check: Not present. This is the opposite of the "inventors bail out within 12 months" tell. Husher and Shum are the recurring inventor pair across at least four related families — e.g., US 11,300,485 B2 / US 10,921,223 B2 ("Process record slide for staining"), WO2018228575A1 and WO2018228576A1 (interchangeably titled for IHC and for special staining), and the related "paraffin shield coating" patents (US 11,662,564 B2, US 12,313,834 B2) — all currently associated with Shenzhen PRS Ltd. They appear to be the founder-principals of the slide business, not employees who left a corporate assignee. No inventor departure is recorded or implied.

Original assignee

Entity on the face of the issued patent: Shenzhen PRS Ltd (Current Assignee: Shenzhen Prs Ltd).

Important discrepancy to flag: Google Patents prints "Original Assignee: Shenzhen Prs Ltd" — this is an echo of the current owner, not a true original-assignee field. Per the recorded assignment history, the first assignee was Sunstone Scientific Ltd., and the inventor→Sunstone assignment (reel 054777/0066) is the only "original" link in the chain. Do not cite Google's "Original Assignee" line as the filing-time owner.

Primary line of business: Microscope-slide consumables and process-quality-control (PQC) slide technology for IHC / ICC / special staining. The specification reads as an operating manufacturer's document, not a licensing abstract — it names real products and processes (Erie Gold Plus conformal-adhesive slides, the "unreleased Veracell" Pap slide, ThinPrep-compatible slides, amino-silane and hydrophobic epoxy/urethane barrier chemistries, pad-stamp and syringe printing of control targets). Related IP covers the paraffin shield coating for microscope slides.

Product embodying the claims: Yes, plausibly — the claims are directed to a physical slide (detection area + control area with control targets), which is the group's stated product. I have no independent sales evidence (no catalog, no 10-K, no distributor page) in the retrieved material; the product-embodiment call rests on the specification's product-level detail plus consistent assignment of the slide portfolio to a single operating entity.

Current status: Active private company; appears to be the group's principal asset-holding and product entity across the family (EP3639080, KR102378095B1, US11662564B2, US12313834B2 all name Shenzhen PRS Ltd/Limited). No bankruptcy, dissolution, or acquisition record surfaced. Both it and its predecessors are private Chinese/Hong Kong entities, so there is no SEC filing trail.

Assignment timeline

Three assignments are recorded. All are ordinary "ASSIGNMENT OF ASSIGNORS INTEREST" conveyances — no security interests, no releases, no mergers, no corrections, no change-of-name filings anywhere in the chain.

• 2020-12-28 → 2020-12-30 (executed, per the range shown: "SIGNING DATES FROM 20201228 TO 20201230") / recorded 2020-12-30 — Reel 054777/0066

  • Conveyance: Assignment of assignors' interest
  • Assignor: Husher, Frederick K. and Shum, Jee J. (the inventors)
  • Assignee: Sunstone Scientific Ltd. (China/HK)
  • Correspondent: not retrieved — no correspondent field in the fetched record; the reel/frame search returned nothing.
  • Context: Formation/founder assignment — inventors convey their rights to their own HK holding company on the filing date.

• 2021-03-12 (effective) / recorded 2021-03-12 — Reel 055578/0550

  • Conveyance: Assignment of assignors' interest
  • Assignor: Sunstone Scientific Ltd.
  • Assignee: Process Record Slide Limited (China)
  • Correspondent: not retrieved. Flag: the searched string "055578/0550" produced only unrelated hits (PCT/CN application numbers containing "055578"), i.e., no indexed assignment abstract matched — this is a retrieval failure, not evidence the record is missing.
  • Context: Internal reorg / entity rollover — the receiving entity's name literally describes the patented subject matter ("Process Record Slide"), indicating a same-group vehicle rather than a third-party buyer.

• 2022-06-16 (effective) / recorded 2022-06-16 — Reel 060223/0646

  • Conveyance: Assignment of assignors' interest
  • Assignor: Process Record Slide Limited
  • Assignee: Shenzhen PRS Limited (China) — the entity on the face of the issued patent
  • Correspondent: not retrieved.
  • Context: Corporate consolidation — intermediate vehicle rolls the asset up to the group's main operating/asset entity, ~6 weeks before grant (2022-08-02) and ~2 years after filing.

Chain summary: The patent changed hands three times in ~18 months, from the inventors to Sunstone Scientific Ltd. (2020-12-30) to Process Record Slide Limited (2021-03-12) to Shenzhen PRS Limited (2022-06-16). Every assignee is a private Chinese/Hong Kong entity tied to the same two inventor-principals and the same slide product line. No post-grant assignment is recorded, and the anticipated expiration is 2040-12-30 per the status line.

USPTO Assignment Center status: Records do exist for this patent (three of them, with reel/frame cites above). I did not retrieve the live abstracts, so the correspondent and address fields remain unverified. Verify at the Assignment Center patent-number search: https://assignmentcenter.uspto.gov/ (mirror/index: https://assignment.uspto.gov/patent/index.html), and cross-check the Google Patents page: https://patents.google.com/patent/US11402396/en

Timeline diagram

timeline
    title Ownership of US 11402396
    2019 : Provisional filed Dec 31
    2020 : Nonprovisional filed Dec 30
         : Inventors assign to Sunstone Scientific
    2021 : Sunstone assigns to Process Record Slide Ltd
    2022 : Process Record Slide Ltd assigns to Shenzhen PRS Ltd
         : Patent issued Aug 2

NPE / troll-pattern signals

1. Shell-entity transfer — Not present. The chain does move to entities bearing portfolio-ish names, but naming alone is not a finding and here the concrete evidence cuts the other way: (a) no name-suffix LLC structure — all parties are limited companies (Ltd./Limited) in China/Hong Kong; (b) no registered-agent service address is disclosed in the retrieved records; (c) the specification is a full manufacturing document naming products and processes (Erie Gold Plus, Veracell, ThinPrep-compatible, amino-silane, epoxy/urethane barrier printing), consistent with an operating concern. The intermediate "Process Record Slide Limited" is the closest thing to a single-purpose vehicle (reel 055578/0550), but I have no evidence of a licensing-only model. Unclear at most, and I would not call it present.

2. Known asserter in the chain — Not present. None of the assignees (Sunstone Scientific Ltd., Process Record Slide Limited, Shenzhen PRS Limited) appears on the enumerated lists — Acacia, Marathon, Intellectual Ventures, IPNav, Wi-LAN, Mosaid/Conversant, Vringo, Pendrell, Innovatio, MPHJ, Lumen View, Round Rock, Document Generation Corp, Spangenberg — nor did targeted searches surface them on RPX or Unified Patents NPE directories.

3. Repeat correspondent across the chain — Unclear / not verifiable. All three recordations would presumably have been filed by one firm for a group this small, but I could not retrieve the correspondent field for any of the three reel/frame entries, so I cannot report recurrence. One lead worth chasing manually: Hauptman Ham, LLP appears as the prosecution agency of record (代理机构) on the sibling case US 11,300,485 B2 under docket/customer number 550024500. That is the prosecution firm, not a confirmed assignment correspondent, and a single appearance would not satisfy this signal anyway — it becomes a finding only if it recurs as correspondent on reels 054777/0066, 055578/0550 and 060223/0646. Action item, not a finding.

4. Cascading transfers — Present (mechanically), but not in the NPE sense. Three recorded assignments in ~18 months, including two within a single 15-month window: 2020-12-30 → 2021-03-12 → 2022-06-16 (reels 054777/0066 → 055578/0550 → 060223/0646). The pattern is real, but the participants share the same two principals (Husher/Shum) and the same product line, and the intermediate entity is named after the product. This reads as HK → intermediate → mainland-China consolidation, not as chained unrelated shells. I score the mechanic present, the inference weak.

5. Pre-litigation transfer — Not present. I found no infringement suit naming US 11,402,396 or its family members in the retrieved material. The 2022-06-16 transfer (reel 060223/0646) lands ~6 weeks before grant and is not followed by any assertion I could locate.

6. Bankruptcy fire-sale — Not present. No Chapter 7/11 proceeding, receiver, or asset-sale record for any assignee; all are private, non-public entities with no bankruptcy trail surfaced.

7. Privateering — Not present. No operating-company → NPE transfer, no SEC disclosure (the assignees are private, so there is nothing to disclose), no Patent Progress/EFF-style coverage surfaced.

8. Defensive aggregator (anti-NPE) — Not present. The chain terminates at Shenzhen PRS Limited (an apparent operating/asset entity), not at RPX, AST, LOT Network, Unified Patents, or OIN. The patent has not been neutralized.

Ancillary note for the record: The citation list in the fetched patent text includes "WO2018228567A1 … 华为技术有限公司 / Bandwidth resource configuration method." That indexing is inconsistent with the same inventor group's actual WO2018228575A1/WO2018228576A1 filings and with the family citation of EP3639079A4 ("Sunstone Scientific Limited — PROCESS RECORDING SLIDE FOR IMMUNOHISTOCHEMICAL STAINING"). Treat that citation row as a likely database artifact, not as a substantive prior-art relationship.

Verdict

Insufficient data.

Justification: the record contains three recorded assignments — reels 054777/0066 (2020-12-30, inventors Husher/Shum → Sunstone Scientific Ltd.), 055578/0550 (2021-03-12, Sunstone → Process Record Slide Limited), and 060223/0646 (2022-06-16, Process Record Slide Limited → Shenzhen PRS Limited) — but every one is a plain intra-group "assignment of assignors' interest" among private China/HK entities sharing the same two inventor-principals, with no known NPE assignee, no security interest, no litigation, and no defensive-aggregator endpoint. That fails both "NPE — high confidence" (0 strong signals; only the cascading-transfer mechanic is arguable) and "Operating-company assertion" (no suit against competitors), and it does not fit the "defensive aggregator" branch either; the genuine blockers are the two unretrieved fields — correspondent of record on all three reels and assertion history — which is why I stop at insufficient rather than a clean "not an NPE."

Verification links: USPTO Assignment Center — https://assignmentcenter.uspto.gov/ (patent-number search) · mirror index — https://assignment.uspto.gov/patent/index.html · patent record — https://patents.google.com/patent/US11402396/en

Recommended next step for a human analyst (30 minutes): pull the three abstracts by reel/frame at Assignment Center and record the correspondent + address for each; if a single firm/attorney appears on all three, that upgrades Signal 3 to present and materially changes the read — a repeat recording agent on a three-hop chain is exactly the pattern that separates "internal reorg" from "assembled-to-assert."

I'll research this systematically. Let me start by verifying the patent and its cited references.

I found the key citations. Let me verify a few details, particularly the third cited reference and the sibling patent.

Prior-Art Analysis — U.S. Patent No. 11,402,396 B2

Building on the earlier litigation section. Because the litigation search returned a negative result, this section focuses on the §102 record: the references that actually appear on the face of the patent and in its family, not on lawsuits.

1. Method and source of the citation set

There is no public "USPTO prior-art database" that separately indexes references against a patent; the authoritative sources are (a) the reference lists imported onto the patent's front page / Google Patents "Citations" and "Family Cites Families" tables, and (b) the file wrapper (PatentCenter) for the application. The lists below are taken from the Google Patents record for US11402396B2 (https://patents.google.com/patent/[US11402396](/patent/US11402396)/en), which itself mirrors the USPTO/EPO bibliographic data, and were spot-checked against Espacenet, the published reference PDFs, and PubChem patent records.

Header data used throughout (literal):

• Patent: US 11,402,396 B2
• Application: US 17/137,911, filed 2020-12-30
• Priority: US 62/955,501, 2019-12-31
• Applicant / current assignee: Shenzhen Prs Ltd (chain: Sunstone Scientific Ltd. → Process Record Slide Limited → Shenzhen PRS Limited)
• Since effective filing (2020) and priority (2019) are post-AIA, the applicable statute is 35 U.S.C. § 102(a)(1) / (a)(2); every reference below predates 2019-12-31 and therefore qualifies as prior art under one or both subsections.

The three examiner-cited patent documents on the face of US 11,402,396 ("Citations (3)"):

Non-Patent Citation (1): International Search Report and Written Opinion issued in PCT/IB2020/062554, dated 2021-03-17, European Patent Office, 12 pp.

2. Reference-by-reference analysis

Reference A — US 2007/0141723 A1

• Full citation: U.S. Patent Application Publication US 2007/0141723 A1, "Immunohistochemistry Staining Controls," inventors Seshi A. Sompuram, Kodela Vani, Steven A. Bogen (NIH grants CA94557 / CA106847).
• Filing date: 2005-12-16; publication date: 2007-06-21. (A search result reports a granted family member numbered US 11,304,574; treat that grant number as reported-but-unverified — the publication number above is the one literally cited.)
• Brief description: A quality-control device for IHC testing. A cell-free moiety (peptide/epitope) is covalently attached to a glass microscope slide; a tissue section is mounted on the same slide. The analyte-binding moiety is designed so the IHC reaction sequence that occurs in the tissue also occurs at the moiety site, producing a colored deposit that serves as an on-slide control. An improvement models formalin fixation so that the control only binds antibody if antigen retrieval (AR) is performed — deliberately letting the user distinguish AR failure from reagent/stain failure. Primary teaching: on-slide, covalently-bound, co-resident control moieties that report intermediate-process (AR) and reagent performance.
• Potential § 102 mapping (anticipation requires every element in one reference):
  • Claim 1 / claim 17 (independent): Discloses a substrate bearing a control target whose reaction mirrors the sample's, and which reports "an error … of intermediate steps" (explicitly AR vs. reagent error). However, it discloses tissue sections, not "a sample comprising loose cells," so it does not appear to anticipate claim 1 or claim 17 on its face — the loose-cell limitation is missing.
  • Dependent claims it can anticipate or render obvious (if the loose-cell element is separately supplied): claim 6 (covalently functionalized slide surface), claim 8 (control dot), claim 12 (control target types — primary/secondary target, antibody, target array), claim 13 (mouse/rabbit primary or secondary antibody capture), claims 14–15 (capture chemistry / H&E capture chemistries), claims 17–20 (method of staining a co-resident control and assessing the result).
  • Assessment: Strong § 102(a)(1)/(a)(2) art against the control-target concept and against the "AR/intermediate-step error" function; weak against the "loose cells" element that the '396 independent claims require.

Reference B — WO 2014/165327 A1

• Full citation: WO 2014/165327 A1, "Microscope Slides With Quality Controls Thereon," Clarient Diagnostic Services, Inc. (inventors incl. R. Chen, Z. Pang, C. McCulloch, M. S. Lazare, R. J. Filkins, F. Ginty). U.S. counterpart publication US 2016/0274008 A1, granted as US 10,082,451 B2; EP counterpart EP 2979078 A1.
• Priority date: 2013-03-30 (US 61/806,841); PCT filed 2014-03-20; published 2014-10-09.
• Brief description: A microscope slide with an elongate planar substrate, a sample-affixing area, and first and second positive control samples affixed at spaced locations adjacent to the sample-affixing area (e.g., diagonally opposite). The spacing is chosen so that the quality of staining of the control samples is indicative of the quality of staining of the tissue sample — real-time detection of incomplete/uneven reagent coverage. Controls may be cell pellets, control tissue, or a carrier loaded with biomaterials (cell homogenates, peptides, proteins, DNA); multiple controls may share a common biomarker. Also claims kits and methods of making/using.
• Potential § 102 mapping:
  • Claim 1 / claim 17 (independent): Discloses a slide with a detection ("sample-affixing") area and a control area comprising control targets spaced around it, used to indicate staining failure and to provide a qualitative/quantitative reference for the sample stain. This closely tracks the "'round the at least one region" and "control target for providing the reference" language. But it does not describe "loose cells" — its samples are tissue sections and cell pellets. So, again, no clean anticipation of claim 1 / 17, though it is very close art.
  • Dependent claims it can anticipate / make obvious: claim 4 (control area at a corner), claim 7 (control area outside the region), claim 8 (control dot), claim 12 (primary/secondary target, antibody, target array), claim 13 (primary/secondary antibody), and the claim 17 method steps of staining control + sample and assessing quality.
  • Assessment: The single most structurally similar third-party reference to the '396 slide geometry (controls ringed around a sample area). Its weakness versus the '396 claims is the absence of the loose-cell / adhesive-capture teaching.

Reference C — WO 2018/228567 A1 ⚠️ identifier anomaly — flag as-is

• Full citation: WO 2018/228567 A1, "Bandwidth resource configuration method, apparatus, and system," applicant 华为技术有限公司 (Huawei); PCT application PCT/CN2018/091668, filed 2018-06-15, published 2018-12-20.
• Brief description (as published): A telecommunications resource-allocation disclosure concerning bandwidth resource configuration — not a slide, sample, staining, or IHC document of any kind.
• Potential § 102 mapping: None. On its face this reference is non-analogous art and cannot anticipate any of claims 1–20, none of which recite networks, bandwidth, or resource configuration.
• Flag / contradiction to surface: Under the strict rule to interpret identifiers literally, I report WO 2018/228567 A1 exactly as cited. However, the content literally attached to that number contradicts the technological field of US 11,402,396, which indicates one of two things: (i) a digitization/transcription error on the Google Patents citation table, or (ii) an incidental citation. The technically coherent reference the citation almost certainly intends is WO 2018/228575 A1 (note the transposed final digits), the applicant's own earlier PCT — analyzed immediately below. I am not auto-correcting the number; I am flagging the discrepancy and analyzing both.

3. The reference the "C" citation most plausibly intended (same-inventor prior art)

WO 2018/228575 A1 — the closest technical prior art to the '396 claims

• Full citation: WO 2018/228575 A1, "Process Record Slide For Immunohistochemical Staining," inventors Frederick Knute Husher; Jee Jong Shum, applicant Sunstone Scientific Limited; PCT/CN2018/091686, filed 2018-06-15, published 2018-12-20. Family members: EP 3639079 A1/A4, JP 2020-523614 A, CN 110741302 A, KR 10-2378095 B1 (note the KR family title "Process recording slides for special coloring").
• Brief description: An adhesive-coated microscope slide carrying a plurality of compounds (control targets) applied as dots in 2D or 3D configurations, sealed under a paraffin coating. "Tissue sections or loose cells are subsequently applied to the same slide and all experience the IHC processing steps from tissue capture through application of a coverslip." The compounds react with primary and/or secondary IHC stain reagents to record the processing experience of the co-resident tissue section or loose cells (paraffin removal, antigen retrieval, reagent efficacy).
• Potential § 102 mapping (this is the important one):
  • Claim 1 (independent): Discloses a slide with a detection area for loose cells, a co-resident control area with control targets, and the control targets serving to record/indicate intermediate processing steps and reagent performance → maps onto nearly every element of claim 1 including the loose-cell element. On the reference's own abstract language this is potentially anticipatory of claim 1 under § 102(a)(1) (it published 2018-12-20, before the 2019-12-31 priority).
  • Claims 6, 8, 11, 12, 13, 14, 15: the adhesive coating, dot/target arrays, 2D/3D targets, primary/secondary antibody capture chemistries are all described or rendered obvious.
  • Claims 17–20 (method): the reference expressly covers IHC processing of loose cells with co-resident control dots → potentially anticipatory of claim 17.
  • Caveat: It is same-inventor art (Husher/Shum). That does not remove it as prior art, but (i) § 102(b)(1)/(b)(2) exceptions and common-ownership/§ 103(c) considerations, and (ii) the question whether it discloses the specific immunohistochemical or cytochemical dual-function and the "antigen density and color density … on and within the stained cells" wording of claim 1, are exactly the issues a validity challenge would litigate. I cannot resolve the § 102(b) exception analysis without the assignment/derivation record.

4. Other family-cited art worth noting (not on the "Citations (3)" list, but relevant § 102/§ 103 context)

• WO 2018/228575 A1 / EP 3639079 A4 / KR 10-2378095 B1 — the applicant's own process-record-slide family (analyzed above). Family Cites Families (7).
• WO 2010/030853 A1 — "Coated slide," Frederick Knute Husher (2008-09-12 priority; 2010-03-18) — supports the adhesive-coating limitations of claim 6 and claim 11.
• WO 2015/070075 A1 — "Quantitative controls and calibrators for cellular analytes," Medical Discovery Partners LLC (2013-11-07 priority; 2015-05-14) — arguably relevant to the "qualitatively or quantitatively determining" language of claim 1.
• JP 2011-188835 A — Tissue microarray / tissue analysis (2010-03-16) — control-array background.
• US 2018/0348218 A1 — Serology assay (Tokitae) — peripheral.
• RU 2018 107453 A — Эссенликс — device/analysis-stage art — peripheral.

5. § 102 anticipation summary (one reference, all elements)

Bottom line on anticipation: On the literal record, none of the three examiner-cited references (A, B, C) provides a clean, single-reference § 102 anticipation of independent claim 1 or claim 17, chiefly because references A and B are directed to tissue sections, not loose cells, and reference C is non-analogous to the field. The most dangerous single-reference art is the same-inventor WO 2018/228575 A1, which does expressly recite loose cells plus co-resident control dots — and which appears to be what the "C" citation intended.

6. Confidence and caveats

• High confidence: citation identity, titles, and dates for References A, B, and the WO 2018/228575 A1 family (corroborated across Google Patents, Espacenet, and PubChem).
• Flagged uncertainty (do not auto-correct):
  1. WO 2018/228567 A1 is literally a Huawei "bandwidth resource configuration" document, which is inconsistent with the field of US 11,402,396. I have not substituted a different number; I flagged the discrepancy and separately analyzed the plausibly intended WO 2018/228575 A1.
  2. The grant number of the Sompuram application (reported as US 11,304,574) is asserted only as a search result; I could not independently confirm the grant in the tool budget.
• What I could not verify: the file-wrapper rejections for US 17/137,911 (i.e., whether References A–C were actually applied under § 102 or only under § 103, and whether Applicant traversed them). "Potentially anticipates" above reflects my element-by-element reading of the references against claims 1–20, not a USPTO Examiner's stated § 102 rejection. To confirm the statutory basis actually used, pull the PatentCenter file wrapper / "References Cited" and Office Actions for application 17/137,911.
• Recommended next searches I did not complete: (a) USPTO PatentCenter / Global Dossier for the 17/137,911 prosecution history; (b) full-text of WO 2014/165327 A1 claims to compare control-placement language verbatim against claims 4, 7, 8, 12, 13; (c) the derivation/assignment record between Sunstone Scientific and Shenzhen PRS to assess any § 102(b) exception for the same-inventor WO 2018/228575 A1.

If you want, I can draft the exact PatentCenter retrieval request for the 17/137,911 file wrapper, or produce a claim-chart mapping each independent claim element to WO 2018/228575 A1.

I'll research the prior art references cited on this patent's page to ground the § 103 analysis.

Obviousness Analysis — U.S. Patent No. 11,402,396 B2

"Process record slide and method of using the same for loose cells"

Statutory frame: 35 U.S.C. § 103; Graham v. John Deere Co., 383 U.S. 1 (1966); KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398 (2007); MPEP §§ 2141–2144.04.

Scope note. This section builds on the claim charting and bibliographic work already produced. It uses only the references listed in the Prior Art portion of the Google Patents page supplied (the Citations (3) table and the Family Cites Families (7) / Similar Documents lists), plus the specification's own admissions. Where I could not retrieve a reference's text, I say so and refrain from characterizing it.

I. The person having ordinary skill in the art (POSITA)

For a 2019 priority date, the POSITA is a histology/cytology scientist (typically an MS or PhD in a biological science, or a BS with 3–5 years of bench experience in an IHC/cytology laboratory) with working knowledge of: (a) microscope-slide surface chemistries (amino-silane, epoxy-silane, aldehyde-silane) and hydrophobic-barrier well formats; (b) IHC/ICC and special-stain reagent behavior (antigen retrieval, DAB, hematoxylin/eosin); and (c) slide-based positive/negative controls. This is a low-to-moderate skill level in a field where the patent's own specification concedes that most of its building blocks were already known. That level matters: at this level, "combining familiar elements according to known methods" is ordinarily obvious unless there is a teaching away or unexpected result (KSR, 550 U.S. at 416–22).

The record is thin. Only three references are listed as cited by the examiner, and of those, one renders as a non-analogous Huawei "bandwidth resource configuration" document (see Part IX, flag 1). The functional claim 1 was allowed over that record. That thinness is itself the central § 103 fact: the claim was not tested against its own closest art.

II. Claim 1 — element-by-element mapping across candidate references

Claim 1 is the gate. Everything else is a narrowing addition. Breaking it into elements:

Result: Every element of claim 1 is disclosed, element-by-element, across Sompuram + Clarient + US6281004, with the "loose cells" element supplied by the applicant's own admitted knowledge (and expressly by WO2018228575A1). That is the classic KSR fact pattern: "a patent composed of several elements is not proved obvious merely by demonstrating that each of its elements was, independently, known in the prior art" — but here there is more: the elements were known to work together for the same purpose, as Part IV shows.

III. Ground 1 — Sompuram '723 + Clarient '327 (+ ordinary cytology knowledge)

What each reference teaches.

• US 2007/0141723 A1 (Sompuram, "Immunohistochemistry staining controls") — https://patents.google.com/patent/US20070141723A1/en. The originating reference for the entire field. It describes a QC device comprising "multiple quality control reagent moieties affixed to a matrix or membrane," adherable to a microscope slide, processed simultaneously with the tissue sample, and generating graded quantitative control signals. Its stated problems — reagent failure, procedural error, wrong/no antibody, lack of standardization — are the same problems the '396 patent recites in its Background.
• WO 2014/165327 A1 (Clarient Diagnostic Services, "Microscope slides with quality controls thereon") — https://patents.google.com/patent/WO2014165327A1/en (U.S. counterpart US 10,082,451 B2). It moves the controls onto the slide itself and teaches placing them adjacent to and around the sample-affixing area (including diagonally across it and at four corners), such that "quality of the staining of the first and second positive control samples is indicative of the quality of the staining of the tissue sample," and expressly to catch "incorrect dispensing of staining solution and incomplete coverage of patient samples."

The combination.

Articulated motivation (MPEP 2143; KSR rationales A, C, D, F):

1. Same field, same problem, same solution class. Both references are directed to on-slide IHC quality control; the '396 Background itself concedes these references exist and identify the same problem. KSR permits combination where the references "are from the same field of endeavor." Where the references address the identical problem, the motivation is inherent.
2. Clarient supplies the solution to Sompuram's admitted deployment weakness. Sompuram's own text criticizes control slides that are tested "once per assay run" rather than being co-resident on each slide, and notes the risk of reagent spilling off a planar slide. Clarient's on-slide, four-corner, periphery placement solves exactly that reagent-coverage problem. Combining Sompuram's quantitative synthetic targets with Clarient's co-resident perimeter placement is the predictable union of two known solutions to one recognized problem.
3. Expected result. Substituting Clarient's control-sample positions for Sompuram's strip on the same slide yields no unpredictable change in function: each reference's stated function (QC readout + coverage verification) is preserved. KSR: "the combination of familiar elements according to known methods is likely to be obvious when it does no more than yield predictable results."
4. Design incentive / obvious-to-try. A POSITA seeking to catch reagent-degradation and mis-dispensing at the point of use would have been motivated to place known synthetic targets at the perimeter of the sample region — the region where, as Clarient recognizes, under-staining first becomes visible.

Gap to close: the "loose cells" limitation. This is closed by (a) the '396 Background's own admission that Pap smears, blood smears, and multi-well patient slides are long-known loose-cell formats, and (b) the fact that Clarient's controls are expressly positioned to indicate whether the entire sample area was reached — an incentive that applies with equal force to cytology smears, where sample spread is even more variable than in tissue sections. Nothing in either reference teaches away from cytology; neither is limited to paraffin-embedded tissue.

IV. Ground 2 — WO 2018/228575 A1 (Sunstone / Husher & Shum), alone or with Sompuram/Clarient

This is the strongest ground, and it must be flagged.

Reference: WO 2018/228575 A1 (Sunstone Scientific Limited; inventors Husher and Shum), "PROCESS RECORD SLIDE FOR IMMUNOHISTOCHEMICAL STAINING," priority 2017-06-15, published 2018-12-20. URL: https://patents.google.com/patent/WO2018228575A1/en ; claims via https://se.espacenet.com/publicationDetails/claims?DB=EPODOC&NR=2018228575A1.

What it discloses (verbatim from its abstract and claims):

"The device encompasses an adhesive coated microscope slide containing a plurality of compounds applied as dots in 2D or 3D configurations and sealed under a paraffin coating. Tissue sections or loose cells are subsequently applied to the same slide and all experience the IHC processing steps from tissue capture through application of a coverslip. The compounds react with either the primary or secondary IHC stain reagents to record the processing experience of the co-resident tissue section or loose cells."

Its dependent claims map almost one-to-one onto the '396 patent:

Prior-art status — this is the crux. WO2018228575A1 published 2018-12-20. The '396 patent's effective filing date is 2019-12-31 (provisional 62/955,501). December 20, 2018 is more than one year before December 31, 2019. Therefore:

• WO2018228575A1 is prior art under § 102(a)(1) as a printed publication.
• The § 102(b)(1)(A) grace-period exception (inventor's own disclosure ≤1 year before the effective filing date) does not apply, because 2018-12-20 falls outside the one-year window.
• Consequently the common-ownership carve-outs in § 102(b)(2)(C) and § 103(c) — which apply only to art that is prior art sole under § 102(a)(2) — do not rescue the '396 claims from this reference. A publication that independently qualifies under § 102(a)(1) remains available for § 103.

Obviousness theory. Even if claim 1 were argued not to be anticipated (e.g., on the theory that "around the at least one region" is not literally met by a dot array), the reference renders claim 1 obvious: it discloses the same slide, the same targets, the same capture chemistry, and the same co-resident loose-cell sample; the only possible difference is placement and orientation of the control dots relative to the sample region. Repositioning known control dots from one location on the same slide to a perimeter/corner arrangement is "a mere change in form" and an obvious design choice with no unexpected result. In re Kuhle; MPEP 2144.04(IV). Combined with Sompuram/Clarient (which supply the "around/periphery" placement), claim 1 falls squarely within § 103. For the dependent claims mapping to the reference's own claim set (12–16), the § 103 showing is even more direct.

Strategic note. The '396 specification itself repeatedly cites "WO2018/228576 by the same inventors" for the chemical-target chemistry — i.e., the applicant treats this family as its own foundation. That candor is double-edged: it confirms the family is the inventor's own work, but it also confirms that the technical content was disclosed and published well before the critical date.

V. Ground 3 — dependent-claim reference set

The following table assigns the strongest available reference(s) to each dependent claim, with the § 103 rationale. All are from the Prior Art section of the page.

Note on claim 14. I was unable to retrieve the text of US5541059A (my search budget was exhausted before that query returned). I rely only on its title as listed in the page's Similar Documents table — "Immunoassay device having an internal control of protein A and methods of using same" — and on the independently well-known fact that Protein A binds the Fc/Fcγ region of IgG. A complete invalidity contention would need the specification text to confirm the FcyRI capture teaching.

VI. Articulated motivations to combine (consolidated)

For each ground, the KSR/MPEP rationale that carries the combination:

1. Same field, same problem, overlapping disclosure (MPEP 2143 / KSR rationale A). Sompuram, Clarient, WO2018228575A1, US6281004B1, and WO2015/070075A1 are all directed to on-slide quality control for IHC/cytochemical staining. The problem to be solved (reagent degradation, intermediate-step error, absence of quantitative on-slide controls for cytology) is the problem the '396 patent states in its own Background. "Where the problem is known and the solution is within the ordinary skill, the combination is obvious."
2. Improvement of a prior device ready for improvement (rationale C). Clarient's stated advance over Sompuram is on-slide, co-resident placement. Applying that improvement to Sompuram's quantitative targets is the "use of a known technique to improve a similar device in the same way."
3. Predictable combination of familiar elements (rationale A). Put control targets on a slide where they were already being put; arrange them around the sample where Clarient already arranged its controls; use the slide adhesive the '396 spec admits was standard. No new function is produced — the claims recite the same functions the references independently recite.
4. Design incentive / "obvious to try" (rationale D/E). Clarient itself identifies the problem the "around the region" limitation solves: catching reagent misfires and incomplete coverage. A POSITA with that incentive would have placed the known controls around the sample region — a finite, predictable number of candidate positions.
5. Technique transfer between adjacent fields (rationale F). Cytology (Pap/blood smear) and histology (tissue-section IHC) are adjoining fields using the same slides, the same autostainers, and the same reagents. "Loose cells" versus "tissue sections" is a substitution of sample type on an otherwise identical platform.

VII. Secondary considerations and rebuttal posture

On the current record, there is little for the patentee to work with:

• No unexpected results are evidenced. The specification asserts advantages (co-resident controls, loose-cell capture) but presents no comparative data against Sompuram, Clarient, or WO2018228575A1. Asserted advantages that are inherent in the prior-art disclosure are not probative.
• The 3D-target numerical ranges (80 nm – 0.5 µm) are the only candidate "critical range" argument. The '396 spec states that "any 3D target between 80 nm and 0.5 um would stain as darkly as the tissue section," while beads >0.6 µm cause optical loss. That range appears in the same-inventor family (WO20200192072A1/US2020/0192072) as a scale-factor teaching. Absent proof that these endpoints are critical relative to the closest prior art, the range argument is vulnerable. This is the best nonobviousness foothold, and it should be probed with the family's own earlier disclosure before relying on it.
• No evidence of commercial success, copying, licensing, or industry praise appears in the record. No secondary-consideration nexus has been established.

VIII. Where the patentee can push back

A candid § 103 opinion must identify the counterarguments:

1. "Loose cells" as a distinct problem. The '396 patent argues that loose-cell capture (cells sinking to an adhesive-coated surface from a slurry) presents problems — cell pile-up toward the well center, staining reagents precipitating at the deposit edge, absence of a hydrophobic barrier being viable for blood smears — that tissue-section controls do not. If the patentee can show that Sompuram's and Clarient's tissue-based controls do not work in a loose-cell slurry environment (e.g., controls washed away, or settling cells burying the targets), that is a genuine "teaching away"/unexpected-result argument. But the burden is the patentee's, and the specification's proposed solution (four equidistant targets at the working periphery so the cell slurry "will generally avoid settling where the targets are") is a placement optimization, not a new structure.
2. Functional-claim indefiniteness cuts both ways. The "configured to indicate an error and performance measure" language is a § 112 concern (see the earlier analysis). It will not defeat § 103, but a court applying § 112(f) may narrow the functional terms — which could help the patentee by importing structure from the specification. That is a litigation posture, not a validity defense on the present art.
3. The claim-1 preamble's "detection area" limitation is not clearly structural; a patentee may argue that the prior-art controls are in a sample-affixing area used for tissue, whereas claim 1's "detection area" is configured for loose cells. This is a labeling argument, and it fails unless the loose-cell configuration requires a structural difference (e.g., an adhesive with a specific capture chemistry) that the prior art lacks. Claim 6 is where any such requirement lives — and claim 6 is squarely met by WO2010030853A1.

IX. Contradictions and flags with the previous analysis / the record

Flag 1 — the third examiner citation is bibliographically anomalous and materially affects the analysis. The Citations (3) table renders the third reference as "WO2018228567A1 — Bandwidth resource configuration method, apparatus, and system — 华为技术有限公司 (Huawei)", 2017-06-16. The specification, by contrast, repeatedly cites its own WO2018/228576 for the chemical-target chemistry, and the Similar Documents / Family Cites Families lists identify WO2018228575A1 (Sunstone Scientific; Husher & Shum) as "Process record slide for immunohistochemical staining." Per the STRICT RULE I have not auto-corrected the identifier: I report that, as rendered, one of the three examiner citations is a Huawei telecom bandwidth-configuration document, which would be non-analogous art and essentially irrelevant to claims 1–20. If the rendering is a bibliographic error and the intended citation was WO2018/228575 (the applicant's own PCT), the prosecution record changes materially — the examiner would have had the closest art before it, which affects both the § 103 analysis and any later inequitable-conduct or Rule 56 inquiry. I cannot resolve this from the supplied page; it should be checked against the file wrapper.

Flag 2 — the previously generated sections place WO2018228575A1 only in the Similar Documents list; it belongs at the center of the § 103 analysis. The prior "Patent summary" treated the family members (US11300485B2, US10921223B2, WO2018228575A1) as "related patents, not litigation." That is correct as to litigation, but understated as to prior art: WO2018228575A1 is a § 102(a)(1) printed publication with a 2018-12-20 date that precedes the '396 effective filing date by more than one year, and it discloses "loose cells" and "co-resident" targets verbatim. This is a correction to emphasis, not a contradiction.

Flag 3 — the earlier "no litigation found" and "zero PTAB proceedings" conclusions do not affect this § 103 analysis but do affect strategy. Because there are no PTAB proceedings, no claim has been adjudicated, no estoppel attaches, and the full § 102/§ 103/§ 112 space remains open to a first challenger. That is consistent with what is written above.

Flag 4 — new artwork cited by third parties since the '396 grant should be treated as prior art, not as litigation. The page's Families Citing this family list includes WO2025128991A1 (Ventana Medical Systems, "Closed loop monitoring of staining results with system control," 2023-12-14) and CN115615789A (深圳市森盈智能科技有限公司, multi-well glass slide for immune cell staining). These were cited by the '396 family, i.e., they post-date it — they are citatory, not prior art to the '396 claims. Do not cite them as § 103 references against '396.

Flag 5 — date inconsistency in the task framing. The system context states today's date as 2026-09-29, while this task states "Current Date: April 26, 2026." Nothing in this analysis turns on the date, but any "as of" statement should be pinned to one date before filing.

X. Bottom line

• Claim 1 is highly vulnerable under § 103. The combination of US 2007/0141723 A1 (Sompuram) + WO 2014/165327 A1 (Clarient) — both of which are already of record — discloses every structural and functional element except "loose cells," and that element is supplied by the applicant's own admission of what Pap-smear, blood-smear, and ThinPrep slides are. The motivation is textual, not conjectural: both references address the same problem the '396 Background identifies, and Clarient's perimeter placement solves Sompuram's own stated co-residency problem.
• The single strongest reference is the applicant's own WO 2018/228575 A1, which is § 102(a)(1) prior art (published 2018-12-20, more than one year before the 2019-12-31 effective filing date), is not rescued by the § 102(b)(2)(C)/§ 103(c) common-ownership carve-outs, discloses "loose cells" and co-resident targets in terms, and maps onto dependent claims 12–16 almost claim-for-claim. This is both an anticipation candidate and the backbone of a § 103 case.
• Most dependent claims fall readily. Claims 2, 4, 5, 7, 8, 10 fall on Clarient + admissions of known slide formats; claim 6 falls on WO2010030853A1 (Husher, "Coated slide"); claim 14 finds a mechanism-specific reference in US5541059A (internal control of protein A); claims 12, 13, 15, 16 fall on WO2018228575A1; claims 17–20 are the inherent method of using the device.
• The only serious nonobviousness foothold is a demonstrated, unexpected failure of tissue-based controls in a loose-cell slurry, and/or criticality of the 80 nm–0.5 µm 3D-target range. Neither is currently supported by comparative data in the specification.
• Two verification tasks precede any invalidity contention: (1) resolve the WO2018228567A1-vs-WO2018228575A1 citation anomaly against the file wrapper (Flag 1); and (2) retrieve the full text of WO2018228575A1 and US5541059A to lock down the element-by-element mapping, which I could not complete within the available searches.

Confidence: High on the claim-1 mapping to Sompuram/Clarient and on the § 102(a)(1) status of WO2018228575A1 (based on dates on the face of the record). Medium on the precise content of US5541059A (title only). No position is taken on litigation or PTAB status, which is addressed in the earlier sections.