US 8093005

I'll search for authoritative information on US patent 8093005, including any CAFC 2026 litigation activity.

Let me run a couple of more targeted searches for litigation and USPTO records specific to this patent number.

US Patent 8,093,005 — Analyst Summary

Search scope note: I ran targeted queries against Google Patents/Justia patent records and web searches for CAFC 2026 activity tied to the literal number 8093005. I did not find any CAFC 2026 docket entry, Federal Circuit appeal, or litigation involving US 8,093,005, and I did not find results for neighboring/similar numbers that could be confused with it. I do not have direct API access to the CAFC docket or USPTO PatentCenter; my negative finding is based on web search only, so treat the "no litigation found" conclusion as stated-with-uncertainty rather than authoritative.

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Bibliographic data

Family: SE 0402476 D0; WO 2006/041392 A1; US 2006/0094060 A1; US 2010/0041127 A1; US 8,093,005 B2.

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Abstract (verbatim)

A method of preparing a protein-resistant reactive solid support surface is disclosed. The method comprises the steps of providing a solid support having a hydrogel coating with a plurality of binding elements, coupling a protein resistant compound to the hydrogel via a first fraction of the binding elements, and coupling at least one binding agent to the hydrogel via a second fraction of the binding elements, whereby the protein resistant compound and the at least one binding agent are co-immobilized to the hydrogel. Also the use of the reactive surface in analysis, such as immunogenicity assays, is disclosed.

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Independent claim — plain-language overview

Claim 1 is the sole independent claim (claims 2–20 all depend, directly or indirectly, on claim 1). Note that although the specification describes a third aspect — a protein-resistant solid support surface per se — the issued claims are method-only; no apparatus/composition claim issued.

Claim 1 (a method of preparing a reactive solid support surface for surface-sensitive detection, comprising):

1. (a) Provide a solid support with a hydrogel coating bearing multiple "binding elements," and activate those binding elements so they can form covalent bonds.
2. (b) Couple a protein-resistant compound (e.g., PEG) to the hydrogel through a first fraction of the activated binding elements.
3. (c) Re-activate the remaining, unreacted binding elements so they can again form covalent bonds.
4. (d) Then couple at least one binding agent (e.g., a ligand/antibody or capture agent) to the hydrogel through a second fraction of binding elements — defined as those remaining after the protein-resistant-compound coupling step.
5. Result: the protein-resistant compound and the binding agent(s) are co-immobilized on the hydrogel via the first and second fractions, respectively, and are intermixed laterally on the surface — and the surface-sensitive detection is a mass-sensing biosensor system.

Practical significance / likely scope-drivers:

• The re-activation step (c) between PEG immobilization and ligand immobilization is a specific limitation, not just conceptual co-immobilization. (The specification notes activation/coupling may be repeated, and the working example re-activates and re-injects PEG to raise the PEG level in Fc2 before IgE coupling.)
• The surface must be for a mass-sensing biosensor — claim 20 narrows this to surface plasmon resonance (SPR) (BIACORE®-type systems; background cites U.S. Pat. Nos. 5,313,264; 5,242,828; 5,436,161; 5,492,840).
• Dependent claim 15 sets protein-resistant compound at ≥ about 2 ng/mm²; claim 16 sets binding agent at ≥ about 9 ng/mm². (In the example, 2,301 RU PEG + 8,265 RU IgE gave materially better positive-sample detection than 1,107 RU PEG or no PEG — see Tables II–V.)
• Other dependent claims cover: covalent coupling via hydrogel functional groups (2, 3); activated groups from reactive ester/hydrazide/thiol/maleimide/reactive disulphide (4); amine/thiol/disulphide groups on PEG and binding agent (5); specific-binding-pair coupling such as avidin/biotin or complementary oligonucleotides (6); hydrophilic polymer / PEG (7, 8); polysaccharide hydrogel — dextran or cellulose or derivatives (9–12); ligand or capture agent (13, 14); metal-layer support, optionally via an ordered alkyl-chain monolayer (17, 18); and array-formatted hydrogel coating (19).

Background art discussed in the patent: U.S. Pat. No. 6,475,808 (Zyomyx); WO 2004/005477 (Chiron); WO 03/005890 (Arizona Board of Regents); US 2003/0040027 A1; plus non-patent citations (Chapman 2000/2001; Siegers 2004; Frederix 2004; Johnsson 1991; Biacore Sensor Surface Handbook 2003).

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CAFC 2026 / litigation status

• No CAFC 2026 docket entry or appeal involving patent 8,093,005 was located. The only Federal Circuit-adjacent 2026 material returned was an unrelated amicus brief in a different matter (Google v. Cellular South), which does not reference this patent.
• The patent is recorded as Expired – Lifetime with an anticipated expiration of 2025-10-11, predating the current date (April 26, 2026) and any 2026 CAFC activity window — consistent with (but not proof of) there being no active enforcement.
• Uncertainty flag: I cannot definitively confirm the absence of litigation from a live PACER/CAFC docket query; the above reflects searchable public web/patent-record evidence only. If you need a certified litigation/assignment history, the authoritative sources are USPTO PatentCenter (application 12/581,431), USPTO Assignment records, and the CAFC/PACER dockets directly.

I'll search for litigation involving US patent 8093005.

Initial searches returned patent documents, not litigation records. Let me search dedicated litigation sources.

Summary Finding

I found no record of any litigation (district court action, CAFC appeal, ITC investigation, PTAB post-grant proceeding, or foreign counterpart suit) involving U.S. Patent No. 8,093,005. Based on the sources searched, I could identify no case in which US 8,093,005 ("Preparation and use of a reactive solid support surface," filed as a divisional of Ser. No. 11/249,038, now assigned to Cytiva Sweden AB) was asserted, challenged, or otherwise at issue.

I want to be explicit that this is a negative finding subject to the limitations noted at the end, not an affirmative confirmation that no case exists.

Sources Consulted

Near-Miss Cases (Expressly NOT Involving US 8,093,005)

To be clear about what I am not reporting as this patent's litigation, the searches surfaced the following Cytiva/GE Healthcare matters, none of which involve the '005 patent:

• Cytiva Sweden AB v. Bio-Rad Laboratories, Inc., No. 1:18-cv-01899 (D. Del.), filed 2018-11-30, terminated 2022-06-30 (Judge Colm F. Connolly). Asserted patents included U.S. 8,022,054 and the '589/'590 chromatography-system patents — not the '005 patent. (Source: drugpatentwatch.com; CourtListener docket 14627841.)
• Cytiva Sweden AB et al. v. JSR Micro NV et al., No. 1:21-cv-00310 (D. Del.) — different patent family (separation media/ chromatography). (Source: Unified Patents portal.)
• Cytiva Sweden AB v. Jiangsu Hanbon Science & Technology Co., Ltd., (2024) 沪73知民初227号 (Shanghai IP Court, China) — involved Chinese patent No. 200980125060.3 ("分离介质浆料罐"); the Chinese patent was invalidated by the CNIPA and the suit was dismissed in Sept. 2025. This is a Chinese patent, not US 8,093,005. (Source: SSE-listed Hanbon disclosure, 2025-09-26.)

I have deliberately not auto-corrected or substituted any of these numbers; they are reported literally as found.

Context Relevant to the Negative Finding

• The '005 patent's term expired 2025-10-11 (anticipated expiration per the Google Patents legal-status data; the patent itself is listed as "Expired – Lifetime"). A patent near or past end of term is a less likely target for new assertion.
• The '005 patent is a divisional of Ser. No. 11/249,038 (now abandoned; published as US 2006/0094060 A1), so any earlier litigation on the parent would also merit checking — but again, none surfaced here.
• Assignee history: original assignee GE Healthcare Bio-Sciences Corp.; current assignee Cytiva Sweden AB (assignment recorded 2020-10-05, change of name from GE Healthcare Bio-Sciences AB).

Caveats / Limitations

1. Search-tool limitations. I relied on publicly indexed sources (Google Patents, CourtListener/RECAP, Unified Patents, Justia, general web). PACER itself and paid docket services (e.g., Docket Navigator, Lex Machina) are not directly searchable here; a sealed, settled, or unindexed complaint could exist without appearing in these results.
2. No auto-correction applied. All identifiers above are reproduced exactly as the sources returned them.
3. This is a research finding, not a legal opinion. Before relying on it — for example, in a freedom-to-operate or clearance analysis — I recommend a direct PACER/PTAB (PATR for PTAB proceedings) docket check and a commercial litigation-database search, since patent owners sometimes assert method claims from expired patents for past damages.

Conclusion: No litigation involving US 8,093,005 is known or was found in the sources searched. If you need certainty, the next step would be a direct PACER and PTAB-PATR query and a check of the foreign family members (e.g., WO 2006/041392 A1, the international counterpart) for ex-US proceedings.

I'll verify the structured data against live sources before writing this up.

Proceedings overview

Zero AIA trial proceedings on file. The structured USPTO ODP block reports no AIA trial proceedings for US 8,093,005, and my independent searches of PTAB-related sources (via Google/web index of ptacts.uspto.gov petition documents, PTAB decisions, and CAFC opinions) surfaced no IPR, PGR, or CBM naming this patent — so the count is 0 active, 0 claims invalidated, 0 claims sustained, 0 settled, 0 institution-denied. The only proceeding number that appears anywhere near "8093005" in search results is unrelated: JSR Corp. v. Cytiva BioProcess R&D AB, IPR2022-00036/-00041/-00043/-00044/-00655/-00656 (Federal Circuit No. 23-2074), which concerns U.S. Pat. Nos. 10,213,765, 10,343,142, and 10,875,007 — different patents, different family (chromatography matrices with Protein A ligands), not the '005 patent. Do not conflate them. The bottom-line defensive posture is therefore not "hardened by surviving two IPRs" and not "claim 1 is dead." It is: all 20 claims are legally untested at the PTAB, but the patent expired on 2025-10-11, which drains most of the practical value from an IPR-based defense and shifts the fight to past damages and the § 286 lookback.

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No proceeding to report

There is no IPR, PGR, or CBM to walk through. Rather than fabricate a proceeding number, panel, or FWD, here is the factual record that substitutes for it:

• Patent: US 8,093,005 B2, "Preparation and use of a reactive solid support surface"
• Owner: Cytiva Sweden AB (assignee of record since 2020-06-12, by change of name from GE Healthcare Bio-Sciences AB)
• Inventors: Tanja Jarhede, Per Kjellin, Anita Larsson, Hans Sjobom
• Prosecution chain: divisional of US 11/249,038 (filed 2005-10-11, now abandoned, published as US 2006/0094060 A1); provisional 60/618,655 and Swedish priority SE 0402476-6, both 2004-10-13
• Filed (this divisional): 2009-10-19
• Granted: 2012-01-10
• Anticipated expiration: 2025-10-11 (20 years from the 2005-10-11 filing date of the parent non-provisional)
• Legal status (verbatim from the structured data): Expired - Lifetime
• Claims: 20 total — one independent method claim (claim 1) and claims 2–20 depending from it. There is no independent apparatus/product claim in the issued set, even though the specification describes a "protein resistant solid support surface for coupling of binding agents."
• Claim 1's operative limits: providing a hydrogel-coated support; activating binding elements to a covalent-bond-forming state; coupling a protein resistant compound via a first fraction; re-activating remaining unreacted binding elements; then coupling a binding agent via the second fraction, the two species being "co-immobilized... and intermixed laterally thereon," with the preamble limited to "surface sensitive detection [that] is a biosensor system based on mass sensing" (claim 20 narrows this to SPR).

No settlement, no termination, no Federal Circuit appeal, and no estoppel attaches to anyone, because no petition was ever filed.

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Strategic summary

Claim status: everything is UNTESTED, but the term is over. No claim of 8,093,005 has ever been canceled by the PTAB, and none has been adjudicated in a public district-court validity ruling that I could locate. So claims 1–20 are all "untested" in the AIA-trial sense — there is no narrow set of surviving claims to point to and no dead claims to exploit. What has changed is not the claims but the clock: the structured record lists an anticipated expiration of 2025-10-11, and the patent's status is Expired - Lifetime. As of today (2026-09-28) the patent has been expired for roughly eleven-and-a-half months. That means no ongoing infringement, no injunction, no reasonable-royalty tail — only damages for pre-expiration infringement, recoverable under the 35 U.S.C. § 286 six-year lookback measured from the date suit is filed. A complaint filed today reaches back only to late 2020, itself bounded by the 2025-10-11 expiration.

Estoppel landscape: empty, and largely moot. § 315(e)(2) estoppel binds only a petitioner, real party in interest, or privy that obtained an institution decision. Nobody instituted, so no defendant is estopped, and every prior-art ground — including the references already of record — remains available in litigation. The flip side is that IPR itself is now a poor instrument: the Board generally will not institute on a patent with no remaining term in which to amend, and the sole benefit of an IPR (avoiding an injunction, knocking out live claims) has already been delivered by expiration. For a defendant, the more useful angle is that claim 1 is a method claim directed to preparing the sensor chip surface — the party that practices it is the chip manufacturer, not a lab that merely runs serum samples on a pre-made CM5 chip. That is a § 271(a)/indirect-infringement and divided-infringement problem for the patent owner, and it is worth developing regardless of validity.

Pattern signals: none on this patent. No petitioner has filed even one petition here, let alone multiple; there is no Unified Patents or other defensive-aggregator footprint on the '005 patent that my searches could identify; and the patent owner has never had a PTAB appeal concerning it. Cytiva is an active PTAB litigant — it defended the six JSR IPRs on its Protein A chromatography patents, lost on 79 claims at the Board, and lost again on 2024-12-04 at the Federal Circuit in No. 23-2074 (122 F.4th 876), which affirmed 79 unpatentable claims and reversed the Board's holding that four claims of the '142 patent and two of the '007 patent survived. That tells you Cytiva is willing to litigate to judgment, but it says nothing about the '005 patent's strength. The absence of any IPR on '005 is a weak signal of low asserted value rather than a signal of robustness: an expired, method-only, chip-manufacture claim simply does not attract AIA petitions.

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Recommended next steps

1. Stop treating this as a PTAB-defensible patent and treat it as a damages-tail patent. There is no FWD to link to because none exists. The governing dates are the 2025-10-11 expiration and the § 286 six-year lookback from the filing of any complaint. Build your exposure model on pre-expiration sales only.
2. Attack the claim-1 method locus. Claim 1 recites preparing a surface — activation/EDC-NHS chemistry, re-activation, sequential coupling of PEG-amine then ligand. If your client buys pre-functionalized chips (e.g., a BIACORE CM5-series chip) and merely immobilizes protein on them, analyze carefully whether the re-activation step in particular is performed by your client or by the manufacturer; that step is the most likely prosecution-driven narrowing point in the claim. This is a non-infringement argument available even though no IPR narrowed the claim.
3. Preserve prior-art grounds — you are unencumbered. Because no petition was ever filed, nothing is estopped. The references already in the record remain fair game: US 5,242,828, US 5,436,161, US 5,492,840, US 5,313,264 (Pharmacia/Biacore hydrogel sensor surfaces), US 6,475,808 and US 6,897,073 (Zyomyx PEG/non-specific-binding-resistant arrays), WO 2004/005477 (Chiron), WO 2003/005890 (Arizona Board of Regents), US 6,800,296 (MIT), plus the non-patent literature cited on the face — Johnson et al., Anal. Biochem. 198:268–277 (1991) (the foundational EDC/NHS carboxymethyldextran immobilization paper), Chapman et al., JACS 122:8303–8304 (2000) and Langmuir 17:1225–1233 (2001), Frederix et al., J. Biochem. Biophys. Methods 58(1):67–74 (2004) ("Reduced nonspecific adsorption... using poly(ethylene oxide) containing blocking agents"), Siegers et al., Chem. Eur. J. 10(11):2831–2838 (2004), and the Biacore Sensor Surface Handbook, Oct. 2003 ed., pp. 84–86. Note that Frederix 2004 and the Biacore Handbook post-date nothing critical here and are squarely on point for the PEG-blocking-plus-ligand-immobilization concept — but because expiration, not validity, is your best defense, deploy these first as § 282 invalidity contentions, not as an IPR petition.
4. If a demand letter arrives citing claims 1–20, respond that (a) the patent expired 2025-10-11 and the asserted term is over, (b) damages are capped by the § 286 lookback and by the patent's own expiration, and (c) claim 1 is a manufacturing-method claim whose steps your client likely does not perform. Request the asserted claims and the accused acts in writing before engaging further.
5. Watch the family, not this patent. The '005 family also includes WO 2006/041392 A1, and Cytiva's more assertable assets are the Protein A chromatography patents it litigated against JSR — where the Board and the Federal Circuit have now invalidated the large majority of claims. If Cytiva is asserting anything against your client, the JSR result (CAFC No. 23-2074) is a useful leverage point on the portfolio generally.

Confidence note: I am confident from the structured ODP data and repeated searches that no AIA proceeding was ever filed against US 8,093,005. I could not verify panel composition, FWD text, or appeal dockets for the '005 patent because none exist. If the ODP index lags on a very recent petition, a direct PTAB E2E search on "8093005" at https://ptacts.uspto.gov would be the definitive confirmation.

I'll research the assignment record and ownership chain for US 8093005. Let me run several targeted searches.

Let me dig deeper on the assignment record, correspondent, and any litigation involving this patent.

Ownership & Assignment Analysis — US 8,093,005 B2

Patent: US 8,093,005 B2 ("Preparation and use of a reactive solid support surface")
App. No.: 12/581,431 (divisional of 11/249,038, filed 2005‑10‑11, now abandoned)
Priority: 2004‑10‑13 (US 60/618,655; SE 0402476‑6)
Grant: 2012‑01‑10 · Status: Expired – Lifetime (term anticipated 2025‑10‑11)

Note on data provenance: I worked from the authoritative full text of US 8,093,005 (Google Patents, incl. its legal‑events block) plus cross‑checks against Justia and international register records. I was not able to pull the live USPTO Assignment Center record (reel/frame detail, correspondent field) for every link in this chain, so I restrict the timeline to what is actually documented and flag the gaps explicitly rather than filling them.

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Inventors

Pattern notes: All four inventors are listed at Uppsala addresses, consistent with the Biacore biosensor business unit that was the GE Healthcare Bio‑Sciences AB operation in Sweden (a unit tracing back to Pharmacia Biosensor AB → Biacore AB → Amersham Biosciences AB). The specification's working example (BIACORE® 3000, Series CM5 chip) is unambiguously the inventors' own employer's platform, which is the normal signature of an in‑house operating‑company filing — not the "all inventors departed within 12 months" pattern that precedes a portfolio fire‑sale. No evidence of inventor departure or inventor‑held (unassigned) rights surfaced.

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Original assignee

• On the issued US patent (Google Patents "Original Assignee"): GE Healthcare Bio‑Sciences Corp. (US entity).
• As reported by Justia's patent history page for 8,093,005: GE Healthcare Bio‑Sciences AB (Uppsala) — i.e., the Swedish entity.
• Current assignee of record (Google Patents / USPTO legal events): Cytiva Sweden AB.

This Corp‑vs‑AB discrepancy is a genuine records inconsistency worth flagging: the inventors sit in Sweden (AB entity), the US front page names the Corp, and the single recorded change of name (see below) runs from the AB entity to Cytiva Sweden AB. I cannot resolve which entity held US legal title at grant from the sources available; treat the title‑holder between 2012 and 2020 as the GE Healthcare Bio‑Sciences family rather than a single named legal person.

Business / product: GE Healthcare Life Sciences (the Biacore line) — label‑free molecular interaction analysis. The claims are embodied in a shipped commercial product: the specification's own example uses a Series CM5 sensor chip (gold surface + covalently linked carboxymethyl‑modified dextran hydrogel, ~100 nm) and a BIACORE® 3000 instrument, and the claimed method (co‑immobilising a protein‑resistant compound and a binding agent on the hydrogel) is precisely the surface‑preparation workflow performed on that chip.

Current status: Operating. GE Healthcare's BioPharma business units (BioProcess, Cell & Gene Therapy, Genomics & Cellular Research) were acquired by Danaher Corporation (announced 2019‑02‑25; closed 2020‑03‑31/04‑01, ~$21.4B). The business rebranded Cytiva; the AB entity is now Cytiva Sweden AB (Björkgatan 30, 751 84 Uppsala). It is a wholly integrated operating subsidiary of a public company — not a licensing shell.

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Assignment timeline

Only one post‑issuance assignment is documented for this patent in the sources consulted. No inventor→company assignment record, and no subsequent transfer, could be retrieved.

• 2020‑06‑12 (executed) / recorded 2020‑10‑05 — Reel 054262/0184
  • Conveyance: Assignment — recorded as CHANGE OF NAME (USPTO event code AS; descriptive text: "CHANGE OF NAME; ASSIGNOR: GE HEALTHCARE BIO‑SCIENCES AB")
  • Assignor: GE Healthcare Bio‑Sciences AB (Björkgatan 30, BL3‑3, 751 84 Uppsala, Sweden)
  • Assignee: Cytiva Sweden AB (Björkgatan 30, 751 84 Uppsala, Sweden)
  • Correspondent: Not retrievable from the sources available to me for reel 054262/0184. I am not able to name the attorney/firm of record, so I make no repeat‑correspondent finding.
  • Context: Change of name only — a same‑address, same‑group name change following Danaher's acquisition of the GE Healthcare Life Sciences BioPharma business; no transfer of beneficial ownership outside the GE→Danaher corporate family.

Related register events (informational, not assignments of this patent):

• Maintenance fees paid 2015‑07‑10 (4th yr), 2019‑06‑24 (8th yr), 2023‑06‑28 (12th yr) — consistent with a continuously maintained operating‑company asset.
• Prior corporate name change in the family: Amersham Biosciences AB → GE Healthcare Bio‑Sciences AB (reflected in foreign patent‑office records, e.g., IP Australia).
• US‑side sibling change: GE Healthcare Bio‑Sciences Corp → Global Life Sciences Solutions USA LLC, effective 2019‑09‑30 (per GE pre‑notification), as part of the Danaher carve‑out.

If the Assignment Center shows additional links (e.g., a 2005 inventor→GE assignment, or a Corp↔AB transfer) that I could not retrieve, the timeline above should be supplemented — but nothing in the retrieved record supports a third‑party transfer.

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Timeline diagram

timeline
    title Ownership of US 8093005
    2004 : Priority date Oct 13
    2005 : Parent app filed Oct 11
    2009 : Divisional app filed Oct 19
    2012 : Patent issued Jan 10
    2020 : GE Healthcare Bio-Sciences AB renamed Cytiva Sweden AB
         : Danaher closes GE Life Sciences BioPharma deal
    2025 : Patent term expires

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NPE / troll-pattern signals

1. Shell-entity transfer — not present. The only recorded transfer is reel 054262/0184 (2020), and it is a name change between two entities at the same Uppsala address. No "IP / Holdings / Ventures" successor, no registered‑agent address, no single‑purpose LLC appears anywhere in the chain. The terminal owner, Cytiva Sweden AB, is an operating Danaher subsidiary (products: Biacore instruments, CM5 chips).

2. Known asserter in the chain — not present. No assignee in the chain matches any public NPE list (Acacia, Marathon, IV, IPNav, Wi‑LAN, Mosaid/Conversant, Vringo, Pendrell, Round Rock, etc.). The chain is confined to GE Healthcare → Cytiva (Danaher).

3. Repeat correspondent across the chain — unclear / not determinable. I could not retrieve the correspondent field for reel 054262/0184, and there is only one recorded link, so recurrence cannot be assessed (a single appearance would not be a finding in any event).

4. Cascading transfers — not present. Exactly one recorded post‑issuance event, dated 2020 (recorded 2020‑10‑05) — no chained LLC hops, and certainly none within <24 months.

5. Pre‑litigation transfer — not present. No infringement suit naming US 8,093,005 surfaced in the searches performed, and the sole assignment predates nothing litigation‑wise. No standing‑laundering pattern.

6. Bankruptcy fire‑sale — not present. No Chapter 7/11 event for GE Healthcare Bio‑Sciences AB / Cytiva Sweden AB. The Danaher transaction was a solvent carve‑out.

7. Privateering — not present. No transfer to an NPE asserting on the operating company's behalf; the patent stayed inside the operating group.

8. Defensive aggregator (anti‑NPE) — not present. The chain does not terminate at RPX, AST, LOT, Unified Patents, or OIN.

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Verdict

Insufficient data (in substance: non‑NPE, no assertion).

The entire documented ownership history is a single change‑of‑name at reel 054262/0184 (executed 2020‑06‑12, recorded 2020‑10‑05) moving the patent from GE Healthcare Bio‑Sciences AB to Cytiva Sweden AB — the same Uppsala address, following Danaher's acquisition of the GE Healthcare Life Sciences BioPharma business. There is no third‑party transfer, no shell entity, no known asserter, no cascading LLC chain, no litigation, and the patent remained an operating‑company asset maintained to term (final maintenance fee 2023‑06‑28; expired lifetime). Under the rubric this falls into the "no ownership transfer beyond the original assignment" bucket, because a change of name does not move beneficial ownership outside the originating corporate family; there are simply not enough assignment events to characterise further, and none of them signal NPE activity.

Verification links:

• USPTO Assignment Center: https://assignmentcenter.uspto.gov/ (search patent 8,093,005)
• Legacy USPTO assignment portal: https://assignment.uspto.gov/patent/index.html
• Google Patents legal events: https://patents.google.com/patent/[US8093005B2](/patent/US8093005B2)/en

I'll ground this analysis with searches against USPTO records and the specific citation set.

Let me verify the remaining citations in parallel.

US 8,093,005 — Prior-Art Analysis (§102 Focus)

Scope note: This section builds on the previously generated bibliographic, claim, and litigation sections and does not repeat them. The patent text supplied in the user message is treated as authoritative. Search results obtained this session are used to verify dates/identity where available; where I could not independently verify a reference this session, I say so and rely on the '005 patent's own citation table, which is itself the record of what was cited.

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1. USPTO / record confirmation for the literal number 8093005

The searches returned the record at US 8,093,005 B2, application 12/581,431, "Preparation and use of a reactive solid support surface," confirming:

• Assignee of record: GE Healthcare Bio-Sciences AB (Uppsala); current owner Cytiva Sweden AB.
• Inventors: Tanja Jarhede, Per Kjellin, Anita Larsson, Hans Sjobom.
• Primary Examiner: Lisa Cook (Justia confirms).
• Filed 2009-10-19; granted 2012-01-10; divisional of Ser. No. 11/249,038 (2005-10-11).
• Solo independent claim: claim 1 (method); claims 2–20 dependent.

Noise to disregard (literal-number rule observed): the searches also returned unrelated documents with superficially similar identifiers — e.g. US 7,307,597 ("Antenna"), a design patent USD876620, and Pacific Biosciences' US 2009/0061429 / US 7,993,891. None of these is US 8,093,005 and none is substituted or auto-corrected into the analysis below.

Discrepancy flag: the fetched Google Patents page presents the same reference set twice, once headed "Patent Citations (15)" and once as "Citations (14)" (the latter appears to be a truncated duplicate scrape). I treat the citation set as 15 references, enumerated below.

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2. §102 framework applied (this is a pre-AIA patent)

Priority is 2004-10-13 (provisional 60/618,655; SE 0402476-6); the parent US application was filed 2005-10-11. Pre-AIA §102 therefore governs, with these working dates:

Critical structural point for the claim mapping: because claims 2–20 all depend from claim 1, no reference can anticipate any claim unless it discloses every element of claim 1, including the non-trivial step (c) "re-activating remaining unreacted binding elements" between the protein-resistant-compound coupling and the binding-agent coupling. On the record before me, no single cited reference discloses step (c), so the §102 exposure of the issued claims is limited to (i) references that come close enough to make claim 1's other elements routine, and (ii) the dependent-claim features they do teach. I state that up front rather than overclaiming anticipation.

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3. Most relevant prior art (ranked)

1. WO 03/005890 A2 (Arizona Board of Regents) — closest single reference: dextran hydrogel on a gold SPR sensor, PEG coupled to the dextran, antibody coupled to the dextran. Admitted in the '005 Background.
2. US 6,475,808 B1 and US 6,897,073 B2 (Zyomyx) — co-immobilization of a protein-resistant PEG layer with protein-immobilizing groups on a selected fraction of the PEG chains.
3. WO 2004/005477 A2 (Chiron) — gold/reflective dielectric surface + functionalized dextran + protein + PEG anti-fouling derivatization.
4. US 2006/0040274 A1 (Biocept, "Microarrays utilizing hydrogels") — §102(e), hydrogel microarray, filed one week before the '005 priority.
5. US 5,242,828 / 5,436,161 / 5,492,840 (Pharmacia Biosensor) — the carboxymethyl-dextran-on-gold sensor-chip lineage (BIAcore) with activation and covalent ligand coupling.
6. Non-patent: Frederix et al. 2004 and the Biacore Sensor Surface Handbook (Oct 2003) — PEO blocking on covalently immobilized protein surfaces; the "Problems with Non-specific Binding" section.

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4. Reference-by-reference analysis (all 15 patent citations)

Format: citation → dates → description → §102 basis → claims implicated. "Claims implicated" = the claims whose additional limitations the reference teaches; formal anticipation of those claims would still require claim 1 to be met by the same reference, which (except where noted) it is not.

4.1 US 5,242,828 (A) — Bergström, Löfäs, Johnsson; Pharmacia Biosensor AB

• "Sensing surfaces capable of selective biomolecular interactions, to be used in biosensor systems."
• Priority SE 8804073, 1988-11-10; PCT filed 1989-11-09 (PCT/SE89/00642); §371/§102(e) date 1991-05-10; WO 90/05303 pub. 1990-05-17; granted 1993-09-07 (verified via Espacenet bibliographic record).
• Description: sensing surface for a biosensor comprising a free-electron metal film (Cu/Ag/Al/Au) and a densely packed monolayer of organic molecule X-R-Y (X = thiol/disulfide/selenol etc.) whose terminal group Y covalently binds ligands or a biocompatible porous matrix (dextran hydrogel). Quantified protein surface concentrations up to ~50 ng/mm²; SPR responses calibrated against β-radiation measurements.
• §102 basis: §102(b) — granted 1993, far more than 1 year before the critical date.
• Claims implicated: elements of 1(a) (support + hydrogel + binding elements + activation), 2, 3 (covalent coupling via hydrogel functional groups), 4, 5 (activated/ligand functional groups), 9, 10, 11 (polysaccharide/dextran hydrogel), 13, 14, 17, 18 (metal layer, ordered alkyl monolayer). It does not teach coupling a protein-resistant compound (PEG) to the hydrogel, and so implies no anticipation of claim 1 or of PEG-specific claims 7, 8, 15.

4.2 US 5,313,264 (A) — Ivarsson, Jonsson, Sjölander, Ståhlberg, Sjödin; Pharmacia Biosensor AB

• "Optical biosensor system."
• Foreign priority CH 8804075-3, 1988-11-10; PCT/SE89/00641 filed 1989-11-09; §371/§102(e) date 1991-05-10; WO 90/05295 pub. 1990-05-17; granted 1994-05-17 (verified via uspto.report and EveryPatent records).
• Description: the foundational SPR/evanescent-wave optical biosensor instrument (four flow cells, wedge-shaped beam streak, anamorphic imaging onto a 2-D photodetector matrix, resonance-angle evaluation, references to a dextran dielectric film at claim 7). This is the BIAcore-type apparatus.
• §102 basis: §102(b).
• Claims implicated: claim 20 (SPR-based mass-sensing biosensor) and the "surface sensitive detection is a biosensor system based on mass sensing" clause of claim 1. It is apparatus, not surface chemistry, so it cannot anticipate claim 1 on its own.

4.3 US 5,436,161 (A) — Bergström et al.; Pharmacia Biosensor AB

• "Matrix coating for sensing surfaces capable of selective biomolecular interactions, to be used in biosensor systems."
• Priority 1988-11-10; granted 1995-07-25. Examiner-cited.
• Description: matrix/dextran coating chemistry for sensing surfaces (same family lineage as US 5,242,828); directed to the hydrogel matrix and its coupling chemistry.
• §102 basis: §102(b).
• Claims implicated: 1(a), 2, 3, 4, 5, 9, 10, 11, 17, 18. No PEG co-immobilization.

4.4 US 5,492,840 (A) — Pharmacia Biosensor AB

• "Surface plasmon resonance sensor unit and its use in biosensor systems."
• Priority 1988-11-10; granted 1996-02-20.
• Description: the SPR sensor unit (gold-coated glass slide carrying the dextran matrix, docking to a flow cell) and its use. This is the physical sensor-chip architecture underlying CM5.
• §102 basis: §102(b).
• Claims implicated: 1(a), 17, 18, 19 (support/metal layer/monolayer/array formatting), 20 (SPR). Not claim 1 as a whole.

4.5 WO 1992/021769 A1 — Abbott Laboratories

• "Reagents containing a nonspecific binding blocker in ion-capture binding assays."
• Priority 1991-05-30; published 1992-12-10.
• Description: assay reagent formulations that include a non-specific-binding blocker for ion-capture immunoassays. The blocker is a solution-phase reagent ingredient, not a compound co-immobilized on a hydrogel.
• §102 basis: §102(b).
• Claims implicated: at most the generic concept of a "protein resistant compound" in claim 1(b)/7 — but it does not teach coupling to a hydrogel, so it is weak art and cannot anticipate any claim here.

4.6 US 6,475,808 B1 — Zyomyx, Incorporated

• "Arrays of proteins and methods of use thereof."
• Priority 1998-07-14; granted 2002-11-05.
• Description (as characterized in the '005 Background, verbatim): assay device with a substrate surface bearing an array of discrete array-regions; "an ordered hydrophobic monolayer of alkyl chains is chemisorbed or physisorbed to the surface, and a hydrophilic monolayer formed from poly(ethylene glycol) chains is covalently linked to the hydrophobic monolayer"; "a plurality of protein-immobilizing groups are covalently attached to a selected fraction of the poly(ethylene glycol) chains within the array regions"; the hydrophobic monolayer and PEG chains "are effective in combination to resist non-specific protein binding."
• §102 basis: §102(b) (granted 2002).
• Claims implicated: 1(b), 1(d) (selective co-immobilization on a fraction of reactive sites), 7, 8 (hydrophilic polymer/PEG), 15 (PEG level), 19 (array). Architectural overlap with 17, 18. Not anticipatory: the "hydrogel" element and the re-activation step are absent, and the surface is an array device rather than a mass-sensing biosensor surface.

4.7 US 6,897,073 B2 — Zyomyx, Inc.

• "Non-specific binding resistant protein arrays and methods for making the same."
• Priority 1998-07-14; granted 2005-05-24. Examiner-cited.
• Description: continuation/companion of the Zyomyx array technology — non-specific-binding-resistant protein arrays using inert (PEG) surface chemistry plus reactive/immobilizing groups. Note the grant date (2005) is after the '005 priority.
• §102 basis: §102(e) only (as of its 1998 U.S. filing date); it is not §102(a)/(b) art on its face because it published after the critical dates. (The 1998 priority in the citation table is a priority claim, not necessarily the actual U.S. filing date — I could not re-verify the exact filing date this session; treat the §102(e) date as needing confirmation from the file wrapper.)
• Claims implicated: same as 4.6 — 1(b)/1(d), 7, 8, 15, 19. Not anticipatory of claim 1.

4.8 US 6,800,296 B1 — Massachusetts Institute of Technology

• "Modification of surfaces using biological recognition events."
• Priority 1999-05-19; granted 2004-10-05. Examiner-cited.
• Description: modifying surfaces by exploiting biological recognition events — i.e., immobilizing species through a specific binding pair rather than purely covalent activation chemistry.
• §102 basis: §102(e) (granted 2004-10-05 is after the 2003-10-13 §102(b) critical date, so it is not §102(b) art).
• Claims implicated: claim 6 (hydrogel bearing one member of a specific binding pair; PEG/binding agent bearing the other) and, generally, claim 1's coupling concept. Not anticipatory of claim 1.

4.9 US 2004/0115721 A1 — Guoqiang Mao

• "Functional surface coating."
• Priority 2001-06-26; published 2004-06-17.
• Description: functional (typically hydrophilic/polymer) surface coatings for substrates to control adsorption/binding.
• §102 basis: §102(a) (published after 2003-10-13, so not §102(b); pre-dates the 2004-10-13 priority, so §102(a) on "by another / before the invention" grounds).
• Claims implicated: 7, 8 (hydrophilic polymer / PEG-containing coating), possibly 17, 18. Not claim 1.

4.10 WO 2003/005890 A2 — Arizona Board of Regents (Arizona State University) — closest art

• "Affinity biosensor for monitoring of biological process."
• Priority 2001-07-09; published 2003-01-23.
• Description (as characterized in the '005 Background, verbatim): "an optical fiber surface plasmon resonance (SPR) sensor having a gold surface to which a dextran layer is bound via a self-assembled monolayer (SAM) of 11-mercapto-dodecanol. Anti-myoglobin antibodies are attached to the dextran via carboxylated hydroxyl groups thereof. To eliminate non-specific binding to the sensor, thiol-terminated poly(ethylene glycol), e.g., methoxy-PEG-thiol, may be coupled to the gold surface through a gold-thiol bond or to the dextran. Immobilized PEG surrounding the sensor will prevent non-specific interactions with the surface while allowing specific receptor-ligand interactions."
• §102 basis: §102(b) (published 2003-01-23, i.e., more than one year before the critical date). If the underlying PCT designated the US and was published in English, a §102(e) date as of its international filing date may also be available — I flag this as unverified, since the WO publication number/date is what the citation table gives; the "priority 2001-07-09" entry is a priority date, not necessarily the international filing date.
• Claims implicated (strongest of the set): on the face of the Background characterization, this reference teaches 1(a) (gold support + dextran hydrogel + carboxyl binding elements), 1(b) (PEG coupled to the dextran), 1(d) (antibody coupled to the dextran via its carboxyl/carboxylated-hydroxyl groups), together with mass-sensing SPR detection (claim 20), polysaccharide/dextran hydrogel (9, 10, 11), ligand (13), metal layer (17), and SAM-on-metal architecture (18); methoxy-PEG-thiol touches claim 5; carboxyl activation chemistry touches claim 4.
• Why it still does not formally anticipate claim 1: it is silent on the intervening step (c) re-activation of the remaining unreacted binding elements before ligand coupling, and (at least on the '005 Background's summary) does not expressly state that PEG and antibody are intermixed laterally on the hydrogel. Those are the two limitations that appear to preserve claim 1. This is the reference a §102 challenge would have to be built around, and it is the reference the '005 claim 1(c) limitation most plausibly was written to clear.

4.11 US 2003/0040027 A1 — Gerd Ritter

• "Method for determining protein component in a biological sample."
• Priority 2001-08-16; published 2003-02-27.
• Description: expressly cited in the '005 Background as describing "use of an SPR-biosensor with a sensor surface having an attached carboxymethyl-modified dextran hydrogel for determination if an immune response against a therapeutic agent has occurred."
• §102 basis: §102(b) (published 2003-02-27).
• Claims implicated: the use/application context of the issued claims — dextran hydrogel on an SPR sensor for immunogenicity/anti-drug-antibody analysis — i.e., 1(a), 9, 11, 13, 20. It does not disclose PEG co-immobilization or re-activation; it bears on the "use" aspect that did not issue as a claim.

4.12 US 2003/0068446 A1 — Northwestern University

• "Protein and peptide nanoarrays."
• Priority 2001-10-02; published 2003-04-10.
• Description: arrays of proteins/peptides at nano-array densities on a substrate.
• §102 basis: §102(b) (published 2003-04-10).
• Claims implicated: claim 19 (hydrogel coating in array form / discrete defined areas) by analogy; otherwise general array background. Not claim 1.

4.13 WO 2004/005477 A2 — Chiron Corporation

• "Protein microarrays on mirrored surfaces for performing proteomic analyses."
• Priority 2002-07-03; published 2004-01-15.
• Description (as characterized in the '005 Background, verbatim): "a microarray which comprises a substrate having a substantially planar surface comprising an organic-chemically modified dielectric-coated reflective metal, e.g., gold, and a plurality of proteins stably attached to the surface via a chemical adapter, e.g., a functionalized dextran. After spotting the proteins onto the substrate surface, the surface may be derivatized with poly(ethylene glycol) or a poly(ethylene glycol) analogue to inhibit non-specific protein adsorption."
• §102 basis: §102(a) (published 2004-01-15, after the 2003-10-13 §102(b) critical date). (Whether a §102(e) date via the international filing is available is unverified here.)
• Claims implicated: 1(a) (reflective metal + functionalized dextran = hydrogel), 9, 11, 13, 17. Important ordering point: Chiron derivatizes with PEG after the protein is attached — the reverse of claim 1's claimed order (b) PEG → (c) re-activate → (d) binding agent. So it cannot anticipate claim 1, although it is highly material to §103.

4.14 US 2006/0040377 A1 — Biocept, Inc.

• "Protein microarrays."
• Priority/filing 2004-08-17; published 2006-02-23.
• Description: protein microarray platform (sibling of the hydrogel-microarray application below).
• §102 basis: §102(e) — U.S. published application filed before the '005 priority date (2004-10-13), notwithstanding its 2006 publication date. This is the pre-AIA §102(e) "secret prior art" posture the examiner's citation implies.
• Claims implicated: 1(a) (substrate/hydrogel with binding elements), 13 (protein ligand), 19 (array). Not claim 1 as a whole.

4.15 US 2006/0040274 A1 — Biocept, Inc.

• "Microarrays utilizing hydrogels."
• Priority/filing 2004-08-19; published 2006-02-23.
• Description: microarrays built on hydrogel layers (as distinct from 4.14's protein-microarray framing).
• §102 basis: §102(e) — filed 2004-08-19, before the 2004-10-13 priority.
• Claims implicated: 1(a) (hydrogel coating with binding elements), 9, 10, 11 (polysaccharide/dextran-type hydrogels), 19 (array), and potentially the co-immobilization concept of 1(b)/1(d) / 7, 8 if the hydrogel carries both an antifouling component and a capture component. Because it is only eight weeks earlier than the '005 priority and touches the same "hydrogel + microarray" space, it is the most temporally sensitive of the citations and the one I would verify against its full text before any validity opinion; the citation table alone does not let me state which of claim 1's steps it discloses.

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5. Non-patent citations (relevant to §102(a)/(b))

The '005 record lists eight non-patent references (Google Patents "Non-Patent Citations (8)"). Two are directly material:

• Frederix, F., et al., "Reduced Nonspecific Adsorption on Covalently Immobilized Protein Surfaces Using Poly(ethylene oxide)-Containing Blocking Agents," J. Biochem. Biophys. Methods 58(1):67–74 (2004). This is essentially the inventive concept at the research-publication level — PEO-containing blockers used on covalently immobilized protein surfaces to cut non-specific adsorption. §102(a) (published in the priority year).
• Biacore, Sensor Surface Handbook, Oct. 2003 ed., "Problems with Non-specific Binding," pp. 84–86. Directly frames the problem the '005 claims address. §102(b)-adjacent (Oct 2003 vs. the 2003-10-13 critical date — its exact publication day matters and should be checked).
• Others (Chapman 2000 & 2001; Siegers 2004 (dendritic polyglycerol on gold); Johnsson et al., Anal. Biochem. 198:268–277 (1991) on protein immobilization to carboxymethyl-dextran gold surfaces; the 2003 SBSC poster "SPR-based Assays for Plasma Samples") are supporting art on protein-resistant surfaces and CM-dextran immobilization chemistry.

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6. Overall §102 conclusion

Claim-drafting defect worth flagging (contradiction check): dependent claim 16 recites "the amount of binding agent that is coupled in step c) of claim 1," but in claim 1 step (c) is the re-activation step and step (d) is the binding-agent coupling. Claim 16's cross-reference appears internally inconsistent with claim 1 as printed. This is consistent with — and does not contradict — the earlier-generated section's statement that claim 16 sets the binding-agent amount at ≥ about 9 ng/mm²; it is an additional observation about the claim's internal referencing, not a correction of it.

Uncertainties I am not papering over:

1. I verified US 5,242,828 and US 5,313,264 bibliographic data against Espacenet/uspto.report/EveryPatent this session. For the remaining 13 citations I relied on the '005 patent's own citation table plus the '005 Background's characterizations (for US 6,475,808, WO 2004/005477, WO 03/005890). I did not independently confirm the actual U.S. filing dates (as opposed to priority dates) for US 6,897,073, US 6,800,296, WO 2004/005477, or WO 03/005890; those matter for the §102(e) analysis and should be checked in the file wrapper / Patent Center.
2. The §102(a) vs §102(b) boundary depends on the '005 chain's earliest U.S. filing date (provisional 60/618,655, 2004-10-13). If for any reason benefit to that provisional were not perfected, the critical date would shift to 2004-10-11 (minus one year from the parent's 2005-10-11 filing), which would move US 6,800,296 (granted 2004-10-05) into §102(b) territory. That is a real, checkable hinge.
3. I have cited specific claims and references above; where I say a reference "implicates" a claim I mean it teaches that claim's additional limitation, not that it anticipates the claim.

Sources used this session: the patent text supplied; Google Patents US8093005B2; Justia 8093005; Espacenet bibliographic record for US5242828A; uspto.report and EveryPatent records for US5313264.

I'll ground my characterization of the load-bearing prior-art references before analyzing.

Obviousness Analysis — US 8,093,005 B2 under 35 U.S.C. § 103

Scope note (building on prior sections): This analysis takes the bibliographic record, claim overview, and litigation findings from the earlier sections as given and does not repeat them. I address only § 103. The relevant statute is pre-AIA § 103(a) — the '005 patent is a divisional of Ser. No. 11/249,038 (filed 2005‑10‑11) claiming benefit of 2004‑10‑13, i.e., before the AIA's 2013‑03‑16 cutoff — so the governing case law is KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398 (2007), Graham v. John Deere, and the MPEP 2141–2144 framework. The effective prior-art date is 2004‑10‑13; references with earlier § 102(e) US filing dates qualify even if published after that date.

Caveat on certainty: I do not have the '005 file history (the Examiner's office actions / reasons for allowance) or the full texts of every cited reference. My characterizations below are drawn from (a) the prior-art descriptions in the '005 specification itself, (b) the reference list on the Google Patents page, and (c) web-grounded checks of the load-bearing references cited below with URLs. Obviousness is ultimately a legal conclusion; what follows is the technical/evidentiary predicate an Examiner or challenger would assemble.

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1. Claim 1 — element decomposition

The two features most likely to have driven allowance are (D) the re-activation step in a PEG→re-activate→ligand sequence and (F) the lateral intermixing of PEG and ligand on a hydrogel. Everything else (hydrogel, activation, covalent coupling, mass-sensing biosensor) is squarely in the prior art.

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2. The prior-art landscape (from this page), grouped by what it teaches

Group I — hydrogel/matrix sensing surfaces and covalent coupling (the 1(A)/1(B)/1(E)/1(G) base):

• US 5,242,828 (Pharmacia Biosensor) and US 5,436,161 (Pharmacia; matrix coating for sensing surfaces) — sensor surfaces with a covalently linked carboxymethyl-modified dextran hydrogel on gold and functional groups for biomolecular coupling. These are the direct ancestors of the CM5 chip. https://patents.google.com/patent/[US5242828A](/patent/US5242828A)/en · https://patents.google.com/patent/[US5436161A](/patent/US5436161A)/en
• US 5,313,264 and US 5,492,840 (Pharmacia) — SPR optical biosensor system / SPR sensor unit, i.e., the "mass-sensing biosensor" of 1(G). https://patents.google.com/patent/[US5313264A](/patent/US5313264A)/en · https://patents.google.com/patent/[US5492840A](/patent/US5492840A)/en
• Johnsson, Löfås & Lindquist (1991), Anal. Biochem. 198:268–277 (non-patent citation on the page) — the canonical teaching that carboxyl groups of a CM-dextran matrix are activated with EDC/NHS to reactive succinimide esters, that ligands with amine groups are immobilized thereby, and (importantly for element D) that unreacted esters must be handled — the surface is blocked with ethanolamine. Cited in the search of the Arizona reference as the standard protocol.

Group II — PEG/hydrophilic layers co-resident with protein-immobilizing groups (elements 1(C)/1(F)):

• US 6,475,808 (Zyomyx) — I verified the claim language: an ordered hydrophobic monolayer of alkyl chains + a hydrophilic monolayer (PEG-type chains) that "are effective in combination to resist non-specific protein binding," with "a plurality of protein-immobilizing groups covalently attached to a selected fraction of said hydrophilic-chains' distal ends." That is, PEG-type chains and protein-attachment sites are deliberately intermixed on the same layer, with only a fraction of chains carrying immobilizing groups. https://patents.google.com/patent/[US6475808B1](/patent/US6475808B1)/en
• US 6,897,073 (Zyomyx, Non-specific binding resistant protein arrays) — the divisional/continuation that teaches the method form: reacting protein capture agents with a first subset of functional groups and then reacting second hydrophilic chains (PEG) with a second, mutually exclusive subset. https://patents.google.com/patent/[US6897073B2](/patent/US6897073B2)/en

Group III — PEG on a dextran hydrogel affinity biosensor (the closest art):

• WO 03/005890 A2 (Arizona Board of Regents) — verified: an optical-fiber SPR biosensor whose probe surface "comprises dextran as immobilization agent," built on the CM-dextran/EDC-NHS chemistry, with anti-myoglobin antibodies immobilized and deactivation with ethanolamine. As the '005 specification itself states, the reference teaches that methoxy-PEG-thiol may be coupled … to the dextran and that "immobilized PEG surrounding the sensor will prevent non-specific interactions with the surface while allowing specific receptor-ligand interactions." https://patents.google.com/patent/WO2003005890A2/en

Group IV — post-immobilization PEG "blocking" to cut NSB (the problem + solution):

• WO 2004/005477 A2 / US 7,148,058 B2 (Chiron) — verified: protein microarrays on a functionalized mirrored substrate; a "chemical block" of PEG or PEG analogues is applied following spotting of the array elements "to decrease non-specific protein binding … and therefore increase array sensitivity," expressly for complex biological mixtures such as serum, whole blood, urine, and expressly to detect "antibodies in serum against potential protein antigens … to determine immune response." https://patents.google.com/patent/WO2004005477A2/en · https://patents.google.com/patent/[US7148058B2](/patent/US7148058B2)/en
• Frederix et al., J. Biochem. Biophys. Methods 58(1):67–74 (2004) — verified abstract: "Following the covalent coupling of proteins, the remaining reactive groups should be blocked … blocking agents containing poly(ethylene oxide) (PEO) groups … show enhanced qualities to avoid nonspecific adsorption," explicitly in SPR technology, replacing ethanolamine/cysteine. https://pubmed.ncbi.nlm.nih.gov/14597190/

Group V — problem recognition in the immunogenicity/serum context:

• US 2003/0040027 A1 (Ritter) — per the '005 specification, "use of an SPR-biosensor with a sensor surface having an attached carboxymethyl-modified dextran hydrogel for determination if an immune response against a therapeutic agent has occurred."
• Biacore, Sensor Surface Handbook (Oct. 2003), "Problems with Non-specific Binding," pp. 84–86; and the 2003 SBS poster "SPR-based Assays for Plasma Samples — Strategies to Improve Plasma Measurements" — both cited on the face of the '005 patent, documenting that NSB is a recognized, quantified problem in exactly the serum/plasma mass-sensing context.

Group VI — arrays (element 19), including near-contemporaneous hydrogel-array art:

• US 2003/0068446 A1 (Northwestern, protein/peptide nanoarrays); US 6,800,296 B1 (MIT); US 2004/0115721 A1 (Mao).
• Biocept, US 2006/0040274 A1 (Microarrays utilizing hydrogels) and US 2006/0040377 A1 (Protein microarrays) — filed 2004‑08‑17/19, i.e., before the 2004‑10‑13 priority date, making them § 102(e) prior art as of their US filing dates. The hydrogel-microarray title is directly on point for claim 19, though I have not verified their full disclosures. https://patents.google.com/patent/US20060040274A1/en · https://patents.google.com/patent/US20060040377A1/en

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3. Primary § 103 combinations rendering claim 1 obvious

Combination A (strongest): Pharmacia hydrogel chip + Zyomyx co-immobilization + Biacore/Ritter problem recognition

Motivation. The Pharmacia references supply the substrate; Zyomyx supplies the known expedient of putting PEG-type chains and protein-attachment chemistry on the same surface layer at fractional coverage to suppress NSB; and the Biacore Handbook / Ritter '027 supply the reason — mass-sensing (SPR) detection integrates all bound mass, so NSB from serum is a recognized, documented source of false signal. A POSITA seeking to use a CM-dextran SPR chip on serum would have found it obvious to adapt Zyomyx's fractional-PEG approach onto the hydrogel surface already in use.

The one gap is that Zyomyx's layer is a monolayer (hydrophobic SAM + PEG), not a hydrogel. That gap is bridged by WO 03/005890, which puts PEG on a dextran layer of an SPR sensor — see Combination B.

Combination B: Pharmacia hydrogel chip + WO 03/005890 + Frederix/Chiron (closes the hydrogel gap)

WO 03/005890 already discloses (i) a dextran affinity layer on an SPR sensor, (ii) the EDC/NHS coupling chemistry, and (iii) PEG coupled to the dextran "surrounding the sensor" to prevent non-specific interactions while permitting specific ones. Frederix (2004) and Chiron '477 independently confirm the then-current practice of using PEO/PEG as the blocking agent on covalently protein-derivatized surfaces, and Chiron expressly extends it to serum/whole-blood samples and to detection of serum antibodies (immunogenicity) — removing any doubt about the field of endeavor and the problem addressed. https://patents.google.com/patent/WO2003005890A2/en

Combination C: Pharmacia hydrogel chip + Chapman 2000/2001 or Siegers 2004 (broad genus coverage for claims 7–8)

Chapman (JACS 2000, 122:8303) and Chapman (Langmuir 2001, 17:1225) and Siegers (Chem. Eur. J. 2004, 10:2831) are cited on the page and each disclose protein-resistant hydrophilic polymers — PEG-type oligomers, and dendritic polyglycerol respectively. These supply the full genus of 1(C)/claims 7–8.

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4. The re-activation step (1(D)) — why it is arguably obvious

This is the feature most likely to be argued as non-obvious, so it deserves care.

1. The chemistry forces it. Johnsson 1991 (cited on the page) and the ordinary CM-dextran protocol teach that EDC/NHS-generated succinimide esters hydrolyze back to carboxylates in aqueous buffer. Any second coupling performed after a first aqueous incubation therefore requires re-activation of the surviving carboxyls. WO 03/005890's own protocol (activate → immobilize antibody → ethanolamine) shows the same activation/deactivation rhythm.
2. The '005 specification concedes the technique is routine. It states the "activation/coupling of protein resistant compound and/or binding agents may be repeated one or more times" and that "the actual coupling steps may optionally be repeated," and that the protein-resistant compound is bound "only to a selected fraction of the activated functional groups, and the binding agent is then bound to remaining activated groups, optionally after repeated activation." A limitation the specification describes as an optional, repeatable procedural step is, by that admission, within the ordinary skill level.
3. Zyomyx teaches the fractional/sequential subset concept (protein to a first subset, PEG to a second subset), including the variant where the second species is added after the first.
4. Biacore's own "aim for ligand level" practice (used in the patent's Example) reflects the routine ability to target a specific coupled-ligand density by controlling how many activated groups are consumed — a design choice, not an invention.

Counter-argument (patentee's): Chiron '477 and Frederix both teach blocking after spotting/coupling the protein, i.e., the reverse order from claim 1. The patentee can argue the art pointed away from PEG-first because pre-consuming activated groups with PEG would be expected to starve the surface of ligand, especially where claims 15–16 demand ≥ 2 ng/mm² PEG and ≥ 9 ng/mm² ligand simultaneously. See § 8.

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5. Motivation-to-combine rationales (MPEP 2143)

The combination is supported by several KSR/MPEP rationales, any one of which suffices:

• (A) Known elements, predictable result. Hydrogel sensing surface (known) + PEG to resist protein adsorption (known) + ligand coupling (known) → predictable: lower NSB, retained specific binding.
• (C) Known technique to improve a similar device in the same way. PEG blocking used on SAM/protein surfaces (Frederix, Chiron, Zyomyx) applied to a CM-dextran hydrogel SPR surface (WO 03/005890 already does this on dextran).
• (D) Applying a known technique to a known device ready for improvement. The Biacore Handbook explicitly frames NSB as the problem to be solved for serum/plasma measurements; that is the "design incentive."
• (E) Obvious to try / finite predictable solutions. Given a set of activated carboxyls, the artisan had a small, identified menu: block with ethanolamine (Frederix's baseline), block with PEG, or co-immobilize; and a small menu of orders (block-first, block-last). Both orders and the PEG option were known.
• (F) Design need / market forces. Immunogenicity assays on serum (Ritter '027; Chiron's stated serum/antibody application) create a direct demand for NSB-resistant sensor surfaces.
• Reasonable expectation of success. All components are shown working in the same or adjacent systems (SPR, dextran, PEG) with predictable chemistry.

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6. Dependent claims 2–20

Bottom line on the dependents: claims 15 and 16 are numerically tied to the working Example and are the most vulnerable to a "routine optimization / In re Aller" argument. The remaining dependents are almost entirely conventional chemistry and known device formats.

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7. Which single reference is most dangerous

• WO 03/005890 A2 is the most dangerous single reference for claim 1. It discloses an SPR biosensor on a dextran layer with EDC/NHS activation, antibody coupling, and PEG coupled to the dextran to suppress non-specific interactions while permitting specific receptor–ligand binding. If its disclosure also shows or suggests sequential coupling of PEG and antibody through re-activated dextran carboxyls, it becomes a § 102 anticipation question, not merely § 103. I have confirmed the PEG-on-dextran and the dextran/EDC-NHS/SPR teaching; I have not confirmed whether it expressly discloses the order PEG→re-activate→antibody.
• US 6,475,808 / US 6,897,073 (Zyomyx) is the most dangerous § 103 reference, because it recites the selected fraction / mutually exclusive subset concept that maps onto the "first fraction / second fraction" language of claim 1.

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8. Counterarguments a patentee would raise (and their force)

1. Order and teaching away. Chiron '477 and Frederix both teach blocking after protein coupling; nothing in Group III/IV expressly teaches pre-blocking the hydrogel with PEG and then re-activating to couple ligand. Force: moderate. The art is silent rather than contrary — silence is not "teaching away" under KSR/In re Kahn unless it criticizes, discourages, or would lead the artisan astray. WO 03/005890's PEG-on-dextran removes much of this.
2. Unexpected result (secondary consideration). The '005 Example reports that increasing surface PEG paradoxically increased the number of positives detected (22 of 29 vs. 10 of 29) even though the specific responses fell — i.e., a signal-to-noise / LOD improvement rather than mere reduction of a background offset (Tables II–V; FIG. 4). Force: moderate to strong. This is the best non-obviousness argument: the artisan would predict that more blocking = less ligand = less signal, and would not necessarily predict an improved detection outcome. A patentee would also point to the simultaneous attainment of ≥2 ng/mm² PEG with ≥9 ng/mm² ligand (claims 15–16) as evidence of a non-obvious balance.
   • Examiner rebuttal: the improvement is the inherent and expected consequence of reducing NSB in a mass-sensing assay (the very point of the Biacore Handbook and Chiron's "increase array sensitivity"); attributing it to the claimed method rather than the known function of PEG blocking would be the "obvious to try" scenario of KSR; and the LOD metric (average + 3 SD) is a standard statistical construct.
3. Claim-preamble/wherein weight. The "for surface-sensitive detection … mass sensing" language is argued to be a positive limitation narrowing claim 1. Force: moderate — but US 5,313,264 and US 5,492,840 make SPR self-evident.
4. Literal drafting defect in claim 16. The reference to "step c)" when the binding agent is coupled in step d) creates an indefiniteness/subject-matter ambiguity (35 U.S.C. § 112(b)) that a challenger can exploit, and that the patentee cannot "auto-correct" without reissue/COC. Reported literally.

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9. Overall assessment

If I were an Examiner: I would reject claim 1 under § 103 over US 5,242,828 (or WO 03/005890) in view of US 6,475,808/US 6,897,073 and US 5,313,264, with the Biacore Handbook and/or US 2003/0040027 as evidence of the recognized NSB problem, and would expect the applicant to rebut principally on (i) the specific PEG-first/re-activation sequence and (ii) the unexpectedly improved LOD. If I were the patentee, I would press the Example's paradoxical result (§ 8.2) as the strongest Graham secondary consideration, and would point out that the two closest blocking references (Chiron '477, Frederix) practice blocking last, i.e., after ligand coupling.

Bottom line: The '005 claims are highly vulnerable to a § 103 attack at the dependent-claim level and moderately vulnerable at independent claim 1, with the outcome hinging on whether the PEG-first + re-activation sequence and the lateral co-immobilization on a hydrogel at the claimed densities are held to be more than routine optimization. I have flagged this as an estimate, not a legal opinion, and it should be validated against the actual '005 prosecution history and the full texts of WO 03/005890 and the Zyomyx references before being relied on.