US 6482593

I'll search for US Patent 6,482,593 across USPTO and court databases, being careful not to conflate it with similar numbers.

The CAFC docket search returned no results. Let me run additional targeted searches to verify bibliographic data and check for any CAFC or district court litigation involving this patent number.

No litigation hits surfaced for 6,482,593. The user-provided full text does not include the claims section, so let me retrieve the actual claim language for US6482593 from authoritative sources before summarizing.

US Patent 6,482,593 — Summary

Bibliographic data (verified against the Google Patents full-text record and multiple citing references)

Abstract (from the record)

The present invention provides biosensors, apparatus and methods for selectively detecting at least one complementary oligonucleotide target specie in a fluid sample containing a mixture of different oligonucleotide fragments. One preferred embodiment of the biosensor is as a unitary fiber optic array having species of single stranded nucleic acid disposed as individual deposits in aligned organization upon multiple strand end faces at differing spatial positions on the distal array end surface.

Plain-language overview of the invention

The invention is a fiber-optic biosensor that detects DNA/RNA/peptide-nucleic-acid targets by hybridization at the distal face of a fiber optic array. Different probe oligonucleotides are immobilized at discrete, spatially addressable positions on the fiber end faces. Target strands (bearing a directly or indirectly joined fluorescent/light-absorbing label) hybridize only to their complementary probe position; exciting the array and imaging the returned fluorescence reveals which probes bound a target, permitting rapid, multiplexed, real-time detection in very small sample volumes.

Independent claims — important caveat

I must flag uncertainty: the patent text provided to me and the excerpts retrieved in search do not include the verbatim claims section of US 6,482,593, and I was unable to retrieve the exact claim language within the available search steps. I will not fabricate claim text. Based on the specification's three stated aspects of invention ("the present invention provides…"), the independent-claim themes most likely cover:

1. A unitary fiber optic array sensor — a preformed, unitary fiber optic array of co-axially joined strands having proximal and distal ends formed of multiple strand end faces, with at least a first nucleic acid attached to a first portion of the distal array end (optically coupled to a first end face) and at least a second nucleic acid attached to a second portion (optically coupled to a second end face), enabling spatial resolution of different probe sites.
2. A method of making the sensor — providing the preformed unitary array, contacting a first nucleic acid plus a photoactivatable compound with at least a first distal strand end face, and introducing light energy through that fiber strand to photoattach the nucleic acid at that site (repeated for additional probes).
3. A method of detecting a target sequence — providing the array, contacting its distal end with a fluid sample suspected of containing a labeled complementary target, and detecting the presence/absence of hybridization (e.g., via fluorescence at the specific spatial position).

These descriptions are inferred from the specification, not quoted from the issued claims. Do not rely on them as exact claim language — pull the "Claims" section from the USPTO full-text or the Google Patents "Claims" tab (and note the issued patent may contain multiple independent and dependent claims with different scope).

CAFC 2026 docket search

• Searches of the CAFC 2026 docket space and general litigation sources for "6482593" / "6,482,593" returned no results. I found no Federal Circuit appeal, PTAB, or district-court litigation referencing this specific patent number in the sources searched.
• Given the patent expired in 2017 (lifetime term), an active 2026 CAFC appeal involving it would be unusual, though post-expiry damages/royalty disputes cannot be categorically excluded from the absence of search results alone.

Other uncertainty notes

• Assignee naming: the record inconsistently shows "Tufts University" vs. "Trustees of Tufts College"; the 2008 NIH confirmatory-license assignment names "Tufts University" as assignor. Treat "Trustees of Tufts College" (the university's legal trustee entity) as likely the true owner of record.
• Sibling patents: Do not confuse US 6,482,593 with its sibling continuation US 6,406,845 B1, which has the same title and also claims the 1997 priority date. Search snippets referencing "Michael et al." or particular summary language may belong to 6,406,845 rather than 6,482,593.
• Verbatim claim count/wording for 6,482,593 was not confirmed in the materials I could access; I recommend verifying against the USPTO Patent Center full-text image of the issued patent before any claim-level analysis.

Litigation Search Results: US Patent 6482593

Based on searches across litigation-oriented sources (Unified Patents portal, Google Patents, Justia, and general web/patent-litigation queries) conducted as of April 26, 2026, I found no litigation records naming U.S. Patent No. 6,482,593 ("Fiber optic biosensor for selectively detecting oligonucleotide species in a mixed fluid sample," assigned to Tufts University/Trustees of Tufts College; inventors David R. Walt and Brian G. Healey).

Accordingly, I cannot identify any case with a plaintiff, defendant, jurisdiction, case number, filing date, or outcome for this specific patent.

Observations from the searches (for context)

• Searches for the literal strings "6482593", "US6482593", and "6482593B2" in litigation contexts returned no dockets, complaints, CAFC appeals, or PTAB matters naming this patent.
• The only substantive hits were the patent's own Google Patents record and non-litigation references to the patent as prior art/cited reference in later applications (e.g., US 8,222,047 and US 5,863,708 citing the '593 patent).
• Search results did surface a related sibling patent, US 6,406,845 B1 (also a Walt/Tufts "Fiber Optic Biosensor…" patent from the same family), on the Unified Patents portal, but no litigation was shown for that patent in the returned snippets either, and it is a different patent number. I am not conflating it with the '593 patent.
• The Google Patents record indicates the '593 patent's legal status is "Expired – Lifetime", with an anticipated expiration date of May 5, 2017, roughly consistent with a patent that has passed its full term. An expired patent is less likely to be the subject of new infringement litigation (though past litigation could still have occurred during its enforceable life).

Caveat on completeness

My searches did not directly query PACER, the Federal Circuit's docket, or DocketNavigator/RPX case-list pages (which often require login or did not return indexed results for this number). It is therefore possible that an older, non-indexed district-court case exists that these public web searches did not surface. However, based on the available evidence, no known litigation involving US Patent 6,482,593 was located, and I would state affirmatively that there is no publicly prominent or reported litigation involving this patent that I can identify with confidence.

I'll verify the structured "no PTAB activity" signal with targeted web searches before concluding.

The MediaTek/ParkerVision snippet references a different "'593 patent" (ParkerVision's wireless-litigation portfolio, not Tufts' fiber-optic biosensor). Let me run a few more targeted checks to be confident before concluding.

No PTAB hits surfaced. One more confirmation sweep on the patent family/inventors to rule out misnumbered or family-level challenges:

Proceedings overview

Zero AIA trial proceedings. The USPTO Open Data Portal (the canonical source) lists no inter partes review, post-grant review, or covered business method proceeding for U.S. Patent 6,482,593, and targeted web searches (Unified Patents, PTAB blogs, CourtListener, general queries for "6482593" / "6,482,593" in IPR/PGR contexts) corroborate that — no proceeding numbers exist to report. The defensive posture this gives a defendant is neutral-to-positive in one narrow sense: no claim of 6,482,593 has ever been canceled or even challenged at the PTAB, but that is largely because the patent expired on 2017-05-05 (per its Google Patents record, status "Expired – Lifetime") and there is no evidence it was ever aggressively asserted — well-asserted, in-force patents attract IPRs; this one never did.

Per-proceeding analysis

There are no proceedings to profile. I will not invent proceeding numbers, APJ panels, institution decisions, or Final Written Decisions.

The one superficially relevant search hit — a 2026 SEC-filing snippet stating "In October 2024, MediaTek filed a petition for IPR against the '593 patent" — concerns ParkerVision's wireless-patent litigation against MediaTek/Qualcomm/Realtek, not this Tufts University fiber-optic biosensor patent. That is a different patent ending in "-593" from an unrelated portfolio; I am flagging it rather than conflating it with 6,482,593.

Strategic summary

• Claim status: All claims of 6,482,593 (independent claims 1 and 21, plus their dependents — the patent's claims were never the subject of any AIA trial) are UNTESTED at the PTAB. None are CANCELED; none have been formally SUSTAINED in an IPR Final Written Decision. The patent's Google Patents record reflects "Expired – Lifetime" with anticipated expiration on 2017-05-05 — the patent is past its full term, and any 35 U.S.C. § 271 infringement exposure ended with the last applicable expiration date.
• Estoppel landscape: § 315(e)(2) estoppel is a non-issue here because no IPR was ever instituted. No petitioner (or privy) is estopped against this patent, and conversely no defendant is barred from raising any prior-art ground in district court — the § 315(b) one-year bar would only bind a defendant who had been sued and let a year pass before petitioning, and the AIA petition window closed with the patent's term in any practical sense (an IPR of an expired patent is statutorily permissible but of no value for staying or defeating damages on a dead patent).
• Pattern signals: None. No petitioner has filed anything against this patent. No defensive aggregator (e.g., Unified Patents) appears in any chain — the Unified Patents portal page that surfaces in searches is for the sibling patent US 6,406,845 B1 (same Walt/Tufts family, also titled "Fiber Optic Biosensor…"), and even that page shows no litigation or IPR activity in the returned results. There is no evidence Tufts ever enforced 6,482,593, and no evidence the patent owner pursued PTAB appeals (there was nothing to appeal).

Recommended next steps

• If you are a defendant facing a demand letter citing 6,482,593: State plainly that there are no PTAB proceedings on file, and more importantly that the patent expired on 2017-05-05. An expired patent cannot support prospective relief (no injunction) and damages are confined to the pre-expiration period; a post-expiration demand predicated on it should be scrutinized under Rule 11 and state bad-faith-demand statutes. Do not spend money on an IPR — the PTAB cannot institute a review that would have any practical effect on a dead patent, and no FWD exists to cite.
• If the demand alleges pre-expiration (pre-2017-05-05) infringement: the prior-art landscape is completely open — no estoppel of any kind attaches, because no ground was ever raised or "reasonably could have been raised" in a non-existent proceeding. Any § 102/§ 103 defense available in district court remains fully available, including art that post-dates the 1997-05-05 priority date analysis but predates the alleged infringement.
• Documentation trail: For a written record, cite (a) the USPTO ODP AIA proceeding search showing no results for 6,482,593, and (b) the Google Patents record (https://patents.google.com/patent/[US6482593](/patent/US6482593)/en) showing "Expired – Lifetime" / anticipated expiration 2017-05-05. Do not cite any PTAB FWD or CAFC opinion, because none exists — fabricating one would be reversible error on your part.

Bottom line: No IPR has ever been filed, no claim has ever been invalidated at the PTAB, and the patent has been expired for nearly a decade. The absence of PTAB activity is itself the signal: this is not a litigated or monetized patent — treat any current assertion of it with deep skepticism on expiration and damages grounds, not on IPR grounds.

I'll start by investigating the assignment record for US 6482593 through available public sources.

Let me search for the actual USPTO assignment records and the NIH confirmatory license details.

I have exhausted the available search capacity for this session and was not able to pull reel/frame-level records directly from the USPTO Assignment Center's live interface. I'll therefore present the assignment reconstruction strictly from the evidence that did surface (Google Patents legal events for this patent number, the fetched patent record, and cross-citations), and I will be explicit about what could not be verified rather than fabricating entries.

Inventors

• David R. Walt — Employer at time of filing: Tufts University (Department of Chemistry / Tufts Center for Biotechnology, Medford, MA). Walt was the laboratory head; the patent's research-support statement (NIH grant GM48142) and the assignment of the entire family to Tufts confirm his affiliation. He remained at Tufts for the subsequent decades (later also HHMI professor and, from ~2006, a co-founder of Quanterix Corp., a Tufts-licensee single-molecule diagnostics company). No departure-from-assignee pattern.
• Brian G. Healey — Employer at time of filing: Tufts University (graduate researcher in the Walt laboratory; co-inventor on the related Tufts fiber-optic biosensor filings of this era, e.g., sibling US 6,406,845 B1). His later post-Tufts career was not verified in this session, so I will not speculate on it.

Pattern note: This is a conventional university PI–student inventorship pair; the PI (Walt) remained at the original assignee for years, so the "all inventors flee the assignee before a fire-sale" pattern is not present.

Original assignee

• Tufts University (recorded in some USPTO/Google citation metadata under its formal legal name, Trustees of Tufts College — the same entity). Google Patents lists both Original Assignee and Current Assignee as Tufts University.
• Line of business: operating academic/research institution, not a product company. Tufts did not "ship" a product embodying the claims; instead the fiber-optic array technology was the seed for university-licensed commercial lines (the Walt bead-array platform lineage ultimately ran through licensees such as Illumina and Quanterix).
• Current status: operating (a major university; no indication of dissolution or bankruptcy).

Assignment timeline

Public-source findings as of 2026-09-07:

1. ~1997–1998 (execution date not retrievable in this session) — original assignment from inventors to Tufts University. I could not retrieve a reel/frame for the inventor→Tufts conveyance from the sources available to me. Its existence is inferred because the application (filed 1998-11-05) and the issued patent (2002-11-19) name Tufts as applicant/assignee. Reel/frame: not verified — do not treat as fabricated.

2. 2008-07-08 (recorded) — the only post-issuance conveyance event that surfaced, via the Google Patents legal-events feed for this patent:

   • Conveyance: Confirmatory License under Executive Order 9424 (Bayh-Dole, 35 U.S.C. § 200–212) — this is a government license, not a transfer of title.
   • Assignor: Tufts University
   • Assignee: National Institutes of Health (NIH), U.S. Dept. of Health and Human Services (DHHS), U.S. Government
   • Correspondent: not retrievable in this session (no reel/frame or correspondent captured from the public search tools used).
   • Context: statutory confirmation of the government's paid-up, non-exclusive license in federally funded (GM48142) invention. Tufts remains the owner.

I could not confirm any other recorded assignments (no transfer to any LLC, no security agreement, no merger, no change of name) through the public web sources queried. If the USPTO Assignment Center in fact shows no additional records, that is consistent with Tufts University still holding title — the 2008 NIH entry is a license, not an assignment of ownership.

Verification link: https://assignmentcenter.uspto.gov/ (search by patent number 6482593; the classic index mirror is https://assignment.uspto.gov/patent/index.html).

Timeline diagram

timeline
    title Ownership of US 6482593
    1997 : Priority application filed
    1998 : Continuation filed by Tufts
    2002 : Patent issued to Tufts
    2008 : NIH confirmatory license recorded

NPE / troll-pattern signals

1. Shell-entity transfer — not present. No conveyance to any "IP / Licensing / Holdings / Ventures" LLC surfaced; the only post-issuance conveyance is to the U.S. government (NIH) as a confirmatory licensee.
2. Known asserter in the chain — not present. Neither Tufts University nor NIH/DHHS appears on any public NPE list (Acacia, Marathon, IV, Wi-LAN, Conversant, etc.). No entity from the Unified Patents / RPX high-frequency-plaintiff directories surfaced in connection with this patent.
3. Repeat correspondent across the chain — unclear / no data. I could not retrieve correspondent names for any reel/frame entry in this session, so recurrence cannot be assessed. No finding either way.
4. Cascading transfers — not present. No chained LLC-to-LLC assignments exist in the record I could access.
5. Pre-litigation transfer — not present / moot. The companion litigation review (prior section) found no suit ever naming US 6482593, so there is no litigation window against which to measure an assignment.
6. Bankruptcy fire-sale — not present. Tufts University has not been through a patent-selling bankruptcy; no Kodak/Nortel-style proceeding.
7. Privateering — not present. No operating-company-to-NPE arrangement surfaced, and no SEC or press coverage indicating Tufts deputized an NPE to assert this patent.
8. Defensive aggregator (anti-NPE) — not present. The chain does not terminate at RPX, AST, LOT, Unified Patents, or OIN; it rests with a university, with the only other interest holder being the U.S. government licensee.

Verdict

Insufficient data — but with an important qualifier: every piece of evidence that did surface points away from NPE activity. The only post-issuance conveyance found is the 2008-07-08 Bayh-Dole confirmatory license from Tufts University to NIH/DHHS (a license, not a title transfer), and no litigation has ever named this patent. Because I could not pull the USPTO Assignment Center reel/frame table directly in this session, I cannot certify that no other recorded document exists; however, on the available public record (Google Patents legal events, cross-citations, litigation databases), Tufts University remains the owner of a patent that was never asserted and has expired (2017-05-05), which is the opposite of an NPE profile. Verify at https://assignmentcenter.uspto.gov/ by searching patent number 6482593 to confirm the absence of any further recorded conveyances.

I'll research the prior art cited against US Patent 6,482,593. Let me start by retrieving the official citation list from the USPTO/Google Patents records.

I need the actual "Patent Citations" list from the '593 patent's Google Patents record. Let me query that page directly.

I need the actual examiner/face-of-patent citation list. Let me search USPTO and other patent database sources directly.

I've reached the tool-call limit, so I'll now synthesize the answer from (a) the authoritative full patent text provided in the task, (b) the USPTO/Google Patents record for the exact number US 6,482,593, and (c) family-related art surfaced in searches. I flag confidence levels throughout rather than inventing data.

Prior-Art Analysis — U.S. Patent 6,482,593 B2

0. Scope, method, and verification caveats (read first)

Patent identified (confirmed): US6482593B2 — "Fiber optic biosensor for selectively detecting oligonucleotide species in a mixed fluid sample." Application 09/187,289, filed 1998-11-05, continuation of U.S. Ser. No. 08/851,203 filed 1997-05-05 (effective priority date May 5, 1997), granted 2002-11-19, assignee Trustees of Tufts College, inventors David R. Walt and Brian G. Healey. I did not pull any different or similar patent numbers.

Critical dates for § 102 analysis (pre-AIA law applies — the application was filed November 5, 1998, and the invention claims priority to May 5, 1997):

• § 102(b) statutory-bar date: anything patented or published more than one year before the effective U.S. filing date — i.e., before May 5, 1996 (using the priority date) or before Nov. 5, 1997 (using the actual filing date). I use the more conservative priority-date analysis below.
• § 102(a)/(e) date: anything described in a printed publication or covered by a U.S. patent application filed by others before May 5, 1997.

Verification caveats, stated explicitly:

1. I was not able to retrieve the examiner's "References Cited" (front-page) list for the '593 patent from the USPTO databases within my search budget. The Google Patents record for the exact patent was retrieved, but its citation table was not returned in the search snippets.
2. The full patent text supplied as authoritative expressly incorporates by reference a specific set of U.S. patents and PCT publications, and cites a set of non-patent publications in the Background section. Those are confirmed citations within the patent document itself, and are treated below as applicant-identified prior art that the examiner necessarily had before him.
3. Search results surfaced additional art from the same Walt/Tufts fiber-optic-array family and adjacent art space (e.g., US 5,298,741; US 5,690,894). I list these in a separate section because I cannot confirm they appear on the face of the '593 patent; they are nonetheless highly relevant for a § 102/103 study.
4. The claims text was not reproduced in the authoritative full-text source provided, so claim-number mapping below is inferred from the Summary of the Invention and from the claim term-tag cloud on the Google Patents record (which shows terms including: fiber, nucleic acid, light energy, target, array, sample, probe, optical fiber, optical, imaging, coherent, excitation, nucleic acid probes, compound, manufacturing process, acrylamide, N-acryloxysuccinimidyl ester (2,5-dioxopyrrolidin-1-yl prop-2-enoate), vinyl acetate, ethylene glycol dimethacrylate, communication). Three independent claim themes are described in the specification: (I) apparatus — a biosensor comprising a preformed, unitary fiber-optic array with first/second nucleic acid probes attached to first/second portions of the distal array end and optically coupled to first/second strand end faces; (II) method of making — photoactivatable-compound attachment of probes to strand end faces by introducing light energy through individual strands; (III) method of detecting — contacting the distal array end with a fluid sample and detecting hybridization of a labeled target.

1. References expressly incorporated by reference / cited in the '593 specification (confirmed as part of the patent document)

1A. U.S. patents expressly incorporated by reference

These are the references the applicant itself identified as the relevant art for the probe-array, photo-immobilization, and detection technology. For several I can only state the number, the proposition for which the '593 cites them, and that I could not verify their titles in this session — I do not fabricate titles for those.

Analyst note on the 7-number photo-immobilization block: The specification cites this group for "the composition of the surface and the method of attachment" in photodeposition, and separately describes the N-oxy-succinimide / amino-modified-oligonucleotide chemistry following Amos et al. (below). Under § 102, anticipation by any single one of these requires that one document alone discloses every element of a given claim — including, for apparatus claims, the preformed unitary fiber-optic array with co-axially joined strands and first/second nucleic acids on first/second distal portions. These references are therefore best treated as § 103 combination references for the fiber-array claims and potential § 102 references only for method claims stripped of the fiber-array limitation (if any such claim exists). I cannot map them to specific claim numbers without the claim text.

1B. PCT publications incorporated by reference

1C. Key non-patent literature cited in the Background (confirmed in the '593 text)

2. Highly relevant art surfaced in the searches — not confirmed to be on the face of the '593 patent (verify on the USPTO front page before relying)

The following were located through family/adjacent-patent citation lists. They are the strongest candidate anticipatory references for the apparatus claims if they are in fact citable and on the record:

2A. US 5,298,741 — Walt et al., "Thin Film Fiber Optic Sensor Array and Apparatus for Concurrent Viewing and Chemical Sensing of a Sample"

• Date: application/priority date shown in the family art list as 1993-01-12; patent issued 1994 (verify). If issued before 1996-05-05, it is a § 102(b) bar; in any event a § 102(a)/(e) candidate if the application predates 1997-05-05.
• Description: A coherent fiber-optic imaging array (preformed unitary array of individually clad, co-axially joined strands) whose distal face carries a thin-film sensing layer, with light conveyed per-strand and imaged at the proximal end — i.e., the same unitary-array substrate and optical-addressing architecture later claimed in the '593 patent. (Same inventor, Walt; appears in the art list of the sibling patent US 6,406,845 from the same family.)
• § 102 mapping: This is the closest art to claim theme (I). It likely supplies nearly every structural element (preformed unitary fiber-optic array; distal end formed of multiple strand faces; first/second portions of the distal end; per-fiber optical communication with the proximal end for excitation and readout). It lacks the nucleic-acid/probe-hybridization functional elements (first and second nucleic acid probes attached to first/second distal portions for selective oligonucleotide detection). A pure § 102 anticipation argument would fail on that gap; § 103 over 5,298,741 + a probe-array reference (e.g., US 5,445,934 or Fodor 1993) is the strongest obviousness pathway.

2B. US 5,690,894 — Pinkel et al., "High Density Array Fabrication and Readout Method for a Fiber Optic Biosensor"

• Date: issued 1997-11-25 (per search snippet). The corresponding WO 97/27326 published July 1997 — i.e., after the '593's May 5, 1997 priority date, so § 102(b) is unavailable; § 102(e) may be available only if the underlying U.S. application was filed before 1997-05-05 (verify the parent filing date; note that a WO published July 1997 typically implies a U.S. filing many months earlier).
• Description: Fiber-optic-bundle/array biosensor with high-density probe arrays fabricated and read out through the fibers — conceptually the same "probes at strand ends, addressed individually by light through the fiber" architecture as the '593.
• § 102 mapping: If its effective date clears the 1997-05-05 threshold, this is the single best candidate to anticipate the apparatus theme (I) claims (and possibly method themes), because it combines the unitary/bundle fiber-optic array substrate with biological probes at discrete strand positions and optical readout. Whether it discloses (i) strands "joined along their lengths" as a preformed unitary array versus a manipulable bundle, (ii) nucleic acid probes specifically, and (iii) "first and second nucleic acids … optically coupled to and in optical communication with a first/second end face," must be checked element-by-element against the actual claim language. I could not verify that US 5,690,894 is listed on the face of the '593 patent.

2C. Family self-publication — WO 98/50782 (and WO 98/53300)

• Dates: WO 98/50782 published 1998-11-12; WO 98/53300 published 1998-12-03 (verify). Both derive from the same May 5, 1997 parent (08/851,203 / sibling cases).
• Why it matters: These are the applicants' own PCT publications of the identical disclosure. Because US 6,482,593 is a continuation of the same U.S. parent and shares inventorship/assignment, these WO publications are not available as § 102 prior art against the '593 claims (same inventive entity; pre-AIA § 102(c)/(e) exclusions and the continuity of disclosure). They should be excluded from an anticipation case — but they are frequently listed on later-patent citation pages and must not be mistaken for third-party art.

3. Bottom-line § 102 assessment (per claim theme)

Because the exact claim text was not available to me, this mapping is thematic, keyed to the three independent claim themes confirmed in the specification and the claim term-tags on the record:

Confidence statement: I have high confidence in (a) the identity/date/family of US 6,482,593 itself, (b) the set of references the patent document expressly incorporates/cites (Section 1), and (c) the general conclusion that no single confirmed on-face reference appears to disclose every element of the unitary fiber-optic-array apparatus claims, making full § 102 anticipation of the independent apparatus claim unlikely on the record I could verify. I have low-to-moderate confidence on the front-page examiner citation list (not retrieved), on the unverified titles/dates flagged above, and on any claim-number-specific mapping — all of which should be confirmed against the USPTO PAIR/full-text claims and the patent's "References Cited" page before this analysis is used in an opinion.

§103 Obviousness Analysis — US Patent 6,482,593 B2

0. Preliminary caveats (read first)

No "Prior Art" section was present in the materials supplied to me for this task, so I could not "use the results from the Prior Art section of this page" literally. I therefore reconstructed the reference set from two sources and flag both as imperfect:

1. References cited inside the specification itself (the full text provided in the prompt), including incorporated-by-reference patents (WO 95/25116; WO 95/35505; U.S. Pat. Nos. 5,700,637; 5,445,934; 5,427,779; 4,973,493; 4,979,959; 5,002,582; 5,217,492; 5,258,041; 5,263,992) and roughly two dozen literature citations (e.g., Fodor et al. 1991/1993; Maskos & Southern 1992; Guo et al. 1994; Khrapko et al. 1991; Piunno et al. 1995; Strachan et al. 1995; Munkholm et al. 1986; Jordan et al. 1987).
2. Independently verified literature retrieved in this session (Ferguson et al., Nat. Biotechnol. 14:1681–1684 (1996), DOI 10.1038/nbt1296-1681; Healey, Matson & Walt, Anal. Biochem. 251:270–279 (1997), DOI 10.1006/abio.1997.2254; Bronk et al., Anal. Chem. 67:2750 (1995); Healey, Foran & Walt, Science 269:1078 (1995); Bronk & Walt, Anal. Chem. 66:3519 (1994); Pantano & Walt, Anal. Chem. 67:481A (1995); Li & Walt, Anal. Chem. 67:3746 (1995); Healey & Walt, Anal. Chem. 67:4471 (1995)).

I did not obtain the verbatim claims of US 6,482,593. As flagged in the earlier patent summary, the claims section was not in the supplied text, and I will not fabricate claim language. This analysis therefore proceeds on the claim themes inferred from the specification and from Google Patents' text-mining of the claim terms, which show the claims recite: a fiber optic sensor/array; optical fibers; a sample; an imaging fiber; coherent; excitation; nucleic acid probes; a manufacturing method; acrylamide and (2,5-dioxopyrrolidin-1-yl) prop-2-enoate (i.e., N-acryloxysuccinimide); vinyl acetate; ethylene glycol dimethacrylate; optical communication. Before any claim-level conclusion is relied upon, pull the issued Claims from USPTO Patent Center. Also note the record's assignee inconsistency: Google's front page lists "Tufts University," while the family records (WO 98/50782; US 6,406,845; citing patents) list "Trustees of Tufts College" — this matches the uncertainty flagged earlier and does not affect the §103 analysis.

Legal framework. The application was filed November 5, 1998, claiming priority to May 5, 1997 (parent 08/851,203), and issued November 19, 2002 — well before the AIA's March 16, 2013 effective date. Analysis is under pre-AIA 35 U.S.C. § 103 and the Graham factors, informed by KSR Int'l Co. v. Teleflex (2007) (common-sense combination, "obvious to try," predictable variation). The patent has expired (2017) and no litigation is known, so this is an analytical exercise, not a live dispute.

1. Person of ordinary skill in the art (POSITA)

A POSITA circa May 1997 would be a team — not a single person — comprising (i) an analytical chemist/biosensor engineer familiar with fiber-optic sensors, imaging fibers, photopolymerization chemistries, and CCD/epifluorescence instrumentation; and (ii) a molecular biologist familiar with oligonucleotide probe design, immobilization chemistries (amino-silane, acrylamide gels, biotin/avidin), hybridization stringency, and PCR labeling. The relevant literature is populated by exactly such joint teams (e.g., Walt's Tufts group; Krull's group; Affymetrix; Southern's group).

2. Reference map (verified bibliographic data)

Category A — DNA hybridization detection on fiber-optic platforms

Category B — Site-selective photodeposition on unitary imaging fibers (the platform feature)

Category C — Light-directed, spatially addressable nucleic acid array fabrication

Category D — Same-family post-priority publication (important nuance, not prior art)

Date/status handling. Ferguson et al. (Dec. 1996) and Healey et al. (Anal. Biochem., Sept. 1997) both post-date May 5, 1996, so neither is a §102(b) bar against claims entitled to the May 5, 1997 priority date; Ferguson (co-authored by inventor Walt) is the stronger §102(a)-type reference, and Healey 1997 is the inventors' own post-priority enabling publication (cf. In re Katz, 687 F.2d 450 (CCPA 1982) — an inventor's own publication is generally not "by others" under §102(a)). For a §103 analysis, however, these references are still highly probative of the state of the art and of what the inventors themselves regarded as conventional — and Ferguson 1996 in particular is the natural primary reference. Nothing in my analysis depends on treating Healey 1997 as §102 art; I use it only to demonstrate that the combination I propose was, in fact, the obvious next step the field (and this same lab) took.

3. Claim-theme mapping (inferred)

Based on the specification's three "the present invention provides" passages and the claim-term metadata, the independent claim themes are:

• Theme 1 (composition): A fiber optic sensor comprising a preformed, unitary fiber optic array of co-axially joined strands (distal/proximal ends formed of multiple strand end faces), with at least first and second nucleic acid probes attached to first and second portions of the distal end, each optically coupled to / in optical communication with a distinct strand end face — permitting spatially resolved, multiplexed hybridization detection.
• Theme 2 (method of making): Providing the array; contacting a first nucleic acid and a photoactivatable compound with at least a first distal strand end face; introducing light through that strand (e.g., from the proximal end, optionally via mask/pinhole) to attach the first nucleic acid at the first position; repeating for additional probes.
• Theme 3 (method of detecting): Contacting the distal end with a fluid sample containing a labeled complementary target; detecting hybridization (fluorescence) at the spatial position(s).

Dependent features evidently include: coherent imaging fiber; polymer matrix of acrylamide/N-acryloxysuccinimide (with optional vinyl acetate, ethylene glycol dimethacrylate); excitation/emission optics; and assay details (biotin/streptavidin labeling, PCR amplicons, competitive quantitation).

4. Primary combinations and motivation

Combination A — Ferguson (1996) + imaging-fiber photodeposition art → Theme 1 (sensor composition)

Proposed combination: Ferguson et al. (1996) as primary reference, in view of Bronk & Walt (1994), Healey et al. Science (1995), Bronk et al. (1995), Pantano & Walt (1995), Li & Walt (1995), and/or U.S. 5,250,264.

Element mapping (inferred claims):

• "Preformed unitary fiber optic array … strands disposed coaxially and joined along their lengths, proximal and distal ends formed of multiple strand faces": taught by the coherent imaging fiber used in Bronk et al. 1995 (350-µm fiber, ~3,000–6,000 elements) and Healey et al. Science 1995 — a fused, non-bundle array in which individual strands cannot be physically separated, exactly matching the specification's definition.
• "At least first and second nucleic acid attached to first and second portions of the distal array end, optically coupled to first and second end faces": taught by Ferguson et al. 1996 for bundles (each fiber carries a different probe; signal read back through the same fiber). Applying the identical probe-per-element concept to the unitary imaging fiber — whose distal face was already known to support spatially discrete, site-selectively photodeposited sensing chemistries (Bronk & Walt 1994; Healey et al. Science 1995; Li & Walt 1995) — is a straightforward substrate substitution.
• "Spatially resolved fluorescence detection via CCD": taught by Bronk et al. 1995 (imaging + sensing with ~6,000 elements, CCD, 4-µm resolution) and Ferguson et al. 1996.

Motivation / reason to combine. A POSITA seeking higher-density, more robust, multiplexed DNA sensors had every reason to move from Ferguson's hand-bundled discrete fibers to the coherent imaging-fiber platform that the same community had already used for chemical sensing arrays: (i) thousands of addressable elements per 350-µm fiber versus a handful in a bundle (Bronk et al. 1995 explicitly emphasizes array density); (ii) elimination of tedious individual-fiber functionalization and of fiber-to-fiber variability; (iii) guaranteed spatial registry between each distal sensing site and its proximal readout pixel — the very property the '593 specification relies on ("precise spatial positional introduction and conveyance of light energy"); (iv) picoliter element volumes enabling sub-microliter samples — an advantage already recognized for imaging-fiber chemical sensors; (v) identical epifluorescence/CCD instrumentation used for both (Bronk 1995 and Ferguson 1996 both image distal-face fluorescence). Under KSR, this is the paradigm "known technique (DNA probe arrays) applied to a known device (imaging-fiber sensor array) ready for improvement, yielding predictable results."

Ferguson's bundle versus unitary distinction. The specification itself stresses that a "preformed unitary array is distinguished from … bundles of individual fibers" because strands "cannot be physically separated." But the unitary imaging fiber and its distal-face photopatterning were already in the prior art (Category B), and nothing in Ferguson or Bronk teaches away from substituting the fused fiber for the bundle; the coherent array preserves (indeed improves) the one-probe-per-element registry that Ferguson relied on. The claimed distinction is thus a design choice with a documented motivation, not a patentable leap.

Combination B — Photoactivation/deposition art + light-directed DNA attachment art → Theme 2 (method of making)

Proposed combination: Bronk & Walt (1994) or Healey et al. Science (1995) or U.S. 5,250,264 (photoactivating reagents on discrete imaging-fiber elements by illuminating through selected strands), combined with Fodor et al. (1991/1993; U.S. 5,445,934; WO 95/25116 and WO 95/35505 as incorporated in the specification) and/or Guo et al. (1994) (amino-modified oligonucleotides covalently coupled to functionalized surfaces).

Element mapping:

• "Contacting a nucleic acid and a photoactivatable compound with at least a first distal strand end face": Bronk & Walt 1994 (photoactivatable aryl-azide chemistry confined to illuminated areas on an imaging-fiber distal tip); Fodor 1991 (photoactivation as the spatial-addressing mechanism for oligonucleotide attachment).
• "Introducing light energy to the first optical fiber strand [to attach the first nucleic acid], repeating for a second nucleic acid": Healey et al. Science 1995 teaches delivering light through individual imaging-fiber elements to create 2.5-µm polymer spots — i.e., fiber-level spatial addressing; Fodor teaches sequential light-directed rounds of different oligonucleotide attachment at defined loci. Combining "light-directed, spatially addressable DNA attachment" (Fodor) with "fiber-element-addressed photodeposition on an imaging fiber" (Healey Science 1995; Bronk & Walt 1994) yields Theme 2 directly. The specification's own "serial photodeposition" and mask/pinhole embodiments are essentially this combination described as preferred modes.

Motivation. By 1997, light-directed spatially addressable synthesis/attachment of DNA arrays (Fodor; Southern; WO 95/25116; WO 95/35505) and fiber-element-addressed photodeposition of sensing polymers (Walt lab) were both mainstream, mature techniques. A POSITA seeking to fabricate a multi-probe unitary fiber array would predictably use the imaging fiber's inherent optical-addressability to perform the photodeprotection/photoattachment serially — this is "obvious to try" with a finite number of identified, predictable options (KSR). No inventive chemistry is required: the photoactivatable attachment of DNA to functionalized supports was known, and the amino-silane/succinimide route (used in the spec) was standard (Guo et al. 1994).

Combination C — Acrylamide-gel probe immobilization + amine-reactive polymer chemistry → dependent polymer-matrix features

Proposed combination: Khrapko et al. (1991) (oligonucleotides immobilized in polyacrylamide gel elements for hybridization) in view of Bronk & Walt (1994)/Healey et al. Science 1995 (photopolymerized gels on imaging fibers) and Guo et al. 1994 / standard N-hydroxysuccinimide–amine bioconjugation chemistry.

Element mapping. Dependent claims reciting an acrylamide / N-acryloxysuccinimide copolymer matrix with covalently attached amino-terminated probes track exactly the "photopolymerize an acrylamide prepolymer bearing succinimidyl esters, then react with 5′-amino oligonucleotides" protocol in the specification's Examples. Every ingredient was conventional: Khrapko et al. 1991 immobilized DNA probes in polyacrylamide gel pads for hybridization; N-acryloxysuccinimide copolymers were a known class of amine-reactive polymers; Munkholm et al. (1986) and Jordan et al. (1987) — cited in the spec — taught photopolymerized indicator polymers for fiber sensors; Bronk & Walt 1994 and Healey et al. Science 1995 taught photopolymerizing such gels selectively on imaging-fiber elements. Choosing acrylamide/NAS (rather than poly-HEMA) for a DNA probe support is an obvious selection of a known amine-reactive, biocompatible hydrogel, with no unexpected property demonstrated in the claims.

Combination D — Labeled-target hybridization detection, PCR amplicons, quantitation → Theme 3 (detection methods)

Proposed combination: Ferguson et al. (1996) in view of Saiki et al. (1989), Piunno et al. (1995), and Strachan et al. (1995).

Element mapping. Theme 3 requires only: provide the array; contact the distal end with a fluid sample; detect the presence/absence of a (labeled) target sequence. Ferguson et al. 1996 discloses every element except the unitary (non-bundle) support, which Combination A supplies. Detection specifics in the specification — fluorescein-labeled targets, biotinylated PCR amplicons revealed with streptavidin-FITC, competitive quantitation, formamide regeneration, stringency-based single-mismatch discrimination — were all standard hybridization practice (Saiki 1989 reverse dot blot with labeled PCR products; Strachan 1995 fiber-optic detection of PCR products; well-known biotin/avidin detection). Single-base-mismatch discrimination by temperature/stringency was textbook (the spec's own Tm data, e.g., −13°C for a one-base mismatch, is a routine thermodynamic result).

5. Synthesis under the Graham factors

1. Scope and content of the prior art. By May 1997 the art contained (a) multiplexed DNA hybridization on fiber bundles with fluorescent readout (Ferguson 1996), (b) site-selective photodeposition and photoactivation of sensing chemistries on unitary coherent imaging fibers with fiber-element spatial addressing (Bronk & Walt 1994; Healey et al. Science 1995; Bronk et al. 1995; U.S. 5,250,264), (c) light-directed spatially addressable oligonucleotide array fabrication (Fodor 1991/1993; U.S. 5,445,934; WO 93/22480), and (d) acrylamide/NAS-type amine-reactive gel chemistries for DNA probes (Khrapko 1991; Guo 1994).
2. Differences between the claimed invention and the prior art. The central difference is the unitary (fused, coherent) fiber optic array bearing multiple nucleic acid probes, rather than Ferguson's bundle of individually functionalized fibers — plus the corresponding photodeposition method of making it. That difference is a known-platform substitution with a documented motivation (density, registry, robustness, sample volume), not a new principle.
3. Level of ordinary skill. Defined above; a multidisciplinary team, matching the authorship of both the primary references and the patent itself.
4. Obviousness conclusion. A POSITA combining Ferguson 1996 with the imaging-fiber photodeposition literature (Bronk 1994/1995; Healey Science 1995; U.S. 5,250,264), and using Fodor-type light-directed DNA attachment or Khrapko/Guo-type amino-reactive gel chemistry, would have arrived at the claimed sensor, its method of manufacture, and its method of use with a reasonable expectation of success. Each combination is of known elements, each performs its known function, and the results (denser arrays, faster hybridization, sub-microliter samples, real-time multiplexed readout) were the predictable benefits the references themselves tout. On the available (inferred) claim themes, the claims would likely be obvious under pre-AIA § 103.

6. Strongest counterarguments (non-obviousness side)

For balance, the best arguments against a § 103 finding are:

1. No express teaching to replace the bundle with a fused array for DNA. Ferguson 1996 deliberately used individually addressable, separately functionalizable fibers — a format that allows each probe to be made and validated independently. The prior-art imaging-fiber chemical sensors (Bronk et al.) did not involve nucleic acids, and the DNA-on-imaging-fiber work (Healey et al., Anal. Biochem. 1997) was the inventors' own post-priority publication. An examiner or court could find that "try the DNA sensor on a unitary imaging fiber" was only one of several plausible paths, and that the specific combination of photodeposited acrylamide/NAS matrices + amino-terminated DNA probes + coherent imaging fiber was not itself disclosed before May 5, 1997.
2. Secondary considerations. None located: the patent expired in 2017; no litigation, licensing, or commercial-success evidence surfaced in the searches. Absence of objective indicia cuts against patentees, but the record is simply silent.
3. Claim-scope uncertainty. Dependent claims reciting particular monomer combinations (acrylamide/NAS with optional vinyl acetate or ethylene glycol dimethacrylate crosslinkers) may recite specific compositions whose prior-art basis (Khrapko's polyacrylamide vs. NAS-active-ester copolymers) is suggestive but not dispositive on the record I could assemble. Without the actual claims, an obviousness holding for every claim cannot be asserted with confidence.

7. Bottom line

• Primary combination most likely to render the claims obvious: Ferguson et al., Nat. Biotechnol. 14:1681 (1996) + Bronk et al., Anal. Chem. 67:2750 (1995) / Healey et al., Science 269:1078 (1995) / Bronk & Walt, Anal. Chem. 66:3519 (1994) / U.S. 5,250,264 — i.e., transplanting Ferguson's multiplexed DNA-probe/hybridization-fluorescence scheme onto the already-proven coherent imaging-fiber platform with fiber-element photodeposition.
• For the method-of-making claims: add Fodor et al. (Science 1991; U.S. 5,445,934) and/or Guo et al. (1994) for light-directed/amino-reactive DNA attachment chemistry.
• For the polymer-matrix dependent claims: add Khrapko et al. (1991) plus conventional N-acryloxysuccinimide/amine bioconjugation.
• For the detection-method claims: Ferguson 1996 plus Saiki 1989 / Strachan 1995 (labeled PCR targets; biotin-streptavidin; stringency control).

Because the earlier patent summary could not confirm the verbatim claim language, and because this page contained no Prior Art section to anchor the analysis, the conclusion above should be treated as a preliminary, claim-theme-level assessment to be re-run against the issued claims and the examiner's actual "References Cited" (obtainable from USPTO Patent Center for US 6,482,593 and its parent US 6,406,845) before being used in any validity opinion.