PTAB

IPR2019-01127

LifeScan Global Corporation v. PHC HOLDINGS CORPORATION

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1. Case Identification

2. Patent Overview

  • Title: Biosensor, Thin Film Electrode Forming Method, Quantification Apparatus, and Quantification Method
  • Brief Description: The ’878 patent relates to biosensors for quantifying a substrate in a sample liquid. The technology involves a pair of insulating supports, at least two electrodes, a reagent layer, and a supply path designed to improve upon prior art biosensors by providing uniform reagent deposition and eliminating the need for separate correction chips.

3. Grounds for Unpatentability

Ground 1: Anticipation by Heller - Claims 1-3, 8, 12-15, 17, and 18 are anticipated by Heller.

  • Prior Art Relied Upon: Heller (International Publication No. WO 1998/035225).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Heller, which discloses a small-volume in vitro analyte sensor, teaches every element of independent claim 1. Heller allegedly discloses an insulating support (Mylar film), a working electrode formed from a noble metal conductive layer (e.g., gold, platinum, or palladium), a "sensing layer" that constitutes a reagent layer, and a spacer layer. Petitioner contended that Heller’s figures and text show this spacer covering part of the reagent layer and defining a sample supply path that is necessarily narrower than the reagent layer. Heller also allegedly discloses a cover with a counter electrode.
    • Prior Art Mapping (Dependent Claims): Petitioner further asserted that Heller anticipates various dependent claims by explicitly teaching the use of palladium, platinum, and gold (claim 3), an electrode separation distance of 0.040 mm which falls within the claimed range of 0.005-0.3 mm (claim 8), and a reagent layer comprising an enzyme and an electron transfer agent (redox mediator) (claim 12).

Ground 2: Obviousness of Electrode Thickness - Claims 4-6 are obvious over Heller in view of Bhullar or Hodges.

  • Prior Art Relied Upon: Heller (WO 1998/035225), Bhullar (Patent 6,662,439), and Hodges (Patent 5,942,102).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner asserted that while Heller discloses the core biosensor, it does not specify the electrode thickness. Bhullar and Hodges, both in the same field, allegedly remedy this. Bhullar was said to teach applying a metallic layer with a thickness of "10 nm to 1 mm," while Hodges was said to teach sputtering palladium electrodes to a thickness of 10-100 nm. Petitioner argued these disclosed ranges meet the limitations of claims 4-6 (3-1000 nm, 3-100 nm, and 3-50 nm).
    • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA), when building the sensor taught by Heller, would have been motivated to look to contemporaneous art like Bhullar and Hodges for conventional manufacturing parameters, such as electrode thickness, which were not specified in Heller.
    • Expectation of Success: A POSITA would have had a reasonable expectation of success because applying a conventional, known thickness to an electrode is a simple, predictable design choice with no unexpected results.

Ground 3: Obviousness with Integrated Correction Data - Claim 16 is obvious over Heller in view of Ito and Applicant-admitted prior art.

  • Prior Art Relied Upon: Heller (WO 1998/035225), Ito (Patent 5,384,028), and Applicant-admitted prior art.
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued claim 16 adds a "correcting unit" to the biosensor of claim 1. The '878 patent specification itself allegedly admits that external correction chips were known in the art but were "considerably troublesome." Ito was argued to disclose a biosensor with an integrated memory for storing correction data, including lot number and sensor characteristics, thereby directly addressing the known problem.
    • Motivation to Combine: A POSITA would combine Heller's sensor with Ito's integrated memory to solve the acknowledged problem of using separate, external correction chips. The motivation was to improve usability, reduce user error, and create a more integrated and reliable device.
    • Expectation of Success: Success would be expected because Ito demonstrates the feasibility and clear benefit of integrating memory onto a biosensor, making its application to another biosensor like Heller's a predictable improvement.
  • Additional Grounds: Petitioner asserted additional anticipation and obviousness challenges based on Ohara (Patent 6,193,873) and Liamos (Patent 6,616,819) as primary references, combined with secondary references like Bhullar, Hodges, Ito, and Ikeda ’417 to teach various claim limitations. A final ground alleged all challenged claims are obvious over Blatt (European Patent Application No. 88105365.6) in view of a combination of all other cited references.

4. Key Claim Construction Positions

  • Petitioner proposed construing "vertical" in claim 2 to mean perpendicular to the plane of the insulating support. This construction was based on the orientation depicted in the patent's figures and was argued to be necessary to give meaning to an otherwise ambiguous term.
  • Petitioner argued "wettability index" in claim 7 should be construed as any parameter indicating the degree to which a substance can be wet by a liquid. This construction was central to its argument that the claimed index value was an inherent, unpatentable property of the prior art's palladium electrodes.

5. Key Technical Contentions (Beyond Claim Construction)

  • A central technical contention spanning multiple grounds was that the claimed "wettability index" of ≥48 dyn/cm is an inherent property of the palladium electrodes already disclosed in prior art references like Heller, Ohara, and Liamos. Petitioner supported this by citing technical articles, Todd (Surface Science 281 (1993)) and Vitos (Surface Science 411 (1998)), which allegedly show that the surface free energy of palladium is substantially higher (over 990 dyn/cm) than the claimed threshold. Petitioner argued that merely discovering and claiming this previously unappreciated, inherent property of a known material in a known device does not confer patentability.

6. Relief Requested

  • Petitioner requests institution of inter partes review and cancellation of claims 1-8 and 12-18 of Patent 8,480,878 as unpatentable.