ABS Global Inc v. Cytonome St LLC

1. Case Identification

• Case #: IPR2021-00088
• Patent #: 10,583,439
• Filed: October 26, 2020
• Petitioner(s): ABS Global, Inc., Genus, PLC
• Patent Owner(s): CYTONOME/ST, LLC
• Challenged Claims: 1, 2, 6, 8, 9

2. Patent Overview

• Title: Hydrodynamic Focusing Apparatus and Methods
• Brief Description: The ’439 patent discloses microfluidic devices and methods for particle analysis. The core technology involves using a specific arrangement of three distinct fluid focusing features—one for lateral confinement and two for vertical confinement—in combination with a vertical shift in the flow channel’s bottom surface to precisely position a sample fluid stream for downstream inspection.

3. Grounds for Unpatentability

Ground 1: Claims 1, 2, 6, and 8 are anticipated by Simonnet

• Prior Art Relied Upon: Simonnet (a 2006 journal article titled "High-throughput and high-resolution flow cytometry in molded microfluidic devices").
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Simonnet discloses every element of the challenged claims in a single embodiment. Simonnet's device uses sheath fluid from Port E for lateral focusing and from Ports A (top) and C (bottom) for vertical focusing, all at different longitudinal locations. Petitioner contended that a vertical "step" feature shown in Simonnet’s channel meets the "upward vertical shift" limitation because a microfluidic chip's orientation is arbitrary, and conceptually flipping the device would show the claimed upward shift without changing its function. An "inspection region" is disclosed as Simonnet's downstream "cytometry channel" where particle detection occurs.

Ground 2: Claim 8 is obvious over Simonnet in view of Kim

• Prior Art Relied Upon: Simonnet (a 2006 journal article) and Kim (a 2009 journal article titled "An efficient 3-dimensional hydrodynamic focusing microfluidic device by means of locally increased aspect ratio").
• Core Argument for this Ground:
  • Prior Art Mapping: Claim 8 requires the flow channel to transition between different cross-sectional shapes. Petitioner contended that if the Board finds Simonnet's transition from a tall-and-narrow to a short-and-wide rectangular cross-section does not meet this limitation, the combination with Kim renders it obvious. Kim explicitly teaches improving upon Simonnet-type designs by varying the channel's cross-section (e.g., creating a square profile) to achieve a "locally increased aspect ratio," which improves focusing.
  • Motivation to Combine: A person of ordinary skill in the art (POSITA) would combine Kim's known technique for improving focusing with Simonnet's foundational device design. Kim is analogous art that directly addresses improving the performance of devices like Simonnet's, providing a clear motivation to incorporate its teachings to achieve the predictable result of enhanced focusing characteristics.
  • Expectation of Success: The combination involved applying a known principle (varying channel geometry) to a known device, which would predictably and successfully improve focusing performance without undue experimentation.

Ground 3: Claim 9 is obvious over Simonnet in view of Kummrow

• Prior Art Relied Upon: Simonnet (a 2006 journal article) and Kummrow (a 2009 journal article titled “Microfluidic structures for flow cytometric analysis of hydrodynamically focussed blood cells...”).

• Core Argument for this Ground:

  • Prior Art Mapping: Claim 9 requires that the multiple fluid focusing features be fed from a single, common focusing fluid inlet. Simonnet uses separate inlets for each focusing feature. Kummrow teaches a device with multiple, cascaded focusing stages that are all supplied by a single, common sheath fluid inlet port.
  • Motivation to Combine: Using a single inlet instead of multiple inlets was a known design choice in the field with recognized advantages. A POSITA would be motivated to modify Simonnet’s design to incorporate Kummrow’s single inlet to simplify device operation, reduce complexity, and eliminate the need to precisely control and balance multiple independent sheath flow rates.
  • Expectation of Success: A POSITA would have had a high expectation of success in making this combination, as it involved substituting one known fluid-delivery architecture for another to achieve the predictable benefit of operational simplicity.

• Additional Grounds: Petitioner asserted an additional obviousness challenge against claims 1, 2, 6, and 8 based on Simonnet alone, arguing that any minor differences, such as the orientation of the vertical shift or the exact location of the inspection region, represented trivial and obvious design modifications.

4. Key Claim Construction Positions

• "focusing": Petitioner argued for the construction "narrowing, pinching, or otherwise confining a sample fluid with sheath fluid." This construction was asserted to be consistent with the term's plain meaning in the art and its use throughout the ’439 patent’s specification. It was presented in contrast to a potentially narrower construction that Petitioner alleged the Patent Owner had advanced in unrelated litigation involving other patents.
• "fluid focusing feature": Petitioner proposed that this term should be construed as "a component that introduces a sheath fluid and focuses a sample fluid." This construction was argued to distinguish the claimed features from purely passive geometric structures (e.g., channel tapering) and to require the active introduction of sheath fluid, which is consistent with all embodiments described in the ’439 patent.

5. Arguments Regarding Discretionary Denial

• Discretionary Denial under Fintiv: Petitioner argued that denial under 35 U.S.C. §314(a) was unwarranted. It contended that the parallel district court litigation was in its infancy, with no discovery yet conducted, no substantive orders issued, and a trial date more than 15 months away. Petitioner asserted that a stay of the litigation was likely, which would prevent inefficiency and duplication of effort.
• Discretionary Denial under §325(d): Petitioner argued against denial under §325(d), asserting that the Examiner never substantively considered the primary prior art reference, Simonnet, despite its inclusion in an Information Disclosure Statement (IDS). Furthermore, the key secondary references, Kummrow and Kim, were never before the Examiner. Petitioner contended this oversight, combined with new expert testimony, justified a full review on the merits.

6. Relief Requested

• Petitioner requested institution of an inter partes review (IPR) and cancellation of claims 1, 2, 6, 8, and 9 of Patent 10,583,439 as unpatentable.