DCT

1:23-cv-00198

Agilent Tech Inc v. Axion Biosystems Inc

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Key Events
Amended Complaint

I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 1:23-cv-00198, D. Del., 11/04/2025
  • Venue Allegations: Venue is alleged to be proper in Delaware as Defendant is incorporated in the state and has purportedly committed acts of infringement and false advertising there.
  • Core Dispute: Plaintiff alleges that Defendant’s Maestro line of bioelectronic cell analysis systems infringes three patents related to real-time, impedance-based monitoring of cellular activity.
  • Technical Context: The technology involves bioelectronics, where microelectrodes are used to non-destructively measure changes in electrical impedance to monitor cellular behavior in real-time for applications like drug discovery and cytotoxicity assays.
  • Key Procedural History: The action was initially filed for patent infringement and unfair competition. The complaint was subsequently amended to add claims for trade secret misappropriation following a discovery revelation that Defendant, through a former Agilent executive, allegedly obtained and used Plaintiff’s confidential strategic and financial documents. The complaint also alleges that Defendant had knowledge of the patents-in-suit as early as October 2015, when it cited one during the prosecution of its own patent application.

Case Timeline

Date Event
2002-07-20 Earliest Priority Date for ’752, ’255, and ’080 Patents
2007-03-20 U.S. Patent No. 7,192,752 Issues
2008-12-23 U.S. Patent No. 7,468,255 Issues
2011-09-27 U.S. Patent No. 8,026,080 Issues
2013-03-10 Axion representatives allegedly attend meeting where Plaintiff's predecessor presented its technology
2015-10-21 Axion cites the ’752 Patent in an Information Disclosure Statement
2018-01-01 Agilent acquires ACEA Biosciences, Inc., the original patent assignee
2019-01-01 Axion allegedly begins infringing use of the patented technology
2023-02-23 Plaintiff files initial complaint
2023-09-15 Axion's counsel notifies Plaintiff's counsel of retained Agilent documents
2025-11-04 Plaintiff files Third Amended Complaint

II. Technology and Patent(s)-in-Suit Analysis

U.S. Patent No. 7,192,752 - "Real Time Electronic Cell Sensing Systems and Applications for Cell-Based Assays"

The Invention Explained

  • Problem Addressed: The patent’s background section states that conventional methods for cellular assays, such as measuring immune responses or screening anticancer drugs, relied on "destructive endpoint assays" (’752 Patent, col. 3:14-21, 3:34-39). These methods provided only a single snapshot in time, which limited the ability to screen large chemical libraries or to obtain high-resolution data on cellular responses over time (Compl. ¶24).
  • The Patented Solution: The invention provides a system for performing non-destructive, real-time assays by monitoring the electrical impedance between electrodes on which cells are cultured (’752 Patent, Abstract). As cells attach, grow, or change shape on the microelectrodes at the bottom of a multi-well plate, they alter the flow of electric current, causing a measurable change in impedance that correlates to cellular behavior (’752 Patent, col. 4:15-24). A key feature is an electrode array with an "approximately uniform electrode resistance distribution," intended to ensure that cells at any location on the array contribute similarly to the measured impedance (Compl. ¶26; ’752 Patent, col. 16:48-53).
  • Technical Importance: This approach enabled label-free, kinetic monitoring of cellular activity, offering a significant advance in throughput and data resolution compared to traditional, static endpoint assays (Compl. ¶25).

Key Claims at a Glance

  • The complaint asserts independent method Claim 11 (Compl. ¶26).
  • Essential elements of Claim 11 include:
    • Providing a system for monitoring cell-substrate impedance, which itself comprises:
      • a multi-well device with individually addressed electrode arrays at the bottom of at least two wells;
      • an impedance analyzer;
      • a device station to connect the arrays to the analyzer; and
      • a software program to control the system and analyze data.
    • Wherein the electrode array has an "approximately uniform electrode resistance distribution" such that resistances between two locations do not differ by more than 30%.
    • Introducing cells into at least one well of the system.
    • Monitoring cell-substrate impedance of the well.
  • The complaint does not explicitly reserve the right to assert dependent claims for this patent.

U.S. Patent No. 7,468,255 - "Method for Assaying for Natural Killer, Cytotoxic T-Lymphocyte and Neutrophil-Mediated Killing of Target Cells Using Real-Time Microelectronic Cell Sensing Technology"

The Invention Explained

  • Problem Addressed: Prior art methods for measuring the cytolytic (cell-killing) activity of immune cells were based on destructive "snapshots" of the activity, often using cumbersome radioactive labeling (e.g., chromium-51) limited to short timeframes of approximately four hours (’255 Patent, col. 3:50-4:10). This prevented real-time or extended-duration analysis of immune cell efficacy (Compl. ¶30).
  • The Patented Solution: The patent discloses a method for measuring cytolytic activity in real-time by monitoring impedance (’255 Patent, Abstract). The method involves placing target cells (e.g., cancer cells) in both "test" and "control" wells of a multi-well plate. Effector cells (e.g., T-cells) are then added only to the test wells. As effector cells kill target cells, the target cells detach from the electrodes, causing a drop in impedance. By comparing the impedance measurements over time between the test and control wells, the viability of the target cells, and thus the killing activity of the effector cells, can be determined (’255 Patent, col. 5:6-13).
  • Technical Importance: The invention provided a non-radioactive, label-free, and continuous method for assessing immune-mediated cell killing, enabling researchers to study the kinetics of cytotoxicity over extended periods (Compl. ¶31).

Key Claims at a Glance

  • The complaint asserts independent method Claim 9 (Compl. ¶32).
  • Essential elements of Claim 9 include:
    • Providing a device capable of monitoring cell-substrate impedance with at least two wells.
    • Adding target cells to at least two wells, where one is a control well and one is a test well.
    • Adding effector cells to the test well.
    • Monitoring impedance of the control and test wells before and after adding the effector cells, comprising measuring impedance during at least two time points.
    • Determining viability of the target cells in the test well by comparing the impedance (or optionally a cell index derived from impedance) of the test well to the control well at a given time point.
  • The complaint does not explicitly reserve the right to assert dependent claims for this patent.

U.S. Patent No. 8,026,080 - "Real Time Electronic Cell Sensing System and Applications for Cell-Based Assays"

  • Patent Identification: U.S. Patent No. 8,026,080, titled “Real Time Electronic Cell Sensing System and Applications for Cell-Based Assays,” issued September 27, 2011.
  • Technology Synopsis: This patent addresses the same technological problem as the ’752 Patent: the limitations of destructive, endpoint assays for applications like drug screening (Compl. ¶36). It claims a method for performing a cell-based assay by monitoring impedance changes in response to test compounds, allowing for label-free, real-time analysis of cellular responses and the calculation of "cell index values" (Compl. ¶35, ¶38).
  • Asserted Claims: The complaint asserts independent method Claim 1 (Compl. ¶38).
  • Accused Features: The complaint alleges that Defendant’s Maestro Platforms, CytoView-Z Plates, and AxIS Z software are used to perform the patented method when conducting assays to monitor cell responses to test compounds, such as in cytotoxicity studies (Compl. ¶208, ¶216-219).

III. The Accused Instrumentality

  • Product Identification: The accused instrumentalities are Defendant Axion’s Maestro Platforms (Maestro Edge, Pro, Z, ZHT, and TrayZ), CytoView-Z Plates (96- and 384-well formats), and AxIS Z software (Compl. ¶6).
  • Functionality and Market Context: The complaint alleges these products form an integrated system for "continuous, label-free, impedance-based monitoring of [] cells" (Compl. ¶41). The CytoView-Z plates contain wells with a "recording electrode embedded in the culture surface" (Compl. ¶41a). The Maestro platform is described as using "impedance measurements (ohms, Ω) to quantify the presence of cells on the electrode" (Compl. ¶41b). The AxIS Z software is alleged to provide for analyzing "changes in cell proliferation, morphology, and viability" in real-time (Compl. ¶42). An illustrative diagram in the complaint shows that impedance measures how much an electrical signal is blocked by the interface between the electrode and the cell (Compl. p. 14, diagram 3). The complaint positions these products as direct competitors to Plaintiff’s xCELLigence systems (Compl. ¶47).

IV. Analysis of Infringement Allegations

'752 Patent Infringement Allegations

Claim Element (from Independent Claim 11) Alleged Infringing Functionality Complaint Citation Patent Citation
providing a system for monitoring cell-substrate impedance, comprising: a) one or more multiple well cell-substrate impedance monitoring devices... Axion provides its CytoView-Z Plates, which are multi-well devices for monitoring impedance. ¶171 col. 4:17-21
wherein at least two of the multiple wells of said device comprise an electrode array at the bottom of the well, wherein said electrode array is individually addressed... The CytoView-Z Plates have wells with an embedded electrode array, which is individually addressed by applying electrical signals via electronic switches. A schematic in the complaint depicts the interdigitated electrode structure within a well (Compl. p. 74). ¶172-173 col. 15:6-15
b) an impedance analyzer; The Maestro Z and Maestro ZHT platforms comprise an impedance analyzer to measure impedance. ¶175 col. 4:21-22
c) a device station comprising electronic circuitry that can engage said device and selectively connect said two or more electrode arrays...to said impedance analyzer; The Maestro Z and Maestro ZHT platforms comprise a device station with circuitry to engage the CytoView-Z plates and connect the electrode arrays to the analyzer. ¶176 col. 4:22-26
d) a software program that can control said device station and record and analyze data obtained from said impedance analyzer; Axion’s AxIS Z software controls the device station and analyzes the impedance data. A workflow diagram illustrates this process (Compl. p. 76). ¶177 col. 4:27-29
wherein said electrode array has an approximately uniform electrode resistance distribution...so that the electrode resistances between two locations on said array do not differ by more than 30%; The complaint alleges upon information and belief that the plates meet this limitation, citing Axion marketing material touting "high sensitivity and repeatability across plates" with "no evidence of drift or edge effects." ¶178 col. 16:32-36
introducing cells into at least one well of said system; Axion uses the Maestro Z system by introducing cells into the wells of the CytoView-Z plate. ¶179 col. 5:35-37
monitoring cell-substrate impedance of said at least one well. Axion uses the Maestro Z system to monitor cell-substrate impedance during attachment, spreading, and proliferation phases. ¶179 col. 5:37-39

'255 Patent Infringement Allegations

Claim Element (from Independent Claim 9) Alleged Infringing Functionality Complaint Citation Patent Citation
a) providing a device capable of monitoring cell-substrate impedance operably connected to an impedance analyzer, wherein said device comprises two or more wells for receiving cells; Axion provides its CytoView-Z Plates, which are devices with multiple wells capable of monitoring cell-substrate impedance, used with the Maestro Z/ZHT impedance analyzer. ¶193 col. 5:6-9
b) adding target cells to at least two wells, wherein at least one well is a control well and at least one well is a test well; In an application note, Axion describes adding target cells (U87MG cells) to both control wells (target cells alone) and test wells. ¶194 col. 5:9-10
c) adding effector cells to said test well; In the same application note, Axion describes adding effector cells (T-cells) to the test wells. ¶194 col. 5:10-11
d) monitoring impedance of said control and said test wells before and after adding said effector cells...wherein said monitoring said impedance comprises measuring said impedance during at least two time points; A graph from an Axion document shows impedance measurements taken continuously over many hours, both before and after the addition of T-cells (effector cells), thereby capturing at least two time points (Compl. p. 83, Figure 4). ¶195 col. 5:11-13
e) determining viability of said target cells in said test well at a given time point after said adding effector cells by comparing said impedance or optionally said cell index of said test well to said control well at said given time point. Axion calculates "percent cytolysis" of the target cells by comparing the impedance of the test well to the control well, which the complaint alleges constitutes determining viability. ¶195 col. 5:13-17
  • Identified Points of Contention:
    • Scope Questions: The infringement analysis for the '752' Patent may turn on the scope of "approximately uniform electrode resistance distribution." The complaint alleges this element is met based on marketing claims of "repeatability" rather than direct technical evidence of the 30% resistance differential required by the claim. This raises the evidentiary question of whether the accused plates technically meet this specific numerical limitation.
    • Technical Questions: A key technical question for the '255' Patent will be whether Axion's calculation of "percent cytolysis" is functionally and legally equivalent to the claimed step of "determining viability." Further, for both the '255' and '080' patents, the relationship between the accused system's outputs and the claimed term "cell index" will be a central point of dispute. The analysis will question whether any parameter derived from impedance qualifies as a "cell index" or if the term is limited to the specific formulas disclosed in the patent specifications.

V. Key Claim Terms for Construction

  • The Term: "approximately uniform electrode resistance distribution" ('752' Patent, Claim 11)

  • Context and Importance: This term is a specific, quantitative limitation in the asserted claim of the '752' Patent. The claim itself defines it as "the electrode resistances between two locations on said array do not differ by more than 30%." Infringement will likely depend on whether Plaintiff can prove the accused CytoView-Z Plates meet this precise numerical constraint, making its construction critical.

  • Intrinsic Evidence for Interpretation:

    • Evidence for a Broader Interpretation: The patent's detailed description explains the purpose of this feature is to "allow all cells, no matter where they land and attach to the electrode surfaces, to contribute similarly to the total impedance change" (’752 Patent, col. 16:48-53). A party might argue that if the accused device achieves this functional goal of similar contribution, it meets the spirit of the limitation, even if minor deviations exceed 30% in some areas.
    • Evidence for a Narrower Interpretation: The claim language provides an explicit, numerical definition ("do not differ by more than 30%"). A party will argue this is a hard, self-defining limit. The specification reinforces this by providing even narrower preferred embodiments of "more than 15%," "more than 5%," and "more than 2%" (’752 Patent, col. 16:36-47), suggesting the 30% figure was a deliberately chosen and precise upper boundary.

  • The Term: "determining viability" ('255' Patent, Claim 9)

  • Context and Importance: This is the culminating step of the claimed method for measuring cytolytic activity. The complaint alleges Axion's calculation of "percent cytolysis" meets this limitation. Practitioners may focus on this term because the case will turn on whether Axion's analytical output falls within the scope of this term.

  • Intrinsic Evidence for Interpretation:

    • Evidence for a Broader Interpretation: The specification links viability to cytolytic activity, stating that a "decrease in the impedance of the cell-substrate suggests reduction of viable target cells or decreased viability of target cells" and that this can be used to "determine the cytolytic activity" (’255 Patent, col. 75:63-66). This language may support an interpretation where any metric that quantifies cell death or killing (such as "percent cytolysis") inherently constitutes "determining viability."
    • Evidence for a Narrower Interpretation: A party could argue that "determining viability" requires a specific, quantitative output (e.g., a count of live vs. dead cells) that is distinct from a relative metric like "percent cytolysis." The specification discusses other methods for assessing viability, such as radioactive labeling, and a party might argue the claimed term should be construed in light of what one of ordinary skill would understand "determining viability" to mean in the context of these conventional assays (’255 Patent, col. 3:55-4:10).

VI. Other Allegations

  • Indirect Infringement: The complaint alleges both induced and contributory infringement for all three patents. Inducement is primarily based on allegations that Axion provides extensive instructional materials, including product brochures, application notes, and culture protocols, that actively encourage and direct customers to use the accused systems in an infringing manner (Compl. ¶182, ¶198, ¶222).
  • Willful Infringement: The complaint alleges willful infringement based on pre-suit knowledge of the patents. The primary basis cited is Axion's disclosure of the '752' Patent in an Information Disclosure Statement filed with the USPTO on October 21, 2015, during the prosecution of its own patent (Compl. ¶46, ¶184). Additional bases include Axion's alleged awareness of Plaintiff's competing xCELLigence products marked with the patent numbers and its hiring of former Agilent employees familiar with the patented technology (Compl. ¶47-52).

VII. Analyst’s Conclusion: Key Questions for the Case

  • A core issue will be one of definitional scope: How will the term "cell index," which the patents define with specific mathematical formulas, be construed? The dispute may center on whether Axion's software calculates a parameter that falls within these definitions or if, as the complaint suggests, any metric "derived from raw, measured impedance" meets the claim limitation.
  • A key evidentiary question will be one of technical proof: Can Plaintiff demonstrate that Axion's CytoView-Z plates meet the '752' Patent's requirement that electrode resistance between any two locations "do not differ by more than 30%"? The complaint's reliance on marketing materials for this element suggests that direct technical evidence may be a central battleground.
  • A critical legal question will concern willfulness and damages: Given the allegation that Axion cited the '752' Patent in a 2015 IDS, the case raises a significant question of whether Axion can establish a good-faith belief of non-infringement or invalidity sufficient to rebut a charge of willful infringement and the potential for enhanced damages.