On October 19, 2023, the United States Court of Appeals for the Federal Circuit issued an opinion that reversed-in-part, vacated, and remanded the United States Patent and Trademark Office’s Patent Trial and Appeal Board (the “Board”) decision that the prior art, including Claire Simonnet & Alex Groisman, High-Throughput and High-Resolution Flow Cytometry in Molded Microfluidic Devices, 78 Analytical Chemistry 5653 (2006) (“Simonnet”), did not render unpatentable Appellee Cytonome/ST, LLC’s (“Cytonome”) U.S. Patent No. 10,583,439 (the “’439 patent”), pursuant to 35 U.S.C. §§ 102 and 103.
ABS Glob., Inc. v. Cytonome/St, LLC, No. 2022-1761, 2023 WL 6885009 (Fed. Cir. Oct. 19, 2023).
The ’439 patent, entitled “Hydrodynamic Focusing Apparatus and Methods,” describes and claims a microfluidic device for processing particles of interest contained in a sample fluid. The ’439 patent involves focusing the flow of a sample fluid by use of other fluids (“hydrodynamic focusing”) in microfluidic devices, which employ small channels to move the fluids. Independent claim 1 of the ’439 patent, in relevant part, recites:
- A microfluidic assembly for use with a particle processing instrument, the microfluidic assembly comprising:
a substrate; and
a flow channel formed in the substrate, the flow channel having:
an inlet configured to receive a sample stream;
a fluid focusing region configured to focus the sample stream, the fluid focusing region having a lateral fluid focusing feature, . . . .
Appellants ABS Global, Inc. and Genus plc (collectively, “ABS”) filed an
inter partes review with the Board, challenging the validity of claims 1, 2, 6, 8, and 9 of the ’439 patent. ABS argued that the ’439 patent is anticipated and/or obvious based on,
inter alia, Simonnet. In a Final Written Decision, the Board held that ABS did not prove that any of the challenged claims were unpatentable. The Board’s sole stated basis for rejecting ABS’s challenges was that Simonnet failed to disclose one claim limitation—
i.e., “the sample stream” component of the “fluid focusing region” element. The Board stated that the ’439 patent’s claim language requires that the flow channel’s focusing region of claim 1 (and hence all challenged claims) be configured for only a single, contiguous sample stream, not more than one. The Board determined that, as a matter of claim construction, “the sample stream” language in claim 1 had a singular-only meaning, not allowing a plurality of streams or a split stream. It then found that Simonnet did not disclose a “fluid focusing region configured to focus the sample stream,” as it did not disclose such a single stream. Because the other prior art references did not remedy the singular-only meaning, the Board rejected ABS’s anticipation and obviousness challenges. ABS appealed.
On appeal, ABS argued,
inter alia, that the Board erred in its claim construction limiting claim 1’s disputed language to a flow channel’s focusing region as configured for only a single sample stream. The Federal Circuit found that the specific claim language at issue was “a fluid focusing region configured to focus the sample stream.” It stated that the use of the definite article, “the,” means that the phrase “the sample stream” refers back to earlier language as an antecedent. The antecedent language is “a sample stream” in the preceding limitation, and it is the singular-only or plural-allowing meaning of that limitation which is determinative.
The Federal Circuit disagreed with the Board’s construction. It found that the reference-back “the” language takes its meaning from the meaning of the antecedent, so if “a sample stream” has a plural-allowing meaning, so does the reference-back “the sample stream” phrase. The Federal Circuit reasoned that two familiar aspects of claim-construction analysis strongly support the plural-allowing meaning. First, “at least in an open-ended ‘comprising’ claim,” like claim 1 of the ’439 patent, “use of ‘a’ or ‘an’ before a noun naming an object” requires that the phrase be construed to mean “‘one or more’ unless the context sufficiently indicates otherwise.”
Lite-Netics, LLC v. Nu Tsai Capital LLC, 60 F.4th 1335, 1345 (Fed. Cir. 2023);
see Salazar v. AT&T Mobility LLC, 64 F.4th 1311, 1315 (Fed. Cir. 2023);
Baldwin Graphic Systems, Inc. v. Siebert, Inc., 512 F.3d 1338, 1342–43 (Fed. Cir. 2008). The Federal Circuit stated that it has called this the “general rule,” adding that an exception “only arises where the language of the claims themselves, the specification, or the prosecution history necessitate a departure from the rule.”
Baldwin, 512 F.3d at 1343. Second, the specification here states: “[F]or the purposes of the present disclosure, the term ‘a’ or ‘an’ entity refers to one or more of that entity. As such, the terms ‘a’ or ‘an,’ ‘one or more’ and ‘at least one’ can be used interchangeably herein.” ’439 patent, col. 18, lines 27–30.
Therefore, the Federal Circuit reversed the Board’s claim construction and held that “the sample stream” is not limited to a singular-only sample stream. And, as a consequence of the Federal Circuit’s claim construction, it concluded that Simonnet anticipates independent claims 1 and 8. The Federal Circuit, however, remanded claims 2, 6, and 9 for the Board’s further consideration consistent with the Federal Circuit’s opinion.
