Prosecution History Estoppel and Claim Vitiation Not Enough to Avoid Willful Infringement

In Bio-Rad Labs., Inc. v. 10X Genomics Inc., No. 2019-2255 (Fed. Cir. Aug. 3, 2020), the Federal Circuit rejected 10X’s prosecution history estoppel and claim vitiation defenses and upheld the jury’s finding of willful infringement under the doctrine of equivalents.

Bio-Rad sued 10X for infringement of three patents covering microscopic droplets of fluids for biochemical reactions, often called “labs-on-a-chip.” Bio-Rad amended the patents’ claim language during prosecution to claim “a non-fluorinated microchannel,” and further argued that, unlike the prior art, the claims require the microchannel be “chemically similar to the carrier fluid and chemically different from the channel walls.” 10X argued that its product, which includes 0.02% of a fluorine-containing resin in its microchannels, did not infringe.

The Court rejected 10X’s prosecution history estoppel argument because the non-fluorine claim element was only tangentially related to the accused equivalents. Bio-Rad amended the claim language to distinguish its invention from prior art product in which a chemical reaction occurs between the fluorine-containing microchannel and the carrier fluid. 10X’s product contained such a small amount of fluorine that it would not chemically react with the carrier fluid; therefore, prosecution history estoppel did not bar Bio-Rad from asserting that microchannels containing a negligible amount of fluorine are equivalent. 10X’s claim vitiation argument similarly failed because the element is not “effectively eliminated” by Bio-Rad’s theory as a fluorine-containing microchannel that reacts with the carrier fluid would not infringe.