The Federal Circuit recently clarified in LifeNet Health v. LifeCell Corporation, No. 2015-1549 (Fed. Cir. Sept. 16, 2016) that a negative functional claim limitation can be used to describe a capability or structural element of an apparatus. The Court affirmed a judgment of direct infringement against a manufacturer where the limitation was found to be satisfied from the moment the apparatus was manufactured, without any further action by a third party physician or customer.
LifeNet’s patent is directed to plasticized soft tissue grafts suitable for transplantation into humans. The claim recites “one or more plasticizers contained in said internal matrix” and that “said one or more plasticizers are not removed from said internal matrix of said plasticized soft tissue graft prior to transplantation into a human.”
LifeCell appealed a judgment of direct infringement from the Eastern District of Virginia. On appeal, LifeCell argued that regardless of how the limitation is construed, LifeCell itself does not directly infringe; rather, independent surgeons or their assistants prepare the grafts for transplantation, including the removal (or non-removal) of plasticizers from the graft.
The Federal Circuit disagreed, relying on Amgen Inc. v. Hoechst Marion Roussel, Inc., 314 F.3d 1313, 1329 (Fed. Cir. 2003) for the proposition that functional limitations recited in the negative may describe a capability or structural element. Regarding LifeNet’s claims, the Court determined that the “the relevant plasticizers are already part of the tissue graft” and “the non-removal limitation simply provides a negative limitation that those plasticizers remain  prior to implantation.”
The Federal Circuit distinguished the claim from two cases that required a customer or physician to take affirmative steps for direct infringement to occur. In Cross Medical Products, Inc. v. Medtronic Sofamor Danek, Inc., 424 F.3d 1293 (Fed. Cir. 2005), the Court held that “surgical implants with an interface that had to be ‘operatively joined’ to a segment of bone could not be directly infringed by the manufacturer. Rather, a third party surgeon had to ‘actually bring the [relevant part] into contact with bone.’” Similarly, in Centillion Data Systems, LLC v. Qwest Communications International, Inc., 631 F.3d 1279 (Fed. Cir. 2011), the Court “held that the accused infringer, who provided software to customers, did not itself practice a limitation requiring a ‘personal computer data processing means’ because ‘it is entirely the decision of the customer whether to install and operate th[e] software on its personal computer data processing means.’” In Cross Medical and Centillion, a claim limitation was found to be absent until an affirmative act by a third party was taken. In the LifeNet claims, however, “[t]his limitation is met without action by a third party. It is satisfied by the graft from the moment it is manufactured unless and until the plasticizer is removed from the internal matrix before transplantation.”
Accordingly, when drafting and prosecuting claims for apparatus and compositions, negative functional limitations may be used to describe such apparatus or composition. However, in order to succeed in asserting direct infringement against a manufacturer, it is crucial that such functional limitation describe a property of the claimed subject matter existing at the time of manufacture, and not a step in a method of using the apparatus. No later action of a third party should be necessary to realize the functional claimed element.