Nanometer-scale components such as nanoparticles are increasingly common in modern cosmetic formulations, and they accomplish (or at least purport to accomplish) a variety of different functions and effects, including improved sunscreening, unique color effects, and even strengthened mechanical and chemical bonding. With such increasing use of nanometer-scale components—that is, particles or structures in the range of 1–100 nm in size—there has also been a corresponding increase in the number of patent applications and patents issued in the field by the US Patent and Trademark Office (PTO). The challenge for an inventor and his or her legal counsel, however, relates to how to describe and claim these nanometer-scale features of the invention in the patent.
Patent law requires that the patent must contain, among other things, a claim or series of claims that “particularly point[s] out and distinctly claim[s] the subject matter which the applicant regards as his invention.” This statutory requirement demands probably the highest degree of clarity and precision that exists in any field of legal drafting, where any ambiguity at all can threaten the validity of the entire patent. Yet nanometer-scale components are inherently difficult to define, detect and quantify, and their effect upon a particular cosmetic composition may not be immediately perceivable or measurable. Thus, formulators working with nanometer-sized materials must work carefully with patent counsel to overcome these inevitable difficulties.
Nonetheless, there are a number of common approaches used by inventors in some recent nanotechnology patents in cosmetics and related fields. Each of these approaches and its advantages and disadvantages are described in the present article. It is likely that no single approach will be correct for every situation but presenting them here, in one place, may at least give inventors and formulators an idea of the range of possibilities in this critical area.
Size-based Claims: The ’734 Patent
The first approach to nanotechnology patent claims uses a particular nanoparticle dimension—and this dimension alone—to distinguish the innovative formulation from everything that preceded it. US Patent No. 7,341,734 for “personal care compositions comprising semiconductor nanocrystals,” granted on March 11, 2008, is a good example of this approach.