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.”1 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.