Trends in nanotechnology patents.

he papers that reported the invention of the scanning tunnelling microscope in 1981 and the atomic force microscope in 1986 have been credited in part with ‘opening the doors to the nanoworld’1, and the fact that these papers have been cited thousands of times by other researchers is a testament to the impact that these two instruments have had in the field of nanoscale science and technology. There were also significant advances in other areas such as molecular selfassembly and nanomechanics around the same time, and these fragmented areas were brought together by the increased availability of techniques to control and restructure matter at the nanoscale at the end of 1990s2. Today, more than 60 countries have national programmes in nanotechnology3 and hundreds of nanotechnology-based products are commercially available4. In addition to scientific papers and commercial products, however, there is another way to gauge the rate of progress in nanotechnology over the past few decades — patents. Various authors have made significant efforts to identify5 and analyse6 nanotechnology patents, but this can be difficult because applicants tend to file patents with their national patent office rather than with foreign patent offices7, and because different patent offices have different policies and examination procedures8,9. To gain a global perspective on trends in nanotechnology patents we have analysed those granted by the United States Patent and Trademark Office (USPTO), the European Patent Office (EPO) and the Japan Patent Office (JPO). These three patent offices cover most of the world’s patents in nanotechnology10,11. Data for this study were collected by searching for a list of nanotechnology keywords in the titles and abstracts of patents published by the USPTO, EPO and JPO between 1976 and 2006. These keywords, which were provided by domain experts10,11, include atomic force microscope (and variations thereon), molecular electronics, nano*, quantum dot, and self assembly. We removed some noise from the data, and included only patents that had been granted in our analysis. (See Table S1 in Supplementary Information for a full list of keywords and details of the analysis).