Thursday, July 20, 2006

US Patent 7077939 - Carbon Nanotube Conduit For Nanofluidic Transport

Microfluidics is an active technology area dealing with the processing of fluids on the microscale. This technology is gradually being extended to the nanoscale for the control of the processing of individual or small groups of molecules. This patent uses a carbon nanotube embedded in a membrane as a molecular sieve/filter useful in sensing and other applications. Claims 1 and 6 are representative.

1. An apparatus comprising: a membrane; a nanotube embedded within the membrane and providing a conduit through the membrane, the ends of the nanotube being flush with respective surfaces of the membrane; and wherein the nanotube is a carbon nanotube.

6. A method of forming a membrane having a small hole disposed therein comprising: surrounding at least a portion of a nanotube with a liquid or gaseous material; allowing the liquid or gaseous material to solidify around the nanotube; and removing by chemical oxidation the at least a portion of the nanotube from the solidified material, leaving the membrane having the small hole disposed therein.

Note to patent attorneys: in this case the Examiner took a very broad interpretation of nanotube and applied art showing a membrane with a nanosized tubular aperture which was interpreted by the Examiner as a "nanotube". While I'm not sure this interpretation would have held at the Board of Appeals and it seems contrary to the understanding of one of ordinary skill in the nanotechnology art, a tube is broadly defined by Merriam-Webster's as "any of various usually cylindrical structures or devices." The prosecuting attorney got around the rejection by specifying "carbon" nanotube in claim 1 which may come back to haunt them if other non-nanotube structures such as charcogenide nanotubes are used as alternatives to practicing this invention.