US Patent 7151209 - Etch and Release of Nanostructures

http://www.freepatentsonline.com/7151209.pdf

Using materials with differential etch rates is a common technique to release microstructural elements such as cantilevers or membranes from a substrate. This patent from Nanosys alleges that applying this technique on the nanoscale to release nanostructures from a substrate is a new idea. Claim 1 reads:

1. A method of harvesting a nanostructure from a substrate, the nanostructure comprising at least a first region comprising a first material and a second region comprising a second material, wherein the first material is differentially etchable from the second material, the method comprising etching away the first material of the nanostructure to release the nanostructure from the substrate at the first region.

Unfortunately the Examiner seems to have missed this patent from Agere Systems
http://www.freepatentsonline.com/6322713.pdf
which may have some prior art relevance.