US Patent 7476765 - Addressable nanoparticle field enhancement microscopy

http://www.freepatentsonline.com/7476787.html

Sharp metallic tips or particles have the propery of electromagnetic field enhancement which is well known to be useful to molecular analysis techniques such as Surface Enhanced Raman Spectroscopy. This patent teaches a method to differentiate the signals from different nanoparticles. Claim 1 reads:

1. A method comprising:

illuminating a nanoscale array of islands with an electromagnetic signal;

addressing the nanoscale array to differentiate signals from different islands of the nanoscale array, the differentiated signals originating from illuminating the nanoscale array; and

applying the differentiated signals to microscopy of a specimen.

However, the broad claims appear to overlook a great deal of prior art involving the use of metal nanoparticles and quantum dots as biotags which would seem to read on the claims. See for example the article "Nanoparticles for bioanalysis" by Penn et al. published in 2003.