US Patent 7288134- Manufacture of dumbell shaped nanoparticles

http://www.freepatentsonline.com/7288134.html

This patent from IBM deals with the manufacture of dumbell (or flower) shaped nanoparticles useful for biotags. The dumbell shape provide for a larger magnetic signal for smaller nanoparticles that are easier to disperse in a solvent. Claim 1 reads:

1. A process of making dumbbell-shaped nanoparticles, said process comprising: mixing nanoparticles with a noble metal precursor and a reducing agent in solvent, wherein each of said nanoparticles comprises a hydrophobic outer coating; heating the mixture; cooling said mixture to room temperature; modifying said hydrophobic outer coating into a hydrophilic outer coating; precipitating product from said mixture; and dispersing said product in solvent to produce nanoparticle dispersion.