US Patent 8168413 - Preparing luminescent nanodiamonds

http://www.freepatentsonline.com/8168413.html

This patent from Academia Sinica teaches luminescent nanodiamonds as an alternative to semiconductor nanocrystals for molecular biolabeling in order to avoid the toxicity of nanocrystals. Claim 1 reads:

1. A method of making luminescent diamond particles, comprising:

irradiating diamond particles with an ion beam, wherein the diamond particles have a diameter of 1 nm to 1 mm and 5 ppm to 1000 ppm color centers and the ion bean has a kinetic energy of 1 KeV to 900 MeV; and

heating the irradiated diamond particles in a non-oxidizing atmosphere at a temperature between 600 and 1000° C.; and

oxidizing the surface of the luminescent diamond particles.