A breakthrough toward industrial production of fluorescent na...( The laboratory Structure - Activit ...)

The laboratory Structure - Activit of Normal & Pathologic Biomolecules SANPB , Inserm / UEVE U829 (Genopole Evry, France) in collaboration with the Material Centre of Mines-ParisTech (Evry, France), the NRG - UMR 5060 CNRS / UTBM (Technology University of Belfort-Montbliard) and the Physic Institute of Stuttgart University (Germany) discovered a novel route to fabricate fluorescent nanoparticles from diamond microcrystals. Results are published in Nanotechnology June10 2009 issue.

Fluorescence is a major tool in life and material sciences. In biology/medicine, the coupling of fluorescent dyes, to proteins or nucleic acids (RNA, DNA) allows one to investigate their fate and interactions in cultured cells or in the body. Similarly, fluorescence is used in material sciences to detect electromagnetic fields, for optic storage or tracking (notably to detect fake products). However, most of fluorescent dyes are made of molecules with a limited life time due to chemical reactivity.

In this context fluorescent diamond nanoparticles present a valuable alternative thanks to their outstanding photophysical properties. They are very bright and possess long-term non-bleaching, non-blinking fluorescence in the red/NIR region. Based on these unique properties, multiple applications are foreseen in physics, material science, biochemistry and biology. However, until recently, the production of such nanoparticles was limited to the laboratory.

A single route is nowadays taken to fabricate such fluorescent nanoparticles. It consists of irradiating substitutional nitrogen-containing diamond nanocrystals, produced by the diamond industry, with electron or ion beams to create vacancies in the crystal lattice. Isolated substitutional nitrogen atoms then trap a moving vacancy during annealing to form a fluorescent NV centre. Unfortunately, the efficiency and yield of this route are low due to amorphization and the loss of moving vacancies to the surfac
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