FLUORESCENT NANODIAMONDS: THE NEW PLATFORM FOR CONSTRUCTION OF CHEMO- AND BIOSENSORS

Over the past few years, fluorescent nanodiamonds (FNDs) have been recognized as potential fluorophores for use in bioimaging, owing to their unique and attractive chemical and particularly spectral properties. The source material for their preparation, synthetic nanodiamond (ND), is non-expensive and commercially available. Notably, NDs have the highest biocompatibility of all carbon nanomaterials and their surface can be chemically modified by various techniques. FNDs are capable of fluorescing with almost quantitative quantum yields from point defects of crystall lattice - nitrogen-vacancy (NV) centers. In particular, the long-wavelength emission, high brightness, no photobleaching, no photoblinking, and an exceptional resistance to chemical degradation make them almost ideal core for development of fluorescent bioimaging probes. Here we show an integrated approach for creation of NV centers in ND, aiming for the development of intracellular chemo-and biosensors. NV centers are prepared using high energy beam irradiation in cyclotron and subsequent thermal annealing of NDs. The influence of surface chemistry on their photoluminiscence is explained using a novel surface band bending model. The NDs are further modified using groups intended for detection of the chemical and molecular recognition events ongoing on the ND surface.