Diamond is a metastable allotrope of carbon, in which the carbon atoms are arranged in a face-centered cubic crystal structure called a diamond lattice. Diamond stands out as a material with exceptional physical qualities, which mainly derive from the strong covalent bond together with the energy of ≈ 7.4 eV per atom. Due to its unique physical, chemical and biological properties, diamond has become a significant candidate material in scientific and industrial applications. It is the stiffest material known to science and has wide-spectrum applications such as high-power, high-frequency semiconductor devices, infrared windows in harsh environments, filters for surface acoustic wave sensors, field emission display devices in the manufacturing industries semiconductors, electrochemical sensors, biomedical imaging, as well as the traditional application of equipment (drilling, cutting…). Approaching the frontiers of nanotechnology towards the smallest achievable nanomaterials, the size of nanodiamond crystals has been strongly motivated by current advances in quantum science and biology. Nanodiamond exhibits most of the superior properties of bulk diamond and delivers them to the nanoscale. These properties include hardness and Young's modulus, high fracture toughness and low coefficient of friction (~0.01 to 0.1), optical properties, high thermal conductivity, electrical resistivity, and chemical stability. Furthermore, nanodiamond exhibits low cytotoxicity and exceptional biocompatibility, thus it has immense potential as a new material suitable for biomedical applications. There is growing interest in using nanodiamonds as biosensors and in fabricating nanoscale fluorescent diamond probes for optical labeling and drugs or... middle of paper... become trapped by the substitutional nitrogen atom which is abundant in most synthetic nanodiamond. Nanodiamonds with a high concentration of nitrogen vacancy (NV) color centers harbor several exceptional characteristics that provide greater advantage to NDs as a preferred candidate for long-term intracellular optical labels in biological and medical imaging compared to commonly used organic fluorophores . Such properties include: emission of bright photoluminescence in the extended red light region, extreme photostability, and ease of surface functionalization for specific or nonspecific binding to nucleic acids, proteins, and hydrophobic chemotherapeutic molecules. NDs >35 nm possess a distinguishable fluorescent emission light above 690 nm, where the fluorescence wavelength signal of cellular endogenous components (autofluorescence) ranges from ~280 to 630 nm