Small and Bright: Nanodiamonds for tissue repair, drug delivery, and biodetection

Transforming diamond sizes from the micron regime into a few billionths of a meter probably doesn't increase their value in jewelry, but it certainly adds an extraordinary value in numerous physical science, engineering, and medical applications. Nanodiamonds are generally defined as synthetic diamond materials that have crystalline or feature sizes (e.g., grain or particle sizes) between 1 and 100 nm (10
^-9
-10
^-7
m) and include two forms: particulate (zero-dimensional) and thin film (two-dimensional). Figure 1 shows particulate nanodiamond (PND) and nanodiamond thin films under a scanning electron microscope (SEM) and atomic force microscope (AFM). Because the nanodiamond thin film is actually composed of nanosized columnar crystals or grains, the material is usually called nanocrystalline diamond (NCD) or ultra-NCD (UNCD, grains sizes <;10 nm).