The successful application of nano-particles depends upon both the synthesis and the surface modification of these particles. Surface modification can improve the inherent characteristics of the nano-particles and serve to prepare nano-composites in existent in nature. Nanoparticles dispersions are suspensions of nanoparticles in water. These dispersions can be used as-is, or diluted with suitable (compatible) solvents. Nanoparticles in dispersions can sometimes settle upon storage, in which case they can be mixed (shake up) before use.