With the increasing use of commercial nanomaterials in many consumer products, it is critical to identify potential impacts of nanomaterials on human health and the environment. The distribution of nanomaterials in the environment is governed by modes of release, physical-chemical properties of nanoparticles, and their interactions with biological substrates. One area of research is focuses on thorough physical-chemical characterization of nanomaterials, including chemical composition, size, morphology, surface area, crystallinity, and other physical-chemical properties of the as-received nanomaterials. In the meantime, efforts have been made to understand the nanoparticle behavior under conditions similar to those for in vitro or in vivo toxicity studies. Proteins, serum, and a variety of chemical surfactants are explored to enhance nanoparticle dispersion and stabilization in cell culture media. The protein-nanoparticle interaction and the important parameters that affect such an interaction are also being explored.