With the rapid expansion of nanotechnology, there has been great concern on safety issue of the nano-product regulated by U.S Food and Drug Administration (FDA).Pre-clinical characterization and quality control during the manufacturing of nano-products is fundamental for understanding resulting safety issues during their wide application.All regulated products are required to submit basic physio-chemical characterization as part of Investigational New Drug (IND) Applications or New Drug Applications (NDA) submitted to the FDA for review.Characterization of gold nanoparticles (Au NPs),silver nanoparticles (Ag NPs) and single walled carbon nanotubes (SWCNTs) will be discussed as cases studies.The nanomaterials were characterized using transmission electron microscopy (TEM), dynamic light scattering (DLS), Raman, and hyperspectral microscopy and other spectroscopy techniques.We examined their uptake and toxicity in primary rat hepatocytes, rat adrenal pheochromocytoma cells (PC12) or in vivo rodent models.Cytotoxicity was assessed by examining cell membrane integrity and mitochondrial activity (LDH, XTT and MTT assay) and oxidative stress (DCF assay;reduced glutathione levels;PCR array for ROS responsive gene expression).Uptake and subcellular localization were monitored using TEM, confocal Raman microscopy and inductively coupled plasma mass spectrometry (ICP-MS) analysis.Although Au NPs were taken up by the cells in a time-and size-dependent manner, no cytotoxicity or ROS stress was detected.Conversely, uptake of SWCNT was cytotoxic and generated ROS in surface coating-dependent manner.PEGylated SWCNT exhibited less potency than uncoated SWCNTs.On the other hand, Ag NPs decreased the body weight and locomotor activities after intravenous exposure in rats.These studies suggest the surface coating, size and composition play import roles in toxicity of the nanomaterials.The multiple characterization approaches used in this study provided the solid basis to understand the biological responses for regulatory purpose.