The surface chemistry of the nanomaterials creates an effective interface between two entirely different worlds: nanotechnology and biology. Understanding the interaction between nanomaterial surface chemistry and biological entities can be useful for a wide variety of biomedical applications as well as can provide crucial information for nanotoxicology. In my research, I have used gold nanoparticles as a model platform to synthesize a family of nanoparticles with atomic level control of their surface properties and probe their interaction with biological systems. First part of my research focused on the understanding the uptake mechanisms, toxicity, and hemolytic properties of cationic nanoparticles, an excellent gene delivery vectors, and provide design parameters to avoid toxic consequences. In the second part of my research, a new class of surface engineered antifouling nanomaterials were fabricated that can eschew plasma protein binding, providing opportunity to interrogate nano-biological behavior without any complications arising from the protein binding to nanomaterial surface. Since the surface chemistry of nanoparticles dictates the interaction between nanomaterials and biological entities, the findings in this thesis can be generalized to nanomaterials with a wide of variety of core materials of unique physical properties
