| As engineered nanomaterials become more prevalent in consumer products and industrial processes, it is becoming increasingly important to understand how these materials interact with the environment. This includes nanomaterials interactions with cell membranes, which act as a protective barrier between a cell and the surrounding environment. When a nanomaterial approaches a cell membrane, the first point of contact is the surface of the nanoparticle and the surface of the cell membrane. Therefore, the chemistry of these surfaces plays a role in determining nanoparticle interactions with biological systems. Although characterizing these surfaces and the interface between them is challenging, it is critical for understanding and predicting nano-bio interactions. To study the role of specific nanomaterial properties (ligand type, charge) and the role of specific cell membrane constituents (lipids, lipopolysaccharides), and extract specific and detailed molecular level information, we use well-characterized nanomaterials and model cell membranes to study how engineered nanomaterials interacts with a biological system.;Using the interface-specific technique second harmonic generation (SHG) spectroscopy to probe model cell membrane-nanoparticle interactions, we have investigated the nano-bio interface with a specific focus on the role of nanoparticle functionalization and size, membrane bound biomolecules, electrostatics, and ionic strength. Here, SHG spectroscopy is used to quantify the interfacial potentials, and surface charge densities of model membranes with and without nanoparticles and ligands present, and to quantify binding constants, adsorption free energies, and adsorbate charge states. Along with complementary experiments, mechanisms for nanoparticle and ligand attachment to model cell membranes are presented. The molecular level, mechanistic information presented here on how nanomaterials interact with model cell membranes may be used in the future to predict the impact of nanomaterials based on their intrinsic chemical and physical properties as well as assist in the design of more sustainable nanoparticles, which retain functionality without causing negative environmental impacts. |
