Nanoparticles have been proposed as an effective tool for biosensing and drug delivery. However, in the context of biological fluids, endogenous proteins will spontaneously adsorb to nanoparticle surfaces, complicating the design of useful nanoparticle-based materials. For example, protein misfolding on nanoparticle-based drugs could potentially induce an unwanted immune response. Conversely, if protein structure is well understood on nanoparticle surfaces, we could design effective molecular sensors that could couple a nanoparticle’s optical properties with protein binding or catalysis. My research focus on a multitude of biophysical and analytical approaches employed to understand how and why protein structure changes upon adsorption