(634h) Competitive Adsorption of Proteins on Gold Nanoparticles: A Simulation-Based Study

A corona of proteins forms around nanoparticles when they are immersed in any biological system, including the human body. The composition of the corona is a result of a competitive adsorption process between many different types of proteins and determines how the nanoparticles interact with their biological surroundings. A better understanding of the competitive adsorption process could help predict the toxicity of nanoparticles and enable rational design of therapeutic nanomaterials. In this work, we investigate how competitive adsorption of proteins on gold nanoparticles depends on the nanoparticle size. A two-bead-per-residue model for proteins is developed by scaling the mainchain-sidechain, sidechain-sidechain and mainchain(sidechain)-gold nanoparticle potentials of mean force obtained from atomistic molecular dynamics simulations and well-tempered metadynamics simulations. Using this model, we investigate the adsorption of lysozyme, myoglobin and their mixtures on gold nanoparticles with radii 0.5, 1.0 and 2.0 nm using discontinuous molecular dynamics simulations. We probe the equilibrated adsorption states by analyzing the numbers and orientation distributions of pure lysozyme and pure myoglobin on these gold nanoparticles. We also investigate the adsorption kinetics by analyzing how the numbers of proteins on nanoparticles vary during the simulation. The competition between the adsorption of lysozyme and myoglobin on the nanoparticle is explored by comparing the equilibrated adsorption states and the kinetics of the adsorption processes for pure lysozyme, pure myoglobin and their mixtures.