Brownian dynamics simulation of the displacement of a protein monolayer by competitive absorption

We present Brownian dynamics simulations of the displacement of a protein monolayer by competitive adsorption. The protein film is modeled as a network of bonded particles adsorbed at a fluid interface. Displacer particles are added having a stronger affinity for the interface than the protein film particles. As these particles diffuse to the interface and adsorb in holes in the network, they start to displace the film particles. Although part of the network remains pinned to the interface, other parts of the film buckle out into the solution, forming a relatively thick layer. Eventually the whole film becomes detached from the interface. We explore the effect of the nature of the direct interaction between film and displacer particles on the displacement process.