AVS 50th International Symposium
    Biomaterial Interfaces Wednesday Sessions
       Session BI-WeM

Paper BI-WeM1
Calculation of Free Energy of Peptide-Surface Adsorption Using Molecular Dynamics Simulations

Wednesday, November 5, 2003, 8:20 am, Room 317

Session: Bionanoscale Analysis: Theory to Experiment
Presenter: V. Raut, Clemson University
Authors: V. Raut, Clemson University
S.J. Stuart, Clemson University
R.A. Latour, Clemson University
Correspondent: Click to Email
Proteins, which are bioactive molecules, adsorb on implants placed in the body and directly influence biocompatibility. Molecular dynamics (MD) modeling provides one of the most direct methods of analyzing individual molecular-level interactions and can be used to simulate protein adsorption behavior using empirical force fields. In order to correctly simulate protein adsorption behavior, a force field must correctly represent the thermodynamic driving forces governing peptide residue-surface interactions (i.e., adsorption enthalpy, entropy & free energy). However, since existing force fields were developed without consideration of protein adsorption, they may not accurately represent this type of molecular behavior. Therefore the objective of our research is to develop computational chemistry methods to calculate thermodynamic parameters of peptide-surface adsorption and compare them with experimental results for the assessment of force field accuracy. Various MD simulations demonstrating individual residue-surface reactions are being studied. These models represent the behavior of small peptides over functionalized SAM surfaces in a water box with periodic boundary conditions. Statistical mechanics methods are being developed based on positionional probability distributions obtained from MD simulations to enable us to calculate the change in enthalpy, entropy & free energy as a function of distance between the peptide & surface. Comparison of these results with experimental results will enable us to determine the accuracy of available force fields. If necessary, the developed methods will then also serve as a basis for the development of a new force field that is specifically parameterized to accurately simulate protein adsorption behavior.