Effect by Diamond Surface Modification on Biomolecular Adhesion.

Yuan Tian,Karin Larsson

doi:10.3390/ma12060865

Abstract

Diamond, as material, show very attractive properties. They include superior electronic properties (when doped), chemical inertness, controllable surface termination, and biocompatibility. It is thus clear that surface termination is very important for those applications where the implant material is based on diamond. The present theoretical work has focused on the effect of diamond surface termination, in combination with type of surface plane, on the adhesion of important biomolecules for vascularization and bone regeneration. These biomolecules include Arginine-Glycine-Aspartic acid (RGD), Chitosan, Heparin, Bone Morphogenetic Protein 2 (BMP2), Angiopoietin 1 (AGP1), Fibronectin and Vascular Endothelial Growth Factor (VEGF). The various surface planes are diamond diamond (100)-2x1 and (111). The theoretical results show that the non-covalent binding of these biomolecules is in proportion with their molecular weights. Moreover, three groups of biomolecules were observed for both types of surface planes. The most strongly binding biomolecule was the BMP2 molecule. The smaller polypeptides (RGD, Chitosan and Heparin) formed a less strongly binding group. Finally, the biomolecules VEGF, Fibronectin and Angiopoietin showed bond strengths numerically in between the other two groups (thereby forming a third group). Moreover, the (111) surface was generally observed to display a stronger bonding of the biomolecules, as compared with the (100)-2x1 surface.

Highlights

Diamond is a material with very attractive properties
The combination of a larger chemical reactivity of individual surface C atoms and a larger surface atom density for the (111) surface, is thereby expected to result in larger adhesion energies for the biomolecules. This was especially the situation with the largest biomolecules that covered a larger part of the diamond surfaces (BMP2, Vascular Endothelial Growth Factor (VEGF), fibronectin, Angiopoietin 1 (AGP1)); 1150–8200 kJ/mol for the (111) surface and 750–5480 kJ/mol for the (100)-2x1 surface
With the purpose to tailor-make the bone implant surfaces by using the unique surface properties of diamond, a theoretical investigation has in the present study been performed in order to more deeply study the interaction between diamond and various biomolecules

Summary

Introduction

(incorporated in CASTEP from Accelrys, Inc. [29,30,31]), whilst the atomic charges for the biomolecules were As force field assigned in the FF calculations. [29,30,31]), whilst the atomic charges for the biomolecules were As force field assigned in the FF calculations. 2, the models of theThe diamond//biomolecule werestudy too big to use on an ultrasoft pseudopotential plane-wave approach. Approximation as developed by Perdew, Burke ab initio force field methods. In order to validate the usefulness of these methods, test calculations and (GGA-PBE). Is Results fromto the initio calculations of surface properties [33]. Diamond surface planesinthereby showed that ab initio FF method is possibleelectron to use in the present. According to the Mulliken method for calculating atomic charges, a projection of the plane wave states study. Onto the localized basis set was used in the present study [35]

Materials and Methods

Adhesion

Adhesion Energies for Various Types of Surface Termination

Adhesion Energies for Individual Biomolecules

Discussion