Enhanced initial protein adsorption on engineered nanostructured cubic zirconia

Area of Science:

• Biomaterials Science
• Computational Chemistry
• Surface Science

Background:

• Experimentally observed enhanced biocompatibility of nanoengineered cubic zirconia (ZrO2) coatings.
• Mesenchymal stromal cells show improved response to ZrO2 nanostructures.
• Need to understand the molecular mechanisms of protein immobilization on these surfaces.

Purpose of the Study:

• To computationally analyze the initial immobilization of a fibronectin fragment on a nanoengineered ZrO2 surface.
• To investigate the role of nanostructure topography in protein adsorption.
• To elucidate the electrostatic interactions driving protein-implant binding.

Main Methods:

• Construction of an atomistic model of a ZrO2 nano-hillock based on experimental imaging (AFM, TEM).
• First-principles quantum mechanical calculations to determine surface electrostatic potential.
• Monte Carlo simulated annealing for protein orientation and adsorption energy calculation, incorporating a distance-dependent dielectric function.

Main Results:

• Significant variation in electrostatic potential on the nanoengineered ZrO2 surface due to features like edges and vertices.
• Adsorption energy for fibronectin fragment on nanostructured ZrO2 is greater than on a smooth surface.
• Strong attractive electrostatic interactions are identified as the primary factor for enhanced adsorption on nanostructured surfaces.

Conclusions:

• The nanostructure of cubic zirconia surfaces significantly enhances protein adsorption compared to flat surfaces.
• Electrostatic interactions, modulated by surface topography, play a crucial role in the improved binding.
• Optimal protein immobilization occurs when there is a synergistic electrostatic and steric fit, minimizing adsorption energy through non-covalent interactions.