A density functional theory study of amino acids on Mg and Mg-based alloys

TL;DR

This study uses density functional theory to analyze how amino acids bind to magnesium and Mg-based alloys, providing insights for biocompatible coatings to improve magnesium's corrosion resistance in biomedical implants.

Contribution

It presents a novel DFT analysis of amino acid adsorption on Mg(0001) surfaces and alloys, including water effects, to inform biocompatible coating development.

Findings

Amino acids bind differently depending on alloy composition.

Water immersion affects amino acid binding strength.

Alloying elements influence surface interactions with amino acids.

Abstract

Magnesium (Mg) has mechanical properties similar to bone tissue, and Mg ions take part in the metabolism. This makes Mg of interest for biocompatible degradable body implants, provided that its high corrosion rate can be inhibited. Slightly alloying Mg and adding surface coatings can slow down the corrosion processes without significantly changing the mechanical properties. Use of coating molecules that are native to the body increase the likelihood of making the surface biocompatible, for example by use of amino acids. We here present a density functional theory (DFT) study of the adsorption on Mg(0001) of the amino acids glycine, L-proline, and L-hydroxyproline (Hyp), the main amino acid content of collagen. We investigate how binding of the functional groups of Hyp are affected when Mg(0001) is slightly alloyed with zinc, lithium or aluminium, and we also model the immersion of the systems in a water environment to see how this affects the binding.