A density functional theory study of amino acids on pristine Mg(0001) and with sparse alloying elements

Artikel i vetenskaplig tidskrift, 2027

Magnesium (Mg) is known for its biocompatibility in degradable body implants, with mechanical properties similar to bone tissue. Pure Mg corrodes too fast for implants, but alloying or coating are methods to slow down the implant surface degradation. Using density functional theory calculations we study the adsorption on Mg(0001) of amino acids glycine (Gly), proline (Pro), and hydroxyproline (Hyp), and a short Gly-Hyp-Pro string. The amino acids are native to the body, form the main amino acid content of collagen, and may by adsorption form nucleation points for coating layers on the surface. We also investigate how binding of the functional groups of Hyp are affected when Mg(0001) is sparsely alloyed with zinc, lithium, calcium or aluminium, and when an aqueous environment is modelled by changing the dielectric constant near the surface from vacuum to the value of water. We find good adhesion of the amino acids overall, and find that the binding improves on alloyed surfaces.