An in-vitro evaluation study on the effects of surface modification via physical vapor deposition on the degradation rates of magnesium-based biomaterials

Abstract

Magnesium (Mg) metal as a degradable biomaterial is under extensive research, but its high corrosion rate limits its application. In this study, an attempt has been made to increase the viability of pure Mg as a degradable biomaterial for cardiovascular applications with surface modification of pure Mg. Pure Iron (Fe) and hydroxyapatite (HaP) were coated on pure Mg substrates. Analysis of their mechanical and biological characteristics was made. The tensile strength for pure Mg was 80 MPa, Fe and HaP coating on Mg increased the tensile strength values by approximately 45% and 21%, respectively. A maximum degradation rate of about 5.4 mm/year was observed for pure Mg. HaP coating decreased the degradation rate by almost 73%. However, galvanic corrosion caused a sixfold rise in the degradation rate for Fe coating. Hemolysis study indicated all three substrates as non-hemolytic, and the cell viability from MTT cytotoxic assay for uncoated, Fe and HaP coated substrates are 96.24%, 94.8% and 97.13%, respectively. Pure Mg is non-hemolytic and non-cytotoxic, coating Fe and HaP does not affect biological properties but improved the mechanical strength. This work, therefore, establishes altered Mg substrates as effective material for cardiovascular applications.