Reduction of corrosion behavior of magnesium alloy by PCL surface treatment

Abstract

INTRODUCTION: Metallic implants are often used for fracture fixation. However, stress-shielding effect may be resulted in some cases and thereby leading to bone loss around the implant1. Therefore those metallic implants may need to be removed after the tissues have healed. The use of degradable metallic materials such as magnesium alloy is a promising candidate that may avoid second surgery. Hence, it helps reduce costs to health care system and morbidity to the patients. However, the major obstacles are the rapid degradation inside the human body and hydrogen gas release upon degradation. The corrosion rate has to be carefully controlled so as to make the alloys available for orthopaedic implantation. Surface modification is used since this method will not alter the bulk properties of magnesium alloy. Various surface treatments such as Plasma Immersion Ion Implantation and Deposition (PIII&D)2 and plasma anodisation3 are applied so that the corrosion resistance of material can be enhanced. Our group has recently developed a unique method to deposit a biodegradable polymer named polycaprolactone (PCL) on the magnesium surface. Previous in-vitro studies suggested that the rate …