natural polymeric coatings on magnesium-based implants for anti-corrosion application: a brief review

Nowadays, the need for bio-implants, which can gradually degrade after fulfilling the therapeutic tasks is continuously increasing. magnesium (mg) and its alloys due to its advantageous mechanical qualities for human bone, together with its biodegradability and bioactivity on osteogenesis have been proposed and extensively studied as the new-generation medical implants. however, mg alloys suffer unacceptably rapid corrosion rates in aqueous environments, including physiological fluid, that may cause an early fracture and further the surgical failure, greatly hindering their broad applications. this necessitates a biodegradable surface barrier coating that should delay the corrosion of the implant until the fractured/damaged bone has healed. by alloying, surface-adjusting, and mechanically treating the magnesium, the problem can be resolved and the rate of degradation can be reduced. surface modification is a practical solution since it enhances corrosion resistance and readies a treated surface for better cell adhesion and bone regeneration. metal coatings, ceramic coatings, and permanent polymers were shown to minimize degradation rates, but inflammation and foreign body responses were also suggested. unlike permanent materials, bioabsorbable polymers typically exhibit the appropriate level of biocompatibility. this review is an attempt to overview the recent advances in polymeric coatings development for diminishing the mg alloys corrosion rate. specifically, biocorrosion was discussed following the introduction of magnesium as an orthopedic metal. the attention next shifted to natural polymers, and varieties that have been employed thus far for coating creation were investigated. the survey included delving into the corrosion tests executed for examining the behavior of the coatings.