Modificação superficial do magnésio laminado a quente para utilização em engenharia de tecidos ósseos

Abstract

Magnesium (Mg) is a non­ferrous metallic material with properties such as low density and modulus of elasticity close to that of bone. It is an essential element for the human body, making it a potential candidate to produce bone implants. However, its high rate of corrosion and hydrogen gas release in physiological media limit its use. Thus, the investigation of strategies to reduce the corrosion rate of magnesium without compromising its biocompatibility is a challenge faced by several authors. This work consisted in modifying the Mg surface with a ceramic coating based on dicalcium phosphate dihydrate (DCPD) and a hybrid film composed of polyvinyl alcohol (PVA) and bioactive glass (BG). The Mg used in this study was initially processed by hot rolling to ensure that this material had favorable mechanical strength for application as a bone implant. The results obtained in this study are presented in the format of two scientific articles. The first one deals with the deposition of DCPD on Mg by means of its immersion in a phosphating bath. The second article evaluated the deposition by dip­coating process of a PVA/BG hybrid film on the previously produced DCPD coating. The structure, corrosion resistance in simulated body environment, and biocompatibility of the prepared materials were evaluated. It was observed that the deposition of the DCPD coating increases the corrosion resistance of Mg and promotes a rapid formation of hydroxyapatite (HAp) on the material. The formation of HAp is an important indication of the biocompatibility of a material since it is the mineral phase of human bone, which favors the integration of the biomaterial with the physiological environment. Flow cytometry test evaluated that the material modified with DCPD did not present toxicity in human embryonic kidney cells. Therefore, the subsequent surface modification of Mg/DCPD with PVA/BG hybrid films further increased its corrosion resistance in simulated body fluid (SBF), achieving higher impedance modulus values and better cell viability response (above 90%). This study contributes to a more effective application of Mg in bone tissue engineering.