In vitro and preliminary in vivo assessment of anodized Mg-based alloy as a potential material for biomedical applications?

MERLO, JULIETA LETICIA; CARRIZO, SABRINA; GÓMEZ-SANCHEZ, ANDREA; SALEMME, ALONSO; CANIZO, JÉSICA; KATUNAR, MARÍA ROSA; TANO DE LA HOZ, FLORENCIA; CERÉ, SILVIA

Mar del Plata

Congreso; LXIII Reunión Anual de la Sociedad Argentina de Investigación Clínica; 2018

SAIC-SAI-SAFIS

Magnesium (Mg)-based alloys are promising candidates for the development of new biodegradable materials for fracture repair implants. However, the high degradation rate of Mg in aqueous media releases hydrogen gas, which causes pain and local swelling. Superficial treatments, such as anodization, emerge as a potential solution to this limitation. The aims of this study were to evaluate the 1) in vitro citocompatibility of anodized Mg-based material on fibroblasts, and 2) the in vivo osteoconductivity of anodized Mg-based implants after 7 days of implantation in a rat model. Anodization of Mg alloy (AZ91) pieces was performed at low voltage for 40 min in potassium hydroxide solution. For the objective 1, bovine fibroblasts were seeded on the materials (anodized or control -without anodization- AZ91 square pieces) and as cellular control, cells were cultured without material (on plastic). Cellular adhesion and proliferation were evaluated after 24 h. For objective 2, adult male rats received two implants (anodized AZ91 or control ?polylactic acid, PLA; biodegradable material used clinically- pins), placed transversely one in each medial area of the femur. At 1 and 6 days after surgery, different fluorochromes were administered intraperitoneally, to be incorporated at mineralization sites of the new bone. Rats were sacrificed 7 days after implantation and femurs were retrieved, cleaned, fixed and embedded in polymethyl methacrylate (PMMA) blocks. Fluorescence and Toluidine blue staining was observed on thin sections (150 µm) of the implanted area of each block. In the in vitro test, an increased adhesion and proliferation of bovine fibroblasts was observed in the anodized pieces, compared with controls. The in vivo preliminary results indicated a higher osteoinductivity of the Mg-based pins, compared with PLA pins, at the site of implantation. In conclusion, anodization at low voltage is a promising superficial treatment for the development of Mg- based biomedical applications.