Human Mesenchymal Stem Cells Response to Magnesium-based Biomaterials

Implants have been used as replacement materials for lost tissues and are mainly from metals such as stainless steel and titanium. Metals implants may release toxic elements, and alternative such as magnesium-based implants are suggested but its high degradation rate in human bio-environment limit its uses. Thus, we proposed alloying the magnesium with zinc atoms and dispersing bioactive hydroxyapatite (HAp) within the magnesium and zinc matrix and assess the effects of the conditioned-medium from the Mg-Zn-HAP on human bone marrow mesenchymal stem cells (hMSC) viability. The Mg with and without Zinc powders were purchased from Merck and Alfa Aesar. The precursor powder has particle size of 0.06-0.3 mm. Powder mixtures with different composition i.e., 100 weight percent (wt%) Mg, 9:1 Mg-Zn, 90:9:1 Mg-Zn-Mn, 9:1 Mg-Zn + 10 wt% HAp and 90:9:1 Mg-Zn-Mn + 10 wt% HAP were sintered at 300 °C. Then, the powder was incubated with culture medium (1.0 mg/ml and 2.0 mg/ml) and placed in an incubator shaker for 4 hours. The medium was filtered using 0.2 μm syringe filter and kept at 4 °C. The conditioned-medium was supplemented with 10% (v/v) fetal bovine serum and 1% Pen/Strep and incubated overnight at 37 °C in a CO2 incubator prior to use on hMSC. The cell viability was assessed using Alamar Blue assays at Days 1, 2, 4 and 7. The hMSC showed increased proliferation when cultured in MgZn- and MgZnMn-conditioned medium when compared to Mg-HAp conditioned medium. These metallic ions may play role in stimulating cell proliferation. The presence of metallic ions such as Mg, Mn and Zn promote hMSC proliferation and may play role as an important elements for regeneration of hard tissue during implantation.