2, University of California, Riverside, Riverside, California, United States
3, Northeastern University, Shenyang, , China
4, University of California, Riverside, Riverside, California, United States
Mg–Zn–Ca ternary alloys have attracted increasing attention for biomedical implant applications, especially for bone repair because of its biocompatibility, biodegradability and similar mechanical properties to cortical bone. The objective of this study was to characterize Mg–2Zn–0.5Ca (ZC21) intramedullary pins, determine the degradation of ZC21 in vitro, and evaluate the cytocompatibility of ZC21 with bone marrow derived mesenchymal stem cells (BMSCs) in direct culture and direct exposure culture. Direct culture is suitable to evaluate direct cell attachment on the biomaterial surfaces. Direct exposure culture is desired for investigating the response of well-established cells in the body with newly implanted biomaterials. Surface microstructure and composition of ZC21 pins were characterized before and after BMSCs culture using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). After 24 hours culture, the ZC21 pins showed a similar degradation behavior compared to pure Mg pins in vitro. The BMSCs adhesion density on ZC21 pins (direct contact) was significantly higher than pure Mg pins in both culture methods. The cell adhesion density around ZC21 pins (indirect contact) was similar to the cell-only positive control in both culture methods. Therefore, ZC21 pins are considered to be cytocompatible with BMSCs. Future study will focus on the improvement of the degradation properties of ZC21 pins and the evaluation of their degradation and biological performance in vivo.