In Vitro Study on Cytocompatibility of Mg Wire/Poly(Lactic Acid) Composite Rods

In order to ensure the safety of materials used in the field of orthopedic internal fixation, cytocompatibility was evaluated by culturing MC3T3-E1 cells with the extracts of Mg-2Zn rods, poly(lactic acid) (PLA) rods, hot pressed and hot drawn Mg wire/PLA composite rods. The adhesion, spread, and growth states of cells on each group of sample were analyzed according to SEM images. The fluorescent micromorphology was analyzed, and the relative growth ratio was calculated to quantitatively evaluate the influence of these extracts on the cell viability. Results displayed that moderate and severe cytotoxicity appeared after cells incubated with extracts of Mg-2Zn rod for 3 and 5 days, but it returned to normal phenomenon after the extracts diluted by 10 times. Extracts of other three groups of sample displayed good cytocompatibility. The growth and proliferation of cells were closely related to the pH value and concentration of Mg²⁺. The osmolality changes of extracts had little influence on cytocompatibility of samples at the early stage. Therefore, we can predict the effect of degradation products of Mg wire/PLA composites on their cytocompatibility during the degradation process, on the basis of pH value, concentration of Mg²⁺, as well as osmolality changes. The good cytocompatibility of Mg wire/PLA composites provided experimental valid and valuable guideline for further material design and scheme selection.