| AVS 64th International Symposium & Exhibition | |
| Biomaterial Interfaces Division | Tuesday Sessions |
| Session BI-TuP |
| Session: | Biomaterial Interfaces Poster Session with Flash presentations |
| Presenter: | Michael Melia, University of Virginia |
| Authors: | M.A. Melia, University of Virginia D.C. Florian, University of Virginia J.R. Scully, University of Virginia J.M. Fitz-Gerald, University of Virginia |
| Correspondent: | Click to Email |
As a lightweight metal with mechanical properties similar to natural bone, Mg and its alloys are great prospects for biodegradable, load bearing implants. However, the United States has yet to clear Mg for any substantial role in the body due to the concerns of electrochemically derived hydrogen gas and unpredictable loss of structural integrity as a result of a dynamic corrosion resistance varying with time. This research investigates how the chemical homogenizing effects of laser processing and the application of a corrosion resistant coating impacts the corrosion resistance, cell viability, and cell adhesion of the AZ31B (3 wt. % Al, 1 wt. % Zn, 0.3 wt. % Mn, and 95.7 wt% Mg) alloy in a physiological solution.
Cell viability and adherence measurements were carried out utilizing the osteosarcoma (MG63) cell line and were plated on the AZ31B specimens in the as-received, laser processed, and coated conditions. In vitro cell viability assays show improved cytocompatibility for both the laser processed and coated specimens over the as-received AZ31B alloy. The coated specimen performed the best with a 5 fold improvement in cell viability over the as-received alloy. Cell adhesion was further investigated by fixation of the MG63 cells and imaging using scanning electron microscopy (SEM). Electron micrographs revealed significant adhesion of cells to the coated specimen with limited adhesion for specimen in the as-received and laser processed condition.
Laser processing utilized a KrF pulsed excimer laser (λ = 248 nm and FWHM = 25 ns) which has been shown to reduce the corrosion rate of Mg alloys by an order of magnitude in NaCl containing solutions. Corrosion experimentation was performed under full immersion in a minimal essential media (MEM). Time dependent corrosion rates and electrochemical kinetics were analyzed using open circuit potential, electrochemical impedance spectroscopy, and potentiodynamic polarization measurements. The corrosion product morphology was investigated using SEM, energy dispersive spectroscopy, and x-ray diffraction. The coated specimens exhibited an order of magnitude reduction in cathodic kinetics after 24 hours of immersion in MEM compared to the as-received AZ31B alloy. The laser processed condition exhibited a 5 fold reduction in cathodic kinetics to the as-received alloy as well as maintaining an open circuit potential 150 mV lower than the coated and as-received specimen. The passivate nature of all three specimen conditions was similar.