In vivo and in vitro Behavior Knowledge Convergence via Nanotomographic Corrosion Analysis: A Pathway to Improved Magnesium Medical Alloys

Outcome/accomplishment: A carefully-planned study of the corrosion of ERC-RMB’s new magnesium alloys using nanotomography revealed deeper insights into their in vitro and in vivo behavior in terms of types and mechanisms of corrosion product formation. This investigation for the first time helps bridge the gap between static and dynamic environments. The knowledge gained is allowing the team to establish protocols for the corrosion testing of biodegradable metals, with an emphasis on experimental design. Iterative application of these protocols are informing the judicious selection of alloying elements that lead a better Mg system with smaller and more uniform grain boundaries and smaller cathodic areas.

Corrosion progression in-vivo (ERC-RMB magnesium alloy) - optical images

Impact/benefits: A critical and indispensable first step in the successful development of medical implants from our newly-developed alloys is to gain a thorough and fundamental understanding of corrosion behavior in vivo. With this, ERC-RMB can better mimic the in vivo environment in in vitro testing and provide clinically relevant testing and characterization methods to ensure success of the implant.  Further impacts include the development of corrosion protocols as well as diminish the level of animal testing.

Explanation/background: Systematic studies to find the most influential parameters that affect corrosion and corrosion product formation are critical to advancing towards the clinical use of magnesium-based biomaterials. While current in vitro testing methods have unique advantages, they are insufficiently accurate in predicting in vivo corrosion behavior in terms of corrosion rate, corrosion product formation and mechanism. The understanding gained from our approach will result in the establishment of in vitro test protocols that better correlate with real-world in vivo behavior. While there remains much yet to be learned, in vivo and in vitro behavior knowledge convergence via nanotomographic corrosion analysis is providing ERC-RMB a pathway to improved magnesium medical alloys.