Page 18 - Magnesium-based supports for stem cell therapy of vascular disease - Mónica Echeverry Rendón

CHAPTER 2
Abstract
Metals are used as base material for fabrication of medical devices to support and improve the quality of life of patients with diseases that range from bone degeneration to cardiovascular disease. Metal stents are widely used to treat vascular lesions such as arterial stenoses. In the body, permanently present implants may induce responses that resemble adverse wound healing, that compromise tissue function. A similar process namely restenosis, fre- quently occurs after arterial stenting. Obviously, the use of non-permanent, resorbable stents, which are degraded upon vascular repair, might prevent restenoses. A promising metal for this application, is magnesium, because it can be modified to degrade without adverse effects to the body. In fact, magnesium is an essential element for human life. In the past two decades, magnesium alloys were developed, and reached clinical application as arterial stents. Critical parameters for the clinical application of magnesium-based resorbable biomaterials, are corrosion re- sistance, biocompatibility, and mechanical properties. This review shows and discusses recent challenges in clinical applications of magnesium-based biomaterials used to treat vascular disease and novel approaches at design-based biomaterials engineering of the same. Design-based methodologies are introduced and discussed in the context of balancing multi-functional properties against adaptation to the complex extreme in vivo environment. Traditional alloying approaches of magnesium-based biomaterials are also discussed in the context of corrosion resistance con- trol by surface modification strategies including conversion techniques: chemical or electrochemical transformation such as anodization and electrophoretic deposition. Plasma electrolytic oxidation (PEO) technique is an example of plasma-enhanced anodization that can also introduce multi-functionality to magnesium-based biomaterials for vascular repair. Finally, the review summarizes recent work on energetic and plasma-based methodologies for sur- face modification and the implications on a robust, non-toxic, low-temperature approach to magnesium-based alloy biomaterials design.
Key words: Stent, cardiovascular disease, magnesium, biodegradation, biocorrosion, surface modification
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