Magnesium Essay

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2.4.1 Magnesium Properties

Magnesium is the essential to human body and naturally it is found in bone and it is the fourth cation in human body. Magnesium is a lightweight metal with a density of 1.74 g/cm3. The fracture toughness of magnesium are greater than the ceramic materials such as hydroxyapatite. Elastic modulus and compressive yield strength of magnesium are similarly to human bone. The disadvantages of magnesium is it has low corrosion resistance and stimulatory effects on the growth of bone tissues (Mark P.Staiger et al., 2006).
Table 2.7: Physical properties of pure magnesium (International Magnesium Association, 1943)
Physical Properties Value
Density (g/cm3) 1.74
Specific Gravity 1.7
Atomic Radius (nm) 0.160
Melting Point
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Hydroxyapatite is the major calcium phosphate bioceramics. It improves the properties and performance of HA when implantation is happen. The characteristics of HA is it has a poor mechanical properties such as strength and fatigue resistance. The major limitation of HA is, it is restricted to be used in load bearing area due to it brittleness (Siwar Sakka et al., 2013). The major problem of synthetic HA is it has low mechanical strength, comparatively poor biological properties and inappropriate degradation rate due to failure in bone regeneration. Synthetic HA face two challenges in the orthopedic application such as poor osteogenic properties if compare to the natural bone and it also have limited angiogenesis in the bone graft. To solve this problems, HA must incorporated with different elements such as sodium (Na), magnesium (Mg), copper (Cu), potassium (K), zinc (Zn) to be doped with HA. By doping there is slight changes in lattice parameters and volume of HA (Senthilguru kulanthaivel et al., 2015). Figure 2.7 represent the crystalline hydroxyapatite structure perpendicular to c and a …show more content…
It is widely used in various biomedical applications and it is present in bone and primarily serve as structural protein of extracellular matrics. The tissues regeneration are often limited by their poor mechanical properties where it can be improved by included the hydroxyapatite compound. The combination of this properties between natural polymer and bioactive ceramic materials make the bone regeneration done smoothly (Maddela Swetha et al., 2010). Collagen is the major components of extracellular matrix such as tendons, ligaments and skin. The biocomposites of hydroxyapatite/collagen are inadequate so magnesium will be used as a doping to improve the mechanical and physical properties of bone in biomedical fields (Nebahat Degirmenbasi et al., 2006). The collagen have good biocompatibility, non-toxicity, non-antigenic and biodegradable that make this collagen are prefer to be used in variety of biomedical applications. It is also osteoconductive agent and haemostatic. The collagen are classified based on their molecules sequences where 27 distinct type with least 42 polypeptide chains of collagen. Mostly, the collagen that present in connective tissues is type 1 which are composed of two α1(1) chains and one α2(1) chain in the form of a triple helix pattern with fiber diameter of about 50nm. Collagen are composed of three polypeptide chains (α

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