**5. Biomedical applications**

Magnesium is present in the form of the mineral is 65% in bones and teeth, and the remaining 35% is present in body fluids and tissues. The biocompatibility and biodegradability make magnesium more suitable for biomedical applications. The researchers are paying much attention to influence the interactive mechanism of biodegradable materials. The magnesium strength has approached the bone strength and is used in orthopedic implants. The magnesium can also be used in other orthopedic surgeries such as screws, plates, and fasteners. The magnesium shows nominal changes in blood composition with six months of implantation without damage to the liver and kidneys [19].

The magnesium is a major alloying element used in biodegradable implant in vivo and in vitro conditions. It has excellent biocompatibility and is the fourth most abundant element present in the human body, and it is an essential nutrient element. Magnesium has a high corrosion rate and releases H2 gas in human body fluid. Modern techniques have been adopted to control the corrosion rate and heal the fractured tissues without the need for secondary surgery to remove the implants. The fraction of the component must be selected as per biocompatibility to avoid toxicity. Thus, extreme concerns must be taken to choose the reinforcement with magnesium to control biomechanical properties and corrosion rate under biological conditions. The selection of bioceramics is very important as they may cause some severe body fluid issues, and some are mentioned in **Table 4** [20, 21]. The pure magnesium implant is degraded much earlier than the tissue heals. Therefore, mechanical and degradation properties are intended to increase.

The addition of alloying elements in pure magnesium improves the grain refinement and strengthen the composites. The most commonly used bioceramics and their effects are presented in **Table 5**. These ceramics are added in magnesium and its alloys to fabricate the magnesium-based composites with excellent strength and biodegradable properties. The biocompatibility of composite in the biological environment is based on strengthening ability degradation and toxicity [22].

The alloying elements can be classified as toxic, nutrient, and allergic, which are present in the human body. The bioinert and bioactive ceramics are significant reinforcements to achieve required biocompatibility and strength. The properties of


#### **Table 4.**

*Bioelements and their effects on biofluids.*


#### **Table 5.**

*Commonly used bioceramics and their characteristics.*

common bioceramics are given in **Table 5**, and the selection of specific bioceramic is important for outstanding performance in toxicity and immunological environment.
