Magnesium degradation products: Effects on tissue and human metabolism

Abstract

Owing to their mechanical properties, metallic materials present a promising solution in the field of resorbable implants. The magnesium metabolism in humans differs depending on its introduction. The natural, oral administration of magnesium via, for example, food, essentially leads to an intracellular enrichment of Mg(2+) . In contrast, introducing magnesium-rich substances or implants into the tissue results in a different decomposition behavior. Here, exposing magnesium to artificial body electrolytes resulted in the formation of the following products: magnesium hydroxide, magnesium oxide, and magnesium chloride, as well as calcium and magnesium apatites. Moreover, it can be assumed that Mg(2+) , OH(-) ions, and gaseous hydrogen are also present and result from the reaction for magnesium in an aqueous environment. With the aid of physiological metabolic processes, the organism succeeds in either excreting the above mentioned products or integrating them into the natural metabolic process. Only a burst release of these products is to be considered a problem. A multitude of general tissue effects and responses from the Mg's degradation products is considered within this review, which is not targeting specific implant classes. Furthermore, common alloying elements of magnesium and their hazardous potential in vivo are taken into account.

Influence of the Composition of the Hank’s Balanced Salt Solution on the Corrosion Behavior of AZ31 and AZ61 Magnesium Alloys

“…A high concentration of Al was considered to possibly cause neurotoxic illnesses such as dementia or Alzheimer's disease. However, when Al is introduced into the human body in small concentrations, for instance during dietary ingestion or consumption from natural or urban water supplies, then it is naturally excreted through urine or in the form of bile [10,[16][17][18][19][20][21].…”

Recent Advances in Biodegradable Metals for Medical Sutures: A Critical Review

“…[146][147][148][149] Good biocompatibility of magnesium and its degradation products are expected because magnesium is an essential element in the human body's natural biological system. [ 148,150 ] In fact, magnesium seems to be an ideal candidate for biodegradable applications as magnesium implants could be a source to cover the human recommended daily Mg intake of 375 to 500 mg. [ 41,151 ] Within the human body, magnesium represents an essential cofactor for numerous metabolic processes. Magnesium particularly assumes signifi cance for phosphate dependant reactions.…”

“…[ 151,152 ] It furthermore serves to stabilize membranes and infl uences neuromuscular conduction and functions of the central nervous system. [ 41,153 ] Overdoses of magnesium have the potential to reduce the excitability of neuromuscle, smooth muscle, and cardiac tissue, potentially resulting in a symptom referred to as "magnesium narcosis". [ 151,152 ] The biocompatibility of Mg alloys can be infl uenced by the alloying elements used and their concentration.…”

“…[ 34,38 ] Their toxicity limits (zinc 100 to 150 mg/day; iron 10 to 17 mg/day) however, are lower than magnesium's (375 to 500 mg/day), restricting their applicability to implants with smaller volumes. [39][40][41] On the other hand, magnesium's high corrosion rate is associated with a potentially harmful hydrogen gas evolution, which may also restrict the size and applicability of magnesium implants. [ 32,42 ] Progress in the development of new biodegradable metals may stimulate the manufacturing of innovative resorbable wires, sutures, and other implants.…”

Influence of Alloying Treatment and Rapid Solidification on the Degradation Behavior and Mechanical Properties of Mg

“…Moreover, it plays essential roles in human metabolism, cellular structure and function, and bone growth [3][4][5]. However, the degradation rate of Mg becomes excessively fast in a physiological environment, resulting in quick loss of mechanical strength [6].…”