Metals and metal ions release from metallic implants in the animal body models: A review of experimental investigations

Abstract

All non-noble metals and alloys will release metallic species into the body. This raises the issue of amount and fate, i.e. transport and storage, of these metal dissolution products. No metal or alloy is completely inert in vivo. Metallic transfer from implants does not stop at surrounding tissues, and metallic elements may be transferred by proteins to become lodged in organs far from the implant. The use of metallic biomaterials in the medical implant devices has become increasingly prevalent over the past few decades. Metals and metal ions release from metallic materials; titanium and titanium and its alloys, nickel-titanium alloys, cobalt-chromium alloys, and magnesium-based alloys implanted into the human body is becoming a major cause of concern. The development of reliable experimental models for the clinical use of biomaterials and in predicting implant success or failure is becoming increasingly important in attaining adequate health and safety conditions. Animal models provide important biomaterial knowledge that eventually leads to the development of more effective clinical treatments of diseases in both humans and animals; therefore, acting as a bridge between In vitro studies and in vivo clinical trials. The most commonly used laboratory animals have turned out to be rats, mice, and rabbits, probably because they are cheaper and easy to handle. In addition, cattle, primates, sheep, swine and guinea pigs are used by researchers in a progressively decreasing order. The present review reported the results of In vitro and in vivo experimental investigations on the release of metallic traces in the biological fluids, tissues and different inner organ tissues resulting from the implantation of the small metallic implants in the animals.