A perspective on molybdenum biocompatibility and antimicrobial activity for applications in implants

The use of biomaterials has become routine in dentistry, reconstructive surgery of the locomotor system, treatment of congenital, traumatic and tumor situations, and knee or hip arthroplasty. The main issue related to metal biomaterials is the systemic release of metal ions and the related biological risks. When placed in contact with a living organism, they must meet a set of criteria: they must be biocompatible and biofunctional, as well as have the ability to produce a specific biological response at the surface, leading to the formation of a bond between the material and the receiving tissue and a surface texture which allows cell adhesion and bone growth; they must also provide adequate structure and mechanical strength, without causing adverse reactions in the surrounding physiological environment; they must not cause oncogenic effects; they must be easy to manipulate during surgery; and they must be amenable to visible imaging and sterilization. The ability to use biomaterials is linked to the degree of biocompatibility and biofunctionality which in turn, are dependent on their physicochemical and mechanical properties, macroscopic and microscopic configuration, and the biological environment where they are deployed. Metal alloys, particularly stainless steel, cobalt, molybdenum, chromium alloys, and titanium-based alloys find wide application in orthopedics for making joint replacement prostheses, systems for external or internal fixation of bone fractures, surgical correction of degenerative conditions, or in the composition of staples, screws, and wires. Any synthetic biomaterial can replace or restore the function of body tissues while maintaining a continuous or intermittent contact with the fluid. When in contact with the fluid, it is essential that materials be biocompatible, so they do not produce adverse biological responses or induce systemic effects. Thus, they must not be toxic, carcinogenic, mutagenic, or antigenic. Bioactive materials with antibacterial properties are also of significant medical interest. Materials exhibiting good antimicrobial activity that minimize the formation of biofilm without the risk of promoting the development of resistant microorganisms are desirable. In this respect, this review briefly summarizes the recent successes of this metal as a biocompatible material with antibacterial activity for biomedical applications.