Preparation and properties of open-cell zinc foams as human bone substitute material

Abstract

M edical metal materials have good mechanical properties and biocompatibility, and have been widely used as human hard tissue repair and replacement materials [1-3]. However, clinical studies have found that many medical metal materials do not match the elastic modulus of human bones, which will produce "stress shielding" phenomenon when implanted in the human body, resulting in loose or broken implants [4-6]. To solve the above problems, scholars have proposed a method of introducing pores into the medical metal materials [7,8]. The density, strength, and modulus of elasticity of porous metal materials can be adjusted by pore size and porosity, thus "stress shielding" can be alleviated or eliminated [9,10]. Porous structure and rough surface are conducive to the adhesion, proliferation, and differentiation of osteocytes, and promote the growth of new osteocytes into the pore [11,12]. Because the pore structure of foam metals is three-dimensionally connected, the body fluids and nutrients can be circulated, promoting tissue regeneration and reconstruction, and quickening the healing process [13,14]. At present, titanium foam and tantalum foam are often used to replace bone tissue. It should be pointed

Corrosion of porous Mg and Fe scaffolds: a review of mechanical and biocompatibility responses

“…Figure 6 summarises the elastic modulus of porous absorbable metals with respect to their corrosion rates. An ideal bone scaffold should have an elastic modulus which is closer to that of natural bone (0.01-20 GPa) [86]. Referring to the figure, the dynamic immersion apparently led to the diminishing of the elasticity of porous Mg scaffolds and to the acceleration of the corrosion rate despite their lower as-fabricated porosity when compared with and Fe-based counterparts.…”

“…The production of porous Fe-based scaffolds in a higher porosity (>80%) considerably deteriorates its elastic modulus to 0.003-0.2 GPa, even though the porosity is in the range of cancellous bone's porosity (40-90%) [86]. Higher porosity can facilitate tissue growth but at the expense of losing elasticity.…”