In vivo biocompatibility and degradability of a Zn–Mg–Fe alloy osteosynthesis system

Abstract

Zinc is generally considered to be one of the most promising materials to be used in biodegradable implants, and many zinc alloys have been optimized to improve implant biocompatibility, degradation, and mechanical properties. However, long-term degradation leads to the prolonged presence of degradation products, which risks foreign body reactions. Herein, we investigated the in vivo biocompatibility and degradation of a biodegradable Zn–Mg–Fe alloy osteosynthesis system in the frontal bone, mandible, and femur in beagles for 1 year. Results of the routine blood, biochemical, trace element, and histological analyses of multiple organs, peripheral blood CD4/CD8a levels, and serum interleukin 2 and 4 levels showed good biocompatibility of the Zn–Mg–Fe alloy. Zinc content analysis revealed zinc accumulation in adjacent bone tissue, but not in the liver, kidney, and spleen, which was related to the degradation of the Zn–Mg–Fe alloy. The alloy demonstrated a uniform slowing degradation rate in vivo . No degradation differences in the frontal bone, mandible, and femur were observed. The degradation products included zinc oxide [ZnO], zinc hydroxide [Zn(OH) 2 ], hydrozincite [Zn 5 (OH) 6 (CO 3 ) 2 ], and hopeite [Zn 3 (PO 4 ) 2 ·4H 2 O]. The good biocompatibility and degradation properties of the Zn–Mg–Fe alloy render it a very attractive osteosynthesis system for clinical applications.

Titanium or Biodegradable Osteosynthesis in Maxillofacial Surgery? In Vitro and In Vivo Performances

“…Besides the currently available biodegradable synthetic copolymeric systems (e.g., PDLLA), novel biodegradable systems composed of degradable metals (e.g., magnesium and zinc alloys) [ 87 , 244 , 245 ] or natural polymers (e.g., amorphous silk fibers derived from the silkworm Bombyx mori ) are being developed [ 18 ].…”

Immune response differences in degradable and non-degradable alloy implants

“…One of the main concerns regarding the usage of Zn-based biodegradable implants is their long-term degradation profile which may lead to the prolonged presence of corrosion materials. This long-term presence increases the risk of foreign body reactions [ 160 ]. In a study, metallic zinc was implanted into the abdominal aorta of rats and the degradation was monitored for 20 months post-implantation.…”

“…The peripheral blood CD4/CD8a lymphocyte ratio showed no significant changes in Zn–Mg–Fe implant, and the serum levels of IL-2 and IL-4 were also the same as no implant samples. The degradation was similar in frontal, mandible and femur with products including zinc oxide [ZnO], zinc hydroxide [Zn(OH)2], hydrozincite [Zn5(OH)6(CO3)2], and hopeite [Zn3(PO4)2·4H2O] that were all tolerable with no immune reaction [ 160 ].…”

Study of biocompatibility <i>in vitro</i> of ultrafine-grained Zn-based bioresorbable alloys

“…% ≤Fe ≤0,5 масс. %) наблюдалось накопление цинка в прилегающих к кости тканях при хорошей биосовместимости in vivo [17]. При этом, несмотря на приведенные результаты, накопленная статистика по исследованию биосовместимости сплавов на основе цинка все еще остается довольно скудной и противоречивой.…”