In vitro and in vivo biocompatibility of Mg–Zn–Ca alloy operative clip

At present,titanium(Ti)and its alloys are most commonly use in hemostasis clip clinical applications.However,the Ti Clip cannot be absorbed in human body and produce artifacts on computed tomography(CT),and induce clinically relevant hypersensitivity in patients.In order to overcome the drawbacks of the non-degradable Ti clips,an Mg-Zn-Ca alloy operative clip was fabricated by combining hot extrusion and blanking processing.In vitro and in vivo biocompatibility of Mg-Zn-Ca alloy operative clip were evaluated by L-929 Cells and SD rat model respectively.It was found that Mg-Zn-Ca alloy exhibited non-cytotoxic to L929 cells.In vivo implantation showed that the newly designed Mg-Zn-Ca clip can successfully ligated carotid artery and no blood leakage occurred post-surgery.During the period of the clip degradation,a small amount of H2 gas formation and no tissue inflammation around the clips were observed.The degradation rate of the clip near the heart ligated the arteries faster than that of clip far away the heart due do the effect of arterial blood.Histological analysis and various blood biochemical parameters in rat serum samples collected at different times after clip implantation showed no tissue inflammation around the clips.

In Vivo and In Vitro Degradation Behavior of Magnesium Alloys as Biomaterials

The corrosion behavior of pure Mg,AZ31,and AZ91D were evaluated in various in vitro and in vivo environments to investigate the potential application of these metals as biodegradable implant materials.DC polarization tests and immersion tests were performed in different simulated body solutions,such as distilled（DI） water,simulated body fluid（SBF） and phosphate buffered solution（PBS）.Mg/Mg alloys were also implanted in different places in a mouse for in vivo weight loss and biocompatibility investigations.The in vivo subcutis bio-corrosion rate was lower than the corrosion rate for all of the in vitro simulated corrosive environments.The Mg/Mg alloys were biocompatible based on histology results for the liver,heart,kidney,skin and lung of the mouse during the two months implantation.Optical microscopy and scanning electron microscopy were carried out to investigate the morphology and topography of Mg/Mg alloys after immersion testing and implantation to understand the corrosion mechanisms.