Lepu Medical Technology Co.

Beijing, China

Lepu Medical Technology Co.

Beijing, China

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Liu X.,Harbin Engineering University | Liu X.,Lepu Medical Technology Co. | Liu X.,National Instruments | Sun J.,Harbin Engineering University | And 7 more authors.
Materials Letters | Year: 2015

In the study, the mechanical properties, degradation behavior and in vitro biocompatibility of an ultra-pure Zn and its mini-tube were evaluated with the high-pure Mg and its mini-tube as controls. Compared with high-pure Mg, ultra-pure Zn had close mechanical properties and cytotoxicity, but it indicated lower corrosion rate (0.011 mm/y) than pure Mg in Hank's solution. Meanwhile, the hematolysis rate (1.00%) was lower than 5%, which means that Zn has no significant destructive effect on erythrocyte. Furthermore, compared with plate specimens, the tube specimens showed higher corrosion rate (Zn ∼0.028 to 0.037 mm/y and Mg ∼0.61 to 0.73 mm/y, respectively) and hemocompatibility (Zn ∼1.19% and Mg ∼9.50%, respectively). In conclusion, the ultra-pure Zn mini-tubes might be considered as a potential bioabsorbable stent material. © 2015, Elsevier B.V. All rights reserved.


Shen C.,PLA Fourth Military Medical University | Liu X.,Harbin Engineering University | Liu X.,Lepu Medical Technology Co. | Liu X.,National Instruments | And 15 more authors.
RSC Advances | Year: 2016

Zn, which is a promising alternative candidate as a biodegradable implant material, possesses excellent biocompatibility and biodegradability. However, the insufficiency of its strength and hardness has largely limited its application. Nevertheless, adding alloying elements and mechanical forming by extrusion have generally enhanced its mechanical properties. In the present work, Zn-1.2Mg alloy has been designed and treated by extrusion. Experimental results demonstrated that the studied alloys were composed of a matrix of Zn and a precipitated phase of Mg2Zn11, and the grain size became smaller and more homogeneous after extrusion. The as-extruded alloy exhibited much higher yield strength (YS 219.61 MPa), ultimate tensile strength (UTS 362.64 MPa), elongation (21.31%) and hardness (96.01 HV). The corrosion rates of the as-extruded alloy were higher compared with those of the as-cast alloy and reached values of 0.19 mm per year in electrochemical tests and 0.11 mm per year after exposure in Hank's solution for 30 days, respectively. Moreover, the as-extruded alloy displayed excellent hemocompatibility (hemolysis rate of 1.85%, superior thromboresistance and no signs of thrombogenicity). The viability of human osteosarcoma HOS cells and MG63 cells cultured in diluted extracts of the alloy exceeded 70%, which demonstrated no potential cytotoxicity and tolerance in cellular applications. © The Royal Society of Chemistry.


Liu X.,Harbin Engineering University | Liu X.,Lepu Medical Technology Co. | Liu X.,National Instruments | Sun J.,Harbin Engineering University | And 9 more authors.
Materials Letters | Year: 2016

The microstructure, mechanical properties, in vitro degradation behavior and hemocompatibility of novel Zn-1Mg-0.1Sr and Zn-1Mg-0.5Sr (wt%) ternary alloys were evaluated with pure Zn as control. The results indicated that Zn-Mg-Sr alloys exhibited much higher yield strength (YS), ultimate tensile strength (UTS), hardness and corrosion rate than those of pure Zn. But their elongation and hemolysis rates were reduced. Furthermore, the hot-rolled Zn-1Mg-0.1Sr alloy presented the superior mechanics performance (196.84±13.20 MPa, 300.08±6.09 MPa, 22.49±2.52%, 104.31±10.18 for YS, UTS, Elongation and hardness, respectively), appropriate corrosion rate (0.15±0.05 mm/year) and excellent hemocompatibility (hematolysis rate of 1.10±0.2% and no signs of thrombogenicity), showing a preferable candidate as the biodegradable implant material. ©2015 Published by Elsevier B.V.


Liu X.,Harbin Engineering University | Liu X.,Lepu Medical Technology Co. | Liu X.,National Instruments | Sun J.,Harbin Engineering University | And 11 more authors.
Materials and Design | Year: 2016

Zn as a novel biodegradable metal holds great potential in bioresorbable implant application since it possesses excellent biocompatibility and more corrosion resistant than Mg. In the present study, the effect of the micro-alloying element Mn on the Zn-Mg alloy was studied with mechanical properties, in vitro degradation behaviors and hemocompatibility being evaluated in comparison with pure Zn as control. The experimental Zn-Mg-Mn alloys were composed of the matrix Zn and secondary phase (MgZn2). Meanwhile, Zn-Mg-Mn alloys ingots exhibited much higher yield strength (YS), ultimate tensile strength (UTS) and hardness compared to pure Zn. But their elongation was reduced. The results of immersion in Hank's solution for 30 days revealed that the sequence of corrosion rates from high to low was: as-cast Zn-1Mg-0.1Mn alloy > as-cast Zn-1.5Mg-0.1Mn alloy > pure Zn. The consequences of electrochemical tests indicated that the calculated corrosion rates followed the ranking order: as-cast Zn-1Mg-0.1Mn alloy > as-cast Zn-1.5Mg-0.1Mn alloy > pure Zn. The results of hemolysis rate and platelet adhesion implied that the studied alloys had good blood compatibility. Furthermore, after hot-rolling, the YS, UTS, elongation and hardness of Zn-1Mg-0.1Mn alloys were further improved and possessed the superior mechanics performance (YS 195.02 MPa, UTS 299.04 MPa, Elongation 26.07%, Hardness 107.82 Hv), appropriate corrosion rate (Vcorr 0.25 mm/year) and excellent hemocompatibility (hemolysis rate of 1.10% and no signs of thrombogenicity), showing the preferable candidate as a biodegradable implant material. © 2015 Published by Elsevier Ltd.


Liu X.,Harbin Engineering University | Liu X.,Lepu Medical Technology Co. | Liu X.,National Instruments | Sun J.,Harbin Engineering University | And 9 more authors.
Journal of Alloys and Compounds | Year: 2016

Zn, a promising biodegradable material, possesses excellent biocompatibility and biodegradability, however its low strength and hardness largely limit its application in biodegradable implants. The addition of alloying elements would generally be suggested as an effective method for improving the mechanical properties. In the current study, alloying with a minor amount of Ca or Sr in Zn-1.5Mg alloy, the ternary alloys were composed of the matrix Zn and precipitated phase (Mg2Zn11 and CaZn13 for Zn-1.5Mg-0.1Ca alloy, Mg2Zn11 and SrZn13 for Zn-1.5Mg-0.1Sr alloy, respectively). Besides, the grain size of ternary alloys became more homogeneous and smaller than that of Zn-1.5Mg alloy. Meanwhile, the effect of alloying elements on the mechanical properties and corrosion behavior of Zn-1.5Mg alloy were analyzed. The results showed that the ternary alloys exhibited much higher yield strength (YS), ultimate tensile strength (UTS) and elongation than those of Zn-1.5Mg alloy. The measured corrosion rates of the ternary alloys were slightly increased due to galvanic corrosion reaction. Besides, a model of the corrosion mechanism in the simulated body fluid was discussed here based on the results of the studied alloys. © 2015 Published by Elsevier B.V.

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