Biomaterials made of
zinc have been widely described to be antioxidative, hypothrombogenic, antiinflammatory and antiproliferative. Additionally in vivo
zinc is toxic only in high concentrations and can completely be metabolized in vivo. Due to these properties
zinc based vascular
stents might be able to reduce the rate of restenosis in comparison to bare
metal stents and
zinc stents might be also able to limit the
foreign body reaction. In the presented study we tested the biocompatibility and degradability of a
stent made of
zinc and characterized by a closed-cell-design to achieve high opening force and to increase
stent stiffness. After 100 days of enzymatic and hydrolytic degradation in 15 ml blood serum (
fetal calf serum) a significant loss of weight (1.72 wt% ) was measured.
Zinc was compared to other metals in terms of degradation rates. After six weeks of incubation in physiologic
sodium chloride solution zinc showed the slowest degradation time, 6 times less than
stainless steel and 4 times less than
magnesium. In the tests for cytotoxic effects the degraded
zinc stent caused no changes in the LDH-release and cell membrane integrity (3T3 cells, mouse fibroblasts) respectively, in the cell activity/proliferation (MTS assay) and in the morphological characteristics of the cells and cell layers in comparison to the control material (
polystyrene). Based on these results the tested
zinc stent proved to be non-cytotoxic and to be characterized by degradation characteristics which might be advantageous in comparison to
magnesium and
stainless steel.