1 research outputs found
Corrosion Characteristics Dictate the Long-Term Inflammatory Profile of Degradable Zinc Arterial Implants
There
has been considerable recent interest to develop a feasible
bioresorbable stent (BRS) metal. Although zinc and its alloys have
many potential advantages, the inflammatory response has not been
carefully examined. Using a modified wire implantation model, we characterize
the inflammatory response elicited by zinc at high purity (4N) [99.99%],
special high grade (SHG)[∼99.7%], and alloyed with 1 wt % (Zn-1Al),
3% (Zn-3Al), and 5.5% (Zn-5Al) aluminum. We found that inflammatory
cells were able to penetrate the thick and porous corrosion layer
that quickly formed around SHG, Zn-1Al, Zn-3Al, and Zn-5Al implants.
In contrast, a delayed entrance of inflammatory cells into the corrosion
layer around 4N zinc due to a significantly lower corrosion rate was
associated with greater fibrous encapsulation, appearance of necrotic
regions, and increased macrophage labeling. Interestingly, cell viability
at the interface decreased from SHG, to Zn-1Al, and then Zn-3Al, a
trend associated with an increased CD68 and CD11b labeling and capsule
thickness. Potentially, the shift to intergranular corrosion due to
the aluminum addition increased the activity of macrophages. We conclude
that the ability of macrophages to penetrate and remain viable within
the corrosion layer may be of fundamental importance for eliciting
biocompatible inflammatory responses around corrodible metals