Interface Engineering of Fully Metallic Stents Enabling Controllable H₂O₂ Generation for Antirestenosis

Abstract

Despite significant advances in the design of metallic materials for bare metal stents (BMSs), restenosis induced by the accumulation of smooth muscle cells (SMCs) has been a major constraint on improving the clinical efficacy of stent implantation. Here, a new strategy for avoiding this issue by utilizing hydrogen peroxide (H 2 O 2 ) generated by the galvanic coupling of nitinol (NiTi) stents and biodegradable magnesium−zinc (Mg−Zn) alloys is reported. The amount of H 2 O 2 released is carefully optimized via the biodegradability engineering of the alloys and by controlling the immersion time to selectively inhibit the proliferation and function of SMCs without harming vascular endothelial cells. Based on demonstrations of its unique capabilities, a fully metallic stent with antirestenotic functionality was successfully fabricated by depositing Mg layers onto commercialized NiTi stents. The introduction of surface engineering to yield a patterned Mg coating ensured the maintenance of a stable interface between Mg and NiTi during the process of NiTi stent expansion, showing high feasibility for clinical application. This new concept of an inert metal/degradable metal hybrid system based on galvanic metal coupling, biodegradability engineering, and surface patterning can serve as a novel way to construct functional and stable BMSs for preventing restenosis.

Nanostructured Surfaces with Multimodal Antimicrobial Action

“…The hypothesis for the generation of superoxide radical oxygen species was postulated to arise from the self-corrosion of the zinc substrate, which subsequently transfers the electrons to the metal semiconductor ZnO nanopillars. The generation of ROS from such mechanisms was previously reported for a Mg/TiO 2 pair, − and there have been no other reports since. The full electron transfer from the zinc substrate to the ZnO conduction band as an intermediary to ground-state oxygen to form superoxide radicals is energetically favored.…”

Coronary Stents Decorated by Heparin/NONOate Nanoparticles for Anticoagulant and Endothelialized Effects

“…Coronary artery disease (CAD), a major threat to human health, has become one of the leading causes of disease and death worldwide. , Currently, drug-eluting stents (DES) are widely used to restore blood flow. , However, there is a risk of restenosis, delayed endothelial healing, and late thrombosis after stent implantation. − The ideal stent should have the surface characteristics of inhibiting intimal hyperplasia, good blood compatibility, and accelerating endothelialization. , However, many drug stents currently contain only small amounts of single drugs or biological molecules, which cannot meet the treatment requirements of complexity of the disease. − Thus, the strategy of modifying DES by combining two or more biomolecules with different functions and utilizing their synergistic effects are becoming more interesting. − …”

Tailoring H2O2 generation kinetics with magnesium alloys for efficient disinfection on titanium surface

“…Fabricating Ti-Mg alloy system and investigating the effects of Ti-Mg alloy system on E. coli and zebrafish embryos. Pure Mg (99.99 wt%), pure Zn pillet (99.99 wt%) and pure Ca powder (99.99 wt%) were utilized to fabricate cylindrical shaped as-cast Mg alloys (Mg-3wt% Zn, pure Mg, and Mg-3wt% Ca), as described previously 19,29 . In detail, Mg alloys were carefully melted by gravity casting under Ar atmosphere.…”

“…In this work, which was inspired by traditional cathodic protection technology that utilizes electrons generated from the degradation process of Mg alloys to reduce the metal ions of a primary metal 15,16 , we applied Mg alloys to reduce O 2 molecules near the primary metal for generating hydrogen peroxide (H 2 O 2 ), which has been widely applied for antibacterial purposes 17,18 . By establishing a simple electric connection between the primary metal, such as Ti, and Mg alloys, H 2 O 2 can be released at the surface of the primary metal according to the following electrochemical reactions 13,19 : The keystone of this technology is to quantitatively control the formation kinetics of H 2 O 2 through the degradation engineering of Mg alloys. By tailoring the microstructures and electrochemical properties of Mg with secondary elements, such as Ca and Zn, we succeeded in regulating the degradation rate of Mg and H 2 O 2 formation kinetics.…”