Magnetically Coated Bioabsorbable Stents for Renormalization of Arterial Vessel Walls after Stent Implantation

Abstract

The insertion of a stent in diseased arteries is a common endovascular procedure that can be compromised by the development of short- and long-term inflammatory responses leading to restenosis and thrombosis, respectively. While treatment with drugs, either systemic or localized, has decreased the incidence of restenosis and thrombosis these complications persist and are associated with a high mortality in those that present with stent thrombosis. We reasoned that if stents could be made to undergo accelerated endothelialization in the deployed region, then such an approach would further decrease the occurrence of stent thrombosis and restenosis thereby improving clinical outcomes. Toward that objective, the first step necessitated efficient capture of progenitor stem cells, which eventually would become the new endothelium. To achieve this objective, we engineered intrinsic ferromagnetism within nonmagnetizable, biodegradable magnesium (Mg) bare metal stents. Mg stents were coated with biodegradable polylactide (PLA) polymer embedding magnetizable iron-platinum (FePt) alloy nanoparticles, nanomagnetic particles, Mags, which increased the surface area and hence magnetization of the stent.Mags uniformly distributed on stents enabled capture, under flow, up to 50 mL/min, of systemically injected iron-oxide-labeled (IO-labeled) progenitor stem cells. Critical parameters enhancing capture efficiency were optimized, and we demonstrated the generality of the approach by showing that Mag-coated stents can capture different cell types. Our work is a potential paradigm shift in engineering stents because implants are rendered as tissue in the body, and this "natural stealthiness" reduces or eliminates issues associated with pro-inflammatory immune responses postimplantation.

Iron Oxide Nanoparticles in Regenerative Medicine and Tissue Engineering

“…In one study, a biocompatible polymer-free composite coating of magnetic mesoporous silica nanoparticles (MMSNs) and carbon nanotubes (CNTs) was prepared, which had a sufficient drug (rapamycin) release performance, and the advantage of rapid endothelialization compared with other commercial polymer-coated drug-eluting stents [ 108 ]. Lee et al coated magnesium stents with biodegradable PLA polymer with embedded magnetizable iron-platinum (FePt) NPs [ 109 ]. These stents allowed efficient and uniform capture of IONPs-labeled progenitor stem cells even under flow conditions.…”

Recent Advances in Nanomaterials for Therapy and Diagnosis of Cardiovascular Disease

“…Further study is needed to comprehensively analyze the toxicity, especially chemotoxicity and inflammatory responses. In addition, future work should plan to introduce novel ways to reduce toxicity, represented in Table 3 [77][78][79][80][81][82][83][84][85] and Table 4 [86][87][88][89].…”

Recent Progress on Mg- and Zn-Based Alloys for Biodegradable Vascular Stent Applications

“…Journal of Nanomaterials flexibility, deliverability, profile, and lifetime integrity [18]. Materials with high UTS and relatively low YS are recommended for vascular stents.…”