Development of nanofiber‐covered stents using electrospinning: In vitro and acute phase in vivo experiments

Abstract

There are some technical difficulties in treating for a broad necked aneurysm and a higher incidence of recurrence. Because of these drawbacks, more innovative techniques for superior endovascular reconstructive treatment are required. We developed a novel covered stent employing electrospinning to deposit fine polyurethane (PU) fibers onto stents. An in vitro water leak test was designed and applied prior to animal testing to estimate the performance of covered stents and to determine the appropriate amount of PU fibers on a stent. Two tenths of a milligram of PU fibers proved to be sufficient to prevent water leakage. Then, the efficacy of the covered stents to that of bare stents was compared using 10 rabbits in which model aneurysms had been formed at the right common carotid artery by the elastase method. Angiographic evaluation on day 1 posttreatment (acute phase) revealed complete occlusion of the aneurysms and the patency of the parent arteries in animals treated with covered stents. At 10 days poststenting (subacute phase), the aneurysm neck was completely covered with neointimal layer as shown by scanning electron microscopic examination. The PU-covered stent holds promise as a device for treating cerebral aneurysms.

The Application of Electrostatic Dry Powder Deposition Technology to Coat Drug-Eluting Stents

“…The coating materials are usually hydrophobic polymers (5), phosphorylcholine-containing polymers (6,7) triblock copolymers or heparin (8,9), which are biocompatible. Techniques such as dip-coating, (10) spraycoating (11), ink-jet technology (12), inorganic-coating (13), sputtering (14), plating (15), electrospinning (16) and layer-bylayer (17) coating technologies have been employed for laboratory and clinical applications. Stent coating has a significant impact on stent design affecting both angiographic and clinical outcomes (4,18).…”

Fabrication of Small Caliber Stent-grafts Using Electrospinning and Balloon Expandable Bare Metal Stents

“…Various polymers have been electrospun by other groups and polyurethane has been proven biostable and biocompatible. Polyurethane is also known to have very little bacterial adherence 13,28 .…”

“…Electrospun nanofibrous polyurethane covered stent-grafts are currently being used for treatment of aneurysms 13 . These stent-grafts are manufactured by sandwiching electrospun material between two stents which results in limited flexibility of the stent-grafts.…”

“…But the development of small caliber stent-grafts is limited by the ability to maintain low profile and flexibility, which aids in deployment of the stent-grafts [11][12][13][14] . PU is an elastomeric polymer with good mechanical strength which is a desired trait for achieving a low profile and good flexibility 15,16 .…”

Poly(2-methacryloyloxyethyl phosphorylcholine) (MPC) nanofibers coated with micro-patterned diamond-like carbon (DLC) for the controlled drug release

“…The 3D-structural approach using fine electrospun fibers made of an antithrombogenic polymer could be highly effective for the design of a stent-graft material with sufficient cell adhesion and additional endothelialization [4][5][6]. Our research group has been investigating the fabrication of electrospun nanofibers of biocompatible poly(2-methacryloyloxyethyl phosphorylcholine) (MPC) [7], one of the most frequently studied phospholipid biopolymers [8,9].…”