Drug‐eluting stent with improved durability and controllability properties, obtained via electrocoated adhesive promotion layer

Abstract

Drug-eluting stents (DES) have become an accepted technology in intravascular intervention. Manufacturing methodologies of DES are based mainly on mechanical processes, which tend to generate coatings that have poor stability properties; these were recently related as a potential hazard. A novel approach for significantly increasing the adhesion of polymer coatings onto DES is presented. The method is based on the electrochemistry of diazonium salts. These substances are organic compounds with the characteristic structure of R-N(2) (+) X(-), where R is an organic residue and X(-) is an anion. The objective of this article is to study the properties of a selected diazonium salt 4-(1-dodecyloxy)-phenyldiazonium tetrafluoroborate, referred as C(12)-phenyldiazonium. This material was found to be a superior adhesive promoter for polymeric coatings applied onto metallic stents. C(12)-phenyldiazonium was synthesized and electrocoated on metallic stents and plates. The multilayer films of C(12)-phenyldiazonium were further characterized through electrochemical (cyclic voltammetry, impedance spectroscopy), physical (light and scanning electron microscopy, X-ray photoelectron spectroscopy, peeling tests), and chemical methodology (high pressure liquid chromatography). Further biocompatibility properties of the electrocoated basecoat were evaluated using in vitro and in vivo models. Synthesized C(12)-phenyldiazonium was successfully electrocoated onto metallic surfaces. Electrochemical tests demonstrated its efficient and controllable electrocoating. C(12)-phenyldiazonium was found to increase polymeric coating stability as was reflected by a standard adhesion test. Electrocoated metallic stents spray-coated with a second polymeric film showed improved durability following incubation in physiological buffer. Furthermore, this improvement in durability exhibits stabilized drug release. In addition, biocompatibility evaluations have demonstrated basecoat's inert properties.

Electrochemical Coating of Medical Implants

“…The diazonium primer was tested and showed inert properties. 137 Protein antifouling surfaces [138][139] usually contain derivatives of polyethylene glycol, known as excellent anticoagulant agents. The ability to directly modify the implant surface (specifically those in contact with blood) with PEG derivatives is of outmost importance and challenging.…”

Biodegradable polymer brush as nanocoupled interface for improving the durability of polymer coating on metal surface

“…Therefore, the biodegradable polymer brushes might be one of the strategies to solve the interfacial problems through improving the physicochemical properties of the metallic surface. Recently, some researchers have tried to resolve these serious problems related to polymer coating via chemical modifications of the metallic surfaces using diazonium or methacrylated derivatives [24][25][26]. In our previous work, a nanocoupling method was used to improve the interaction between metallic surface and coating layer, but it did not show superior properties to address the coating defects [27].…”

Effects of interfacial layer wettability and thickness on the coating morphology and sirolimus release for drug-eluting stent

“…Some researchers have investigated the modification of stent surface using ultrathin layer of polymer coating or brushes [18][19][20][21]. Recently, our group focused on studies of polymer brushes effects as an interface for the adhesion and durability of a biodegradable polymer for DES [22,23].…”