Poly(methyl methacrylate) Grafting onto Stainless Steel Surfaces: Application to Drug-Eluting Stents

Abstract

Drug-eluting stents (DESs) have been associated with adverse clinical effects. Moreover, recent publications have shown that the coating of DESs suffers from defects. The purpose of this contribution is to examine a three-step process for surface modification as a means of improving the durability of DESs. In the first step, 4-(2-bromoethyl)benzenediazonium tetrafluoroborate was electrografted onto a stainless steel (SS) stent. X-ray photoelectron spectroscopy (XPS) of the modified stent confirmed the formation of the organic layer. In the second step, methyl methacrylate was polymerized onto the grafted surface by atom-transfer radical polymerization. XPS, electrochemical impedance spectroscopy, and contact-angle measurements were used to characterize the polymer brushes. The last step involved spray-coating of the stent with a drug-in-polymer matrix [poly(n-butyl methacrylate)/poly(ethylene-co-vinyl acetate) + paclitaxel]. Scanning electron microscopy confirmed the considerably improved durability of the drug-in-polymer matrix. Bare controls showed greater cracking and delamination of the coating than did the two-step modified stents after incubation under physiological (37 degrees C) and accelerated (60 degrees C) conditions. Finally, paclitaxel controlled release from the modified SS DESs was moderate compared with that of nontreated samples. In conclusion, the proposed method significantly improves the durability of drug-in-polymer matrixes on a SS DESs.

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

“…On the other side, the CC-PHEMA200, CC-PHEMA50-g-PCL, and CC-PHEMA200-g-PCL showed 52% release of the initial drug amount. These results is correlated with the previous report that demonstrated a correlation between coating stability and drug release pattern[20]. After 28 days of release, the control Co-Cr showed a burst release of almost 88% due to coating detachment, which refers to the instability of the SRL-in-PDLLA coating on the control Co-Cr alloy surface.…”

“…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].…”

Carbohydrate polymer grafting on stainless steel surface and its biocompatibility study

“…As a representative biomaterial, stainless steel has been extensively used in orthopedic implants, prostheses, and stents due to its excellent mechanical strength and corrosion resistance [14,15]. However, the use of bare stainless steel without any surface treatment is not recommended as it can cause an unfavorable response from the living body [16][17][18].…”

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].…”