Effect of PLLA coating on corrosion and biocompatibility of zinc in vascular environment
Department of Biomedical Engineering; Department of Materials Science and Engineering
Zinc (Zn) has recently been introduced as a promising new metal candidate for biodegradable vascular stent applications with a favorable degradation rate and biocompatibility. Corrosion-resistant metal stents are often coated with drug-eluting polymer layers to inhibit harmful biological responses. Here, the authors aimed to investigate the interaction between biodegradable zinc metal and a conventional biodegradable polymer coating. Zinc wires with a diameter of 0·25 mm were surface-modified using 3-(trimethoxysilyl)propyl methacrylate (MPS) and then coated with a 1–12 μm film of poly(l-lactic acid) (PLLA). The corrosion behavior of PLLA/MPS-coated zinc wires was studied in simulated body fluid using electrochemical impedance spectroscopy. An increase in the impedance from <1000 to >15 000 Ω cm2 was recorded for the zinc wires after being coated with PLLA. The PLLA/MPS-coated zinc specimens were implanted into the abdominal rat aorta to assess their biodegradation and biocompatibility compared to uncoated zinc wires. PLLA/MPS-coated wires corroded at approximately half the rate of unmodified zinc during the first 4·5 months. A histological analysis of the biological tissue surrounding the zinc implants revealed a reduction in the biocompatibility of the polymer-coated samples, as indicated by increasing cell toxicity and neointimal hyperplasia.
Arab Shomali, A.,
Guillory, R. J.,
Drelich, J. W.
Effect of PLLA coating on corrosion and biocompatibility of zinc in vascular environment.
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