Acrylonitrile-Based Nitric Oxide Releasing Melt-Spun Fibers for Enhanced Wound Healing

Nitric oxide (NO) plays an important role in physiological functions in the body, naturally synthesized by nitric oxide synthase. NO was discovered as the endothelium-derived relaxing factor, allowing for vasodilation to occur in blood vessels, thus preventing platelet aggregation. It is also known as an antimicrobial agent. As it has been shown to enhance wound healing, recent efforts have been made to incorporate NO into thromboresistant polymers for medical devices. In this work, an acrylonitrile-co-1-vinylimidazole (AN/VIM) copolymer was melt-spun to produce a surgical suture type material with high durability and tensile strength which can store and release NO. The acrylonitrile (AN) comonomers are stabilized in the melt-spinning process, allowing for the formation of the NO molecular donor group, a diazeniumdiolate or NONOate. When AN/VIM is reacted with NO, the NONOate will form on AN segments. Each NONOate releases two molar equivalents of NO upon reaction with a proton source. The fiber mechanical properties were maintained after the polymer is reacted with NO. To control the release of NO, the suture is dipped in polycaprolactone (PCL), creating a porous coating on the fiber. A delayed release is desired in order for NO to be effective in wound healing over long periods of time. The biodegradable coating significantly slows release of the NO compared to the uncoated fiber. Over a course of 3 days, the PCL coated melt-spun AN/VIM copolymer releases a total of 84 mu mol NO/g.