Conceptual Study for Tissue-Regenerative Biodegradable Magnesium Implant Integrated with Nitric Oxide-Releasing Nanofibers

The excessive initial corrosion rate of Mg is a critical limitation in the clinical application of biodegradable Mg implants because the device loses its fixation strength before the fractured bone heals. This study suggests a new approach to overcome this hurdle by accelerating tissue regeneration instead of delaying the implant biodegradation. As angiogenesis is an essential process in early bone regeneration, a Mg implant coated with electrospun nanofibers containing nitric oxide (NO), which physiologically promotes angiogenesis, is designed. The integrated device enables adjustable amounts of NO to be stored on the NO donor-conjugated nanofiber coating, stably delivered, and released to the fractured bone tissue near the implanted sites. An in vitro corrosion test reveals no adverse effect of the released NO on the corrosion behavior of the Mg implant. Simultaneously, the optimal concentration level of NO released from the implant significantly enhances tube network formation of human umbilical vein endothelial cells without any cytotoxicity problem. This indicates that angiogenesis can be accelerated by combining NO-releasing nanofibers with a Mg implant. With its proven feasibility, the proposed approach could be a novel solution for the initial stability problem of biodegradable Mg implants, leading to successful bone fixation.