Authors: Yuliya Lyakhovich
Source: eScholarship@McGill (McGill) (article, 2019-01-01)
Field: Materials Science — Biomaterials

Silk as a biomaterial for tissue-engineered vascular conduits Small diameter vascular grafts are required for surgical applications in coronary bypass procedures, hemodialysis patients with end-stage renal disease and reconstructive operations. When autologous vessels are not available, synthetic materials such as Dacron and polytetrafluoroethylene (PTFE) are the only viable options. These synthetic materials have been successful for large vessel applications (greater than 8 mm) but their use for small vessel applications (below 6 mm) is increasingly poor as a result of anastomotic intimal hyperplasia and thrombosis. Patency rates of 40% at 6 months and 25% at 3 years (Rocco et al., 2014) have been reported demonstrating a need for a better material with optimal mechanical properties, biocompatibility, non-immunogenicity, porosity, degradability, cost efficiency and processability. Here we propose the utilization of acellular and absorbable gel spun silk vascular graft as an alternative material to the current synthetic materials in patients where autologous vessels are not available. Gel spinning conditions had been previously optimized in vitro (Lovett et al., 2010) for their luminal smoothness, porosity, and degradation profiles. Here I demonstrate the ability to make drug bulk modified silk tubes post modified via water annealing. Silk tubes were made using four different types of drugs: Argatroban, Eptifibatide, Heparin and Sirolimous. Their release kinetic study was quantified using LCMS. Furthermore, bilayered gel spun scaffolds were made using two different layers paving the way for bilayered grafts with multiple functionality for future in vivo work.%%%%Des greffes vasculaires de petit diametre sont necessaires pour les applications chirurgicales dans les procedures de pontage coronarien, pour les patients hemodialyses presentant une insuffisance renale terminale et les chirurgies de reconstruction. Quand des vaisseaux autologues ne sont pas disponibles, des materiaux synthetiques tels que le Dacron et le polytetrafluoroethylene (PTFE) sont les seules options viables. Ces materiaux ont ete utilise avec succes pour les applications de grands vaisseaux (plus grands de 8 mm), mais on eu moins de succes avec les petits vaisseaux (inferieures a 6 mm) a cause de l'hyperplasie intime anastomotique et la thrombose. Les taux de permeabilite de 40% a 6 mois et de 25% a 3 ans (Rocco et al., 2014) ont demontre un besoin de meilleur materiel avec des proprietes mecaniques optimales, biocompatible, non-immunogene, poreux, degradable, et un temps de production court et rentable. Nous proposons ici l'utilisation de la greffe vasculaire en soie filee en gel acellulaire et resorbable en tant que materiel alternatif aux materiaux synthetiques actuels chez les patients pour lesquels des vaisseaux autologues ne sont pas disponibles. Les conditions de filage en gel avaient ete prealablement optimisees in vitro (Lovett et al., 2010) pour leur finesse de paroi, porosite et profils de degradation. Ici, je demontre la capacite de fabriquer des tubes de soie modifies avec des medicaments par une… Biocompatibility ; Biomedical engineering ; Biomaterial ; Vascular graft ; Intimal hyperplasia ; Tissue engineering ; Surgery ; Medicine ; Materials science Silk-based biomaterials and applications ; Electrospun Nanofibers in Biomedical Applications ; Periodontal Regeneration and Treatments