(L-469) Mechanical Characterization of Vascular Grafts Constructed from Leatherleaf

Introduction:: Decellularized vascular grafts for bypass surgery composed of animal tissue have been used extensively since the 1960’s. Decellularized plant tissues have been researched as potential vascular graft candidates since the end of the 20th century. Plant tissues are promising as they exhibit similar characteristics to animal tissues. They can both be shaped for specific applications, have no negative effects when interacting with native body tissue, and they exhibit great strength. We have recently been able to demonstrate the use of decellularized Leatherleaf Viburnum for 3D grafts. The aim was to determine the best gelatin concentration to use for gluing the leaves around a 2mm rod in order to construct 3D grafts. This would allow the grafts to withstand blood pressures in the body.

Materials and Methods:: Fresh Leatherleaf Viburnum leaves were decellularized for 72 hours in 2% SDS followed by 6 hours in clearing solution, composed of 10% bleach and .01% Triton X-100 in deionized water. Following decellularization, the leaves were sterilized in 70% ethanol for 1 hour. The decellularized leaves were then cut to 25mm x 21mm and wrapped once around a 2mm diameter acrylic rod. 6uL of 25% glutaraldehyde along with 44 uL of 30, 40, 50 or 60% gelatin was applied in a straight line over the width of the leaf, and then the leftover leaf was rolled around the 2mm acrylic rod. After incubating overnight, the grafts were removed from the rods and ready for burst pressure testing. A barb-NPT fitting was attached to the pressure sensor and used to record pressures. The graft was cannulated on the barb and Parafilm was used to create a seal, to prevent water from leaking out of the end. The other end had a 5mL syringe which pushed water through the graft.

Results, Conclusions, and Discussions:: Gelatin at a concentration of 50% was determined to be optimal with an 8.62Psi burst pressure, which is comparable to the physiological pressure of 2.7Psi in the human coronary artery. Although the 60% gelatin had a burst pressure of 9.53Psi, it solidified within seconds, making it difficult to roll the leaves. The 30% and 40% gelatin concentrations created a weaker crosslink with the glutaraldehyde, resulting in burst pressures of 1.72Psi and 4.50Psi, respectively. Different Gelatin concentrations 30%, 40%, and 60% were tested for optimal crosslinking with glutaraldehyde to preserve the strength of the decellularized leatherleaf. The lower concentrations had inadequate burst pressure values, but 50% gelatin concentration stabilized leaf integrity and exceeded native burst pressures before failure. Future plans include implanting these 3D scaffolds in a small animal model to evaluate thrombosis and patency of the graft after implantation.

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