Creating a hemocompatible small-diameter vascular graft

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Creating a hemocompatible small-diameter vascular graft. Ali Serpe South Carolina Governor’s School for Science and Mathematics, SCGSSM Mentor: Dr. Ning Zhang Clemson-MUSC Joint Bioengineering Program Charleston, SC. Small-diameter Vascular Graft. - PowerPoint PPT Presentation

Transcript of Creating a hemocompatible small-diameter vascular graft

  • Creating a hemocompatible small-diameter vascular graft Ali Serpe South Carolina Governors School for Science and Mathematics, SCGSSM Mentor: Dr. Ning Zhang Clemson-MUSC Joint Bioengineering Program Charleston, SC

  • Small-diameter Vascular GraftVascular grafting is a common surgical procedure in the repair or replacement of occluded, dysfunctional, or diseased blood vessels that underlie strokes and many cardiovascular pathologies/traumas. Mechanisms of Graft FailureThrombosis formation/presence of a blood clot in the blood vesselNeointimal Thickening thickening of the walls of the blood vessel which prevents blood from flowing properlyInfectionCurrent grafts are made of Dacron and TeflonRelatively successful for large diameter vesselsPoor patency (state of being open) for small-diameter grafts (
  • Project Aims:The long-term goal is to create a small-diameter vascular graft with:Microstructures and mechanical properties of the native vesselsHemocompatiblityPrevention of clotting and adhesion of bloodLong-term patency in vivo

  • Progress 1Mimicking the mechanical properties of the native small- diameter blood vessels using nanofiber composites Electrospinning techniqueNanofiber array composites to mimic native vessels Straight PU (elastin) Wavy PCL (collagen)Vince Beachley (PhD Candidate)Pictures of the Natural VesselWavy and straight components

  • Mechanical testing indicates a match of the J shape stress-strain behaviors of natural blood vessels

    Progress 1 Continued

  • Progress 2 (Current Project)Immobilization of heparinStandard technique to impart hemocompatibility to surfacesEDC as a crosslinkerActs as a spacerChemically binds heparin to the surface

    Enhancing the hemocompatibility of the vascular graft through heparin immobilizationEDC reaction scheme for carboxyl-to-amine crosslinking

  • Experimental Design and Methods

    Creating Films of nanofiber compositesElectrospinningSpin CoatingWater Contact AngleHeparinization

    Toluidine Blue AssayPlasma Recalcification TimeActivated Partial Thromboplastin Time

  • Water Contact Angle (Spin-coated flims)

  • Water Contact Angle (Electrospun fiber composites)

  • Results- Toluidine Blue

    % PEG0%1%1%10%30%NH2NoNoYesYesYesMolecular Weightn/a300800800800

  • Results- Plasma Recalcification Time

  • Results: Activated Partial Thromboplastin Time

  • ConclusionsThe toluidine blue shows favorable results to heparin binding, but could not be quantifiedThe water contact angle measurements and the APTT showed favorable results to heparin bindingThe PRT showed results unfavorable to heparin bindingFurther testing must be conducted

  • Future workMove to the animal modelUse arteriotomy model in ratsImplant graft and evaluateLong-term efficacyLong-term patencyLong-term stability

  • AcknowledgmentsThe Governors School for Science and MathematicsThe Medical University of South CarolinaDr. Ning ZhangVince BeachleyClyde Smith

    Good Afternoon, I am Ali Serpe and I attend the Governors School for Science and Mathematics. For the past six weeks I have been given the opportunity to work in a lab under the mentorship of Dr. Zhang. My research focus has been creating a hemocompatible small-diameter vascular graft. *Vascular grafting is a common surgical procedure used in the repairing or replacing of occluded, dysfunctional, or diseased blood vessels. It is these vessels that underlie strokes, and many other cardiovascular traumas. The common graft procedure sees failure from thrombosis, neointinal thickening and infection. The current grafts used are made of dacron and teflon. These have shown to be relatively successful for large diameter vessels. But, vascular grafts are seeing poor patency for small-diameter vessels. Small diameter vessels are considered to be