3D printing in the manufacturing of vascular grafts

Abstract

The global rise in end-stage renal disease requires effective dialysis treatment using vascular grafts. Current synthetic grafts like Dacron® and Gore-Tex® often fail in small-diameter applications due to infection, poor mechanical properties (compliance mismatch, kinking), and insufficient endothelialization (poor hydrophilicity). This thesis combined fused deposition modeling (FDM) and hot melt extrusion (HME), to manufacture vascular grafts with enhanced properties for dialysis. The research includes three stages: material selection, drug-loaded graft preparation and performance evaluation, and antibacterial performance assessment. Initially, grafts with different shapes were designed using computer-aided design (CAD) and printed using various materials through FDM, with TPU85 identified as optimal due to its elasticity, mechanical strength, and hydrophilicity. The second stage involved enhancing the anti-infection capabilities of grafts by integrating levofloxacin and chitosan into TPU85 via HME, achieving improved hydrophilicity and controlled drug release without compromising mechanical integrity. The final stage tested the antimicrobial activity of the drug-loaded grafts against Escherichia coli and Staphylococcus aureus, the most common pathogens in vascular graft infections. The results showed that the grafts, particularly those containing 1% chitosan and 0.5% levofloxacin in TPU85, achieved the minimum inhibitory concentration and minimum bactericidal concentration within 1 hr, demonstrating good potential for infection prevention and treatment.

In summary, the research successfully utilized FDM 3D printing technology and HME technology to manufacture a new type of anti-kinking, drug-loaded vascular graft. Grafts exhibit excellent mechanical properties, hydrophilicity, antimicrobial activity, and controlled drug release, potentially significantly improving the therapeutic efficacy of current clinical vascular grafts. The study offers new possibilities for the personalized customization and precision medicine of vascular grafts, providing more effective treatment options for patients with ESRD.

Thesis is embargoed until 31 July 2029.

Date of Award	Jul 2025
Original language	English
Awarding Institution	Queen's University Belfast
Supervisor	Dimitrios Lamprou (Supervisor) & Matthew Wylie (Supervisor)