V42 - Design and Evaluation of 3D-Printed Arteriovenous Grafts to Enhance Tissue-Graft Integration

Friday, October 10, 2025

10:00 AM - 11:00 AM PDT

Location: Exhibit Hall F, G & H

Presenting Author(s)

Eve J. Dougan

Undergraduate Researcher
University of Massachusetts, Amherst, United States

Co-Author(s)

RW

Reyla B. Williams

Graduate Researcher
Worcester Polytechnic Institute, United States

Last Author(s)

Yonghui Ding

Assistant Professor
Worcester Polytechnic Institute
Worcester, Massachusetts, United States

Primary Investigator(s)

Yonghui Ding

Assistant Professor
Worcester Polytechnic Institute
Worcester, Massachusetts, United States

Introduction: : Chronic Kidney Disease affects roughly 1 in 7 adults, with approximately 35.5 million in the US. Among these, nearly 808,000 people have end-stage kidney disease, and approximately 557,500 rely on hemodialysis for treatment.
The arteriovenous fistula (AVF) and the arteriovenous graft (AVG) are two common methods to create vascular access necessary during hemodialysis. While AVFs, which surgically connect an artery to a vein, are preferred due to lower infection and thrombosis rates, they often fail to mature, particularly in patients with diabetes, older age, or small vessels. Synthetic AVGs, which use a synthetic conduit, made from expanded polytetrafluoroethylene to connect arteries and veins, offer an alternative to AVFs (Figure 1A). Unfortunately, current AVGs have low long-term primary patency, with roughly 50% failing within one year, primarily due to the lack of tissue-graft integration and intimal hyperplasia.
The goal of this research is to fabricate a 3D-printed, biodegradable AVG with engineered luminal topography designed to promote endothelial cell (EC) regeneration and tissue-graft integration for use in vascular access during dialysis. We hypothesize that the addition of grooved microtopography on the graft’s luminal surface will enhance EC migration and proliferation, thereby accelerating EC integration. To test this hypothesis, we fabricated an in vitro AVG-vein junction model to evaluate how surface topography influences EC migration from the graft-vein anastomosis into the graft and its subsequent endothelialization.

Materials and

Methods: : Polymer ink consisting of 90 wt% methacrylate poly(1,12-dodecamethylene citrate), 0.5 wt% 2-nitrophenyl phenyl sulfide, 4.3 wt% ethanol, 2.2 wt% phenylbis(2, 4, 6-trimethylbenzoyl) phosphine oxide, and 3 wt% ethyl 4-dimethylamino benzoate is homogenized in a Branson Ultrasonic Cleaner (Marshall Scientific, Hampton, NH) at 20-25˚C. AVG-vein junction models are fabricated using a custom-built micro-continuous liquid production-based 3D-printer using a resin vat with an oxygen-permeable Teflon AF-2400 membrane (Biogeneral Inc., San Diego, CA). CAD models are created in SOLIDWORKS (Dassault Systèmes, Waltham, MA) and sliced using CHITUBOX (Chitu Systems, Shenzhen, China) with 8 µm layer thickness (Figure 1G). Each layer is projected onto the resin vat window for 1.4 seconds to initiate photopolymerization. Printed samples are post processed, leached in ethanol for 24 hours, then UV-sterilized with 70% ethanol in Dulbecco’s phosphate buffered saline (DPBS) (Cytiva, Marlborough, MA) for 15 minutes, and rinsed with DPBS before 24-hour incubation in DPBS with antibiotics. 40 µl of 10 wt% gelatin methacrylate in DPBS is pipetted into the graft zone of the model and solidified for 10 minutes to block regional cell adhesion. The venous zone of the graft is seeded with 25,000 human umbilical vein endothelial cells (HUVECs) per cm2. Samples are cultured for 1, 3, and 7 days, then fixed with 4% paraformaldehyde, washed with DPBS, and permeabilized using 0.2% Triton X-100. Samples are blocked with 1.5% Bovine Serum Albumin before immunofluorescent staining for F-actin and nuclei. Images were taken using a Nikon Spinning Disk Confocal.

Results, Conclusions, and Discussions:: The major issues with AVGs are poor tissue-graft integration and stenosis at the graft-vein junction, due to incomplete endothelialization and intimal hyperplasia, respectively. While we are currently focused on achieving proper endothelialization of the graft, it is also important to consider that abnormal fluid dynamics at the graft-vein junction have been shown to result in intimal hyperplasia. Thus, we designed and fabricated the graft with different graft-vein anastomotic curvatures: smooth and straight (Figure 1B). We expect that the smooth graft will result in improved fluid dynamics as compared to the straight graft, which needs to be verified by computational fluid dynamics simulation. To test the impacts of anastomotic curvature on EC regeneration in static conditions, we evaluated the EC migration from the vein into the graft over 1, 3, and 7 days. HUVECs were seeded into the vein section only on day 0. No apparent cell migration into the graft was observed on day 1. Significant migration was detected at day 3, although no significant difference was shown between the smooth and straight grafts. Notably, after 7 days, the smooth graft model resulted in decreased cell migration into the graft with an average of 939.5 µm migrated compared to 1116.4 µm into the straight graft (Figure 1C-D). These results informed the latest print design, in which we used the straight model to study topography. We are currently working on the fabrication of the graft with luminal groove topography. We expect that the addition of groove topography in the graft will increase migration and proliferation of ECs, leading to enhanced endothelialization of the graft (Figure E). These results demonstrate the critical influence of graft design on EC regeneration and tissue-graft integration, essential for improving long-term AVG performance. By advancing the development of 3D-printed, biodegradable AVGs with engineered surface topography, this work contributes to the creation of more durable and functional vascular access for hemodialysis patients.

Acknowledgements and/or References (Optional): :