# Hannover team prints PCL vascular graft scaffold with artery-like mechanics, endothelialized in vitro

- Published: 2026-11-13 21:53 UTC
- Section: Life & Health › Medicine
- Tags: small-diameter vascular graft, tissue-engineered vascular graft, melt electrowriting, poly-ε-caprolactone scaffold, endothelialization, pulsatile flow bioreactor, burst pressure, fibrin compression molding, Hannover Medical School
- URL: https://realtech.media/news/rt-144ce0ff1d838eae75e74dac_hannover_team_prints/

**A 3D-printed PCL–fibrin tube carried a flow-aligned endothelial layer after 7 days of pulsatile culture in vitro. Around 75% of synthetic grafts under 6 mm fail within 3 years.**

![Hannover team prints PCL vascular graft scaffold with artery-like mechanics, endothelialized in vitro](https://realtech.media/media/2026/11/6941b6339975f36c.jpg)
*bioengineer.org*

Researchers from Leibniz University Hannover and Hannover Medical School, with colleagues in Hildesheim, described a framework for a customizable 3D-printed tubular scaffold made of poly-ε-caprolactone (PCL) for small-diameter vascular grafts. The work was published in Frontiers in Bioengineering and Biotechnology on 13 November 2026 (doi.org) [1]. The scaffold was combined with fibrin, seeded with endothelial cells and cultured for 7 days under pulsatile flow with shear stress of up to 20 dyn·cm⁻² [1]. All results come from laboratory experiments; the graft was not implanted.

## Clinical problem

The authors note that about 75% of synthetic conduits with a diameter below 6 mm fail within 3 years, mostly because they lack a luminal endothelial cell layer. This leads to thrombosis, calcification and intimal hyperplasia [1]. Dacron and ePTFE grafts are also stiffer than native arteries, and a mechanical mismatch between graft and vessel can cause complications [1].

## Scaffold geometry and mechanics

The scaffold was printed by melt electrowriting, and its geometry was tuned by varying winding angle, fiber diameter and fiber distance. The final design had a fiber diameter of 128 μm, a winding angle of 52.5° and a fiber distance of 500 µm [1]. A fibrin compression molding technique was adapted to make the structure leak-free and suitable for cell adhesion [1].

The PCL scaffold printed with long-chain PCL had a radial Young's modulus of 1.12 ± 0.35 MPa and a radial tensile strength of 3.89 ± 0.81 MPa. The authors describe these values as similar to native arteries, for which they cite 2.45 ± 0.79 MPa [1]. The fibrin-PCL scaffold showed a burst pressure of 1,600.4 ± 502.85 mmHg and a suture strength of 1.62 ± 0.29 N. Its longitudinal tensile strength was 1.07 ± 0.22 MPa, similar to native arteries, while its radial tensile strength was lower at 0.80 ± 0.20 MPa [1].

## Endothelialization under flow

After 7 days of pulsatile dynamic culture at 20 dyn·cm⁻², the endothelial cells covered the graft and aligned with the direction of flow [1]. The cultivated graft retained a radial Young's modulus of 3.03 MPa and a radial tensile strength of 1.56 MPa [1]. According to the authors, this is the first demonstration of an endothelialized graft with mechanical properties similar to those of native arteries [1].

## Sources

1. [doi.org](https://doi.org/10.3389/fbioe.2026.1963671)
2. [bioengineer.org](https://bioengineer.org/melt-electrowritten-polymer-scaffolds-match-native-arterial-mechanics-under-pulsatile-flow)

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Source: RealTech, realtech.media — https://realtech.media/news/rt-144ce0ff1d838eae75e74dac_hannover_team_prints/