Abstract
Microvascular anastomosis is fundamental to free-flap reconstruction, yet hand-sutured techniques remain highly skill-dependent and prolong ischemic time, contributing to thrombosis and flap loss. Current suture-less devices accelerate anastomosis but are constrained by vessel-size mismatch, eversion-related intimal injury, and inconsistent arterial performance. A clinically adaptable, arterial-capable system is needed. We developed a customizable, 3D-printed intraluminal coupler with a snap-fit connection and elastic external clasp that avoids vessel eversion and preserves length. Devices were fabricated via SLA or PolyJet printing using clinically used resins. Benchtop evaluation included burst-pressure testing, tensile testing, wettability and endothelial cytocompatibility assays with oxygen-plasma surface modification. Deployment was assessed ex vivo using porcine coronary vessels and in vivo in a porcine carotid arterial model with patency monitoring over 4 h. Couplers sustained leakage pressures of ~ 90 mmHg vs. ~16 mmHg for hand-sutured controls (P < 0.01), while maintaining comparable mechanical strength (≈ 2–3 N). Plasma surface treatment reduced water contact angles (≈ 85°→≈60°) and tripled endothelial attachment, restoring confluent morphology. Ex vivo deployment achieved completion in 9.47 ± 1.20 min, a ~ 62.5% reduction vs. published suturing times. In vivo, couplers restored immediate perfusion with no leakage or thrombosis. This 3D-printed intraluminal coupler demonstrates mechanical feasibility, rapid deploy-ability, and surface-modifiable endothelial compatibility in benchtop and short-term large-animal feasibility testing, supporting its potential for further preclinical development as a vascular anastomosis technology. Future survival studies and anti-thrombogenic surface engineering will advance readiness for clinical implementation.
Data availability
Data and material sharing available on requests. Please contact the corresponding author johnloh@nus.edu.sg/john.ser.pheng.loh@ki.se.
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Acknowledgements
The authors would like to thank Ms Nurazreen Binte Mohamed Zaid (Senior Manager, Dean’s Office, National University of Singapore, Dentistry) and Mr Chua Wei Chieh (Research Engineer , Technology Transfer & Innovation, National Uninversity of Singapore) for their patience, invaluable advice and support and most of all, friendship. We also thank Dr Diego Pitta de Araujo, PhD (National University Healthcare System, Singapore) for the artwork and illustrations in the manuscript.
Funding
Open access funding provided by Karolinska Institute. Principal Investigator John Ser Pheng Loh, National University Health System Seed Fund, Singapore (NUHSRO/2024/014/RO5 + 6/Seed-Sep23/07). Principal Investigator, John Ser Pheng Loh, National Additive Manufacturing Innovation Cluster Full Project Funding, Singapore, M23N2K0033.
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**JSPL, JKST and YY: ** Conceptualization; supervision; project administration; writing – original draft; writing – review and editing., **KCF, ZY** : Conceptualization, Project administration; visualization; writing. **RH, LR, JKST, HLL, RJ** : project administration; supervision; writing – review and editing.
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Loh, J.S.P., Feng, KC., Yuan, Y. et al. In vitro and in vivo validation of a novel 3D-printed vessel anastomosis device for microvascular surgery. Sci Rep (2026). https://doi.org/10.1038/s41598-026-39181-4
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DOI: https://doi.org/10.1038/s41598-026-39181-4
