3D printing blood vessels using hydrogels

3D printing is transforming medicine. One exciting innovation is printing blood vessels using hydrogels—soft, water-rich materials designed to mimic human tissue. Blood vessels are essential for delivering oxygen and nutrients, so synthesizing them is a major leap toward building artificial organs or repairing damaged tissues.

Hydrogels provide a scaffold that supports cell growth while closely resembling the body’s natural environment. Common types include Gelatin Methacryloyl (GelMA), alginate, and polyethylene glycol (PEG). These materials are customizable in strength, absorption, and compatibility with cells. The primary technique is extrusion-based bioprinting, which deposits hydrogel layers mixed with cells to build tubular structures shaped like blood vessels. Another approach is sacrificial bioprinting: a removable template is printed to form hollow channels and then dissolved, leaving behind a network ready for cells. 

Researchers now combine 3D-printed vessel scaffolds with biochemical signals such as growth factors. These cues encourage endothelial cells lining the vessel walls to sprout and form smaller capillary-like branches, making the structure more physiologically similar to the human body. Novel strategies, like void-free multi-material printing, ensure these channels maintain their shape while allowing cell lining for more effective blood flow.

Creating realistic blood vessels still faces hurdles. Hydrogels are soft and can collapse under pressure, and mimicking the precise branching patterns and stability of natural vessels is difficult. Designing vessels narrow enough for real clinical use—less than 10 mm in diameter—adds even more complexity. To overcome these challenges, scientists are developing new hydrogel blends that are stronger and more biocompatible. They aim to create patient-specific vascular grafts and tissue models for drug research and testing. Advanced 3D printing approaches, along with rapid modeling of complex vascular trees using algorithms, are key to scaling this technology for real-world medical applications.

3D printing blood vessels with hydrogels is a cutting-edge area that blends creativity and biotechnology. While challenges regarding durability and complexity remain, ongoing research suggests that we’re getting closer to engineered tissues with living vascular systems—a breakthrough that could one day revolutionize organ transplantation and regenerative medicine.

References:

“3D Bioprinting of Vascularized Tissues for In Vitro and In Vivo Applications.” Frontiers in Bioengineering and Biotechnology, vol. 9, article 664188, May 2021, https://www.frontiersin.org/journals/bioengineering-and-biotechnology/articles/10.3389/fbioe.2021.664188/full 

Kolesky, David B., et al. "3D Bioprinting of Vascularized, Heterogeneous, Cell-Laden Tissue Constructs." Advanced Materials, vol. 26, no. 19, 2014, p. 3124, https://pubmed.ncbi.nlm.nih.gov/24550124/ 

“3D Bioprinting for Vascularized Tissue Fabrication.” PMC, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5124424/ 

Quiz: