A hydrogel can perform well in standard laboratory tests yet still clog a printing nozzle or flow unevenly through a needle. Researchers at Radboudumc have developed XTRUDE, a system that measures what happens while a hydrogel is being pushed through a narrow opening. The approach could help researchers develop more reliable materials for 3D bioprinting and injectable therapies.
What standard measurements miss
Hydrogels are soft, water-rich materials used to print tissue-like structures and explored for injectable treatments, for example to support tissue repair. In both cases, the hydrogel must be pushed through a narrow opening, such as a printing nozzle or syringe needle. This process is known as extrusion.
For successful printing or injection, the material needs to flow smoothly and consistently. Standard laboratory tests can characterize a hydrogel beforehand, but they do not fully show how it behaves during extrusion.
Looking inside the nozzle
XTRUDE measures pressure and temperature as a hydrogel moves through a small channel comparable to a printing nozzle or needle. Researchers can then relate these measurements to the material that emerges.
Farhad Sanaei (header image) and colleagues, led by Mani Diba of Regenerative Biomaterials at the Department of Dentistry, developed the system and used it to study different types of hydrogels. Their study was published in Advanced Functional Materials.
The system was able to detect problems such as clogging and separation of liquid from the hydrogel during extrusion. Fluctuations in pressure were also associated with uneven shapes in the extruded hydrogel strands.
These measurements provide information that conventional material tests can miss and can help explain why a hydrogel flows smoothly in one situation but becomes unstable in another.
Reducing trial and error
By monitoring the extrusion process itself, XTRUDE could help researchers make better-informed choices about both materials and processing conditions. This may reduce some of the trial and error currently involved in developing hydrogels for bioprinting and injectable therapies.
The researchers will now apply XTRUDE to a broader range of materials and extrusion conditions. Ultimately, a better understanding of how hydrogels behave during extrusion could help make printing and injection more consistent and predictable.
Video XTRUDE | Credits: Diba Lab, Radboudumc
About the publication
Sanaei F, Bertsch P, Lafosse J, Leeuwenburgh SCG, Diba M. (2026). XTRUDE: A Process-Informed Framework for High-Fidelity Analysis of Hydrogel Extrusion. Advanced Functional Materials. Published online 29 September 2026. Read the open-access article
