A crew on the Bioengineering Institute of Expertise, Universitat Internacional de Catalunya, has developed a DIY coaxial 3D bioprinter by modifying a Creality Ender 3 Professional desktop 3D printer. The open-source system prices below €600 and permits simultaneous extrusion of two hydrogel bioinks by way of a coaxial nozzle. The machine was validated by printing mesenchymal stem cell (MSC)-laden hydrogels with excessive form constancy and cell viability. Particulars of the mission had been printed in Nature Communications.
Creality, a Chinese language producer of low-cost FDM printers, produces the Ender 3 Professional, which was tailored by changing its hotend with two stepper motor-driven syringe pump extruders. The 3D printer’s motherboard was upgraded to a 32-bit SKR 2.0 Rev B, enabling unbiased management of each extruders. Firmware was configured utilizing the open-source Marlin platform. A customized coaxial nozzle was fabricated utilizing Liqcreate Clear Affect resin and printed on a Phrozen Sonic Mighty 8K DLP printer. The nozzle featured a 27-gauge inside needle for core materials and a 14-gauge shell inlet, assembled concentrically to help coaxial move.
Two nozzle configurations had been examined, each with 200 µm inside diameters and outer diameters of 640 µm and 840 µm, respectively. Circulation simulations in COMSOL Multiphysics confirmed that the broader nozzle induced higher velocity variations between shell and core, whereas the narrower configuration yielded extra uniform move. Rheological testing confirmed {that a} thermoresponsive methylcellulose-based shell may crosslink a gelatin-alginate core in situ. Scaffold constructions remained steady when extruding core bioink concentrations as little as 0.5% alginate, with elastic modulus halved in comparison with the 1.5% formulation.
Printing efficiency was evaluated at a pace of three mm/s with move charges of 0.917 µl/s (slim nozzle) and 1.529 µl/s (extensive nozzle). Scaffold constancy was quantified by evaluating relative top throughout numerous core-shell ratios. Buildings started to break down when core move exceeded 40% with out calcium crosslinking, however remained intact when CaCl₂ was included within the shell hydrogel. Massive woodpile and vase constructions had been printed utilizing a gradient extrusion operate (M166 command in Marlin), permitting automated variation in core-shell composition over the Z-axis. The printed scaffolds displayed constant geometry, open porosity, and localized materials transitions.
MSCs had been harvested from five-week-old male Sprague-Dawley rats following authorized protocols on the Autonomous College of Barcelona. Cells had been encapsulated within the alginate-gelatin hydrogel core and printed into sq. scaffold constructions utilizing the slim nozzle configuration at a 30–70 core-shell ratio. Dwell-dead staining at 1, 7, and 14 days confirmed excessive cell viability, with printed situations exceeding 90% by day 7 and sustaining viability by way of day 14. Outcomes confirmed that the methylcellulose-based shell allowed ample nutrient diffusion and guarded embedded cells throughout extrusion.
Business coaxial bioprinters usually depend on fastened stainless-steel nozzle designs and lateral feed geometries that restrict compatibility with viscous or particulate-rich bioinks. Against this, the design offered on this examine accommodates high-viscosity supplies and reduces clogging threat when bioinks are co-optimized with nozzle geometry. The shell layer additionally prevents dehydration of the core throughout lengthy print periods. CAD information, firmware modifications, and a full supplies listing had been printed alongside the examine to help replication and additional improvement.
This method expands the obtainable toolset for labs exploring complicated scaffold architectures with out entry to high-end bioprinters. Whereas coaxial nozzles inherently cut back decision as a result of their dual-channel format, they provide the flexibility to spatially compartmentalize completely different supplies or cell sorts. The researchers be aware that decision trade-offs are justified in circumstances requiring mechanical gradient tuning or managed organic compartmentalization. With its low price and versatile structure, the system may help improvement of multiaxial or microfluidic printheads, enabling broader functions in tissue engineering analysis.
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Featured picture exhibits schematic of 3D extrusion bioprinter and coaxial nozzle meeting. Picture by way of Nature Communications.
