Converting a 3D Printer into a High-Resolution Gelatin Methacryloyl Bioprinter: Development of an Extrusion 3D Bioprinter Equipped with a Temperature-Controlled Printhead

We present a flexible and cost-effective design for a do-it-yourself (DIY) bioprinter capable of printing gelatin methacryloyl (GelMA) constructs at printing flow rates of 0.01–0.04mL/min, linear speed of 1-10 mm/s and effective resolutions of 500–700 µm, values that compete with those exhibited by state-of-the-art commercial bioprinters.

The most distinctive feature of our bioprinter is its ability to control the rheology of bioinks by controlling the extrusion temperature during printing. This is achieved by circulating cold water within a printhead that is engineered as a single 3D-printed piece consisting of a water-recirculation jacket engineered around the extrusion tube. Our bioprinter also accepts any commercial needle as a printhead tip.

We show that our bioprinter is capable of printing simple GelMA constructs composed of up to 3 layers of cell-laden GelMA. We also demonstrate that mouse C2C12 myoblast cells printed through needle tips of 300 µm retain excellent post-printing viability (~90%). Velocity and shear stress profiles were calculated using computational fluid dynamic (CFD) simulations for different printing conditions (bioink flow rates and printhead linear speeds).

The feasibility of controlling the temperature of the nozzle while printing enables the direct use of matrices with complex rheology (i.e., GelMA). Furthermore, we envision that engineering temperature control capabilities into a DYI printer will greatly expand the use of bioprinting in academic laboratories and startups.