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International Journal of Bioprinting Affordable temperature-controlled bioprinter

Figure 4. Printing with 25% Pluronic F-217 at different temperatures, flow rates, and feed rates. (A) The rheology of Pluronic-based hydrogels depends
strongly on the printing temperature: (i) viscosity and (ii) storage and loss moduli of 25% (w/v) Pluronic F127 at different temperatures. (B) A triad of
squares (programmed in G-code) was used to analyze the resolution of Pluronic printings at different feed rates (linear printhead speeds) and flow rates.
(C) Side-by-side comparison of a 25% Pluronic F-127 ink printed with a temperature control set at (i) 15°C, (ii) 25°C, and (iii) 35°C.
20°C to 25°C (Figure 4Ai). Our Pluronic ink transitions experiments resulted in self-standing structures with
to gel at approximately 22.5°C (Figure 4Aii). Consistently, good fidelity. We were able to print a high-resolution
controlling the printing temperature above this value (in and self-standing hexagonal grid of up to 5 layers of 5%
this case, by heating) greatly improves their printability (w/v) GelMA (Figure 5Aii). Furthermore, the prints
(Figure 4B and C). of the Alvarez-Trujillo Lab name and Tecnologico de
Monterrey logos were successful; this printing exercise
3.4. Multilayer and multimaterial printing clearly confirmed the capability of our DiY bioprinter to
Ideally, a bioprinter should be able to print several layers of follow curved trajectories (Figure 5B and C) with GelMA
hydrogel-based inks. Therefore, we tested the “stackability” (Figure 5Cii) and Pluronic-based inks (Figure 5Ciii).
of GelMA with this bioprinter. We designed models using The printing of the Alvarez-Trujillo Lab logo and the
CAD software (SolidWorks) and then sliced the STL files Tecnologico de Monterrey sports logo, a bicolor ram,
to generate different G-codes (i.e., a single-layer multi- verified the ability of our bioprinter to perform sequential
hexagon array (Figure 5Ai), a multilayer hexagon array multi-material printing (Figure 5D and E). In this case,
(Figure 5Aii, iii), our own Lab name (Figure 5B), and the we first printed the blue ink, then deposited the black and
Tecnologico de Monterrey logo (Figure 5C). All of these yellow ink, and finally deposited the blue ink. Note that the

Volume 9 Issue 6 (2023) 104 https://doi.org/10.36922/ijb.0244